Pulling timing with high intake temps on E85?

fbody83

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I'm planning on running E85 some day and I'm interested to know if people have their tunes set to pull timing with high IAT2 temps? I know on pump gas a lot of people start pulling timing at 140 degrees but I'm sure E85 is much more forgiving. What is everyone's input on this?
 
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cj428mach

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I'm going to be going E85 some day and I'm interested to know if people have their tunes set to pull timing with high IAT2 temps? I know on pump gas a lot of people start pulling timing at 140 degrees but I'm sure E85 is much more forgiving. What is everyone's input on this?

I think on pump most people keep the stock settings of pulling timing after about 100 degrees.
 

fbody83

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I think on pump most people keep the stock settings of pulling timing after about 100 degrees.

I've read that tuners will usually increase this to 130 - 140. Mine is set to 140 right now on pump gas/torco.

What is yours set to on E85?
 

JeremyH

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Talk to your tuner, but you are right e85 likes heat to an extent and is much more forgiving when it comes to iat's.
 

ctgreddy

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I've heard that e85 is so forgiving that people turn that off. It's very hard for cars to detonate on e85 thus being the reason for that. On my tune I have my car pulling timing at 140 degrees and when I switch to e85 I'll probably move that up to 180 or so just incase my intercooler pump takes a crap.
 

Tractionless1

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I've heard that e85 is so forgiving that people turn that off. It's very hard for cars to detonate on e85 thus being the reason for that. On my tune I have my car pulling timing at 140 degrees and when I switch to e85 I'll probably move that up to 180 or so just incase my intercooler pump takes a crap.

The main reason E85 makes more power is the ability to run more timing. With that said if you get a Killer Chiller you'll never have to worry about pulling timing. My IAT2's through the traps are 105*.
 

BADASS03SVT

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I've heard that e85 is so forgiving that people turn that off. It's very hard for cars to detonate on e85 thus being the reason for that. On my tune I have my car pulling timing at 140 degrees and when I switch to e85 I'll probably move that up to 180 or so just incase my intercooler pump takes a crap.

if your pump goes out and your hit 180+ at full timing you'll run into other issues. No reason your IC temps should be over 140-150 so why not leave it there?
 

MalcolmV8

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My 91 pump gas / methanol injection tune starts pulling timing at 140F and my E85 tune starts at 150. How ever on 91 I'm pulling as much timing at 150F as I am at 180F on E85.
 

JeremyH

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My tuner had a pump fail and car go lean as shit on the dyno with e85. Car just shut off, no detonation.
 

cj428mach

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if your pump goes out and your hit 180+ at full timing you'll run into other issues. No reason your IC temps should be over 140-150 so why not leave it there?

Mine is setup to not pull timing until way past 150 degrees. It can take it on e85 so why not bump it up?
 

leegro1015

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Isn't there a trade off here. The reason you run e-85 is to increase power by running more timing. If you are running that much more timing wouldn't you be near the knock limit anyways? Adding more heat is not going to be good. Now if you are running moderate timing and the temp goes up you may be safe.
 

cj428mach

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Isn't there a trade off here. The reason you run e-85 is to increase power by running more timing. If you are running that much more timing wouldn't you be near the knock limit anyways? Adding more heat is not going to be good. Now if you are running moderate timing and the temp goes up you may be safe.

With E85 the cooling happens post IAT2. Here is some good reading on the subject

http://www.modularfords.com/threads/194918-What-Is-The-In-Cylinder-IAT-Drop-With-e85
 

JeremyH

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Just swapping fuels with out adding timing will gain power as well. This proves the reduction in iat and cylinder temperature. I've seen a whipple setup where they changed from 93 to e85, only changed the stoich in the tune and picked up 70rwhp without adding any timing. So there is definetly a colder denser charge with e85. The higher your iat's the more temperature delta and the more benefit you will see from these properties.
 

MalcolmV8

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Just swapping fuels with out adding timing will gain power as well. This proves the reduction in iat and cylinder temperature. I've seen a whipple setup where they changed from 93 to e85, only changed the stoich in the tune and picked up 70rwhp without adding any timing. So there is definetly a colder denser charge with e85. The higher your iat's the more temperature delta and the more benefit you will see from these properties.

I don't think that proves E85 is cooling the intake charge. I'm not saying it isn't, because it might be. However isn't the extra power because of the ethanol and because the fuel is so oxygenated?

You are right though the fuel definitely makes more power. I've personally switched from 91 with methanol injection to E85 and changed nothing but stoich in the tune and picked up 70 ~ 75 whp. I find it hard to believe that's because the E85 was cooling the intake charge. In fact the fuel doesn't even touch the majority of the intake charge does it? The injector squirts it on the back of the valve right before it opens and as it opens the first part of the charge going in takes in the fuel... at least that's how I understand it. I could be off on that.

Whatever the case may be it certainly makes the power.
 

JeremyH

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Don't look at it as just cooling iat's, even though it does just as menthanol does (even when it's direct port sprayed in the intake runner next to the injector). But, no, ethanol doesnt contain more oxygen and energy than regular gasoline, but there is more volume of fuel being consumed which in turn allows for more oxygen, the injectors are pumping out 20-30% more fuel per cycle and your burning more of the fuel mixture. To make power you increase air and fuel delivery to the engine. As the ethanol vaporizes it removes alot more heat from the surroundings, so even though it has less energy(than gasoline) and puts out less btu's(generates less heat during combustion) it allows for a more complete burn of the fuel to get the most out of the fuel mixture, also because of the cooling properties of ethanol, the effective octane is greatly increased. So what all this does for you is allow for a cooler air/fuel charge with more fuel volume and a more complete burn, which means denser, more powerful combustion. This also helps remove carbon buildup and varnish in the engine and reduce emmissions. When you run more gasoline(either 100% or e10), a higher percentage of tha gasoline is not consumed during combustion which yields less efficient combustion and more deposits and emmissions.

It is the cooling/octane boosting properties of the ethanol that resists detonation. This is what also allows for alot more timing to be run safely for even more power.
 
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MalcolmV8

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Don't look at it as just cooling iat's, even though it does just as menthanol does still even when direct port sprayed in the intake runner next to an injector. But, no, ethanol doesnt contain more oxygen and energy than regular gasoline, but there is more volume of fuel being consumed, the injectors are pumping out 20-30% more fuel per cycle and your burning more of the fuel mixture. To make power you increase air and fuel delivery to the engine. As the ethanol vaporizes it removes alot more heat from the surroundings, so even though it has less energy(less gasoline) and puts out less btu's(generates less heat during combustion) it allows for a more complete burn of the gasoline to get the most out of the fuel mixture, also because of the cooling properties of ethanol, the effective octane is greatly increased. So what all this does for you is allow for a cooler air/fuel charge with more fuel volume and a more complete burn, which means denser, more powerful combustion. This also helps remove carbon buildup and varnish in the engine and reduce emmissions. When you run more gasoline(either 100% or e10), a higher percentage of tha gasoline is not consumed during combustion which yields less efficient combustion and more deposits and emmissions.

Jeremy,

If it's cooling the intake charge as it's going into the cylinder and making for a denser air charge going into the motor would it be safe to say then I should see a drop in boost on E85 vs pump gas? Because in theory the engine is consuming more of the blower's air charge on E85 right? At least the way I'm understanding your explanation.
 

JeremyH

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No, not that would be noticeable. When air cools and gets denser pressure does drop, but now you have more air in the same space as well as more fuel so overall theres not a net change that you would notice from the cooling of the air in the combustion chamber. My compelete system, 3.5" charge piping and big ass fmic has alot more volume to fill and I loose less than 1psi from turbos through intercooler to the intake manifold so I dont see you being able to register any boost drop from the cooling or air in the combustion chamber. You can get a denser charge two ways, add more fuel volume to the charge and add more air. The colder the air is the more dense it is. So e85 does both.


When ethanol vaporizes it removes heat from everything not just the air, some ofther cooling benefits I've noticed. I have a return fuel system and on a hot day my fuel rails would be burning hot underhood, too hot to touch. With e85 they are luke warm at best now, quite suprising. Also had my fan fuse pop in stop in go traffic on a 90 degree day and the car was overheating, my water temp guage never got over 220, previous overheating situation with gasoline would peg my temp guage at 260.
 
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MalcolmV8

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Thanks for the info Jeremy. The only thing you lost me on was the fuel temps on the fuel rail on a hot day. I've done extensive testing with that and my fuel rails would be 200F plus. I don't see how yours could possibly not be unless you had just pumped in a fresh cool tank of fuel and that's what was circulating in the rails.

See this thread where I did my fuel temp testings. This was all done on E85 and yes my E85 fuel was over 200F.

http://www.svtperformance.com/forum...rastically-dropped-my-fuel-temps-by-over-100F
 

JeremyH

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Here was my temp on a 45 degree day with 93 octane. 114 degrees.

http://i14.photobucket.com/albums/a341/lightblade543/20130105_125504.jpg


That's hot enough that you can't keep your hand on it long even on a very cold day. The day where I noticed my rails were luke warm to the touch with e85 was a much hotter day 80-90degrees out, I could put my hand on them and hold it there no problem. I don't have a temp reading from a similar outside temp though. But I cant contribute it to anything other than the ethanol absorbing heat from the rails pulling heat from the engine bay.

Different return setups will play a large part in putting heat in the fuel as well. I have a staged controller so only one pump runs at idle and cruise with 8an feed and return and regulator after rails.

I have a pump gas tune and an e85 tune so maybe I will get around to doing some back to back temp readings with the different fuels under similar run conditions.
 
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