Shitty Texas fuel!

[Dubstep Shep]

I've gained as much as 45rwhp peak and 75 in certain rpms going from 92 to e85 with nothing changed in the tune except for the fuel stoich.

Once the spark advance was increased it made even more power. It just doesn't seem to follow the "rules" of gasoline for an internal combustion engine.

Not sure I understand that first statement.

You're saying that with no changes other than the fuel, with each fuel running at stoichiometric you saw that increase in power?

Because every flex fuel vehicle I've ever seen bone stock OEM on the dyno makes less power on e85 than 91.

 

[BruceH]

Yes. The e85 base tune was nothing more than the 92 octane tune with the stoich changed to 9.8. Everything else being the same (supercharged Whipple) it made 575rwhp at 5700 rpms vs a peak of 53x at 6500 with 92.

The pull had to be stopped because the fuel system couldn't supply enough fuel. Once a bap was added max power with that setup was 599rwhp but that also included a spark advance of 23 degrees iirc. It's been about 4 years.

I have no idea what a flex fuel vehicle does for tuning or torque control. I have heard that most gm products gain torque with e85 but I haven't seen it first hand.

This is one of the facts that isn't really an apples to apples comparison. In order to get power and economy out of e85 it needs compression. An e85 specific motor will make a tremendous amount of power and have about the same mpg at 14.5:1 compression. Running gasoline in such a motor will destroy it. The solution for car makers is to use normal compression because e85 will still power a lower compression motor.

You don't have to believe me. It's a hard one to take sight unseen. If you ever see it in person you will remember this exchange though. Absolutely everyone was surprised at the increase in power without increasing spark advance.

It could be because of the volume of fuel, or the increased cooling, or something entirely different. Others on this site have had similar experiences. IIRC Turbo Pete gained close to 100rwhp when switching fuels. Jeremy just switched over but I don't have any of his data or impressions other than he's happy with e85.

Not sure I understand that first statement.

You're saying that with no changes other than the fuel, with each fuel running at stoichiometric you saw that increase in power?

Because every flex fuel vehicle I've ever seen bone stock OEM on the dyno makes less power on e85 than 91.

 

[Dubstep Shep]

I have zero doubt that a vehicle with a purpose built e85 system will make more power than a gasoline counterpart; as you said there's a lot to take advantage of there.

I suppose your setup was probably better suited for e85 than gasoline, whereas most OEM cars are designed for gasoline.

 

[psfracer]

Absolutely everyone was surprised at the increase in power without increasing spark advance.

It could be because of the volume of fuel, or the increased cooling, or something entirely different. Others on this site have had similar experiences. IIRC Turbo Pete gained close to 100rwhp when switching fuels. Jeremy just switched over but I don't have any of his data or impressions other than he's happy with e85.

Increased cooling. Its a well known fact that lower IATs makes more power, ESPECIALLY on a whipple or similar twin screw set up. We didn't throw ice on top of the whipple before a pass for nothing.....or throw 7 lbs of ice in the intercooler tank in the trunk for that matter....

Same reason why most cars run better when the air is cooler. Air is more dense (better DA basically).

 

[Pentalab]

One of the fellow's on the roush forum switched from 91 gas to E85..and picked up 51 hp..using the 91 tune... but changed the stoich to 9.8 afr of course. He then increased the timing by a whole bunch.... and picked up another 54 hp. Total increase was 105 hp. E85 is supposed to be the eq of 105-107 octane. I read somewhere that E85, when tested was as low as E75...in winter. And as high as E87 in summer.

Bruce, is E85 cool to the touch, when you put your finger's in it ?

 

[Dubstep Shep]

Increased cooling. Its a well known fact that lower IATs makes more power, ESPECIALLY on a whipple or similar twin screw set up. We didn't throw ice on top of the whipple before a pass for nothing.....or throw 7 lbs of ice in the intercooler tank in the trunk for that matter....

Same reason why most cars run better when the air is cooler. Air is more dense (better DA basically).

How exactly are IATs cooler because of the fuel?

I understand that the cylinder temp during compression will be lower, but IAT is usually measured before the fuel is injected, no?

 

[BruceH]

One of the fellow's on the roush forum switched from 91 gas to E85..and picked up 51 hp..using the 91 tune... but changed the stoich to 9.8 afr of course. He then increased the timing by a whole bunch.... and picked up another 54 hp. Total increase was 105 hp. E85 is supposed to be the eq of 105-107 octane. I read somewhere that E85, when tested was as low as E75...in winter. And as high as E87 in summer.

Bruce, is E85 cool to the touch, when you put your finger's in it ?

I haven't really put my fingers in it, lol. It smells like really bad whiskey. The "Woodpecker" brand in Germany would be a good example.

I've read white papers from various Universities that studied ethanol as a fuel. One the ratio was 50% or higher they couldn't get a motor to detonate.

How exactly are IATs cooler because of the fuel?

I understand that the cylinder temp during compression will be lower, but IAT is usually measured before the fuel is injected, no?

Measured iats no. Actual iats that enter the cylinder yes. And that's where it counts, in the cylinder.

 

[Dubstep Shep]

Okay that's what I thought...

Bruce you know your stuff pretty well, what else is in e85 besides ethanol? And what would happen if you ran your car on like on near pure alcohol? We actually joked about it as one of my college buddies brews 93% ethanol.

And ass to the college experiment, any references? I'd love to see what kind of data they came up with. Here's to 13:1 and 25lbs boost hehehe

 

[BruceH]

Okay that's what I thought...

Bruce you know your stuff pretty well, what else is in e85 besides ethanol? And what would happen if you ran your car on like on near pure alcohol? We actually joked about it as one of my college buddies brews 93% ethanol.

And ass to the college experiment, any references? I'd love to see what kind of data they came up with. Here's to 13:1 and 25lbs boost hehehe

I didn't save the links. It was a time when I was doing a whole lot of research. IIRC it was the University of Michigan, Minnesota, or MIT. There are a whole lot of papers out there.

AFAIK it's gasoline. Usually it's not the best gasoline either. People do run E98. E98 is used in one European city for their diesel busses. All it takes is a little more compression than a normal diesel has and the E98 will auto ignite from compression.

 

[Dubstep Shep]

I didn't save the links. It was a time when I was doing a whole lot of research. IIRC it was the University of Michigan, Minnesota, or MIT. There are a whole lot of papers out there.

AFAIK it's gasoline. Usually it's not the best gasoline either. People do run E98. E98 is used in one European city for their diesel busses. All it takes is a little more compression than a normal diesel has and the E98 will auto ignite from compression.

So it doesn't detonate, but it will auto ignite? I'm not 100% on the difference between the two, care to explain to a noob?

 

[BruceH]

Detonation is combustion before it's supposed to happen. When that happens the crank stroke is not where it's supposed to be for that cylinder and all kinds of bad things can happen.

Auto ignition in a diesel is happening at very high compression. The cylinder isn't going to reach max compression until the piston is very far up the cylinder. It's combusting where it's supposed to.

So it doesn't detonate, but it will auto ignite? I'm not 100% on the difference between the two, care to explain to a noob?

 

[Dubstep Shep]

Okay, so the only real difference is whether it's planned or not.

You have any links to overall compression calculators or tutorials?

 

[BruceH]

Okay, so the only real difference is whether it's planned or not.

You have any links to overall compression calculators or tutorials?

Sorry, no links. Just information I've gathered for personal use. I wish I would of kept some of them.

Searches will turn up quite a lot of information.

 

[psfracer]

How exactly are IATs cooler because of the fuel?

I understand that the cylinder temp during compression will be lower, but IAT is usually measured before the fuel is injected, no?

I guess most do measure before the injector, but as Bruce mentions, regardless of where its actually measured, the IAT before the cylinder will be cooler with E85. My IAT gauge for my whipple set up we place as low as possible on the intake manifold right before the head to measure IATs after the intercooler.

Like I said, on a Kenne Bell setup, a car with E85 made the same power as C16. Its awesome stuff.

 

[05stroker]

I gained 3 or 4/10s on my switch to e85 from c16. Never dynoed the e85 tune but the calculators show I had to be over 900 rwhp to run a 9.38 at 4060lbs. I was at 807 on the c16.

Oh and just so we stay on topic.

 

[BruceH]

That's a huge amount of time especially at your level imo. Everyone I know including myself has gained from the switch. The more hp being made on gasoline the bigger the gain from e85.

I gained 3 or 4/10s on my switch to e85 from c16. Never dynoed the e85 tune but the calculators show I had to be over 900 rwhp to run a 9.38 at 4060lbs. I was at 807 on the c16.

Oh and just so we stay on topic.

 

[psfracer]

I gained 3 or 4/10s on my switch to e85 from c16. Never dynoed the e85 tune but the calculators show I had to be over 900 rwhp to run a 9.38 at 4060lbs. I was at 807 on the c16.

Makes sense as that Procharger was generating a bunch of heat I bet.