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      01-15-2020, 01:02 PM   #30
ZM2
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Drives: 2017 LBB M2
Join Date: Mar 2017
Location: Baltimore

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Quote:
Originally Posted by F87source View Post
Honestly it's mostly trail and error when experimenting with ethanol mixtures, looking at logs and contrasting that with your goals. For example people who just need octane can expect to Max out ps2 with anywhere from E35-E50 depending on their altitude, iat's, mods etc and don't really need to exceed this. There have been users that have hit 700 whp on E50 when using the appropriate sized turbo and intercooler. So for those individuals there is no need to go pass E50 and worry about ethanol causing a lack of lubrication in the cylinders, fuel pumps, and possible drying out seals which generally gets worse past 50% concentration. However those of us who seek to use ethanol for it's evaporative cooling effect in reducing cylinder temps will want to run as much ethanol as possible to help the motor run cooler for track use. For example motoiq reported a drop of 20-30F (iirc) when using full e85 on both coolant and oil temps. But when using this concentration of ethanol you'll need a top cylinder lube like what power plus cells to keep ethanol from causing lubrication based issues. Of course a fuel stabilizer to prevent moisture from ending up in the ethanol is important too. For me I'm going to run full e85 especially since it's available at the pump now where I live.



Probably not the stage 1 turbo upgrades are already being pushed to the max even on pump gas. You'll likely be pushing the turbo out of it's efficiency range. You'll likely be able to run richer afrs though with an upgrade hpfp which is good. A really general idea to figure out if you're passing the efficiency range check the amount of power you gain with 1 psi increase vs. how much more the iat's spike. If iat starts to increase more than power you're starting to pass the efficiency range. Otherwise with full turbo upgrades they usually come with efficiency range charts. Altitude plays a huge roll too, the higher you are the harder your turbo has to work.



You'll probably be able to hit 500 whp on E35, and depending on your intercooler you may need a bit more in the summer when iat's spike.
Thanks.

Hearing all this, I’ll probably just run E47-48 (half E10, half E85) so I don’t have to constantly calc Emix amounts when filling up, or take extra lubrication precautions if using full E85. I know ethanol concentration varies in E85, so some safety would be baked into any custom tunes I do.

For now I’ll upgrade the HPFP and continue to run the BM3 Stg 2 E30 map with my Dinan turbo so I can run E47-48 year round.

Maybe later this year I’ll upgrade the turbo and then do a couple custom tunes: one for the street with max power and good for a few pulls, and one for the track that’s dialed back to help keep IATs in check.

It sounds like Dorch or Spool Stage 1 HPFP’s will be good enough for this plan, but if Stage 2 is only a couple hundred bucks more I’ll jump on one of those.