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E85 vs 91octane; how much power is left on table with 91?

 
Old 04-23-2017, 09:19 AM
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Even at like timing and NA, e85 will make more power. Matt just posted a good example. Add the fact that you have roughly twice the knock threshold over 91 octane. It's pretty impressive stuff.

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Old 04-23-2017, 03:57 PM
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Originally Posted by BCNUL8R View Post
Long term goal is over 700 rwhp with auto trans and irs in a GTO. I can't get there all in one year financially. So trying to decide...procharger first on stock cam only motor or built motor first then boost later. I originally didn't like the idea of having a built motor with only 10:1 built for boost, but running NA for a year. If E85 will allow 11:1 and enough boost to get to 700+ rwhp safely and reliably that option looks a lot better.

E85 isn't a problem to get here in Iowa it's actually more readily available then 93 octane.
I'd put the blower on the stock motor now. See how you like it, work the bugs out. Then when you're ready, if you still decide you need more, put in the forged motor. I've always been told break in a motor how you plan to use it, so I don't typically like breaking in a motor NA and then a year or so later add boost.
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Old 04-24-2017, 03:57 AM
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Originally Posted by ddnspider View Post
I'd put the blower on the stock motor now. See how you like it, work the bugs out. Then when you're ready, if you still decide you need more, put in the forged motor. I've always been told break in a motor how you plan to use it, so I don't typically like breaking in a motor NA and then a year or so later add boost.
I'm kind of leaning that way now. Car only has 28,000 miles on it so I might as well use this stock bottom end as long as I can. Just make sure I have the cash for at least a forged 347 on hand in case.
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Old 04-24-2017, 07:07 AM
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Originally Posted by BCNUL8R View Post
I'm kind of leaning that way now. Car only has 28,000 miles on it so I might as well use this stock bottom end as long as I can. Just make sure I have the cash for at least a forged 347 on hand in case.
just make sure the tune is good and don't go overboard on power and it should last awhile.
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Old 04-25-2017, 04:11 AM
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Originally Posted by ddnspider View Post
just make sure the tune is good and don't go overboard on power and it should last awhile.
So in a procharged setup with stock bottom end which do you feel is better...figuring in cost, ease of use, and safety as far as making it last...

93 octane +meth

or

E85

?
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Old 04-25-2017, 06:44 AM
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Originally Posted by BCNUL8R View Post
So in a procharged setup with stock bottom end which do you feel is better...figuring in cost, ease of use, and safety as far as making it last...

93 octane +meth

or

E85

?
E85 all day long assuming you have it available. But if you're going to do that, do a good fuel system right from the start with room to grow. E85 needs larger injectors and pumps than a 93 octane setup.
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Old 04-25-2017, 11:25 AM
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This shed some light for me in a scientific/direct type of explanation.
https://www.6speedonline.com/forums/997-turbo-gt2/277040-hot-cold-e85-vs-gas-theoretical-analysis.html
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Old 04-26-2017, 10:40 AM
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Thank you for all the good info so far.

It sounds like mild gains just from fuel swap... but going to E85 allows major turn up on turbo. So potentially I'd leave a lot of power on the table.

I do have an E85 near by that won't do me any good on the trail but it was ~$1 cheaper than 91 octane per gallon.

Originally Posted by ddnspider View Post
E85 all day long assuming you have it available. But if you're going to do that, do a good fuel system right from the start with room to grow. E85 needs larger injectors and pumps than a 93 octane setup.
Would you clarify what a good fuel system would be? And what larger injectors would mean?

Currently, I've only got some injectors: Deka 80lb. Sufficient for my 500 to 600hp goal using E85?

I am going with a custom fuel tank and was planning on using the stock Camaro sending canister with different fuel pump.

Should I be going with 8an(1/2") line? Or is 6an(3/8") line sufficient?
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Old 04-26-2017, 11:48 AM
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Originally Posted by Lil'John View Post
Thank you for all the good info so far.

It sounds like mild gains just from fuel swap... but going to E85 allows major turn up on turbo. So potentially I'd leave a lot of power on the table.

I do have an E85 near by that won't do me any good on the trail but it was ~$1 cheaper than 91 octane per gallon.



Would you clarify what a good fuel system would be? And what larger injectors would mean?

Currently, I've only got some injectors: Deka 80lb. Sufficient for my 500 to 600hp goal using E85?

I am going with a custom fuel tank and was planning on using the stock Camaro sending canister with different fuel pump.

Should I be going with 8an(1/2") line? Or is 6an(3/8") line sufficient?
There are plenty of people who know better about E85 and whats acceptable based on goals. I just know it requires significantly more fuel and in some instances, E85 tolerance stuff like fuel pump. If your end goal is 700-750rwhp I don't believe 80lb injectors will suffice.
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Old 04-26-2017, 01:10 PM
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On YB there are plenty of guys running 80 lbs. injectors and well over 700rwhp at above 100% duty cycle. There is an entire thread you can read to but I think I will get flagged if I post the link. Type in E85 and 80 lbs...should be one of the first threads.
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Old 04-26-2017, 01:14 PM
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Originally Posted by 2muchboostNY View Post
On YB there are plenty of guys running 80 lbs. injectors and well over 700rwhp at above 100% duty cycle. There is an entire thread you can read to but I think I will get flagged if I post the link. Type in E85 and 80 lbs...should be one of the first threads.
A) over 100% DC isn't physically possible despite what their PCM tells them.
B) its a terrible idea running a DC that high.
The whole point is to do it right the first time and get a pump and injectors that will comfortably support the end goal instead of having to rebuy halfway through.
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Old 04-26-2017, 01:41 PM
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Since ~e50 provides approx 99% of the benefits of E85, why not just run that and not run bigger injectors and fuel pumps/lines etc??

Is achieving e50 just a matter of mixing premium fuel and whatever "E" is available??
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Old 04-26-2017, 01:46 PM
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Or mix 50% pump with same amount of E100

I know guys who've used regular ethanol for heating purposes as their base fuel, because race versions of ethanol cost a fortune and it isnt available at any pumps where they live.
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Old 04-26-2017, 02:39 PM
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My point is that for 500-600 rwhp with those Deka 80 lbs. there shouldnt be too much concern. I understand what you are saying about running a setup safely but those guys are running some capable pumps and pushing the injectors to their capacity above 700hp. And from what I can tell, there werent too many negative comments running them to the 700hp+ mark, which again...is above the power the OP was looking to extract.

So again, if there are quite a number of guys pushing those 80 lbs. well above the OP's goals then why be concerned? As noted, a proper pump, fuel system components, and tune would be needed but the injectors themselves are capable at his power goals. In post #28 OP mentions 500-600 hp not 700-750 hp. I have seen threads about twin 255's + stock lines + E85 & 80 lbs. making 600 hp....just saying.
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Old 04-26-2017, 03:03 PM
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Originally Posted by 69-chvl View Post
Since ~e50 provides approx 99% of the benefits of E85, why not just run that and not run bigger injectors and fuel pumps/lines etc??

Is achieving e50 just a matter of mixing premium fuel and whatever "E" is available??
Yes, the ratio is of E85 to E10 (most pumps fuels) is roughly 3:2 respectifully. 3 gallons of E85 to 2 gallons of 91,92 or 93 pump would give you E55. Obviously just multiply for larger quantities. Just easy math.
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Old 04-26-2017, 08:44 PM
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Originally Posted by 2muchboostNY View Post
My point is that for 500-600 rwhp with those Deka 80 lbs. there shouldnt be too much concern. I understand what you are saying about running a setup safely but those guys are running some capable pumps and pushing the injectors to their capacity above 700hp. And from what I can tell, there werent too many negative comments running them to the 700hp+ mark, which again...is above the power the OP was looking to extract.

So again, if there are quite a number of guys pushing those 80 lbs. well above the OP's goals then why be concerned? As noted, a proper pump, fuel system components, and tune would be needed but the injectors themselves are capable at his power goals. In post #28 OP mentions 500-600 hp not 700-750 hp. I have seen threads about twin 255's + stock lines + E85 & 80 lbs. making 600 hp....just saying.
so again....so again.....and my point is if the end goal is 700+rwhp than buying injectors that are good for 5-600rwhp doesn't really mean anything. On top of the fact that you mention in your 1st post that they're over 100% DC but now that no one complains and it's fine? There's plenty of calculators online that let you figure out injector size for E85 based on hp, bsfc, and DC. 900hp with a 20% driveline loss is 720rwhp. Seconds of using that calculator and it shows you need a little over 100lb/hr fuel injectors at 80% DC which is typically the max people recommend. Plenty go above, but that's generally accepted. What happens if we want 750rwhp???

And please read post 12 from the OP about goals. 5-600rw is the interim goal, not the final.
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Old 04-26-2017, 08:50 PM
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Originally Posted by ddnspider View Post
And please read post 12 from the OP about goals. 5-600rw is the interim goal, not the final.
I'm the OP... post 12 is not by me

My goal is 500 to 600hp or push it to find the limit then back the tune off 10% or so to be extra safe. No race conditions, no dyno dick comparison numbers.
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Old 04-26-2017, 09:41 PM
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Originally Posted by Lil'John View Post
I'm the OP... post 12 is not by me

My goal is 500 to 600hp or push it to find the limit then back the tune off 10% or so to be extra safe. No race conditions, no dyno dick comparison numbers.
there is a lot less hassle to running a shot of meth than to deal with E85 at 500-600bhp. Keeping 93 will allow you to keep fuel economy reasonable as well. That power range is practically stock engine territory. A 3000lb vehicle with 500 to the wheel on 93 + meth should also put down 27-30mpg using an overdrive transmission. E85 isn't going to touch that economy, even if it is a 'better' fuel alternative (higher quality fuel). You can drive it around at 400rwhp~ without the meth activating to conserve it, with a stock engine.
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Old 04-27-2017, 06:42 AM
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Originally Posted by Lil'John View Post
I'm the OP... post 12 is not by me

My goal is 500 to 600hp or push it to find the limit then back the tune off 10% or so to be extra safe. No race conditions, no dyno dick comparison numbers.
Youre completely right. You made the original post and then BCNUL8R jumped in asking about his setup so it was a response to his goals which were 700rwhp through an A4.
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Old 04-27-2017, 07:52 PM
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Originally Posted by Lil'John View Post
I'm the OP... post 12 is not by me

My goal is 500 to 600hp or push it to find the limit then back the tune off 10% or so to be extra safe. No race conditions, no dyno dick comparison numbers.
91 octane has supported 600+ rwhp for a while, no need for E85 or meth in your case.

E85 allows more boost and timing along with a larger tuning window but your goals are far below that need.

Don't listen to the guy saying boost is boost when he doesn't run E. When you want big power then you make the jump.
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