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e85 guys...

gtpsleeper

gtpsleeper

New member
alright.... after messing with the tune for a while now and doing some reading on e85, im wondering if its better to run a richer mixture even if your not knocking? I haven been able to get on a dyno (and butt dyno cant tell) for any type of proof or anything but after some reading, its lookin like leaner is not necissarily meaner when it comes to this stuff...

any input?
 


ethanol has dimishing gains, but never gets to a point where it makes less power from being too rich. the more you can burn the more power you can make. you can run it down to like 7.0:1 and still be making fantastic power.
 
right, but can the same be said for leaner bio?

im running 20* of timing WOT and can run 13.0 : 1 withought seeing KR (do I? no...).... Im just wondering how lean you can run to where your not losing power if that makes since?
 
the theory behind a motor (even power adders) is that the more fuel you can burn the more power you can make. it is a physical property and will always be there. i have no doubt that the more fuel you (PROPERLY) burn, the more power you'll make. leaner is better in most cases because in most cases you arent burning ALL of the fuel properly that you are using. leaner is meaner in most cases because you physically CANNOT burn all of the fuel properly. this is where ignition systems come into play and what not.

the only way for you to figure out what you want to run for your AFR and see how it reacts is to play with it.
 


We should clarify on the a/f ratios for any future readers as well, in short we do not convert all the tables in the pcm to run ethanol AFR's, we add ~30% fuel to the injector or IFR table so we don't have to switch the AFR's to ethanol, so 14.7 gas afr we are reading is really a 9.76 (85% ethanol stoich afr) 11.5 gas afr is 7.5 e85. You can figure it out by taking gas afr/1.5 = e85 afr. Or switching your wideband to lambda, everything is = 1.0 stoich. This may differ in winter blends, next point...

One of the reasons why you may not want to go too lean is because the mixture in the full summer blend is 85% ethanol + 15% 87 octane =109 Octane is different than the winter blend which is 70% ethanol + 30% 87 octane = 105 octane. You will run .5 - 1.0 leaner reading in gas AFR in the summer than the winter if tune is unchanged, they also gradually change blends in the spring in fall. For that fact you may want to stick with a 11.5 summer tune and run richer or retune in the winter.

All in all, there are guys out there running high timing and in the 12.5+ afrs who say they are making more power, but while you don't see knock you also aren't keeping track of egt's, cylinder pressures, etc. E85 basically "can" free you of knock, but it can't completely free you of head gasket failures/engine problems. It's very forgiving fuel, but i don't see the point of running on the edge to squeeze that extra 10hp out while the a/c is still functional.
 
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ya thats true alot of people do forget that just because your not knocking doesn mean your not doing damage either...

while I have a few of you in here have you guys used Tiny Tuner at all with the HPT? (dont feel like making another thread...)
 
eh i need to just pony up and get on a dyno... itd be alot more accurate than the track cuz there wouldn be as many X factors
 


Actually...the only benefit from a dyno would be WOT settings. You need to just find a long ass back road and drive it at all throttle positions.

I know there are plenty in Kansas...since there is nothing there ;)
 
bluegtp91 said:
Actually...the only benefit from a dyno would be WOT settings. You need to just find a long ass back road and drive it at all throttle positions.

I know there are plenty in Kansas...since there is nothing there ;)
Click to expand...

the WOT settings is what i need :)

need to run some different mixtures to see what makes more powaa!!
 
gtpsleeper said:
eh i need to just pony up and get on a dyno... itd be alot more accurate than the track cuz there wouldn be as many X factors
Click to expand...


I get paid to tune on the dyno so I know what you mean. :th_winking:

I find my car is consistent enough to tune at the track. Also, much easier to tune at the track, since I rely on PE enrichment vs. Time.
 
jdmgtp said:
I get paid to tune on the dyno so I know what you mean. :th_winking:

I find my car is consistent enough to tune at the track. Also, much easier to tune at the track, since I rely on PE enrichment vs. Time.
Click to expand...

Never use the time function, its not needed anyway when you have access to RPM based PE.
 


I have to richen it up or it will knock. It allows me to run 22* and 11.5 off the line and richen up to 10.8 and 16* by redline in 2nd. I ran a [email protected] with a 2.07 60ft completely heat soaked. When I run constant timing and a/f ratio I run 4 tenths and 2mph slower.
 
It's pretty easy just make sure you have enough injector and tune. Also it's a good idea to change the fuel filter after a tank or two
 
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