E85 fuel pump question

[racer35]

Hey guys.. Heres what i have. A na ka24de circle track race car..One 9.8 engine,one 11:5 compression engine,
Both have bc stage 2 cams
Both 4:1 header
2.5 straight through spiral muffler(mandatory)
Stock maf rule
Stock injectors
Underdrive pulleys
Stock auto ecu for the 9.8:1 engine
Jwt ecu for the 11.5:1 ( must use stock style ecu rule)
11lb flywheel
Roughly racing from 4000-6600 rpms


I currently run 110 octane sunoco race fuel on both engines but i have a set of sr 370cc injectors and i wanna try the e85 on a practice day this week. I currently have a stock fuel pump and was wondering if i needed to upgrade to a walbro 255 or should my pump be sufficent for what i wanna try doing?

[Chris28]

You'd probably fine just testing with the stock fuel pump, but if you plan to stay e85 you should probably upgrade. You might even want to upgrade anyways since you're running high compression.

I would call jwt and order an e85 specific tune so you can swap chips when you swap fuel. Chances are if you just swap injectors and try to run e85 you will lose some power.

[racer35]

Thanks.. How bout if i switch and bump the timing up quite a bit with it? On these circle track cars ill take the measly 3,4,5hp,or whatever it may be for a gain(if there is one) no care of fuel consumption here. Lol. But if u think theres nothing to be had with it, with what im doing then maybe im wasting my time

[Chris28]

Ehhh I wouldn't recommend it. The increased timing might offset the little bit richer you will run with the larger injectors and e85, but just bumping up your timing via the dizzy is pretty risky. I'd call up JWT and explain what you want to do, chances are he can tune for e85 and will be able to get you noticeable gains with a new tune.

[Croustibat]

Originally Posted by Chris28

[...] Chances are if you just swap injectors and try to run e85 you will lose some power.

Not just "chances", it wont run at all. e85 needs more fuel and a different timing. If you get really lucky, you could find injectors that compensate exactly for the fuel requirement difference for a given rpm range, but thats it. And timing will be way off.

Originally Posted by racer35

Thanks.. How bout if i switch and bump the timing up quite a bit with it? On these circle track cars ill take the measly 3,4,5hp,or whatever it may be for a gain(if there is one) no care of fuel consumption here. Lol. But if u think theres nothing to be had with it, with what im doing then maybe im wasting my time

e85 is a major gain on turbo cars over standard pump fuel for 2 reasons:
1/it has 104 octane
2/it is alcohol based, and alcohol based fuel tend to absorb more heat when vaporising, so it also cools the engine better.

If your 110 octane fuel is not based on alcohol, switching to e85 will help cooling, but will not add power... except if your engine reach the temperature where tuner pulls timing.

There is something i dont understand though ... you are running a mail order tune ? If so get that car tuned on a dyno, and you will get the power gain you are looking for.

You also dont need to change your ECU for that, just get a nistune, put it in the socket your ECU already have, tune or have the car tuned, and then either keep the nistune or have the maps burnt on an eprom and put it on the socket. If you can find a tuner that use a nistune, you wont even have to buy one, he will put his in the car, do the job and then burn the maps on eprom.

As far as timing goes, e85 require a real timing change, not just an offset. Basically you have to add quite a lot of timing at low and high load, but not so much at maximum VE efficiency.

Anothing thing you have to account for is that e85 is detergent (not corrosive), meaning it will clean your fuel system and engine thoroughly. The problem is that it will clog your fuel filter VERY FAST while doing so. when i switched, i clogged it twice, first time after roughly 300 miles, second time after 1500 miles. After that it was ok.

[Drift_FX]

one doesn't simply try E85.... you either do it or not....

[Chris28]

Originally Posted by Croustibat

Not just "chances", it wont run at all. e85 needs more fuel and a different timing. If you get really lucky, you could find injectors that compensate exactly for the fuel requirement difference for a given rpm range, but thats it. And timing will be way off.



e85 is a major gain on turbo cars over standard pump fuel for 2 reasons:
1/it has 104 octane
2/it is alcohol based, and alcohol based fuel tend to absorb more heat when vaporising, so it also cools the engine better.

If your 110 octane fuel is not based on alcohol, switching to e85 will help cooling, but will not add power... except if your engine reach the temperature where tuner pulls timing.

There is something i dont understand though ... you are running a mail order tune ? If so get that car tuned on a dyno, and you will get the power gain you are looking for.

You also dont need to change your ECU for that, just get a nistune, put it in the socket your ECU already have, tune or have the car tuned, and then either keep the nistune or have the maps burnt on an eprom and put it on the socket. If you can find a tuner that use a nistune, you wont even have to buy one, he will put his in the car, do the job and then burn the maps on eprom.

As far as timing goes, e85 require a real timing change, not just an offset. Basically you have to add quite a lot of timing at low and high load, but not so much at maximum VE efficiency.

Anothing thing you have to account for is that e85 is detergent (not corrosive), meaning it will clean your fuel system and engine thoroughly. The problem is that it will clog your fuel filter VERY FAST while doing so. when i switched, i clogged it twice, first time after roughly 300 miles, second time after 1500 miles. After that it was ok.

e85 uses roughly 30% more fuel than gasoline, so if he's running stock KA injectors the SR 370's are pretty close to 30% bigger.

But yeah, everything else is right. If you want to run e85 you're going to need a lot of groundwork to get it set up properly.

[racer35]

Thanks for the input guys.. I really appreciate it. I think wit what ya said i dont have really much to gain with my mild na application so ill just hold off