Tuning for cruising and the spark map....

[V8 Freak]

Hi.... I now have a 1:1.003 transfer box installed (Thanks to Fridge for the box and Les for the skills...) and I'm looking to set up the spark map for balanced driving including crawling, general loud stuff on playful roads and cruise @ 60 MPH for the longer journeys.

For reference it's a 4.6 with standard bottom end and cam, 45mm shortened plenum trumpets and ported inlet manifold, ported heads with oversized valves (Double sprung), matched exhaust ports through 3.9 4-2-1 stock manifolds and custom exhaust system..

I went out for a drive the other night and recorded the drive to see where the KPA was at various speeds/revs on various pieces of road.

Upshot is that the truck now cruises admirably at 60 at around 1800 RPM

I've got pretty good crawling / low speed control now with the lower revs mapped out pretty flat.. Works well.

Looking at the journey I've played with a map showing the key areas I'm keen to map.

Looking into the "How To" thread that has grown up in this forum, a very knowledgable person once wrote...

Tom G .................... your spark map is OK, but you have not taken into account the extra advance that can be used when cruising ........... this would have been taken care of by the vacuum advance in the dizzy ............ on the RV8 IIRC it was about 10 degrees max. Race cars can do without this as they are always foot to the floor, but a road car needs it for economy and to help the burn time ............... i.e mechanical max was 28 .......... plus up to 10 degrees of vacuum = 38dregrees ...... but as you can often get away with a dynamic 34 degrees on an RV8 then add in the cruising / off / light throttle of 10 degrees and you get a max of 44 degrees.

Ian

So, the big question.... Do I try the map I've got, auto tuning and allowing a lot of control to the ECU to see how it goes?

Based on the quote above, should I get more adventurous and go for 35 - 44 degrees in the 60MPH cruise area ?

Do I dare lean the AFR off slightly from 14.7 target to 14.4 say for the added touch of economy ? (Cruise area only)

I'm not often up at or past the 4000RPM area so I could re-do the map with less fields / columns in the higher revs to give more programmable boxes in the range between 1400 - 2500 RPM for extra control and less extrapolation for the ECU.

The truck now finds a natural balance of power/weight/air resistance at around 80MPH in 5th.... To go faster I drop a few more gallons in the top, drop a gear and off she goes....

What should I try spark wise at 2500 RPM / 95 KPA to see if I can overcome this wall/limit and get the truck to pull faster in 5th if I so desire ?

(All this will be on Private Roads of course...)

More advance?

Any advice welcome.... What shall I try ?

Neil

[AncientGeek]

14.4 is richer not leaner. I've seen a dyno-tuned 4.6 spark map running 45 degrees at cruise which was in the 2500 rpm 50 Kpa range, dropping to 40 degrees at 60Kpa. Mixture was somewhere in the 15.5 to 16:1 range. This was however done at high altitude. Also this was for normal gearing. At WOT it was about about 24 degrees at above 2500 rpm at 13.5:1, no higher.

[V8 Freak]

Doh.. Thanks... Brain clearly not engaged on my part.

Great to read your comments. I'll have a play with the spark map over the weekend an post up again for all to comment on.

I've already changed the rev spacing to give more cells in the cruise areas so will go for a drive and record the cells in cruise more accurately then amend the spark based on the above. I'll probably not go as far as 45 degrees on early attempts!

Will also smudge the AFR table for tuning but not deviate much from 14.7:1 until I'm happy with the spark map....

Thanks so far.. Any more comments for me to consider people ?

Neil

[Hybrid_From_Hell]

MORE spark also = MORE Heat and leaner burn, 4.6 liners do NOT like getting ferkin hot

P38 and much of the liner issues is as a result of motorway long trips and super lean ECU maps for fuel economy effort,

but the lean burn + Hard spark = Heat and liner probs.

For better economy you can back off the spark and lean mixture, this will give you less power, but not the mass heat build up

There is a point where too much spark is less power, and worse power and heat massive, MBT is where the spark is

at its max as is the power and outputs, but heat can still be an issue.

The heat as such is also not going to always show on the temp gauge, this is core bore heat, which can be hugely localised and not affected by the coolant as such, the coolant is at one temp but hot spots develop and damange can be done, esp if "Constant" which motorway / cruising runs tend to be.

Spark and Fuel as youhave sussed are interrelated, but need to be looked at both jointly and seperately.

For real accuracy on spark you need a knock sensor and the ability to back it off fast when it reaches the point, and this is often a rolling road, prob is when you tweak the spark via Knock, the fuel ratio changes , change the fuelling and the spark is not not spot on and so it goes....

Too much spark = damage + Heat + Prob lean + lprob less performance

Too little spark = Flat performance + possible Bore wipe (over fuelling) Plug Probs

Too much fuel = Damaged performance, flat spots, fluffing on WOT bore wipe

Too Little fuel = heat +damage +predetonation + poor power + noise

Easy innit

Compression is another factor to factor in 98 RONcan take and run if set properly around 12.5:1 Comp Ratio, if you run higher octane

then yes you can get high spark etc, but if you then use by accident or desperation lower fuelling it will be dnmagerous if tweaked to run the high octane,

additives are regarded by many as another good route, but can't ALWAYSguarantee to have a bottle with you

with spark correct you can go to 13:1 AFR or 3.8% Co for max torque and BHP, peeps say this is too lean but set right it will give power

but this is more for racing where the rpm is up and down so the lean 13:1 is "Visited" rather than "Sat in" for a hour ........

With the head design the max spark for V8 WOT is less than other V8, partly due to Head design

most people have too much spark and too little spark in wrong places, and too much fuel and too little in others

Overfuelling can as a side effect cool hot spots from over sparking, but that like having the fire bridage turn up

as you set fire to your house in 27 differing places

Hope this helps - might ramble a bit more laters when I have some more time

Nige

[FridgeFreezer]

Worth noting that 4.6's have bosses in the side for knock sensors, there was much research in the MS community on it a few years ago but I never really looked into it or kept track of how far they got with it. Could be worth a look, I'd certainly be interested to see if there was a good solution as it makes tuning spark that bit nicer/safer.

[V8 Freak]

And the answer is fit LS engine and stock ECU ??

Your answer is pretty mucn on the fence Nige....

So I go a tad richer at WOT....

Lean off "a touch" on the identified cruise areas....

Always use 95 RON...

Will see if I get any time with the truck this weekend.. I'll post up proposed Spark and AFR maps when I've been "creative" and then run them and buy a new engine !

Neil

[V8 Freak]

If there is something easy I can do to introduce knock sensors John and employ your help with ECU/Loom I'd be willing to try on my engine!

However, it's still going to be dependent on the spark map being robust isn't it ? So that would ideally mean mapping power output on rolling road / direct dyno.

(Or am I grabbing the wrong end of the stick again?)

[Hybrid_From_Hell]

plus you should really use a 4wd roling road not a 2wd and remove prop

Nige

[landroversforever]

plus you should really use a 4wd roling road not a 2wd and remove prop

Nige

Surely you have a rolling road in your shed Nige?

I find all this tuning stuff fascinating... but sadly its not much use on my 200tdi!

[FridgeFreezer]

There is a lot of knock-sensor monitoring in other tuning circles, the Subaru boys often run with a little bunch of LED's on the dash connected to a knock sensor.

Since knock sensors are basically tuned microphones you can, with varying levels of effort, pipe the knock sensor to your car stereo or a pair of headphones which gives you a very basic but surprisingly senstive method of hearing knock way before you would with the naked ear. The biggest problem is ignoring all the other noises your engine makes the rest of the time.

Like I said, I never really had the time to dive into the stuff the MS forums were on about, and I don't know how far any of it progressed, but well worth a squint round.

[Hybrid_From_Hell]

Since knock sensors are basically tuned microphones you can, with varying levels of effort, pipe the knock sensor to your car stereo or a pair of headphones which gives you a very basic but surprisingly senstive method of hearing knock way before you would with the naked ear., and your engine self destructing in high definition Stereo , this way esp with headphones you have the added benifit of not hearing all the other noises your engine makes for the short reminaing time of its life

Edited & Corrected for you Mr Fridge

nige

[bobtail84]

Edited & Corrected for you Mr Fridge

nige

:hysterical:

[AncientGeek]

The example I quoted was done at 2000 metres so yoiu should probably chop 5 degreees off that. There isn't much point of running a lot of advance at cruise if you don't also lean the mixture. Lean mixture burns slower, thats why you need the extra advance. More advance at stoich might even drop the power as others have said. Heat is problem at lean burn and high advance but its more of a danger at wider throttle. Although you should probably be extra cautious because of your gearing. A lot of the maps given in this forum and on the web are for performance, not economy. I find most of them too advanced at 80-100Pka for me, but there are lots of regional differences like air temperature.

Also if you are running MS1 with NB sensor in standard trim MS in normal config it will always try to pull the mixture back to 14.7 (except at open loop). WB sensor and target AFR's is better for economy tuning but you can battle along with MSLV, etc to tune the AFR and then afterwards turn the O2 correction off or reduce it. And then watch out for heat soak which can be a problem even at cruise, this will cause MS to lean out the mixture. Fun fun fun.

[V8 Freak]

Any comments on the attached??

Not gone extreme, just want to start the process....

Thanks in advance.

Neil

[bobtail84]

Why?... what are you trying to do. Retard not advance.

[V8 Freak]

Looking to map so that I get a little more economy when pottering / cruising along around 60 KPA.

[Quagmire]

Check extra efi.co.UK they have some kind of conditioner box that allows you to hook knock sensors to ms and have it retard timing when knock detected.

Not gonna achieve max power etc just by installing and leaving it to it, but maybe offers some protection from tuning screwups...

[Bowie69]

Neil,

Those figures seem quite a jump, I would be smoothing the edges of the cruise 'box' and not going quite so high.

You seem to have a bit of an odd spark map tbh, lots of advance at idle, and not as much as I expected at the top end, I've attached my spark map for comparison.

Or is this because you are 4.6?

My map for a 4.0 P38 engine, I think derived from Nige's Megajolt tune initally.

[V8 Freak]

Thanks so far...

I'll check extra efi.co.UK later to see what's on offer.

Hi there Mr Bowie Sir, it's 4.6 and in the reading I've done it all suggests not to go above 30 degrees, although Mr BBC did suggest it would be good to go to potentially 44 degrees in cells specifically for cruise. (Quoted him in an earlier post)

Most maps posted so far on LR4X4 are 3.9 / 4.0 derived and as such I've gone a bit soft on it.

I've advanced low end for ease of use off road and when crawling around. Seems to work. When down at 12 degrees it tends to bunny hop around at low revs and feels like it's giving the drive train a hard time. (O2 correction off under 1400 RPM)

I've trusted my TDC mark up to this point but may invest some time this weekend to verify it is accurate...

Neil

[Bowie69]

Hi there Mr Bowie Sir, it's 4.6 and in the reading I've done it all suggests not to go above 30 degrees, although Mr BBC did suggest it would be good to go to potentially 44 degrees in cells specifically for cruise. (Quoted him in an earlier post)

Most maps posted so far on LR4X4 are 3.9 / 4.0 derived and as such I've gone a bit soft on it.

Sounds good, sorry I missed that bit from Ian above.

I've advanced low end for ease of use off road and when crawling around. Seems to work. When down at 12 degrees it tends to bunny hop around at low revs and feels like it's giving the drive train a hard time. (O2 correction off under 1400 RPM)

That's some good stuff to know and for me to try for off-road too.

I seem to remember that there was some way to get an instantaneous MPG from Tunerstudio/Megatune using a compatible vehicle speed sensor somehow, anyone played with this?

[V8 Freak]

I seem to remember that there was some way to get an instantaneous MPG from Tunerstudio/Megatune using a compatible vehicle speed sensor somehow, anyone played with this?

That'd be scary !!! Are speed sensors fed from wheel/gearbox revolutions or can they be calibrated to the vehicle? Never looked at these before.

[Bowie69]

Pretty sure you calibrate it to pulses per mile, a magnet and reed switch is all that's required, IIRC.

However, a bit of searching found this:

http://ecomodder.com/forum/showthread.php/how-get-instant-fuel-consumption-megasquirt-5474.html

No extra hardware required, and makes sense when you think about it, just a bit of jiggery pokery required

[FridgeFreezer]

I believe the MPG readout trick (and it is a trick) can also be used to display a BHP or torque gauge too - very bling, not shockingly inaccurate in comparison with most backstreet rolling roads etc. but nor is it really to be taken as anything other than an indication. I believe the calculations were originally based on a wideband lambda sensor plus either engine RPM or road speed sensor (VSS). The posted link does a similar thing.

If you know (or guess at) a few bits of information (vehicle weight, gearing, aerodynamic drag, BSFC of the engine) you can then work out* MPG/BHP etc. on the fly from the air:fuel ratio, injector pulsewidth, RPM etc.

* = Take a broad stab at given the huge opportunity for error and exaggeration in any of the numbers.

I note the ExtraEFI page actually says:

The best option as far as tuning goes, is to use a pair of air defenders without any wadding in them. Simply get a peice of copper pipe (brake pipe) and flatten one end of it enough to bolt it to the cylinder head. Then attach a peice of plastic tube (fish tank air pipe) on the other end of the copper pipe. Drill a small hole in one of the ear peices and push the other end of the pipe into it. Now any knock you will be able to hear clearly whilst tuning.

I'd be interested to know what's in the knock conditioner box.

[V8 Freak]

I'd be interested to know what's in the knock conditioner box.

Shall I get one for a looksee?

Neil

[AncientGeek]

I think you are on the right track. I would go a little more advanced at idle and bit more retarded at WOT. I would drop 1 degree at 70Kpa in your cruise zone. Unfornunately I can't post the 4.6 dyno tuned map because its not mine to post but I can make some observations. Other than at cruise his max advance is about 30. At cruise its between 39 and 45 and I suspect he is running very lean here. His max advance at WOT is a mere 12 and at 85 KPa maxes out at 18. His advance is all in by 2500 rpm and hardly goes up after that. In fact he has an interesting little valley above 2500 and above 70Kpa where it retards a bit and then goes up again by 4500 rpm. If you have a modified plenum this would probably change. He has no valley at 1500 rpm like that which so many people advocate.