E85 fueled L61 - Performance Forum

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E85 fueled L61
Sunday, September 30, 2018 12:54 PM
I've searched a read up on the topic, but I've got some variables that are a bit different.

First off, at risk of sounding like an old grouch, I don't want to hear the "ethanol is bad for the earth" or "you'll get worse milage". Save those for another thread.

This is for a circle track dirt car, 1/4 mile. Our rules are "100% absolutly positivly bone stock"...... Now hear me out - those rules have been bent and broken for years. One guy goes out and buys .456"/.453" 264°/268° 113°LSA cams, so does everyone else. One guy builds a LE5/L61 hybrid, so does everyone else. One guy gets a mail order tune, they all do.

Here is the parameters I work with. The car only runs in summer, so cold start isn't an issue. The car runs every week, one race at 10 laps, one race at 25. The track is a short /wide 1/4 mile (think ALMOST a circle). Coming out of the corners we are turning 5000RPM, fast roll onto the throttle to WOT, run up to 7000 - 7200RPM, and off throttle. Rinse lather repeat.

LE5 bottom end, balance deletes, Comp cams listed above, L61 head bone stock, L61 intake, ported stock exhaust manifold, mail order tune that's supposed to be for the above setup. Manual trans, lightened stock flywheel.

Yes, we'd love to run the LE5 intake. They look for it. We'd love to run a header. They look for it. And I'm well aware of the "turbo it" or "SC it" thoughts..... not gonna happen.

I recently purchased HP Tuners. Ive yet to write a file. Ive looked at my file, but havent done any flashing yet. As far as tuning, I'm a total newby. As far as theory of operation on ICE engines, I have more than enough knowledge.

Here's what I'm thinking. I want to switch to E85. At the same time, I want to have the head shaved. At the same time, I want to retard the cams.

If I retard the cams (I'm thinking either 7 or 14 degrees - each tooth is 7 degrees), I will lose bottom end, but gain top end. Let's leave the debate for retarding cams to another thread please. I just wanted to get it out there what we're doing.

If I shave the head, I'm bumping the compression. If I bump the compression, I risk knock. Hence E85. There's one competetor who has a head shaved at .040 aledgedly. I had HPT scanner hooked up, and no load reving it he has knock retard, so I believe he has a shaved head. Dont know if I believe .040. Yes, I'm aware this is an interference engine. It is my intention to clay a head @ 7 degrees and at 14 degrees to check for clearance. I intend on starting another thread for the head shaving, so i ask we keep the debate for that there.

As far as tuning, I do NOT have a dyno. But, I have a long open off street stretch I can simulate several laps on (5000-7200RPM pulls) and can tune off that.

Without buying $1000 injectors, is there a factory injector I can swap in? Obviously, high RPM/high volume demands of this application the stock injectors will not keep up.

Once my injectors are installed, will my factory fuel pump suffice? What is a good replacement?

Any other E85 suggestions?

Re: E85 fueled L61
Saturday, October 06, 2018 5:49 PM
Ok so to do E85 you need roughly 30% more fueling. Cobalt SS/SC stock injectors are 36lb, and the SS/SC stage 2 injectors are 42lb. Even without shaving the head and retarding the cams running E85 raises octane and should allow for more timing, timing can be power. Fuel pump will be on the limits. A few options for pumps which have been posted on here.

FU Tuning

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