E85 vs 93 vs Spark vs Boost
Thread Starter
Joined: Sep 2007
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From: Texas Hill Country
E85 vs 93 vs Spark vs Boost What will make more power assuming E85 maxes out the fuel system:
E85 at 9psi and 15 degrees of spark timing
or
93 at 12 psi and however much timing it could take...7 or 8 or whatever.
Basically, if I am fuel capacity limited on E85 (and more fuel is not an option at this time) is it better to stay on E85 or move to 93 for more headroom?
E85 at 9psi and 15 degrees of spark timing
or
93 at 12 psi and however much timing it could take...7 or 8 or whatever.
Basically, if I am fuel capacity limited on E85 (and more fuel is not an option at this time) is it better to stay on E85 or move to 93 for more headroom?
Thread Starter
Joined: Sep 2007
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From: Texas Hill Country
It's hypothetical. Maybe E85 will take more than 15 as well?
Let's call the setup a 416ci that makes 550rwhp NA. We will put on a D1SC or F1A supercharger at 9 or 10 psi and make 715rwhp on E85, whatever the timing. Will I make more power on 93 and more boost/corresponding timing or E85 and less boost/corresponding timing, all else equal?
Remember, E85 will max out the fuel system, 93 still has 30% more headroom for fuel, which I would max out by applying more boost.
Let's call the setup a 416ci that makes 550rwhp NA. We will put on a D1SC or F1A supercharger at 9 or 10 psi and make 715rwhp on E85, whatever the timing. Will I make more power on 93 and more boost/corresponding timing or E85 and less boost/corresponding timing, all else equal?
Remember, E85 will max out the fuel system, 93 still has 30% more headroom for fuel, which I would max out by applying more boost.
Thread Starter
Joined: Sep 2007
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From: Texas Hill Country
This is going on a 12:1 416ci engine..... How much power did you guys put down with those setups?
I am thinking my fuel system (direct injection so no upgrade right now) will be maxed on E85 around 715-725 rwhp..... I am trying to figure out if I will make more or less on 93 since I will have more fuel (and therefore potential for more air) but less resistance to detonation and a hotter combustion temp.
I am thinking my fuel system (direct injection so no upgrade right now) will be maxed on E85 around 715-725 rwhp..... I am trying to figure out if I will make more or less on 93 since I will have more fuel (and therefore potential for more air) but less resistance to detonation and a hotter combustion temp.
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Thread Starter
Joined: Sep 2007
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From: Texas Hill Country
So does it sound right to just size the head unit according to how much airflow my fuel system will support then?
D1SC or F1A or?? Any recommendations? My only requirement is a self contained head unit.
D1SC or F1A or?? Any recommendations? My only requirement is a self contained head unit.
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That’s a really high SCR. I wouldn’t trust pump on it NA. Even on E85 you’re pushing it. Either run race gas so your fuel system can keep up, or upgrade the fuel system.
Get the biggest blower your class allows. It will heat the air charge the least per pound.
Get the biggest blower your class allows. It will heat the air charge the least per pound.
Thread Starter
Joined: Sep 2007
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From: Texas Hill Country
This is just a street car, for fun. There are no upgrades to the DI fuel systems available yet, which is why that's a constraint. I am going to use a high pressure pump from a Z06 and a lash cap to get it to open more, Z06 injectors, and command more rail fuel pressure to get the most out of it, I just don't know where I will be at the end.
What are we working on? There are a lot of things that can be done tune wise with E85 to get further. I was on stock pump, stock cams, stock di injectors in my cobalt at 500 whp. However that was only 110 oct. On the same set up with e85 I could only manage in the 430 whp range we figured, never dynoed that set up.
Thread Starter
Joined: Sep 2007
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From: Texas Hill Country
Direct injection 416ci small cam C7 with all supporting mods, 12:1 compression, long tubes, worked heads, etc. Direct injection really mitigates concerns over compression.
Going to add either a D1SC or F1A. Not sure if I should run 93 or E85 or something in between because I can't just add aftermarket fuel system parts as there are none available.
My stock fuel system is basically maxed on E85 NA at 550 whp. I can swap for the Z06 HPFP and a lash cap, injectors and pick up about 30-35% more fuel. regardless of what blower I run, I am going to do this anyways. So does that give me 30% more air flow capability or 30% more horsepower capability? Because that would be 715rwhp.
Or will I make more power with 93 octane because I will have a lot more fuel available?
DI boosted motors are safe in the 12.25 - 12.5 range. Just not sure about the blower choice and spark timing differences.
It's been recommended to run a mix around E50 and I will get 90% of the E85 gains and still retain fuel headroom....
Ideal goal is around 850 rwhp if I have the fuel for it. It's either 93 or E85 or something in between.....no race gas, no meth system. This is a street car.
Otherwise, if it's a total lost cause, I will just spray it but that's such a pita.
Going to add either a D1SC or F1A. Not sure if I should run 93 or E85 or something in between because I can't just add aftermarket fuel system parts as there are none available.
My stock fuel system is basically maxed on E85 NA at 550 whp. I can swap for the Z06 HPFP and a lash cap, injectors and pick up about 30-35% more fuel. regardless of what blower I run, I am going to do this anyways. So does that give me 30% more air flow capability or 30% more horsepower capability? Because that would be 715rwhp.
Or will I make more power with 93 octane because I will have a lot more fuel available?
DI boosted motors are safe in the 12.25 - 12.5 range. Just not sure about the blower choice and spark timing differences.
It's been recommended to run a mix around E50 and I will get 90% of the E85 gains and still retain fuel headroom....
Ideal goal is around 850 rwhp if I have the fuel for it. It's either 93 or E85 or something in between.....no race gas, no meth system. This is a street car.
Otherwise, if it's a total lost cause, I will just spray it but that's such a pita.
Thread Starter
Joined: Sep 2007
Posts: 367
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From: Texas Hill Country
It sounds like maybe a blower is not the right thing for this one.
DI doesn't get rid of the octane concerns at all. Sure it helps but it will still be very evident you are going to be severely octane limited on pump. This motor sounds like it's not even built yet, why are you going so high on the compression with boost?
I've tuned a bunch of supercharged C7s at this point and the ones with lower compression are MUCH happier with limited octane and make more power in the process.
I've tuned a bunch of supercharged C7s at this point and the ones with lower compression are MUCH happier with limited octane and make more power in the process.
Fill this up with M1 and problem solved, plus it helps crutch your crippled fuel system.
http://www.alcoholinjectionsystems.c...roducts_id=101
Thread Starter
Joined: Sep 2007
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From: Texas Hill Country
You quoted me saying it is not a daily driver, so you are correct when you say it doesn't sound like it's a daily driver. ;-)
I don't want to add meth or a boost a pump, etc. I am ok replacing parts but I do not want to add anything to the "system." I didn't mean to imply a meth system makes it "not a street car." The sentences are next to each other in my post, thats all.
Is it ok if we move on? What will be the best blower for this motor between an F1A and the D1SC?
I don't want to add meth or a boost a pump, etc. I am ok replacing parts but I do not want to add anything to the "system." I didn't mean to imply a meth system makes it "not a street car." The sentences are next to each other in my post, thats all.
Is it ok if we move on? What will be the best blower for this motor between an F1A and the D1SC?