E-85
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1/4 mile/AutoX
Joined: Jun 2014
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From: Buffalo Texas
E-85
has anyone converted their C 5 to E-85 ??? pro's / con's, is there a pin for flex fuel in the PCM ??? (1999) no 93 here in Oklahoma 
Last edited by Pounder; Feb 6, 2019 at 05:05 PM.
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I've been running straight e85 (no flex) on my car for about a couple of years, good stuff if you can actually take advantage of it... on a naturally aspirated setup it won't pick up a whole lot, even less if it's just light bolt on mods... I have typed up a ton of info in the past if you do some digging around, it's just too much to type over and over again lol
Burning Brakes
Joined: Apr 2004
Posts: 786
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From: Tucson, AZ
I’ve run E30 to E47 mixing flex and pump since I purchased 5yrs ago. It’s primarily track car with about 50 track days so far (110k miles). No issues... I tune myself.
I mix 50/50 pump and flex... AZ changed from E85 to E54 thus the mixes above. E30 is much higher octane than 93. I’ve run 240 coolant temps in 105 ambient with minimal retard.
I mix 50/50 pump and flex... AZ changed from E85 to E54 thus the mixes above. E30 is much higher octane than 93. I’ve run 240 coolant temps in 105 ambient with minimal retard.
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I turned my meth kit off after switching to e85, it really isn't a necessity like it is when just on pump gas on a boosted car... meth will cool iats but it still has to ignite and from what I understand it burns hot, ethanol on the other hand does the opposite... it will do nothing to cool you iats but it burns much cooler than pump gas or methanol and does a really good job of removing heat from the combustion process... I'd have to pull up some old logs but I'm pretty sure I've hit around 150-160 degree iats on a long pull with no knock and no timing being pulled, of course some of that will have to do with the tune as well but on an n/a setup I don't think you would ever see iats anywhere near that high
Burning Brakes
Joined: Apr 2004
Posts: 786
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From: Tucson, AZ
I turned my meth kit off after switching to e85, it really isn't a necessity like it is when just on pump gas on a boosted car... meth will cool iats but it still has to ignite and from what I understand it burns hot, ethanol on the other hand does the opposite... it will do nothing to cool you iats but it burns much cooler than pump gas or methanol and does a really good job of removing heat from the combustion process... I'd have to pull up some old logs but I'm pretty sure I've hit around 150-160 degree iats on a long pull with no knock and no timing being pulled, of course some of that will have to do with the tune as well but on an n/a setup I don't think you would ever see iats anywhere near that high
N54 is DI, so not equal comparison but despite meth having more cooling (latent heat of evaporation) you’d waste much of it unless injecting very close to cylinder. Plus have to worry about distribution. E is very good and much easier.
The stated octane for E is based on carbonated test engine. Actual octane is higher in PI and much higher in DI, since cooling depends where vaporized.
Burning Brakes
Joined: Apr 2004
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From: Tucson, AZ
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ethanol is pretty corrosive to certain materials and if left exposed to the factory pump and injectors for extended periods of time it could rust the internal parts and leave you in trouble... basically if you run it in high concentration full time you should switch to parts with stainless internals... if you dilute the mixture down that would be safer as long as you have enough room without running out of injector/pump... if you don't run flex fuel you will need to keep the mixture fairly close to what you are tuned on that way your afr doesn't swing too far either way and cause problems... you can get an ethanol % tester or you can also use a graduated cylinder to test what's coming out of your pump, even though it's advertised as e85 there is a minimum number it can actually be that varies by state
Last edited by StingrayRebel; Feb 6, 2019 at 10:37 PM.
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From: Fort Worth, TX
E85 is magic when it comes to boost. What I could pull off with boost and timing and NO intercooler on my Regal was insane. However, in that car, there is no PCM support for a fuel composition sensor, so it's stuck on E85 unless I swap pulleys and flash a gas tune back on. With the 0411 PCM, some OS's support fuel composition sensors. However, I'm no LS tuning expert, so it's worth asking around.
That being said, I'm fairly sure I wouldn't bother doing it on an N/A motor with normal compression. I might mess around with that on the C5 this summer for something to do.
That being said, I'm fairly sure I wouldn't bother doing it on an N/A motor with normal compression. I might mess around with that on the C5 this summer for something to do.
Thread Starter
1/4 mile/AutoX
Joined: Jun 2014
Posts: 11,439
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From: Buffalo Texas
E85 is magic when it comes to boost. What I could pull off with boost and timing and NO intercooler on my Regal was insane. However, in that car, there is no PCM support for a fuel composition sensor, so it's stuck on E85 unless I swap pulleys and flash a gas tune back on. With the 0411 PCM, some OS's support fuel composition sensors. However, I'm no LS tuning expert, so it's worth asking around.
That being said, I'm fairly sure I wouldn't bother doing it on an N/A motor with normal compression. I might mess around with that on the C5 this summer for something to do.
That being said, I'm fairly sure I wouldn't bother doing it on an N/A motor with normal compression. I might mess around with that on the C5 this summer for something to do.
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some of the older truck pcms have flex and will work in the c5, from there it's just a matter of wiring and adding the flex sensor and I don't know what all needs to be done tuning wise but my tuner said it can be done... if you have 91 and e85 available in your area you can test the e85 out of the pump and mix it with 91 to get 93 (or higher if you want) but like I said if you get tuned on that and don't do flex you just need to pay attention to what you put in the tank and watch your afr at wot, it takes a little bit of discipline but worth it if you need it... what size injectors do you have now and do you know your max duty cycle?... since you have done heads and cam already I'm guessing the injectors would have already been changed so you might have enough room to add a little ethanol without changing them out and on the pump you might be able to get away with a 255lph and be ok as long as you aren't running straight ethanol... lots of options lol
Burning Brakes
Joined: Apr 2004
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From: Tucson, AZ
Mix isn’t a big deal IMO. Let’s say variation from 30-60% E in flex… (if mixing 50/50) that’s a 0.06 diff in lambda. And less E means richer AFR and more E is leaner which are the directions you’d want to swing. But at least my station is very very consistent.
Thread Starter
1/4 mile/AutoX
Joined: Jun 2014
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From: Buffalo Texas
My tuner was to set it up using a sensor for the % of Ethanol so it wouldn't matter how much or little of the % the PCM would compensate ???
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your fuel trims will compensate for it to an extent under normal driving conditions whether you are running flex or not but under wot you run a commanded afr so say you are tuned for e85 and only running pump gas then you will have a bad afr problem lol... to my understanding on flex you will get tuned for pump gas and ethanol and once those values are set the pcm will determine fueling based on ethanol %
Last edited by StingrayRebel; Feb 7, 2019 at 04:38 PM.
Burning Brakes
Joined: Apr 2004
Posts: 786
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From: Tucson, AZ
WOT will also trim based on closed loop cells, but only add fuel... will not take out. I think a flex sensor is unnecessary unless you plan going from gas to E regularly. Otherwise can just load your 91 tune.
Melting Slicks
Joined: Sep 2011
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From: Appleton WI
As info, engines that are designed for E85 have different materials used for the valve seats. Engines that are designed for E10 can experience corrosion/ erosion at the valve seat/head interface. Engines designed for E10 can tolerate up to E20 without issue as they were designed and tested for it to allow variation in the E10 gas.