Megasquirt Timing and Fuel Map Thread

[downforce22]

ms2, m20b31, itb's...

I'm at sea level now and your ve map is the only one that looks anything like the autotuner function generates for me.

also noticed that your maps start at 10 instead on 30 as on most. how about going as far as 0, ? just wondering.

BTW, e30tech.com is running right now !!!

Good to hear. As for the map, my engine seems to idle between about 30 - 26 kpa and it pulls more vacuum when engine braking so I just included the area below 20 so it is still on the map, not 100% necessary to go that low. You could get rid of that area and get better resolution in the center of the map. Going down to 0 would be 0 psi, probably near impossible to pull that much vacuum on any engine so going lower on the map is not necessary and you will never see it when driving.

Due to my altitude (6000 ft, 80 kpa atmospheric pressure) I have less atmospheric pressure which is why cars lose power at altitude. So I would only see 80 kpa at full throttle. You should see near 100 kpa at sea level. Not sure how itbs change things, but probably not much as far as fueling.

I saw the e30 tech, will have to scour through that reference for more maps and post them here.

[fporro]

I have been working on my tune and finally got it pretty close.

Engine Specs: 3.1L M20, 89.6mm stroke, 135 mm forged rods, JE forged pistons 86 mm bore, MLS headgasket, stock 885 head and cam, gates racing belt, head bolts, 9.5:1 CR, running 91 octane

Turbo Manifold: RSI/ Good & Tight t3/t4 M20 manifold

Turbo: Precision 5862 Billet Journal Bearing

Compressor Wheel: 58.00 mm 76.20 mm

Turbine Wheel: 71.00 mm 61.90 mm

Boost Level: 10 psi now, adding MBC soon

Injectors: Bosch 0-280-150-911 (30# at 2.7 bar = 33.3# at 3 bar, or 350 cc/min) Probably nearing 80% duty cycle and maxing these out (~300 hp)

Ignition Map:


Fuel Map:


Comments: Fast!! Since I live at 6000 feet I hit boost above 80 kpa. My current MAP sensor only goes to 120 kpa (6 psi here at altitude) so its only tuned to that point on the map. The stroker is so torquey at low rpm so boost comes on fast and smooth with these maps. Timing and fuel above 120 kpa could use some work but it drives very smooth,and boost builds quick! Perfect combo for the highway, not really for autocross. Just reworked the timing (removed 3-4 degrees) at 120 kpa because I was getting some detonation. Haven't driven in hot weather yet which could increase likelihood to knock.

ms2, m20b31, itb's...

I'm at sea level now and your ve map is the only one that looks anything like the autotuner function generates for me.

also noticed that your maps start at 10 instead on 30 as on most. how about going as far as 0, ? just wondering.

BTW, e30tech.com is running right now !!!

[Brettclarke]

327iT

Eta bottom end
885 head
600cc injectors
16 psi
Holset hx35
3" exaust
Ls truck coils on waisted spark
Walbro 255

Dyno results 300hp exactly, 346fp of torque at the wheels.

[fergie]

I rescaled my igniton and fuel maps as suggested, much easier to tune my fuel now that i can see the resolution better.

[fergie]

so I added about 2.5 degrees across my 130kpa range, so my inital timing of 33 degrees at 100kpa is now about 27.5 degrees at peak torque in the 130kpa range. I went for a test drive and noticed right away my initial boost pressure builds quicker now. I just need to data log it and see how much it has improved.

Previously in 3rd gear I would hit 12-13psi at 3400rpms, with boost starting at about 2800rpms.

[ForcedFirebird]

I plan on going back to the dyno and turn up the boost another 4-5psi. I agree with the initial spark retard above 100kpa. I notice the turbo is slow to spool at around 2-3psi and ive thought it had to do with the timing being pulled so much initially.

Turbo will spool slower, EGT's will spike, exhaust pressure will increase, creates unnecessary heat etc. Taper the numbers more and changing your resolution, you will ultimately have more control and can have a much better behaving street car (smoother transients). You can put another few rows between that ~10 degree pull in timing.

And yes, that table is super conservative.

[fergie]

My $.02.. You (or your tuner) should re-scale those maps. If you are at ~13psi (180kpa or so), no need to go to 250kpa and waste resolution up there. It might not make much difference in power, but when daily driving and you go just over 100kpa (boost starting to come on), you spark table is jumping from 33 to 24. Sure the MS extrapolates (or should I say interpolate??) the values surrounding the number, but pulling that is a pretty big jump for the same RPM and only a few kpa difference.

I plan on going back to the dyno and turn up the boost another 4-5psi. I agree with the initial spark retard above 100kpa. I notice the turbo is slow to spool at around 2-3psi and ive thought it had to do with the timing being pulled so much initially.

[ForcedFirebird]

m20b25
ARP head studs
Holset H1C with 0.63AR turbine housing
38mm external gate recirculated w/ EBC at 12-13psi
3" turbo back to single magnaflow muffler
Wasted spark MSD Coils
36# injectors
94 octane no ethanol
afr under boost is 11.6-12.0

ignition table was setup on a mustang dyno and is considered conservative

My $.02.. You (or your tuner) should re-scale those maps. If you are at ~13psi (180kpa or so), no need to go to 250kpa and waste resolution up there. It might not make much difference in power, but when daily driving and you go just over 100kpa (boost starting to come on), you spark table is jumping from 33 to 24. Sure the MS extrapolates (or should I say interpolate??) the values surrounding the number, but pulling that is a pretty big jump for the same RPM and only a few kpa difference.

[ForcedFirebird]

Not that it makes a bit of difference, but rather than posting the VE tables, shouldn't we be looking at target AFR's? I have found that unless a drive train moved from one car to another the VE always needs a fair bit of tweaking.

Hopefully people aren't copy/pasting VE numbers into their ECU's. On the other hand, I have found that similar combinations require similar spark tables - albeit a "2.7i" with flat pistons/885 is no where near the same as a true seta 2.7. The flat pistons want more advance (showing less efficiency).

[fergie]

m20b25
ARP head studs
Holset H1C with 0.63AR turbine housing
38mm external gate recirculated w/ EBC at 12-13psi
3" turbo back to single magnaflow muffler
Wasted spark MSD Coils
36# injectors
94 octane no ethanol
afr under boost is 11.6-12.0

ignition table was setup on a mustang dyno and is considered conservative

[2002tiiguy]

I ran around with these numbers this morning (although I have greentop injectors) and I had to scale back every cell 15 points on the fuel table to run around at 12.9-13.0 at WOT. Just running your numbers as is gave me 10 at wot and cruise. Do you have an AFR gauge? What do you see?

Does anyone know how much of a difference going from 14.5lb to 17lb injectors make?

that was with m50 injectors installed, i had it set for 17 pounders cause thats what i thought i had, and i was running 13.2:1 WOT, now running green giants. ill post the new ve table soon

[varg]

I ran around with these numbers this morning (although I have greentop injectors) and I had to scale back every cell 15 points on the fuel table to run around at 12.9-13.0 at WOT. Just running your numbers as is gave me 10 at wot and cruise. Do you have an AFR gauge? What do you see?

Does anyone know how much of a difference going from 14.5lb to 17lb injectors make?

Well... If I'm not making any gross logical errors, there's a 17% increase in fuel flow, which would change the measured AFR by 17% under ideal circumstances, and on top of that, there are differences in other parts of the tune which could change how large this effect is based your particular fuel delivery equation variables such as REQ_fuel error, injector dead time error, MAT/Baro correction error, number of pulses per cycle...

All good reasons to be careful when using other people's tables, even if your engines are exactly the same you never know how your fueling equation differs due to errors made by you or the other guy during tuning. There are less variables with timing but it's equally dangerous because if guy A has a larger trigger offset angle than guy B and guy B uses guy A's ignition table, the result could be pretty bad for the engine.

[Kershaw]

stock ix motor 885 head. ms2 n/a for now (stay tuned for twinscroll)

im pretty happy with how it runs. steve, or nomansland91 is helping me put together a quick spooling relatively low boost setup. power goal tentatively 250 whp.

I ran around with these numbers this morning (although I have greentop injectors) and I had to scale back every cell 15 points on the fuel table to run around at 12.9-13.0 at WOT. Just running your numbers as is gave me 10 at wot and cruise. Do you have an AFR gauge? What do you see?

Does anyone know how much of a difference going from 14.5lb to 17lb injectors make?

[bruner]

Bumpski, let's get some more info on this thread. Anybody have m10 (turbo or NA) tables that I could use as a base?

[2002tiiguy]

stock ix motor 885 head. ms2 n/a for now (stay tuned for twinscroll)

im pretty happy with how it runs. steve, or nomansland91 is helping me put together a quick spooling relatively low boost setup. power goal tentatively 250 whp.