Megasquirt Timing and Fuel Map Thread

[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.

[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]

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]

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.

[fergie]

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

[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.

[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 !!!

[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.

[SLEEPYDUB]

Anyone have an M20 E85 timing map they would like to share?

[2002tiiguy]

bump to keep this up top

[SLEEPYDUB]

Here is my M20 E85 timing map.
Setup is 885 head with a 280/274 cam and a 2.7ETA bottom end. Car runs very good and is very fast.

Most importantly, my Tooth Angle #1 is set to 83 and falling edge. That is important to remember so don't just load these figures in unless you realize what that means!

This is a lot of timing in boost, but it is a 2.7 bottom so the quench is not as good as an 885 head that would require less timing. So this may be way too aggressive for a normal M20B25!

Would like some feedback on the map if anyone has any. I am still going to be making revisions to it once I hit the dyno.

Sent from my SAMSUNG-SM-G935A using Tapatalk

[redsubdivisions]

Here is my M20 E85 timing map.
Setup is 885 head with a 280/274 cam and a 2.7ETA bottom end. Car runs very good and is very fast.

Most importantly, my Tooth Angle #1 is set to 83 and falling edge. That is important to remember so don't just load these figures in unless you realize what that means!

This is a lot of timing in boost, but it is a 2.7 bottom so the quench is not as good as an 885 head that would require less timing. So this may be way too aggressive for a normal M20B25!

Would like some feedback on the map if anyone has any. I am still going to be making revisions to it once I hit the dyno.

Sent from my SAMSUNG-SM-G935A using Tapatalk

I'm curious about your bottom RPM range. 19 degrees seems like a bit much? I had that on my 2.7 at one point but for whatever reason I felt like it was too much advance, so I redid my tables to nearly 16 degrees and adjusted the VE fuel tables as well.

[SLEEPYDUB]

I'm curious about your bottom RPM range. 19 degrees seems like a bit much? I had that on my 2.7 at one point but for whatever reason I felt like it was too much advance, so I redid my tables to nearly 16 degrees and adjusted the VE fuel tables as well.

To be honest I'm not sure what is too much and what isnt on this setup. I really won't know how it responds to changes in that area until I hit the dyno. Maybe 19* is too much, but why?

Sent from my SAMSUNG-SM-G935A using Tapatalk

[redsubdivisions]

To be honest I'm not sure what is too much and what isnt on this setup. I really won't know how it responds to changes in that area until I hit the dyno. Maybe 19* is too much, but why?

Sent from my SAMSUNG-SM-G935A using Tapatalk

Report back when you get it on the dyno. I'm curious.

[cleanasse30]

Bump, interested in seeing more Turbo M20 timing tables!