OK, I'm thinking of making the move to E85. The new motor will be high compression, and it will force me to race gas, or E85. I'd like this thread to be based on fact (you can back up what you are posting), or personal experience. I already know fuel requirements will increase 30-40%, so I'll need bigger injectors and a bigger pump. I currently run 24 lb injectors with a 190 lph fuel pump. I figure the new motor to put down around 325-335 RWHP, so I need some opinions on injectors (I'm thinking 42 lb) and fuel pump (biggest in tank stock replacement available is a 255 lph). Paging Donnie Bowles!!
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Leaving all my opinions out of this...
You already know the BTU's are down in E85 vs. gasoline (hence the need to supply more fuel).
You probably only need something from low 30's (under 34# if you do the math on the very conservative side) injector-wise at normal low fuel pressure, but 42's are very cheap, so they're "fine." That's 75% more injector than you currently run. 255lph pumps are cheap, too. That's plenty of pump for it by rough calculation I did.
Now, the interesting part would be to experiment more with jacking rail pressure and running smaller injectors to see if this increases output with your combination. That's the case with any application, really. High pressures and interesting atomization gains don't get a lot of thought, but when you're looking for every last ounce...
There are lots of little things like that you can do once you have it together...
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I have the 39# injectors in my car with a stock '99 cobra motor. Mine have four spray holes, I believe. I haven't had any problems with low duty cycle. I also have fuel taken out of the tune for higher fuel pressure (further decreasing duty cycle). Ran these in my pure street engine as well. On the dyno with that engine I increased the fuel pressure in 5 psi increments and saw a slight increase in HP. Keep in mind, duty cycle is also a function of RPMs. If you are going to increase your engine speed you have less time to inject the same amount of fuel. One of my friends switched his car to E85 and picked up a little over tenth. He has ran it for over a year now. likes everything about it but the mileage
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this is from another member in the same discussion.....
Well, hope this helps you out. I have driven my convertible 600 hp on the street with E85 for 2 years now. Did the initial tune on the street with my wide band, before I bought my dyno and perfected the tune. I have tuned several other's cars on E85 as well. Different combos from stock 96 GT's with PI heads and intake to full out supercharged 3V. What it boils down to is this, unless you need 105+ octane, you won't see any benefits from E85.
Now, you said the magic word, compression, a high compression engine can take full advantage of alcohols oxidizing and cooling effects. It works really well at inhibiting detonation and making smooth, reliable power. But compression is the key. Either that or boost.
As for your fuel requirements, I make 600 hp with 60lb injectors, they are working fine, I have twin walbro inline pumps pumping through -8 up to the engine and then -6 back, but using a -10 feed line. Before that, I used a GSS340 intank fuel pump and a booster inline pump, but the engine ran out of fuel at 4500 rpm's. The new system feeds it fine. The point is, if my old stock rails and piggy back set up could support the 450 odd hp it was making below those rpm's and mine is boosted to boot, your single GSS340 should be good to go even with the increased demand of E85.
On to the next question, you don't need more than 25% more fuel capacity for your system. I would say 30's would be sufficient imho, and in reality be more than you need still. There are a lot of myths about E85 out there, and one is the amount of increased fuel demand load on the system. It's not that much. I think most of the cars iirc were between 17 and 20% increase in fuel delivery to get the a/f ratio good.
Which brings me to another point, the target a/f. You will read about different 'stoichs' for E85 on the internet. Well, since the dyno and wide band you are using will be cal'd for gasoline, you tune it to the same a/f ratio your car made peak power at, on gasoline. the reading is just the computer's interpretation of the O2's readings, stoich is stoich in lamda. O2's read lamda. So tune to the a/f ratio that made the most power before and then try a little leaner and a little richer to see what your cam/compression/head combo likes best.
As for the 'corrosiveness' of E85, also bs. Have not had ONE problem with my car that was fuel related, and not really had any 'problems' out of it since I put it together.
Spark plug gap. You've heard guys talk that run nitrous about closing up the gaps on their plugs, and boosted guys say the same thing. Well the reason for that is the dense fuel charge that comes into the cylinder, it is hard to fire by jumping a wide plug gap, and the spark can get extinguished or snuffed before it even starts. So it is with E85, you will be pushing 20% roughly more fuel into the same air, and it's similar to the same problems nitrous and boosted cars experience, so tighten up the gaps, you'll know when it's right because you will no longer have flame blow out at higher rpm's.
If you have any other questions, I get on here from time to time, and I'd be happy to answer them. I am also building a purpose built car specifically for going very fast with E85, yet still be street friendly and fun.
Hope this helps.
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Got my Quick Fuel E-85 tester the other day. I went and bought 1 gallon of E-85 today so I could test it. The Ethenol content was 88%...or E-88! So much for the winter/summer blend stuff in this area! Anyone have a clean fuel drum? The odd thing was the price...$2.41 a gallon, same as 87 octane. The winter blend is supposed to have more gas in it for easier starting, so you'd think summer blend would be cheaper since it has less gasoline?
