Megasquirt - The Advanced Thread -For ADVANCED Discussions

[Hybrid_From_Hell]

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

[landybehr]

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 )

[Hybrid_From_Hell]

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

[landybehr]

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.

[FridgeFreezer]

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

[Bull Bar Cowboy]

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

[landybehr]

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.

[FridgeFreezer]

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.

[landybehr]

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.

[landybehr]

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 ??

[Hybrid_From_Hell]

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

[FridgeFreezer]

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

[landybehr]

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 ?

[Bill Shurvinton]

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.

[Bill Shurvinton]

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...

[Bull Bar Cowboy]

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

[Hybrid_From_Hell]

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

[Bill Shurvinton]

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).

[Bill Shurvinton]

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 B) 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.

[Hybrid_From_Hell]

Ok,

Heres a topic I would like some input on :

AE Tuning on MS

Basically I have this (normal enrichment) on mine :

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

[Bill Shurvinton]

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

[Hybrid_From_Hell]

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

[TomG]

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

[Bill Shurvinton]

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

[Hybrid_From_Hell]

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