E 85 in high horsepower engines

So I've read some threads about running E 85 in big horsepower engines(TT). I was always under the impression these engines required higher octane and that E 85 has less. What is it about E 85 that lets those engines live?

I believe it's the alcohol content in it. I know a lot of the GN racer guys are running it now and those guys are squeezing a lot of hp out of their motors.

E85 has a higher octane rating than unleaded premium.

Listing the octane rating for E85 isn't reuired by law, so what you see on the pump might be optimistic.
Some sources say it has an octane rating of 113, some say 100 - 105, and some conservative estimates place it around 96.

But E85 carries less energy, so you burn more of it, compared to gasoline.

farmo83 said:

So I've read some threads about running E 85 in big horsepower engines(TT). I was always under the impression these engines required higher octane and that E 85 has less. What is it about E 85 that lets those engines live?

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Define "live"

Ultra high compression engines running on alcohol normally get torn apart on a regular basis. They don't need to "live" too long.

Ok so maybe "live" wasn't the best choice of words.

I guess I'm just curious as I know E 85 has less energy then gasoline so I would infer from that it would be more likely to detonate or pre ignite. Apperently this isn't the case as I've seen threads about high horsepower engines running on E 85 or having an E85 EFI tune. I was curious as to how this was being done.

Octane is based on the ability to resist knok.

E85 has an increased ability to resist knock (higher octane then say 91 gas), but has less energy by volume.

So you can run more compression but need to feed it more volume while do so.

If your running injected, you may need to go up about 20# on injector size

farmo83 said:

Ok so maybe "live" wasn't the best choice of words.

I guess I'm just curious as I know E 85 has less energy then gasoline so I would infer from that it would be more likely to detonate or pre ignite. Apperently this isn't the case as I've seen threads about high horsepower engines running on E 85 or having an E85 EFI tune. I was curious as to how this was being done.

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The readers digest version is...

You need close to double the amount of alcohol as you do gas. Just by this fact alone, that helps keep the cylinder temps cooler.

Since it has less energy, you need a 14:1 compression ratio, to make good use of it.

Of course there is more to it than I am saying here, but this is the basis of how alcohol engines work.

rivermobster said:

The readers digest version is...

You need close to double the amount of alcohol as you do gas. Just by this fact alone, that helps keep the cylinder temps cooler.

Since it has less energy, you need a 14:1 compression ratio, to make good use of it.

Of course there is more to it than I am saying here, but this is the basis of how alcohol engines work.

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I had quite a conversation with Gretch about the stuff up in Burley, since he is running it in the little E boat, and the guy I build dirt modified engines for is getting ready to try it out in a week or so on one of my engines he has been running race gas in. Another of my engines that belongs to a board member, with twin turbos has been running it for awhile now also.

I had actually wanted to do a direct dyno comparison while I was in Idaho, since I had gone up there to be present while one of my Comp Jet engines was run, but he got some kind of advice saying it would not work so he didn't try to lay his hands on a carb that we could test with.

obnoxious001 said:

I had quite a conversation with Gretch about the stuff up in Burley, since he is running it in the little E boat, and the guy I build dirt modified engines for is getting ready to try it out in a week or so on one of my engines he has been running race gas in. Another of my engines that belongs to a board member, with twin turbos has been running it for awhile now also.

I had actually wanted to do a direct dyno comparison while I was in Idaho, since I had gone up there to be present while one of my Comp Jet engines was run, but he got some kind of advice saying it would not work so he didn't try to lay his hands on a carb that we could test with.

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I consider E-85 as at least 105 octane. Probably equal to 110 when you take into consideration the cooling effect of the ethanol. My green Schiada TT 496 cu. has been on E-85 for about 4 yrs. at 18# of boost and I love it. Am currently changing it from carbs to EFI. I changed my MFI on alcohol PS 13.5/1 engine to carbed on E-85 and love it!!!! Barry also built my 622 cu. in. 10.2/1 TT motor that will see 20-25 #'s of boost on E-85. I have a 427 stroker motor 13/1 with Crower stack inj. on E-85 that is going into my 1965 Campbell woody soon.

One of the benefits of E85 is the Stoich of the fuel. 110 Octane has a Stoich of around 14.53 VP C16 has a stoich of 14.77. while E 85 depending on ethanol content is around 9.8. AFR is Labda times Stoich. stoich is the measurement of air to 1 part fuel to achieve complete combustion. Its not only the higher octane but its the lower Stoich of E85 it makes the fuel more resistant to knock so you can add more timing to the engine than gas and still resist knock which allows for more power. The nice thing about E85 besides the cheap factor is if the vehicle goes lean it won't knock as easily as gas. Downside is its around 30% less efficient than gas.

farmo83 said:

Ok so maybe "live" wasn't the best choice of words.

I guess I'm just curious as I know E 85 has less energy then gasoline so I would infer from that it would be more likely to detonate or pre ignite. Apperently this isn't the case as I've seen threads about high horsepower engines running on E 85 or having an E85 EFI tune. I was curious as to how this was being done.

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energy in various fuels, generally measured in BTU's, has nothing to do with the fuel resistance to creating knock. so to understand this correctly, knock needs to be more clearly defined. Knock comes in various forms, but is actually the end result of a couple different operating conditions. More correctly stated, "pre-ignition" is when the fuel begins to burn BEFORE the spark instant. this has the effect of creating cylinder pressure before the piston has reached TDC, essentially trying to force the motor to rotate backwards, causing the piston to "rattle in the bore" which creates the audible knock. detonation is when the fuel "explodes" rather than burns at a consistent rate, again end result being knock. either of these conditions are engine killers if left unchecked.

octane rating is the fuels resistance to begin the combustion event early due to high heat and compression. think about it this way, the fuel is highly atomized (mixed with air and wanting to ignite) and we then ingest it into a high temperature cylinder and then compress it and expect it NOT to burn until the spark instant. octane rating is a direct measurement (among other things) of the fuel resisting uncontrolled burn. this is why direct injection modern engine can run at such high compression ratios and make the power they do on pump fuels as the injection instant basically occurs at or very near TDC so knock is almost entirely eliminated as there is no fuel present during the compression stroke.

the use of e85 has two primary advantages, first, it does have an octane rating considerably higher than pump gas. the second advantage is the cooling effect the alcohol has, think of it as a type of "intercooling effect" that reduces potential knock.

the reason you don't find much on the actual e85 octane rating is because the engineering standard ASTM 5798 specifies E85 can range in its dilution with gasoline anywhere from 50-80%. so when you go to fill up at the pump, you are not getting consistent fuel. this is very dangerous for a high horsepower engine as you may not be running anywhere near the octane the engine was designed for. Factory cars today get away with it because they run a flex-fuel sensor that can tell the engine computer what the fuel composition is and adjust engine fuel and spark based on the composition of the fuel.

E85 was considered "poor mans race gas" due to the high octane. but its already been pointed out it doesn't have the same BTU energy than gasoline does so you have to burn more of it. some potential savings is lost. There are race fuel like VP that sell E85 and guarantee consistency, but it isn't any cheaper than good race gas. another downside to e85 is the fuel absorbs water much more dramatically than gasoline and the ethanol/alcohol can wreak havoc on plumbing and other rubber not specifically designed to be used with it. you can even see this with todays pump fuel where there is a small amount of ethanol in it (by mandate of the govt) and older cars/boats are having all sorts of problems with rubber lines deteriorating.

when you talk about having an "e85 tune", yes, the fuel delivery demands and spark requirements are vastly different than gasoline and need to be tuned accordingly.

steveo143 said:

I consider E-85 as at least 105 octane. Probably equal to 110 when you take into consideration the cooling effect of the ethanol. My green Schiada TT 496 cu. has been on E-85 for about 4 yrs. at 18# of boost and I love it. Am currently changing it from carbs to EFI. I changed my MFI on alcohol PS 13.5/1 engine to carbed on E-85 and love it!!!! Barry also built my 622 cu. in. 10.2/1 TT motor that will see 20-25 #'s of boost on E-85. I have a 427 stroker motor 13/1 with Crower stack inj. on E-85 that is going into my 1965 Campbell woody soon.

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this e85 is starting to get my attention and consideration for my next motor. what is the general availability of this fuel at most gas stations? I think this would be a consideration on my final decision.

Thanks

I've heard of octane quality being different from batch to batch, some drag racers trying to get the most out of it were saying unreliable octane ratings...and Boom, rebuild start over

msmeads said:

this e85 is starting to get my attention and consideration for my next motor. what is the general availability of this fuel at most gas stations? I think this would be a consideration on my final decision.

Thanks

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http://propelfuels.com/locations

You can also buy an e85 test kit from summit for a few dollars. Put a few ounces of e85 and some water shake it up and it will give you the ethanol content. We don't get much of the winter blend here in So Cal i get mine from one of these locations and its normally around 90% ethanol.

When it comes to race e85 you should consult your engine builder. E85 has a lower boiling point and race E85 has an even lower boiling point if your fuel rails see decent heat might get vapor lock with the race E85 from sunoco or VP.

msmeads said:

this e85 is starting to get my attention and consideration for my next motor. what is the general availability of this fuel at most gas stations? I think this would be a consideration on my final decision.

Thanks

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E85 got everyone's attention when it first came out, but not so much anyone.
As others have pointed out, there are too many drawbacks to it to make it a viable option.

Consult Your engine builder for details.

It would appear DaveH stayed at a Holiday Inn last night.

👍👍

im running a 522 blown bbc 9.1 comp, dart heads, 8-71 stripped kuhl blower @ 5% over making 10psi of boost, w/ two e-85 1150 doms, and 30* of timing. this motor is a pretty conservative lake motor turn key every weekend, cruises the lake at 3000rpm all day (other than fuel stops), and will spin 7300rpm at the stomp of the peddle. i say this because this motor makes 1003hp @7300 rpm, and 850+ ft lbs trq @ 5800 rpm, on joeys groses dyno. just saying, i love e-85

Bought a boat last month. Running a 498, supposedly 10.1 on E85.. Heres a before pic

And heres after 20 minutes at midrange 3000-3500 rpm on 3 when the guys who tuned it say it was 'super rich' and 'impossible' to hurt. I think ill be going back to gas expensive lesson

Oh man.

WOW!! I'd say they were a little off on their estimate of it being tuned rich.

Levoe210 said:

Bought a boat last month. Running a 498, supposedly 10.1 on E85.. Heres a before pic

View attachment 366460

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Levoe210 said:

And heres after 20 minutes at midrange 3000-3500 rpm on 3 when the guys who tuned it say it was 'super rich' and 'impossible' to hurt. I think ill be going back to gas expensive lesson

View attachment 366461

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Looking at those domes, assuming 4.25 stroke combination, I #1 really have to question the reality of 10-1 compression, and #2 question the wisdom of running that fuel on a high compression blown engine. When you said "3", were you meaning 3 lbs of boost? How much ignition timing?

so what happened? it looks like something broke and went threw the motor:yikes:thumbsdown

obnoxious001 said:

Looking at those domes, assuming 4.25 stroke combination, I #1 really have to question the reality of 10-1 compression, and #2 question the wisdom of running that fuel on a high compression blown engine. When you said "3", were you meaning 3 lbs of boost? How much ignition timing?

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I can't remember what my motor guy said he measured it out to be. The guy I bought it from said 498 but my guy said 500".. Its a tall deck if that helps? I'll find out. I question everything only because a lot of things were different than I was originally told. I was told carrillo rods, they're scat, i was told hydraulic roller, its solid roller, I was told it was set up super rich, but obviously its lean. They were saying it was 6 - 8 lbs of boost, top pulley is a 50 bottom is a 46 if I remember right. And I don't know what timing they ran. I obviously trusted the guys that sold it and bought a broken motor. Expensive lesson, but yeah, my guy is saying if I want to run the blower it should be down around 8-1 compression.

All 8 pistons were rattled from the detonation and broke the top of the piston at the 1-2 o'clock position. I guess thats common in that condition because thats where the heat is? All the parts are out getting checked now to see what i can re-use. The seller is still answering his phone and says he may or may not help me out depending on how much it is. But he still thinks I heated the motor up and caused the damage. Not the first time Ive heard this story, just didn't think it would happen to me. Just threw it in this post because I've heard E85 can be tricky to set up. These guys seemed super knowledgable and trustworthy but? it happens

Levoe210 said:

I can't remember what my motor guy said he measured it out to be. The guy I bought it from said 498 but my guy said 500".. Its a tall deck if that helps? I'll find out. I question everything only because a lot of things were different than I was originally told. I was told carrillo rods, they're scat, i was told hydraulic roller, its solid roller, I was told it was set up super rich, but obviously its lean. They were saying it was 6 - 8 lbs of boost, top pulley is a 50 bottom is a 46 if I remember right. And I don't know what timing they ran. I obviously trusted the guys that sold it and bought a broken motor. Expensive lesson, but yeah, my guy is saying if I want to run the blower it should be down around 8-1 compression.

All 8 pistons were rattled from the detonation and broke the top of the piston at the 1-2 o'clock position. I guess thats common in that condition because thats where the heat is? All the parts are out getting checked now to see what i can re-use. The seller is still answering his phone and says he may or may not help me out depending on how much it is. But he still thinks I heated the motor up and caused the damage. Not the first time Ive heard this story, just didn't think it would happen to me. Just threw it in this post because I've heard E85 can be tricky to set up. These guys seemed super knowledgable and trustworthy but? it happens

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Right, they burned in the "normal" location due to detonation. Do you have a boost gauge? With high compression and that pulley combination (starting with their 10-1 figure for compression, and possibly 10 psi boost based on charts from BDS you may have effectively 17-1 compression! My gut from the photo is that compression is higher than that, if you have a 110 cc chamber, and a dome that may be 3/8" tall or something? Coupled with not getting the parts you expected, it seems like you maybe got sold a bill of goods. All of that damage may have occurred in 20 minutes. I guess you have someone you trust helping you with it now,, feel free to PM if I can be of help.

If you are able to get either a part number or dome height on the piston (even a kind of rouogh guess with caliper or even ruler), we can get a ball park compression calculation. Flat tops in a .060" over bore with 4.250" crank yield about 8.75:1 compression,, depending on deck height and gasket. My guess (I can't tell dome size from photo, but looks large) is that it has more compression than you were told.

PS E85 is supposed to have a wider "safe" tuning range, but I think you may have been running compression that may have only been successful with blown alcohol.

PPS,, if it's a 4.25" crank,, .070" over bore(4.320"), it calculates to 498.3 cubic inches. Next bore that is commonly done is 4.350", or .100" over,, yielding 505 cubic inches. I am only guessing at the 4.25" crank since that's the most common stroker crank in a factory type block.

check your fuel!!!!

this is what i have been warning people about with the inconsistencies of E85. you may find that it isnt blened at 85% alcohol like everyone thinks they are getting. this would explain the detonation that killed the motor.

Reservoir Dog said:

so what happened? it looks like something broke and went threw the motor:yikes:thumbsdown

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I agree looks like something broke and was bouncing around in the cylinders in question.

Darren