Thread: The defacto guide to tuning your car for e85.

Originally Posted by chrsmi1

Not using your method of tuning dude. Tuning it via changing the skew rate instead of all the stoic values. So still using the gas afr values. At least I'm assuming that's what he's doing too

It's not a method. It's the chemical property of the fuel you're using that I'm referring too. If your thinking in gas then that stoichiometric is 14.68. If your personal is 11 then yes that's fine. Same concept of e85 which is 9.85 so your really dipping down into the 6 range which is reality of what your doing. That's all I'm saying. The correct terms not tuning methods. The computer would adjust though If you input the proper afr(stoich) instead.

Originally Posted by chrsmi1

Not using your method of tuning dude. Tuning it via changing the skew rate instead of all the stoic values. So still using the gas afr values. At least I'm assuming that's what he's doing too

This is what I did as well, on both the bonne and regal I just set the injector skew to 130%, and ltft's are +/-5% (10% on the bonne).

Shoot for 10.5 - 11 range. (Assuming a gas calibrated wideband). Boost psi is irrelevant with these engines and the m90. Stop looking at it. Stop logging it. Disconnect the gauge. Doesn't matter. It will be different based on a thousand differnt factors including the weather.

Pick a reasonable pulley size. Set timing to 15* Check for REAL kr. If she knocks go up a pulley size or two. If it looks good change to 20* of timing. If it still doesn't knock drop a pulley size or two. Rinse and repeat until you find a pulley that's happy at 15* but KRs at 20* Set timing to 16*. Enjoy.

Ignore the people that claim timing > boost on these engines. In my experiance boost trumps all on these engines. I have played on the dyno and using the above tuning method I have seen less then a 2 horsepower difference between 15* and 20* once on the final pulley.

Here is my concern with boost... I always thought 9 or 10 psi was max for M90 efficiency. I have a genV bolted on.

But right now I am pushing ~12.2PSI and it's taking it fine. I think I can easily drop to a 2.8" and probably a 2.7".
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But is 14PSI too much!? I want to know how much PSI you experienced guys are pushing. I am not trying to blow my engine up over 1 PSI.

I am sure I can push 14 or maybe even 15PSI but what is too much? Is that ok? 16PSI!? This is my concern. Hope you understand.

Boost pressure on a supercharger is dumb and irrelevant. Flow is much note relevant. Stop worrying about pressure, my 2.8 gen v setup pushed 19-20 psi in -10* air. Until you go turbo PSI is pointless.

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thanks, guys. Please bear with me. I am still a noob.

So if I currently have a 2.9" pulley with 18* WOT timing and 0 KR you guys are saying its perfectly safe to drop down pulleys regardless of what my boost # is as long as I can make ~16* timing at WOT with 0 kr? even if my boost shows 16PSI this is perfectly safe? As long as I show 0 KR?

Yeah don't get caught up on boost numbers, if you're not seeing kr you're good to go. What are you seeing on the maf in hz? I would imagine you should be maxing a stock one out at this point. Maf numbers are a pretty good measure of how well your engine is flowing air, as well.

Mid 10ks on LQ4 MAF right now.

I am totally caught up in boost numbers. I need to know that running 14-15PSI while seeing 16-18* timing with 0KR is perfectly safe. It will put my mind at ease knowing that these numbers are ok with my current build. Please understand.

I have never boosted this high and I am entering unexplored territory with my build. I want to be sure these numbers are perfectly safe if I am seeing 0 KR before I start pushing further on. I was raised on the thought that as long as you are seeing 0KR all is good, but I dont know anyone that is boosting over 12PSI personally. The idea terrifies me.

Frosty, i watched your vid and saw 16s and blips of 17PSI! THAT IS INSANE TO ME. Is everyone else boosting this high and I am just out of the loop on this? I always thought 9-11psi was best. Please put my worries to rest. Thank you

I've been on a 3.0 for about 5 months. Regularly making anywhere from 13 to 15 psi. I went to a 2.8 for a few days for testing and saw a little knock (this was two weeks ago) and hit 16-17 psi. People have run this setup long term. I saw knock so I went back to a 3.0 but I wouldn't hesitate to run a 2.8 and hit 16 or 17 psi daily. If your car is running well, do it.

Originally Posted by charlieRobinson

Mid 10ks on LQ4 MAF right now.

I am totally caught up in boost numbers. I need to know that running 14-15PSI while seeing 16-18* timing with 0KR is perfectly safe. It will put my mind at ease knowing that these numbers are ok with my current build. Please understand.

I have never boosted this high and I am entering unexplored territory with my build. I want to be sure these numbers are perfectly safe if I am seeing 0 KR before I start pushing further on. I was raised on the thought that as long as you are seeing 0KR all is good, but I dont know anyone that is boosting over 12PSI personally. The idea terrifies me.

Frosty, i watched your vid and saw 16s and blips of 17PSI! THAT IS INSANE TO ME. Is everyone else boosting this high and I am just out of the loop on this? I always thought 9-11psi was best. Please put my worries to rest. Thank you

I literally just went outside and unhooked my boost gauge. Stop looking at boost.

Did the switch today. #42 Ford injectors, 15.17 gallons of E85 for $26.26 No tune yet, but maxing out at +16.4 LTFT at idle. Any amount of throttle brings me down to +0.07 LTFT so I probably have a vac leak somewhere.

Hey, guys. Ran a 13.70 with 2.10 60' time yesterday. ~13psi @ 17* timing 0 KR shifting at 6000RPM. AFR is 11.1-10.9
Please note, im running a 4000 pound Riviera and not a grand prix!

Going for a 13.5 next week!

^^^ that's what I'd like to know too. 13# with an xp cam, must be like 3"? Not that I know much about the gen v though.

Damnit, you just said you don't even look at boost, now you notice a 4 psi change just from weather!?

Originally Posted by 99GT2dr

Damnit, you just said you don't even look at boost, now you notice a 4 psi change just from weather!?

Lol