This is probably going to sound like an odd thread

1st If you don't have a soundish understanding of Megasquirt
how it works, .....how to fit it, .....in fact if you don't have a working MS'd engine - then stop reading NOW

Go to one of the other threads like :

A-Z of how to Megasquirt your Rover V8 Thread"


Why ?

Well, there are a number of Members now who have MS'd 4x4 mainly V8s and as such they tinker tweak and look for "More",
the "More" is probably via this thread, this is the thread for discussions around Meagasquirt Once you have a fundemental undertsanding,
and maybe want more. Whatever that "More is"

Why is this thread seperate ?

Basically as the threads on this forum stand a "New to Megasquirt and seriously thinking about doing it" would find nice simple and hopefully clear and reassuring guidance as to how it works and basicaly what to do, and enough info to get a V8 Rover running and quite well at that. The thread though is now used by Members who want more, extra info, details and answers to Qs that may make this same interested person run away screaming "Carbs 4 Me" - which is NOT the idea.

As such as a Mod in 'Tools & Fab', (and having had a number of PMs) and seen the High(er) High Tech Posts now in the basic "How To"thread, after a series of PMs with Landybehr this thread is born. This way rather than have a load of threads created everytime a Member has a Q there are 2 threads to post to - This one and the basic one

This is a thread that will be around the higher end tech Qs, How to do something maybe not covered in the other threads and a working document keeping all this forums knowledge and development in the understanding usage and improvement for all Members on MS in one handy place, It may die (I hope not) it may grow slowly or it may be a huge thread - time will tell.

To give all a better understanding I have copied and rewritten a PM to Landybehr from myself re the 'Question' as to moving this forums knowledge in MS to the next level, why, why not, and and how it could be detrimentral to the current thread(s), and hence this new thread.



"Hi, Ok, I see what you are saying, and it sort of makes sense,
I will try to outline some of my thoughts which prob cut across both your thinking and Bill Shurvingtons recent posts too ...and an idea for the future...
and how I value Bills comments posts and Knowledge and your thought Questions and Queries but am concerned for the forum thread for a newbie

Why I have MS at all. ?

Basically with my Flapper system apart form the "Hunt the misfire" probs using old poor quality old technology, the engine ran appallingingly.
Partly due to the state of tune and the ECU which was modded to enrich the entire spectrum,
which was fine for 'WOT' ....dreadfull for dragging a 90 with trailer and kit on in heavy traffic,
and also as with the slightest dumping of water the engine being a V8 couhed and misfired and or stopped
So for me MS was to have a 'waterproof 4x4' off road engine to keep up with diesels etc, and to have an engine that ran "Nicely"

And I think the 'Nicely' sort of sums it up.

Even with my 'early' tuning efforts of the engine the results were hugely impressive,
I had a 4WD Rolling road map for saprk, and I did my own Datalogging for VE on MLV and I learnt and used my 20+ years racing knowledge
and mates and others to then improve further. But, (and its a big one), my engine is just a part of my truck.
I have equally spent time and money and effort on other parts of it, designing the 2x twin hydro winch ssytem,
building the cage, making the suspension etc etc, the engine is just one 'part' of that.

When you go on say the MS forums, the hobby there is frankly 'MS', not as in say our cases '4x4' off road competitions
and MS is 'PART' of that. As 4x4ing is my hobby I shove a lot of time and effort into it, the MS is thus part of that,
and as such it gets or got a poroprtion of that effort and time.

For the guys on the MS Forums ALL of their time now and future is on MS, and that is a huge key difference.
My engine is a Race JED 4.5, and it runs fine now, fine, not "Optimal" but fines good for me.
Yes, if I spent hours and hours more on it I could get it better, but would I really see any difference ?
But if others chose to do, and discover things that would be good for me and you and we could all benifit.
Some people have an urge (Oooer Mum) to do this, and we should encourage and hold this info for the improvement of all.

If mine was a 'Track Car' then maybe I would spend more time myself, being in 3 foot of heavy deep mud ?...no I won't.

So for me it has to be a compromise between getting the state of tune to a point that is as good as I can for the time money
and effort I can put into it, and being a 'nurd' that fiddles tweaks and neaver leaves the F thing alone I am somewhere between the 2
sadly to say. I also think that as in life returns do drop vs time vs effort as you progress
ie when I 1st started the MS V8 up it was dreadfull,
a few HOURS ONLY and it was running hugely better,
a vast number of hours more and it ran a bit better,
weeks and week of study play and fine tunning - only a little better,
so I COULD spend hours and hours and days and weeks on it now, and yes I could improve on it -
but by how much and is it frankly worth it when I have loads of other things I need to do -
Body dmaage - new panels, roll cage changes, hydro winch rebuild etc etc etc ?

As such I accept that the quality of my MS System is prob around 7-8/10ish maybe even a bit higher,
but I'll acept it (for the mo maybe) what I am fairly certain of is that the 2/10 which maybe isn't as good as it could be
it is "Safe". ie it may not be 100% as good as it could be but it won't damage the engine,
I would say the spark is softer in areas (Low MAP MAX advance) than maybe it could be, but
a softer spark is safe - to agressive a spark in the 2/10 section and you'll be doing damage,
getting the figures more optimum means mucho time .............
and then you have to be sure that taking away the saftey factor to gain a very small improvement is correct ?

Hope you can see what I am getting at here ?

What might therefore be an idea is to have a 'MS tuning thread' started,
where this sort of developmental work could be discussed,
The downside is the 'time vs effort vs results vs input' (there are only a few of us)
but it would I think "Add" to to current MS thread via a specialist thread and not confuse or take away,
ie if you were a newbie thinking of maybe MS your V8 my and others threads are quite encouraging,
but if you then read and got into this sort of info as we discuss (and maybe argue / agree / debate issues -
now THAT could frighten anyone away !!. Thus a seperate tunning thread for those who wnat more could work,

The plus side also is that if we are sensible we can keep it in english,
I sometimes think on the 'MS site' (which is OUTSTANDING in info attitude helpa dn support BTW) I am reading alien !...
its very hard going to sometimes take on board what they are saying, the expression "A Tad Geeky" sums it up ?...
.....BOY they do really really really know their stuff, ......but its hard going for 'leccy plebs' like me !

And there we are

This then is a place to discuss ask and query MS V8 tunning ideas issues probs thoughts, nice n tidy and you may help others here imptove what they have now.

As a start I have moved over SOME of the last threads from the How To MS Thread, with a link to this one in there for those who wnat "More"

OT stuff or anything unsuitable will be delted without warning, 'keep it MS'........... and see how it goes

Hope this new thread meets with approval ?

Nige

Hi there,

==========
1
==========
I fear the coolant temp. sender is different between the 3.5 and 3.9.
With the data Friged provided MS thinks it runs at 72°C while the thermostate determinates 82°C.
No problem, is as good as solved.



==========
2 (this is why I´m really posting)
==========
ANOTHER THING:

I tune with a WB sond. And somehow I feel the AFR table is quite important, because it is what MEgaLogViewer looks at when it changes the VE table.
I would be just too curious what a spark and AFR map for the P38 could be, but certainly nobody knows. And of course nobody will bother to run a P38 with an extra WB in the exhaust (or splicing in a wire to the original WB in place and datalog somehow while driving).

BUT it would help really much if I could cheat at other´s AFR table.

AND if you could tell me at what MAP you usually idle, and cruise at given speeds (60mph most important). Sure that different engines will differe here. But a baisc "picture" might evolve ?


==========
3)
==========
Something else: Why is it that our V8 have such a moderate spark advance at WOT. And, by the way, the advance tables that many of you use are "moderate" too at low MAP conditions. The default table, which is for a big block Corvette is way more advanced. And I think more advance makes sense not only following-the-RPM-rising but also MAP based.

Well, I´, looking forward for you to comment the spark table I used.
BTW: I have reduced the advance at >3000RPM and >80kPa to less than 32° meanwhile. But idling and cruising with these values seems just fine.

http://up.picr.de/850797.jpg
(hmm .. once I was able to let the pic appear in a post. Cannot do any more )

Ok,

1st things 1st : Can you outline the spec and build of your Rover V8, CC Cam Tweaks etc ?

This would then help re the above

However Having had a quick look at your spark map I can honesty say I don't like it, I will try to outline "Why"

On the spark table you have posted up I would say that you are running too much adavnce at the bottom of the 500+ rpm buckets,
the step from 300 is HUGE.

Additionally 300 RPM is a level the engine doesn't really run at, tickover is around the 700-900 rpm level, 300 is near cranking speed,
as such the engine is rarely going to see 300 rpm. Even with the interpolation, the jumop to the 500+ RPM buckets is massive.

When you look at the RPM buckets you have

300 (mentioned above) 500 800 1000 1200 1400 1500 1700 2300.

All of these buckets are within 200-300 rpm of each other, this gives little benifit as you really want to have a Spark MAP that has a selection of bucket RPMs that give a 100% spread across the engine, the rpm range, and also makes the most of the dynamics of the engine, hence to see if you can work out where the cam "Comes on" and then kick in with advance accordingly.

You then have

3000 4000 6000

The colums for 3000 4000 and 6000 serve no purpose - they are the same, and does you ensgine go to 6000+ ?

therefore the steps and buckets are not smooth even and you have too many buckets within a couple of hundred RPM and the 1st one serves little purpose, and the last 3 are the exact same so your working from a 9 column table

the KPA up the RHS is 99% ok couple of suggestions.

1st drop 100 to 98

This is as I have found that when you foot is hard down between 1 part of say the bottom of a hill and another higher you can't get 100, but you can get 98 !. this way you are guarnateed 100% advance at foot hard down . Similarly I have aded a 10 kpa to my map, and yes I do get into that row !

As to the Spark advance itself I would say (depends on what the engine is you say it is) either the max spark (100 KPA) is too high and too often too high, and 2nd that the other end of the scale (20 in your case) is also too extreme to heavy handed and not blended anywhere near enough.

Too much advance can cause huge probs - dentonation - which in the sorts of 4x4s we have you may not hear over the other noises !, and even engine damage as a result - I would not run you map on anything other than maybe a very highly tunned 3.5, anything bigger CC would be too much..and even then I would want to see use and benifit of all 12 rows, frankly the map is not even suitable on second thoughts for a tunned 3.5 as the buckets and steps are just not in keeping with what could be achived


To finish and give you some idea of where I see this MAP:

You have EIGHT buckets represting the majority of the MAP,
this goes from 500-2300 rpm,
that means you have EIGHT buckets for just 1800 rpm movement
and you actually have 12 colums to play with
3 or your at the far end for 3000-6000+ are identicial
The park is too advanced and uneven and too high on overrun

You COULD have 12 buckets for say 700- 5500-6000 RPM and make each one count for something ?

AFR is a whole other issue, many 4.6s have probs due to being too lean at cruising speed as an effort to get economy, Mark Adams who is prob the expert in V8 tunning ECU etc has said he richens this up when he tunes the 4.6s etc. The 14.7 for a V8 is also too lean, really 14.3:1 is a better target for a big Capacity V8. However before you wo0rry too much about VE / Fuelling you have to have the Spark right, as effecting the spark has a knock on effect on the fuelling, so at the mo I would say forget fuelling, and in many ways forget this Map you have posted up - the ones in this thread are for V8 of 4.5 and 3.9 worked out from hours on a rolling road, the difference between these and yours is vast in many ways inc the text above and more.

Sorry if this isn't what you wnat to hear, but I think you are on the wrong path at the mo

What I am puzzled on is why you have a MAP a la the above when there is so much already on this thread re this very isuue ?

Nige

Hi Nige,

no problem with letting me hear sth. you think I´d might not wish to.
Well, what I demand from myself is whenever possible not to follow where the wind takes me and not to follow any ideas that just pop up into my head. I prefer to discuss, weigh up and when all the factors are taken into consideration there can be something like (close to or equivalent to) truth which is something I can hold onto.
So, this said you cannot offend me by objective criticism. It´s wellcomed.

a) the first row at 300RPM is easy to explain. It´s nothing you should bother about It´s my very own idea of cranking aid. I have the EDIS-cranking trigger set to "calculated" so that it uses this first row to set the cranking rather than the limp-home 10° built into the unit. That way I don´t have to worry about cranking and batteries at very low temperatures. Once the engine is running this row is never used, that much ist true. The 500RPM bin is set lower than any RPM the engine will see in life.
I´ve had this discussed on msefi.com and learned that the relatively low static timing of 6°BTC of the 3.9 distributor was done for easy starting rather than for combustion needs. Second, Rover wouldn´t have accepted too much advance at low RPM or idle because the exhaust gas temperature lowers and the cats might stop working.
You can read it here: http://www.msefi.com/viewtopic.php?p=18518...=advance#185183

b ) You know, I´ve been quite shy to use a lot of advance. Especially at low RPMs. But it´s not that I haven´t discussed it before. There are areas in the maps that are quite lean. You might have followed the thread on MSefi :
http://www.msefi.com/viewtopic.php?t=30605
At the moment that thread is educative for sure, but not that I´ve made a clear message out of it for me. Which is probably due to my limited understanding and that I´ve not involved into the matter by profession. But it becomes clear that there are some views or so called facts around that are just true under certain conditions as they are not based on all the parameters that influence. What I think I´ve got as a "take home message" that one of the mistakes with lean mixtures (lean but not unrealistic lean) that engines are driven with not enough advance then.
After all, my map is - as all the other maps - just a draft. An approach. I am doing a lot of changes and making my experience.

c) Ok, my engine is bog standard. 4.2l V8. Standard cam and pistons. EDIS. LC-1. TopFlanged cylinder liners. Airway from airfilter to TB is 70mm all way ID. I have a knock sensor with Boris´ knocksense, this gives me a LED flash whenever it thinks it should. TIFWIW, and I´ve not yet adjusted it good enough.


d) I´ve always been inclined to follow the default tables of the MS-Manual as much as possible. So, I thought, when someone like Lance did some bin-spacing I could imitate it and then see where my engine has different needs. When you look at the msq. that JIM published in the first link I provided in this post you see how much (indeed) advance some people run. That makes the above table look like a compromise. Not saying that this makes it "good".

e) I´ve too followed this thread all time. I´ll re-read it for the advance table. I´m inclined to forget a lot

f) for comparison purpose I may provide a pic which someone took out of a Bosch book. It compares a distributor (lower graph) to an electronic ignition system (upper graph). "Last" means Load, "Drehzahl" = RPM, and the "z" axis of course tells "degree of advance".


g) so there are some maps made completely different to the degree of advance and at what regions of the map to advance more or less. One should compare. I´m sure the map pictured at f) has been made with all the effort a manufacturer can do.

>> Puuhhh, I´ve written a lot. Please, if I may sound offensive, that is never ment to be the case. First sentence I wrote is very true. If I sound like that it´s due to english not being my first language.

English isn't my first language either, I speak fluent Rubbish

Hendrik,

The EFI coolant sensors are the same on the 3.5 & 3.9. The thermostat on very early carb engines was 82degrees.............. all EFI engines are 88degrees.

The bosch 3D graph you have posted is not for a dished piston, open wedge shape combustion chamber like the Rover V8 ……………… it looks more like the 3D graph I would expect to see from a cross flow or maybe Carotid engine design.


The MS spark map you have posted will cause the engine to severely ‘pink’ or ‘knock’ at any above 2000rpm when the engine is under moderate load…………in fact I would class it as quite a ‘dangerous’ map with regard to the health of the engine.


The 6 degrees BTDC was not chosen for starting purposes ……… with distributor ignition systems the static timing is a design function that is determined by the advance curve, which in turn is a design function of the camshaft, valve size, combustion chamber shape, and piston crown shape (it is all to do with how fast the flame front can travel)……… the designer then also has to take into account the emissions requirement. The important design parameter that we are interested in is the max advance ………..the Rover design is 28 degrees @ about 4000rpm. This allows for engine use in areas of poor fuel quality. The Max the engine will tolerate under full load will be about 34 degrees, however, this will be dependent upon the camshaft, and compression ratio used. Mine will only tolerate 30 degrees (using 95 Octane unleaded fuel). When running LPG the figure is about 10 degrees higher due to the much higher octane rating of the gas ……….. but you should also remember that due to the calorific value LPG is about 10% less efficient.

I think your worries about timing related cold starting are unfounded. With cold starting it is the fuelling that is much more important. EDIS is a proven technology that works remarkably well………….but don’t use that timing map you have posted !





Ian

Aha !

Ok,

I have tried that map meanwhile and have not heard any knock. But, of course, there are too many noises as to say there isn´t any unheard.
So I´ll switch to a proven & safe map then.

Unless knock is pretty bad it's undetectable to the human ear anyway, knock sensors will trigger way before you would even know anything was wrong.

Hi,

makes sense.

I had only very rare occasions on WOT when the knock sense LED flashed. There was one datalog of MLV of 20minutes where the (for trial) enabled knock retard was active only once.
But, I have already accepted that 36° are too much. Dyno testing will have proved as Nige said.
Clue is, as I just have browsed through my msqm - I have had the IAT based retard been active all the time by 2-3° because my sub-optimal location just ahead of the throttle disc in the plenum housing provides a temperature of 30-35°C all the time.
Plan had been to keep the loom all together at the engine and that the sensor would be cooled by intake air. Will be no problem to move it to the air filter like Nige did. Or put a 2nd one in there to gain less (usually) unwanted influence on the advance map.


Ok, while there´s no doubt about the upper-right part of the bin and the part just "right" of the center. What about the idle advance. Manual says it helps the idle stability to limit the advance to 20°. Which in turn means that about 20° is something common.

Hi,

to bring some more stuff into the discussion:

This is an advance table for a 4.3l natural aspirated GM-V6. It´s from one of the US-Forum users.
I tried that map and can say the engine idled very swiftly.
The WOT and upper-right regions are, I think, not too far away from what´s accepted.
Interesting part are the low-load regions. Point of interest is the fuel saving aspect. At other place it was considerd as "ok, but a little ´linear´ looking, like having read-out a distributor. In the mean MAP and RPM areas it would benefit from a little tweaking to save fuel".
The advance looks fairly high there. But you have the centrifugal advance and with lower MAP the vacuum advance in addition. So who knows how much the OEM distributor can advance at maximum ?

The last, right RPM bin was made to act like a Rev-limiter. The guy who made that table has had difficulties with the spark-retard Rev-limiert function of MS2.

Now here it is:


What do you think ??

What do I think ?

Honesty ?


I think you are Waaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaay over compliacting things, and reinventing the wheel.

There are MAPs for spark and fuel on here which will be close to optimum for your engine, a bit of logging and tweaking and the only way to then improve would be a 4wd rolling road loads of money and someone expensive who knows their stuff.

The Spark MAP of mine up in here was from a Rolling road, Ian (BBC) took this and modded it for his 3.9 - also on here, and I used yet another varinat when I tuned Fridges Motor not that long ago, its a very solid close spark MAPs which will be what you wnat

Can't see any point in trying maps from V6s, vespas or anything else, frankly wasting time and potential to damage your engine, it doesn't need to much spark and lean VE for long to make a impact. If you wnat to waste your time then thats your right, just seems daft

Well....You asked

Nige

What Nige said ^^^ there are maps on here for Rover V8's so why are you trying maps from other engines that are nothing to do with your car? I'm sure Lewis Hamilton has an excellent fuel & spark map for his car but it would be about as much use to you as any of the other ones you've tried

Hi,

I´m wasting webspace. Less time. Therefore I´ll come to an end with the spark-argueing, really Just a last pleading ..

Anyway. What I basically did was to "question" something you regard as good, solid, right. The maps in this thread have background of dynos and money changed hands and a very reputable person´s mind is in the map. So your answer to the question whether the maps could be improved is "no". Arguments are good though and I´ll use them like that.

BUT it should be allowed not to take something for granted.
Please read my small anecdote to see >>
A Professor once worked at Boston Hospital which happened to be a huge building and to see his now-wife it was a long walk. Especially in the evening he had to take a long walk around as floors were closed. There was this freight elevator (which might have shortened the walk a lot) but it was not allowed to be used. After a few nights he was fed up walking and took the elvevator. He went in, the doors closed, he depressed the knob .. and nothing happend. He punched the board, hit the knobs and started jumping - and then the lift moved. Next time he dared to take it again it was the same game: some jumping and the thing moved. He immediately told his friend who would benefit from taking the elevator in having a shorter walk too. And his friend told him that he made the same experience long ago. Well, some days later a mechanic worked on the elevator and when the Professor told him that the thing only began to move after someone jumped around in it, the mechanic answered that there was a simple time delay built in.
MORAL: there are results of good and fair research and often they are backed up by others who you do trust. Still you could be wrong.

In a nutshell - my impression was that the maps were mimicking a distributor. Which needn´t be bad. On the other hand is there this nice electric ignition module which has potential to get around the distributors shortcomings other than being resistant against water. A bit obtrusively, I have to admit, offering different maps to discussion was done to see if there were ideas in them encouraging enough to change given thing. Or to reconfirm what you got.
There are enough examples of brilliant people who did miss something - Linus Pauling, those who said there are no little things like bacteria, those who disbelieved C.F.Gaus´s prove of the planets, the AFR thread with lean mixtures and cumbustion heat. It can happen.
And to prove/discuss/exclude and finally agree that this is not the case seems to be something good for me. Waste of time ?

There are some good questions being asked. I'll try and answer some of them over the next couple of days. Safe to say that there is a lot of difference between a dyno tune and an optimised spark map for the truck. And this will change depending on what you use the vehicle for.

As promised, although this may take some time...

Need to first introduce a few concepts. First of these is load, which sounds easy but can take some getting your head around.

Imagine revving the engine on the drive. The engine is effectively under no load. Now imagine it on the dyno, full throttle, but held in place by the retarder. This is full load. In normal operation you will be somewhere between these 2. But bear in mind that full throttle is NOT full load. If you are accelerating then the engine is not fully loaded. This is important.

Now imagine a rorty V8 that has been tuned on an engine dyno, giving best power advance numbers. If you put that engine in (say) an MGB you could pretty much use the dyno numbers. If you put that engine in a defender you would need to modify them as the engine is under more load in the truck application. If you spent a lot of time towing a 3 ton trailer you would need to modify it more. conversely the truck map in the MGB would result in a loss of power and MPG. But why?

In the MGB you floor it in 3rd and it will set off like a scalded cat (not much load)
Do the same in the defender and it will accelerate well, but not as fast (more load)
Do the same with the 3 ton trailer and it will groan and lumber forwards (heavy load)

The more load you are under the more heat is generated in the engine and the more you have to add fuel and retard spark to prevent overheating/detonation. Of course it isn't quite that simple as in fact the MGB will probably never even reach a bunch of the low rpm high load sites, but the principle is sound. You need to tweek things for the intended use.

OEMs spend a couple of thousand hourse getting from the dyno produced map to the final one. Admittedly a lot of that is emissions and drivability, but a lot is also optimising for the vehicle application.

Next installment will be drivability...

Its just a lot quicker to set the timing on a rolling road ...........................essentailly you are looking for the minimum timing that gives the best torque at any given revs and load................

A dizzy being a mechanical device is very much a compromise as often it is not possible to get the mechanical advance to follow the engine requirement..................

If you understand the fundamentals of how a dizzy works, how the vaccum advance works, how timing is related to torque, and how timing is related to how fast the flame front travels, then it is fairly easy to set a map that works quite well. The open wedge combustion chamber of the RV8 dictates that at full load the engine will not tollerate much above 34 - 36 degrees advance. Rover set this figure at 28 degrees to allow the use of less than perfect fuel anywhere in the world. Typically most engine tuners will intially set the timing to a max of 34 degrees @4000prm as a safe (ish) setting.

If you study the dizzt data then its easy to set the intermediate points at full load............ after the full load settings then set the light load (cruise) part of the map ............... all the rest will then fall into place.

When I put mine on the rolling road it was pretty much spot on, which was something that I was not expecting.




Ian

As usual Bill is quite right


The 90 on the rolling road was gradually increased in both RPM, and Load and then the MAP tweaked.

the map vs the Dizzy was a HUGE Change, the main one being is (I will try to explain this as best I can )

A Dizzy is limited by the mechanical functions within it
If you wnat a performance dizzy you can play about with the weights (speed of advance)
You can modify and tweak it
But it is fundementally limited
If you say want to have 30 degrees adavnce at 3800 rpm
Then thats what you set it for on the drive

All is then well you have the advance you wnat
But, and its a big one
EVERYTHING else is a compromise
Or as good as you can get it
Tickover may be far from ideal (was in my case)
Tickover was around 17 Degrees

With MS you do not have these limits
with the 12x12 table you can set whatever value you want at whatever rpm and Vacumn (within 12x12 limits)
This gives HUGE tunability

I can have the Spark I want (or the engine needs) at High RPM AND a tickover at 11

Transforms the engine

What Bill S is one about is what you are tunning for, and the spark table could be modified to have say a mild road MAP and VE Table, then a "Sports" mode, then a Race mode etc, dependant on what you wnat from the engine. WHATEVER you tune for more spark is not nessacarily better, you should try to obtain the MAXIMUM BHP AND TORQUE for a cell with the minimum amount of advance, there is a point where more advance = less power - this is the skill bit, and why a 4wd rolling road is the way to obatin this, you also need someone who knows what they are doing - which is less than you think, and also costs more than you will think

You also sometimes have to compromise to get tractability, ie you can build a engine / V8 with Big Valve heads, ported to death massive agressive cam, huge compression balanced and then tune it to find its almost undrivable as you have a fag paper for a power band nothing below high cam coming in rpm, but you can soften this effect with carefull tuning, however better if the engine is built towards a target spec and requirement, I have driven "Cammy" cars - great fun in the power band, but hard work to drive, and frankly a softer state of tune can make a quicker lap time tricky to explain but belive me been there !

However, my point to landybe was a LITLE bit of too much advance he won't feel, but the engine will, and damage can be fast and very very severe

I have now had the chance to tune Mr Fridges MAP generally, a huge amount has changed been altered and the main difference I belive is the still unbelivable grin that he has now the full(er) potential has been unleashed, I am sure it could be made better, we spend the best part of around 4+ hours on it, and the cost was chocolate bars and fuel and thats it, 4+ hours on a rolling road would be terrifying

I will leave fridge to commnet on the above re before n after .............

Nige

But a major point is still being missed on the basics. The Dyno map cannot allow for the effects of driving up an alp with a full vehicle, where you are at high load for long periods, allowing heat to build up in the head and potentially knackering your engine. Well it could if you help it at load points monitoring knock and CHT, but there is rarely time for that.

Good tuners will know what and where to change from best power, but still there is some work needed by the owner to get the perfect map. Ideal ( and used by OEMs) is a timed retard/enrichment algorithm, which starts on best power and then pulls spark and adds fuel if you hang around that load site for any length of time.

back on the dizzy topic. They suck, but are a good starting point. Idle to 3000 they are always badly compromised. If all you have is the dizzy data then there is a good calculator for advance curves I can dig up that calculates how advance should change with MAP and VE. (basically spark curve should start off following torque curve).

A bleeding edge spark map will have a dip at peak torque as this is usually where knock is most likely (depending on engine design).

work is pissing me off, so a first few notes on drivability. This is the bit where you tune things for how you want the truck to behave. There is no right or wrong answer to this, just what you want. This is an area where fully 3D mapped ignition is a boon (and a curse cos you keep tweeking it).

Discussing this could run into pages, so a couple of examples to help.

1. crawling (slight cheat here as IAC also involved). If you are in low box and lift off the clutch without touching the throttle a number of things might occur

a.) engine stalls
b.) engine picks up and you crawl gently forwards at 850-1000RPM
c.) engine picks up and you go rather faster than you intended.

All to a degree could be tuned in depending on what you want. I suspect would be the preferred option and can be done with a combination of IAC control and an agressive spark map below and above idle.

2. Traction. Now I know stuff all about driving in mud, but I suspect you don't want a vertical torque pickup as this would encourage loss of traction. In this case you might want to considerably modify the spark curve from best power to give you a truck that is easy to drive. Again back on the OEMs they purposely put a torque dip in low down to help with wet traction and town driving.

Just 2 examples of many possibilities. With EFI you have the tools to make the engine behave the way you want it to.

Ok,

Heres a topic I would like some input on :

AE Tuning on MS

Basically I have this (normal enrichment) on mine :

Click to view attachment


Now,

I am also working on a mates racer.

We have tweaked and twiddled with many settings, we have upped the spark and dropped the VE Fuelling and each time it goes better and better, but it doesn't go like a bat out of hell which it did on a 4 barrel and a dizzy (modified)

The engine is a VERY high state of tune 3.5 V8, with just about everything tweaked and ported, runs 3.9 Hotwire system MS 1 V3 MS n Extra and EDIS. Edis is siolid at 10 degrees, and the engine DOES run and run well, just doesn't "GO" like it should.

He is using a much modded MSQ of mine, as such I have just seen I have "Normal AE" as oppossed to RPM Based AE.

I have read an interesting article on RPM AE, but would like some idea as to if this may be a better route for AE on the MSQ File ?

Also

If I change to RPM AE

Does this affect the base VE MAP
ie is it still safe or could the AE RPM if wrong make for lean engine
(we only get to test when racing !!)

Any thoughts

Nige

Nige,

slightly confused about what seems wrong. AE only affect that initial boot of the throttle. If its wrong then initial pickup will be poor, but then it will quickly recover. If it seems down on power all round that it is a different issue.

Easiest way to see if you have an AE problem is to log with a wideband and see if you go majorly lean when you hoof it.

And remember, AE is the last thing you setup. It is not a way of getting around a bad map.

Bill

Yep with you (amazingly) so far

The MAP I am running at the mo has the AE as the pic above.

The article I read discussed differening ways of Setting AE, either via the Normal Enrichment method, or the RPM based method, and it was agruing that the RPM method was more "Tunable" and refined, and then lost me for a while and then I sort of understood later.

What it was saying was the Normal whilst good could be beaten via RPM based, and then also went into realms about how to about it.

As with all things MS I am wondering just how much better RPM could be over normal, and is it worth the ag trying ?

As to the 3.5 racer that could be loads of things, I think too much fuelling (making it sluggish and drag) mate thinks MORE SPARK and too lean, I know that too rich often makes people think too lean......

The AE was sort of mixed in with this, RPM based seems suited more to engines that jump massively around the RPM buckets and MAPs as the Decel seting comes into play and on and offing the loud pedal can cause real troubles, I am also thinking of cylces vs RPM on AE and the way that can work.

I haven't done really anything on my AE since getting it to the state of tune it is now, just wondering really

Hope the above makes sense ?

Nige

AE was what had me stumped for ages.

I couldn't get a fast response to sudden AE from idle, the engine would hesitate, rpm would momentarily drop and then pick up.
Logs from the wideband O2 showed it going way lean then way rich when the throttle was blipped.

I tried all different values (large & small) of MAP based, TPS based and RPM based AE. The extra fuel was going in but too late. The solution I found was to change (under Constants) the Injections per Engine Cycle to 4 and Injector Staging to simultaneous. This causes MS to calculate the PW more often per engine cycle than before. I was running 2 squirts alternating before i think.
Instantly better throttle response! Found I needed to reduce the AE values (PW) from before as it was adding too much fuel.

It's probably still not perfect, can bog if the engine is labouring and you thump the loud pedal.

Downside is less injector / fuel precision at idle - the AFR wonders about a bit (though i think the hi-res MS1Extra code or MS2 has 3 x the injector resolution)

MS2Extra has EAE (Enhanced Acceleration Enrichment) which as far as i know is similar to how OEM ECUs do it:
Kinda boggles my mind
http://www.msextra.com/ms2extra/MS2-Extra_...Manual.html#EAE

Just thought i'd add my thoughts, happy to be corrected

It very much depends on the engine and intake config how much AE you need. different engines behave differently. AEA is a simplified version of the OEM solution that uses a wall wetting equation to work out how much fuel to add. It is very good, but for a racer you wouldn't need it.

At the end of the day, if you can't feel any problems when with transient events, then you don't need to change things

Hmmmm

On the subject of AE and tuning have just read a very very lengthy article on datalogging and tuning.

Basically it was saying when you datalog and tune with megatune, switch OFF AE Enrichment, but leave EGO Correction ON.

Whilst I understand the logic of this, whats the risks to the engine whilst logging and driving when you hit WOT ??

Thoughts please ?

Nige

I think the early versions of MegaLogViewer you had to but not now as it filters out AE and overrun fuel cut events:

http://www.ideasandsolutions.biz/MegaLogVi...isFAQ.html#gego

From what i understand (i may be wrong here):
If wideband is used and EGO Correction is on, it will try to adjust the fuelling in the usual closed loop way so the EGO matches the Target AFR table.
Below 90kpa it will adjust fuelling up to the value specified in Controller Authority (+/- 15% on mine).
Over 90kpa it will adjust +/-5% (value set under Lambda AFR Targets).

If Narrowband then it would need to go open loop over a certain load value (otherwise i guess it'd try and adjust to 14.7 on WOT which would be bad)

AE is only for changes in throttle position

For logging and tuning you want to try and hold steady state so you get clean samples. lots of throttle changes mess this all up and should be avoided. you can drive around at WOT without needing AE, so where is the problem? you just get there a little more gently than perhaps your usual driving style

Bill

Yep AE is about right methinks after some playing, I have done a load of reading seems the later versions of MLV aren't infected with AE switcvhed on , but Bill may have a point in try not to have too much AE one when data logging.

Anyway, on to the current project within me MS

Starting

PITFA - it does, and runs horribly until over 72 Degrees, and until now I have put up with it.

Today I needed to get out of the house fast, and the MS starting meant it didn't like being driven until warm, but it drove, coughed and sneezed, and I thought, I can get this better (this seem to be a comment MS Cry from the fiddlers - me now included )

SO, mucho reading I had done I turned myself to the starting.

Yes I do need a PWM Valve, and one is due to go one soon, but, even without that it runs dreadfully untill warmed up, even if I manually keep the throttle open - it doesn't like it, and takes around 10 cranks to start

From my reading I understand(ish)

there are 3 levels to starting :

• Cranking to getting engine to fire
• Then when it fires - Afterstart enrichment to keep running short time
• Then a table of Temp vs fuelling called Warm up Enrichment - to warmed up engine

Then the engine goes to the VE Table. The MS ECU uses a VAST amount of its computing power in the 3x areas above (inc the PWM needs)


I have massively altered the tables, enclosed are before and afters of these 3x tables above.

I have just popped the 90 back in the Garage, it started on the 5th crank, and sounded HUGELY happier, it would actually tick over on it own when it reached around 60ish degrees, (didn't before until nearer 75+ degrees) and sounded sweeter and happier generally, I think I can improve more, but you only get a 2x try a day on cold starting

Enclosed are the before and after pics,

Cranking settings :

Click to view attachmentClick to view attachment


After Start Enrichment (ASE) :

Click to view attachmentClick to view attachment


Warm Up Wizard :

Click to view attachmentClick to view attachment

I would be interested in comments thoughts advice and views please



Nige

Hi Nige,

I do appreciate this thread a lot. Was a good idea. Unfortunately work was and is taking its toll. So I´m not able to keep my test mule running ..

What I managed was to start it for charging the battery today. I tinkered with the advance at idle. As said, I´m inclined toward 20° figures at idle and low MAP to improve fuel consumption. With that advance I had an idle RPM of 950, MAP was 36. When I reduced the advance to 11° the RPM dropped to 870 and MAP seemed to stay at 36 if not was raising a tad.
What were your observations that led to the lower advance ?

Hmmmm

Ignition timing and all that goes with it is tricky to put up in a single post, could wear a keyboard out

Basically you must stop thinking in terms of "My Dizzy Had" and look to more "What the engine would really run best with" type of thinking.

Most dizzys operate in a restricted environment - ie it is a mechanical unit and the advance curve is limited by what it possible in a dizzy. As such When I had set in the dizzy what i NEEDED at say 3500 rpm (around 32 degrees) tickover ended up at whatever tickover was as the bob weights and advance settled down, thus my tickover was around 16-17 degrees lumpy and horrible. What it NEEDED at tickover was less advance (and less fuel and less map too) around 14 ish degrees and thats partly due to the wild cam, a std cam should be NEEDING around 10-12ish dependant on the individual engine.

And thats another point

As you now have a fully programmable ignition, you can actaully take 2x 3.9 factory V8s with some mileage and find that each NEEDS something different to the other - they SHOULD be identical, but not definately. Think about the V8 or any other engine owner who says "Mine starts on the button every time no probs" and yet the same engine spec can give the "mines always been a pig to start" problem (and here I mean that evrything on both engines is in good condiotn)

Hence to a degree (jeeez - no pun intended ) you'll need to discover what advance you engine is happiest with. this is a bit trial and error, but I would say for tickover 20 degrees is too much. You wnat to try to get the Map low, and also you need a CO2 reader up the exhaustr pipe, and then work on the ignition and the VE to get to the setting for CO2 you wnat.

With my engine the valve overlap means that I have set the VE Buckets around tickover far far far too high (near 40) just to get it to behave on the CO2 machine, with the valve overlap some of the fuel is coming straight out of the exhaust ports before detonation, so I have to over richebn it to get the MOT % and smooth running, changing the advance affects the MAP AND the VE. Too lean also feels and behaves like too rich, don't be fooled !

I would suggest you should aim for around 10-15 degrees advance, (a dizzys static was around 2-6 and can be improved on by more advance this is done as say a std dizzy with say 6 degrees BTDCand then the normal 22 degrees advance on top giving you 28 degrees adance in total which is all the mechanical unit can do) and fiddle the VE and as you do this see what the MAP does. bear in mind auto don't like as much advance as it causes labouring problems and detonation rather than the manual where you drop a gear. on idle static timing bigger cc V8s need less sp say a 3.5 13-16, 4.5 10-12 and similarly in between, hairy cam can alter this, as does high compression engine- for HC engines (10.5+:1 less advance. I have previous posted up MAXIMUM Adavnce number by V8 engine cc, so bear this in mind too. You should also check you EDIS is 100% set at 10 degrees - set all Ignition buckets to 10 and then do a timing light strobe check, ensure its 10 exactly. To help HC Engines run advance run high grade fuel, mine much prefers 98 ron vs std ron.

Tickover esp on a tuned engine is a compromise. I am assuming you have set the plenum chamber butterfly correctly with a feeler guage (if not see tech arvive and 3.9 hotwire diagnostic manual I have posted in there) and then adjust the allen scre in the front part of the butterfly part of the plenum.

As you fiddle with the VE Advance and tickover recheck the plenum settings - its like trying sometimes to level up a three legged chair

HTH

Nige

Just to re-state something Nige said, dizzy timing is only ever the relatively clumsy product of two curves: The curve of the bob weights and their springs against RPM, and the pull of the vacuum unit against MAP. True over the years manufacturers have got it to be a pretty decent result, but you're still governed by the basic curves of the two things, when your engine may need a more complicated shape than a curve.

The same holds true for carburettors, although with added complexity they can be tuned a bit further they still can't match a fully mapped ECU.

Specifically @ fridge,
Cos he's met me, I was the nutter who saw you at bunny lane and asked all kind of questions about how to MS a V8....
I have gone down the MegaJolt route for now (paupers choice) and I have the option for MegaSquirt later.
Has your map changed a lot since the last one you posted?
Cos thats the basis for the map I'm using on my MJ unit.
If it has can I leech?
Please...

@ anyone else who has a spark table that they feel is working well, please share
I have played with mine all over but cannot hear detonation ever!
Checking with a timing light shows it working though.
SO worried about blowing the thing up when all I wanted was a waterproofed V8
which it is....

I know I can use the safe map, but that seems lame after the graft to put the thing in.
RR

I will let fridge explain ..................................

Nige

Yes it has, let me turn overrun fuel cut off and upload a new map... may take a few days as I'm running around on business and the truck is on axle stands

Nige/fridge

Thanks for the PM's and posts. I only need the ignition side, as I don't have all the MS stuff on yet.
I will have to tweak the map anyway as I have only got 10 x 10 bins (pauper)
Thanks guys.
Nige, did u ever sort the fuel consumption probs that I remember reading about some time ago?

rr

Sub Topic: Wading......

Not exactly high end tuning but a problem to me all the same:

Typical of my lastest wading antics is to be able to wade to full height of the snorkel without issue or the slightest miss-fire for any short length of time - the time it takes to reduce the engine coolant temp to about 30°, then it seems that the warmup fueling starts to flood the previously warm engine.

So, how do I set the ecu to allow me to wade, cool the engine, and yet not overfuel?

Im thinking of making use of the fuel map switching, i.e. having the second map (which is currently used for economy) set to a "false table" where the ve buckets are say (guess) 50% down, this combined with the automatic warmup would then give me a normal fuel amount?

I must admit to being slightly confused, to me a cold engine needs the same amount of fuel regardless of the time taken to reduce its temp, underwater or not. But the laptop does report running silly rich and it does feel rough (in a rich carb setup kind of way) when the temp drops.

Easier to just change the WUE ASE settings so 100% only at 30 degrees ?

Get engine running / warmed up then switch maps.

That said having typed this you might need the extra fuelling if it cools the engine

Maybe somewhere in between ?

Nige

Might be worth a punt - Im glad you dont see an instant answer - perhaps this could be a true trial and error one?

Erm

No

Actaully I have had a though

ASE & WUE are exactlt that, after start and warm up, not sure that if the engine temp drops hugely it goes back to it, ans the engine is warmed up and running (a MS grown up will be needed to confirm this ).

If thats the case then the issue will be EGO as the O2 goes cold, so switch it off .

I think then doesn't matter what the MAT sensor may read, it will solely run off the VE Map ?

Nige

There is an easy fix

Yes WUE is warmup enrichment, triggered by engine temp, you need it there for good starting from cold but since the thing's underwater the coolant (&sensor) goes cold even though the internals are happily around operating temperature. ECU thinks engine is cold and chucks in more fuel, which can then be tending towards flooding (with fuel, not water ).

So instead of switching fuel tables, you switch the coolant temp sensor off. If you ground the sensor wire, it will hit the limp-home value of "the engine's probably warm enough":

Thermfactor.inc for RV8 CTS

You could be really swanky and stick a 330R resistor from the switch to ground, simulating a temperature of about 80^C. If you want an adult to solder it up for you I can stick a switch in the post for you

How this works (AKA the science bit):
The ECU has an analogue-to-digital converter in it to convert the voltage from the sensor circuit into a number between 0 and 255.
As the sensor is a resistor, it will almost always have a resistance that is inside it's normal range (-94 to +260 degrees ).
So - it will never actually hit zero or top resistance unless you move to the moon, which means the sensor circuit will never send exactly 0v or 5v to the ECU.
The Thermfactor file tells the ECU a list of temperatures-vs-ADC counts (0 to 255) for your sensor.
But, since we can assume it's never going to really hit 0 or 255 (or if it does, it's gone way beyond happy-time anyway) we know that if it does, either the sensor has failed short circuit or the wire's shorted to ground (ADC=0) or has shorted to something live / is disconnected (the wire will "float up" to 5v with nothing on the end, giving ADC=255)
In either case, we know the reading of 0 or 255 will likely not be correct, so we use a "limp home" value of 77^C which should be roughly OK to use under most conditions.
This means that to disable the sensor, grounding the wire (0v) will make the ECU use the limp-home value of 77^C. Everything else will run as normal (there is no actual limp-home mode like some factory ECU's which limit power / speed etc.).

The lambda sensors, even if heated, will probably be struggling to stay anywhere near a useful temperature underwater as they are bolted to a huge heat-sink (your exhaust) immersed in cold water. Widebands will be doubly unhappy as they need to "breathe" outside air to work properly.

Nige,
What have you done to my engine?....

From the top,
MUCH Smoother idle, tho still occasionally stalls when load applied, ie winch, PS pump Alternator
"I can feel it" tm better acceleration
No nasty popping sounds on the overrun
Feels a lot smoother all round
and the exhaust note is a wonderful burble rather than a shuddering heap.
Thanks
RR
ps Drove 15 miles for the hell of it on special tracks.
O well another fiver gone...

OT why doesn't my avatar appear?
I've uploaded a picture to my profile?

Smart Arse Good Idea



Yes please, suitable funding will come in addition to the funds for recently ordered squirting box!

Glad to help,
Seems your chuffed with the "HFH-Phone-Tune™" diagnostic service then ?

Nige

I guess this is probably to thread in which to talk about air density correction based upon the IAT.


I am currently playing with this to find a solution to the age old problem of sensor heatsoak causing the IAT to rise significantly when stationary, moving slowly, or off road driving.................. once on the open road with some air flow the IAT soon settles down to a sensible number.

For those not familiar with the problem............... the IAT sensor under heatsoak conditions gives rise to IAT's of 30C - 40C . These temperatures are notified to the ECU which in turn correctly leans the mixture. Although the IAT sensor thinks it is reading correctly, it is actually reading the heat that is rising from the hot engine and just being slightly cooled by the incoming air. So ......... after a decent run and then being stationary for 10 minutes, upon a restart the end will struggle to idle correctly as its now running lean ............... the same applies to slow moving in off road situations or traffic chaos on a hot day. Heatsoak is a natural phenomena as all the hot air from a station engine will tend to rise out of the air intake.............. we just need to correct it for the time period that it taskes to clear the hot air and revert back to reading the true incoming air temp. A gander at the MS algorithm that calculates the fueling shows that the IAT has a significant input to the final answer..........

MS does have a facility to correct this ................ 'air density correction based upon IAT' (you could also base it upon CLT but that is OK)

Currently I am thinking that maybe something like +15% (VE) correction from idle to 2000 rpm when IAT is at 30C rising to maybe +30% when it gets to 40C.............. I will work on the required curve and report back...........





Ian

Nige,
I should have thanked you ages ago, but didn't I'm sorry.
Just an aside, and reading your answer to another thread,
should I have higher values mimicking the vacuum advance in the mid range of my map?
Please bear in mind that I have 12 degrees of advance before I start!
Click to view attachment

I assume that you have 12 degrees advance + the table .............why ?

If that is the case then your map looks Ok ish ..................... but it would be better to set up the timing to give you TDC static and then use the table to its full advantage.




Ian

Cos I'm a numpty and didn't get the sensor in the right place!
I have bought a new bracket, but dont want to to take the pulley off again, yet.
Got a competition this weekend.
It's eating fuel (what v8 doesn't)
I was thinking about the vac advance bit, that the mid table value on the right, should be higher than the WOT value of advance.
This is on a 3.9 with lucarse ecu.

OK

Table look OK ish

Real prob is your table is back-2-front for us with MAP Having got my brain around that couple of comments :

Your 4500 and 5000+ table colums are exactly the same, as such there it a column 100% wasted, so re jig and use it.

Your running at WOT 19+12=31 degrees, can't rememebr your engine, so look back in this thread for what the Most advance you can have at WOT per Engine CC is ??

that may give you your last column chnages

Your 600 column is all zeros (12) thats not too clever - and a tad high as well ??, and the other columns IMHO similarly have not much variances, have a look at the other MAP tables here on this thread for spark and see how the numbers move within the columns - this is prob why the huge Fuel consumption

I will have a closer look prob next week when back at work
Nige

I am running MAP!
Maybe it's my understanding of it that's flawed here.
Basically the top right of the map is closed throttle high rpm
bottom right WOT high rpm.?

So maybe I did have extra values of advance in at small throttle openings and higher rpm?

oh, and 12 degrees of advance, cos I cant get any less..........

Bloomin 3d maps...

Yes ........we know you have 'MAP' not 'TPS'

BUT

We run our MAP Column 100 down to 0
you run your MAP Column 0 down to 100

...and it hurts me head

Nige