100 octance to e85...how big injector needed?

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Old May 22, 2011 | 06:36 PM
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Y2K Si FBP's Avatar
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Default 100 octance to e85...how big injector needed?

made 237 whp (dyno dynamics) on 100 octane (no tune on pump gas)

fuel system consists of the following:

dual walbro 255 pumps
precision 525 cc injectors
golden eagle fuel rail
full fuel lines -8 for a feed and -6 for return
tuned for a base 65 psi

tuned by hondata s300...i dont have it avail to me at the moment to see duty cycle.

just wondering if i have enough injector or need larger injectors to switch to e85.


thanks in advance! any help appreciated!
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Old May 22, 2011 | 06:47 PM
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Default Re: 100 octance to e85...how big injector needed?

I am no expert on this, but a buddy of mine had to up the size of his injectors when making his switch. Forgive me for not remembering the exact size he needed. but as i have been reading that a "simple" calculation would be to multiply your current injector size by 1.47

This was done by multiplying the lb/hour by 1.74

So your calculation would be 50 lb/hr for your current 525cc injector multiplied by 1.47 which would equal 770cc injectors. Please note that this is what i found in a little bit of research. You still will want to consult with your tuner.

Based on your dual pumps, i would say that you are covered in that area. That should be more than enough to keep lph good.
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Old May 22, 2011 | 06:56 PM
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Default Re: 100 octance to e85...how big injector needed?

depends on how much power you want to wind up making
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Old May 22, 2011 | 07:00 PM
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Default Re: 100 octance to e85...how big injector needed?

Originally Posted by sanman000719
depends on how much power you want to wind up making
This is also true.
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Old May 22, 2011 | 07:15 PM
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Default Re: 100 octance to e85...how big injector needed?

you need 30% more fuel when using e85 to make the same power. so depending on your injector duty cycle now you can get an idea of how much more they got in them.
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Old May 22, 2011 | 07:35 PM
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Y2K Si FBP's Avatar
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Default Re: 100 octance to e85...how big injector needed?

Not looking to change any other variables at this time other than tuning for the switch in fuel...Just whatever the gain is

From 100 octane to e85...motor is n/a

If my 525s are big enough I'm leaving the setup as is...

Right now 100 octane is 6.99 a gallon. If I can gain a few % in power and save a few dollars a gallon (yeah I know e85 uses more fuel) I'm happy
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Old May 22, 2011 | 08:21 PM
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Default Re: 100 octance to e85...how big injector needed?

E85 does require more fuel.
On dsm's I did around 250 to the wheels those are 450's I think.
I would switch to e85 and get some bigger injectors just to be safe. It reduces knock also and is rated at 105 octane so theres benifits all over. The only downside is if its available at more than one station in your area. Theres only two in mine at about 35 miles both ways from me. But nothing a 10 gallon gas can cant fix.
Also I wouldnt take knownworldwide's advice I read a couple of his post and decided not to read em anymore see what im gettin at
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Old May 22, 2011 | 08:33 PM
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Default Re: 100 octance to e85...how big injector needed?

Go with ID725cc's
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Old May 22, 2011 | 09:16 PM
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Default Re: 100 octance to e85...how big injector needed?

Originally Posted by turbohatch96y7
E85 does require more fuel.
On dsm's I did around 250 to the wheels those are 450's I think.
I would switch to e85 and get some bigger injectors just to be safe. It reduces knock also and is rated at 105 octane so theres benifits all over. The only downside is if its available at more than one station in your area. Theres only two in mine at about 35 miles both ways from me. But nothing a 10 gallon gas can cant fix.
Also I wouldnt take knownworldwide's advice I read a couple of his post and decided not to read em anymore see what im gettin at
Can the guy not research for himself and find out that it will require 30-40% increase in fuel? Yes he could have, as i stated im no expert and neither are you. Your "general" statement above, "i would switch to e85 and get some bigger injectors just to be safe." proves that you know just as much as i do. You did not give him a specific answer to his question. Any idiot could have posted that. You cant even remember what size injectors are on your own car! And were supposed to believe you? Uhhhh 450's.... I think! LOL.
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Old May 23, 2011 | 03:46 AM
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Default Re: 100 octance to e85...how big injector needed?

Go with ID725cc's

this sounds like solid advice to me
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Old May 23, 2011 | 05:08 AM
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Default Re: 100 octance to e85...how big injector needed?

Just a thought though. If you do upgrade your injectors don't limit yourself from furthur growth. If you see yourself boosting in the future you might as well go with 1000's or bigger depending on your HP goals. I'd hate to see you go to 750-770's then in 6 months from now needing to upgrade again. Everyone's build plans change. Again IMHO.

I was going to get tuned on E85 and my tuner said that I was fine with 440's with my setup. So I know it can be done with 440's+.

My Fuel setup:

Walbro 255
Stock injectors
AEM fuel rail
Pretty much the same fuel lines

Again my tuner just wanted me to upgrade my injectors. I was going to go 440's and he said that was fine I just decided to wait till I have the money for 1000's because I plan to boost.
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