E10 and 0.87 Lambda
yea . . the scary thing is i had my original tune done on 91 lol and some other gases 93 still gets me knock lol
Well when I dynoed my car (had it 2-3 weeks) we found it was already tuned! The tuner (Church Automotive in So Cal) is familiar with the SS/TC and had just tuned one THAT MORNING (with mods on)! We found that it was pinging (he heard it) and right off he said *we need to take care of that*. The timing was too agressive (it was an AZ car..maybe that's why?) and he wanted to RICHEN it up too. So here's the before (GREEN) and after (BLUE) AFR's. You can see that he added torque and power lower down as well. Some hear think AFR's are too rich..well, the graphs speak for themselves. BTW it's 91 Octane out here.
If you are tuning a car with an egt gauge, leaning cars out to 12.5 is acceptable if that is where the car is making peak power and egt's are reasonable.
In most cases you will find a sweet spot of .5 to .75 of a point a/f that will achive peak power. I try to stay on the rich side of that sweet spot to keep egt's in check. In most cars I tune, I find this to be ~11.5-12.3 ish.
Here is a good example of how a .5 to .7 difference in AF makes no addtional power.....so why not stay on the rich side and be safer.
btw...this is an audi s4
http://www.6speedonline.com/forums/9...ml#post1063937
BYT already posted he made more power on the dyno at .88 lambda and my fastest 60-100 runs were on .88 lambda as well. Term2 also.
Some of us that can adjust our own tunes and log same will run what works best for us. If you want to stay with what you call safe, go with the tunes you wish. Personal preference.
My KR, plugs and times tell me what works for my fuel & engine.
Some of us that can adjust our own tunes and log same will run what works best for us. If you want to stay with what you call safe, go with the tunes you wish. Personal preference.
My KR, plugs and times tell me what works for my fuel & engine.
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Joined: 09-22-08
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From: Metro Detroit
Stoich actually has nothing to do with power, it is simply the ratio at which the fuel burns most completely. By running a richer fuel mixture the fuel burns faster which creates more power, but only to a certain point. Every car has a different AFR where they make the best power with ideal timing for that AFR and RPM. The LNF, being direct injection, can achieve a faster burn at a leaner AFR due to way it injects the fuel directly into the combustion chamber, while also achieving a better chemical cooling effect then typical port injected engines which also allows a leaner AFR to be run.
Makes sense you'd make more power, since I imagine you add fuel to lower the AFR, not reduce the amount of air.
I'm a little freaked out now. I usually alternate between Shell 91 (highest octane gas here at Shell here in Calgary) or I use 93 from Husky (but I know that stuff is blended with Ethanol) and when I was doing logs for Vince I would alternate between those two different gasolines. 
I'm a little freaked out now. I usually alternate between Shell 91 (highest octane gas here at Shell here in Calgary) or I use 93 from Husky (but I know that stuff is blended with Ethanol) and when I was doing logs for Vince I would alternate between those two different gasolines.
You are also not direct injected on an LSJ.
Last edited by Iam Broke; Jul 9, 2010 at 11:30 AM. Reason: Automerged Doublepost
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Joined: 02-09-09
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From: Tejas
I'm a little freaked out now. I usually alternate between Shell 91 (highest octane gas here at Shell here in Calgary) or I use 93 from Husky (but I know that stuff is blended with Ethanol) and when I was doing logs for Vince I would alternate between those two different gasolines.
Found this:
If you are tuning a car with an egt gauge, leaning cars out to 12.5 is acceptable if that is where the car is making peak power and egt's are reasonable.
In most cases you will find a sweet spot of .5 to .75 of a point a/f that will achive peak power. I try to stay on the rich side of that sweet spot to keep egt's in check. In most cars I tune, I find this to be ~11.5-12.3 ish.
Here is a good example of how a .5 to .7 difference in AF makes no addtional power.....so why not stay on the rich side and be safer.
btw...this is an audi s4
http://www.6speedonline.com/forums/9...ml#post1063937
If you are tuning a car with an egt gauge, leaning cars out to 12.5 is acceptable if that is where the car is making peak power and egt's are reasonable.
In most cases you will find a sweet spot of .5 to .75 of a point a/f that will achive peak power. I try to stay on the rich side of that sweet spot to keep egt's in check. In most cars I tune, I find this to be ~11.5-12.3 ish.
Here is a good example of how a .5 to .7 difference in AF makes no addtional power.....so why not stay on the rich side and be safer.
btw...this is an audi s4
http://www.6speedonline.com/forums/9...ml#post1063937
Quote "By virtue of better dispersion and homogeneity of the directly injected fuel, the cylinder and piston are cooled, thereby permitting higher compression ratios and more aggressive ignition timing, with resultant enhanced power output. More precise management of the fuel injection event also enables better control of emissions. Finally, the homogeneity of the fuel mixture allows for leaner air/fuel ratios..."
Hell, take a look at a GMS1 tune and see how GM runs .88 at 5k and .867 from there on out and that's with 20-21psi....
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Joined: 07-25-08
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From: Florida
This is also an apples to oranges comparison because there is quite a difference between SMPFI and GDI.
Quote "By virtue of better dispersion and homogeneity of the directly injected fuel, the cylinder and piston are cooled, thereby permitting higher compression ratios and more aggressive ignition timing, with resultant enhanced power output. More precise management of the fuel injection event also enables better control of emissions. Finally, the homogeneity of the fuel mixture allows for leaner air/fuel ratios..."
Hell, take a look at a GMS1 tune and see how GM runs .88 at 5k and .867 from there on out and that's with 20-21psi....
Quote "By virtue of better dispersion and homogeneity of the directly injected fuel, the cylinder and piston are cooled, thereby permitting higher compression ratios and more aggressive ignition timing, with resultant enhanced power output. More precise management of the fuel injection event also enables better control of emissions. Finally, the homogeneity of the fuel mixture allows for leaner air/fuel ratios..."
Hell, take a look at a GMS1 tune and see how GM runs .88 at 5k and .867 from there on out and that's with 20-21psi....
Well all I can say is that my motor was PINGING on the dyno (20-22Lbs WOT) with AFs in the mid 12s. Could have been aggressive timing as well, but we dialed more fuel for 11.5-12 AFR. Keep in mind, this is Ca 91 Octane!
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From: Still fixing others mistakes.
you can not blanket tune a car with someone else's suggest afr. it doesn't not work in your favor. ever. every car will want something different. end of discussion. period. every car will take a different timing curve as well. no 2 motors are exactly the same.
Yeah... I'm not that ballsy to run it that lean through the mid-range with 91 octane and 100+ degree temps. 
Not knocking you or your setup but for you to try and make a blanket statement about being "safe" with regard to .79-.8 lambda and then using a completely different platform/injection format to validate your blanket statement is mis-information.
Totally understood and I value your opinion/agree with you. But can you honestly say that a GDi motor will be "safer" @ 11.5ish AFR/.79 lambda?
Totally understood and I value your opinion/agree with you. But can you honestly say that a GDi motor will be "safer" @ 11.5ish AFR/.79 lambda?
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From: Still fixing others mistakes.
i am new to tuning but i am always using e10 so i want to change my stoich afr but keep my wot afr the same
will i need to change my setting in the pe table
like for wot you do 14.7/11.8 and you get 1.245
now will i need to do 14.13/11.8 and you get 1.197
will i need to change my setting in the pe table
like for wot you do 14.7/11.8 and you get 1.245
now will i need to do 14.13/11.8 and you get 1.197
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From: Tejas
If you're able to change the hardcoded 14.7 stoich to 14.13, you should be able to keep the 0.87 Lambda, and it would be correct for E10, since the Lambda would then be based off of the 14.13 stoich base.
I'm not sure if HPT has that capability though, or if you'd have to go in an manually make the adjustments. I don't think I've stumbled across that capability yet though on HPT. I'll have to look sometime.
I tried running .83 Lambda today just to compare, butt dyno feels no difference so far. I adjusted the trims at lunch and Im going to do a 60-100 on the way home just to see how it stacks up. My guess is it will be close whether slightly better or worse.
