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10.8:1 Crossy E85

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I know the topic has been touched on before, but has anyone done the conversion from ULP to E85 on a relatively high comp crossy?
The benefits of ethanol have been proven for boosted applications, but what are the opinions on cost vs. gains on an aspirated solid cammed crossy?

 

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I haven't done it but pretty sure having spoken to a few people that the benefits are all definitely all there. You won't see the same huge advantages in boosted applications but nat asp it would still be all positives. The much higher octane rating alone and the huge knock resistance will allow you to dial in a lot more timing which crossflows respond very well too. There are heaps of benefits, there will probably be others than can give you a much more in depth explanation but yeah. Mines pretty high comp (around 12:1) and i run on 98 + octane boosted to 100 (wish i didn't go flat tops but oh well all done now) which means i have always struggled with pinging and timing, but last week managed to get it on a dyno to check all the A/F ratios and all. Moved the base timing from around 7-8 degrees (hard to tell exactly) to 10 degrees, so around a 2-3 degree shift. It picked up 4rwhp peak and shifted it slightly earlier in the rev range, but more importantantly it picked up an average of around 26rwhp throughout the good part of rev range before tapering off. This was the only movement in timing i did and stopped there because it was the first time the car had actually been working in like 2 years so i left with a smile haha! (Definitely a lot more in it just wasn't up for exploring it on that day, 10 minutes on and off the dyno)

 

So with E85, on a high comp motor like yours as well, i reckon the extra head room from the higher octane rating alone would allow you to muck around with the timing in small increments and see pretty noticeable gains i would think. Just from my experience tho hope some of the others can add as well should be a good thread!

 

Michael

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10.8:1 is up there that is for sure and E85 would love that sort of comp.  You will gain more torque than HP by converting to e85 and that is important.  Torque will make more HP but the main thing is that it will give you more seat of the pants oomph. 

 

Just be careful with the timing on e85 with high compression.  Make sure both your AFR's and EGT's are at target, the second being more important that the 1st IMHO before you chase timing.  

 

But I would go for it.  I see e85 as the future in high performance, street applications, maybe not justifiable for an everyday street car but for a seldom used weekend warrior - I'd go for it. 

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the variance in '98' is the problem and also to a certain extent the 'booster'.  e85 is an alcohol based fuel so its burn time is different to petrol and allows for timing changes designed to make torque etc.  You just can't do that with a 98 type fuel, It will not take the comp as well as the e85 and will not have the cooling ability of the slower burning fuel. 

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