can you get away with a slightly larger turbo running e85?

[henschman]

I am shopping for a turbo right now, and i have found pretty good deals on a few. i basically want to get a turbo that will work well with the stock converter OR with the 2800 converter i have sitting around.

i am planning on switching my car to e85 as soon as i get it running again, and i was thinking that might factor into what turbo i should get. it seems to me that with e-85, you are putting more fuel and more air into the cylinders, so it makes sense to me that they would be moving more exhaust, so higher exhaust velocity, and could spool a turbo a little faster than a car burning gasoline. everybody that goes to e85 says it makes their car really torquey, too.

so has anybody noticed that they can build more boost/spool faster after going to e85? The turbos i am looking at right now are a gt3255, a ta49, and a pt51. What do you think would be the best on a stock converter car with e85?

 

[GNVYUS 1]

If you're going to run E85 and am concerned about power than don't bother with the stock or restalled stock converter, they totally suck and will hold you back.

The E85 will allow you to run more boost but it won't specifically help you spool up a T66 on a stock converter. Get a 3200 9.5 PTC or 5 Disc Precision and put whatever turbo you want on the GN and run big psi with big smiles.

BTW a couple people on here are running 28-29psi with E85 so think about selling both your converters so you can really wake up that beast with a big turbo.

 

[Hot Air]

Burning E85 will not impact the turbo selection to any measurable extent. Turbo selection is dependent on the size of the engine, the max rpm, and the hp to be made. The turbo moves the air, not the fuel. So, even though running E85 requires 25-30% more fuel, the turbo doesn't care.

As I have said before, run E85 if you need the additional octane (105) and/or want the additional charge cooling due to the higher latent heat of vaporization (i.e. - chemical intercooling). Don't run it because it is cheaper than high-test gas because you will have to burn 30% MORE E85 to get the same BTU's and the cost has to be 30% LESS than unleaded high test to break even.

If you have to run racing gas, E85 will probably be a bargain!

Conrad

 

[henschman]

this is a pure street car -- i don't want it to stall really high. and i'm not going to be able to afford to upgrade the injectors and pump for a while (i currently have 60 pounders and walbro 240) so i'll probably be talking about running 25 psi max for now on e85.

i am on a very limited budget right now, and i am just trying to get this thing running and make it a decently quick stock converter, daily driver capable car for now. i'm just buying a used turbo off the forums. Big plans like a built 4.1 and a BB turbo will come later (like maybe after i graduate law school!).

I know e85 won't magically make me able to brake boost a t66 on my stock motor or anything, but what i was wondering is if it would make a turbo that is normally slightly laggy on a stock converter, such as a pt-51, be able to work ok. what do you think? Everybody is reccomending i get a gt3255 for a stock or 2800 converter car, but I was wondering if the fact that I am going to be running e85 might change that any.

i have a pretty good deal lined up on a pt51, and i was trying to figure out if it would be laggy on my car or not once its switched to e85

 

[henschman]

Burning E85 will not impact the turbo selection to any measurable extent. Turbo selection is dependent on the size of the engine, the max rpm, and the hp to be made. The turbo moves the air, not the fuel. So, even though running E85 requires 25-30% more fuel, the turbo doesn't care.

As I have said before, run E85 if you need the additional octane (105) and/or want the additional charge cooling due to the higher latent heat of vaporization (i.e. - chemical intercooling). Don't run it because it is cheaper than high-test gas because you will have to burn 30% MORE E85 to get the same BTU's and the cost has to be 30% LESS than unleaded high test to break even.

If you have to run racing gas, E85 will probably be a bargain!

Conrad

but aren't you mainly thinking about the induction side of the turbo? i'm saying that if you are forcing more air and more fuel into your cylinders, like you do with e85, combustion pretty much has to produce more exhaust gas than gasoline would to achieve the same amount of power. more gas moving through the exhaust, hence through the turbine, would tend to spool the turbo faster than a gasoline motor would to my way of thinking. am i right?

yeah, i'm definitely not planning on going to e85 for fuel economy... the alternative for me would be running alky injection. i figure with the cost of the alky kit, the cost of the alcohol, and the pain in the ass factor of filling it all the time, plus the facts that i would probably be able to run more boost with e85 anyway and that e85 is almost as good if not as good of a deal as 91 octane (which is the highest you can get at the pump around here) switching to e85 would be worth it.

 

[Hotair85]

but aren't you mainly thinking about the induction side of the turbo? i'm saying that if you are forcing more air and more fuel into your cylinders, like you do with e85, combustion pretty much has to produce more exhaust gas than gasoline would to achieve the same amount of power. more gas moving through the exhaust, hence through the turbine, would tend to spool the turbo faster than a gasoline motor would to my way of thinking. am i right?

yeah, i'm definitely not planning on going to e85 for fuel economy... the alternative for me would be running alky injection. i figure with the cost of the alky kit, the cost of the alcohol, and the pain in the ass factor of filling it all the time, plus the facts that i would probably be able to run more boost with e85 anyway and that e85 is almost as good if not as good of a deal as 91 octane (which is the highest you can get at the pump around here) switching to e85 would be worth it.

OK here's my logic on all this, Dan-o. Not knowing a damn thing about E85, I would deduce that you need the 60lb injectors to achieve what, say, 30lb injectors or so would with gasoline. E85, I assume, burns a LOT cooler than gasoline. Hence the need for a bigger injector. You need more e85 crammed into the airstream to achieve the same result as less gasoline. I figure the main perk of E85, from these previous posts, is the cooling effect and NOT necessarily the fuel economy. Which is what I thought about it to begin with.

So yeah, you can run ungodly amounts of boost because of its cooling effect, but consider that you'll be using a LOT more fuel to get there. That's basically what Hot Air was trying to say, I think. Don't really sound practical for a daily driver to me, but I could be wrong. Others who know more than me (and I know nothing) will have to chime in to say if I'm right or not.

 

[henschman]

i'm not even concerned about the fuel economy issue at all. i'm just trying to figure out what turbo would be best for an e85 car with a stock converter.

i know that for people running regular gasoline, generally a gt3255 or a ta49 is best for the stock converter. But do you guys think a slightly larger turbo, like a pt51, would spool OK on an e85 car? i've heard its a bit laggy normally.

 

[Jerryl]

i'm not even concerned about the fuel economy issue at all. i'm just trying to figure out what turbo would be best for an e85 car with a stock converter.

i know that for people running regular gasoline, generally a gt3255 or a ta49 is best for the stock converter. But do you guys think a slightly larger turbo, like a pt51, would spool OK on an e85 car? i've heard its a bit laggy normally.

The answer is "Yes, it will spool faster" (in Theory)
Is the reduction in spool measurable? That my friend is the $1,000 question.

In my mind, "Lag" is a very relative term, and, the tune and condition of the combo / engine will make a BIG difference in spool.
The theory is correct, but there is only one way to determe if the "lag" is acceptable to you, on your car, on a given day (we know how much temp changes effect spool on these cars). :smile:

Edit;
The decrease in temps should produce more torque as well, so that is a nother factor of spool.
Again, maybe not measurable, but it will / should.