E85 flex tune for 350

[NipSC4328]

Damn, makes me think twice about a flex fuel tune, Sunoco looking better.

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[Voodooo]

I haven't tried the E85 flex fuel with my gt350 and I'm not sure I will either. I've been happy with the Sunoco 260GT. It definitely cost more, but since this isn't a daily driver I'm ok with it. It kinda had me skeptical running e85 in my car for as little as I'm able to drive it at this time and the effects of storage.

 

[NipSC4328]

I haven't tried the E85 flex fuel with my gt350 and I'm not sure I will either. I've been happy with the Sunoco 260GT. It definitely cost more, but since this isn't a daily driver I'm ok with it. It kinda had me skeptical running e85 in my car for as little as I'm able to drive it at this time and the effects of storage.

I don't plan on making mine a daily driver either, but definitely not a garage queen. I know the car is designed to be a road course car, but I have no history in that venue so I will probably do some mods leaning towards street\drag performance (blasphemy, I know). I've crewed for a Comp Eliminator team as well as running Super Comp in NHRA and yes, as a stupid teen many years ago I've street raced some, though I much prefer the track. I'm thinking headers, heavier rear axles, lower rear gear, a tune for race fuel, and probably a few more things ... the larger throttle body comes to mind. This car will set more than it gets driven so I'm a little leery of E85 too.

 

[superman07]

superman07,
I just saw your post on the other thread so I see where you're coming from. Each time I fill up I just drive the car normally and wait for it to learn. I would think that the more dissimilar the fuel is that you're adding the longer it will take the pcm to learn.

do me a favor, the next time your learning, watch your percentage and see if idling versus driving at rpm causes the adjustment to favor lowering or increasing values.

i am not going to idle learn any tanks from now on unless it was on e. I am also going to drive it enough to mix fuel and not shut it down until my percentage is what my calculations suggest.

 

[65sohc]

I think the fact I top off frequently might be the difference, As a habit I normally do not run a whole tank out. As these cars were not flex fuel I think the learning function is too easily locked in, perhaps the fuel isn't mixing well in the tank. My father always preached never being low on Gas, maybe it was from the crisis in the 70s.

what I don't get is why doing a 3k rpm hold will cause the car to start dropping percentage, but letting it idle then causes the percentage to go back up, give it some rpm the percentage starts dropping again. its the same gas in the line at that point. I need to figure out where the sensor is.

perhaps the sensor is located by the pickup in the tank, the high rpm hold, or driving increases the volume pumped, perhaps mixing the fuel better. My car was not running great the last day or two, I might have had some partially phase separated crap siting at the bottom of the tank and not mixing. I don't know.

I Put 3 gallons in the car about 15 minutes ago, idling the percentage of course started going up from 69, not wanting a repeat of the car potentially learning a percentage I KNOW IS WAY TO HIGH I went to a 3k rpm hold. I have to feather the gas to actually keep it on 3k as the tune started to adjust slightly and the percentage dropped to 57, but locked in ridiculously fast.

I wonder if there is an upper bound on the time where it just locks in, I may try to see if disconnecting the battery will force a relearn.

for now I am going to try running tanks closer to e, hopefully it helps, I was running 10 gallons of e85 and 6 or 93 for a while. My car likes this the best.

There isn't an acutal ethanol sensor. The pcm infers the e% via the O2 sensors. Don't ask me how as that is about the extent of my understanding. There are some knowledgeable guys on the GT forum that have explained it. I think the more consistent your fuel is the less learning will be required. that's why I just fill up with straight e85 every time.

 

[65sohc]

I've noticed a rough start up since switching to the flex fuel tune but the highest ethanol percentage I've gotten to is 77%. I also notice some hesitation when the car is still warming up in 1st and 2nd gears right before needing to shift during normal driving which I don't remember before the tune. However, after the car warms up to temp (usually 180-200) it goes away and runs like a champ. Not sure if anyone else has noticed this.

Interesting video about the ethanol sensor.

My first start of the day is a tad rough but as soon as it fires it runs fine. I use very light throttle and shift at 2500 until the oil is warm. I can feel a little bit of "adjustment" occurring but I wouldn't call it a hesitation.

 

[superman07]

http://opensiuc.lib.siu.edu/cgi/viewcontent.cgi?article=1001&context=auto_pres

Ford needs 10 percent fuel gain or KAM reset to relearn Alc %. I wonder what other aspects of the KAM might effect the tune and or ECU. There is not from what I can tell any subsequent verification, or any detection if the ionization signal later deviates as the fuel mixes etc.

http://www.google.com/patents/US7921704

Apparently the virtual sensor is the best approach, however all of this confirms my suspicion. Best to run e10 or e85, at least keeping in the same general band. true flexing from e15-70 confuses the car too much. 3 tanks in a row of e50 ish however worked well.

I will not ever idle learn the fuel % outside of a fill up on a seriously empty tank. Post fill up while idle learning I have witnessed completely wrong percentage numbers. If the ionization method for learning the fuel differs with RPM It may be best to do RPM holds. Lund had recommended this once if I was in a hurry. It will be my new defacto rule.

My next fill up I am going to let it learn at 3k rpm , then reset the KAM and let it learn again. Provided its close or hopefully the same percent I will keep using the tune and lock in on doing the math to keep it at e50-55. If I get a second value different enough to throw off AFR all bets are off.

e85 was not a great daily driving experience for me. too much backfire etc. This could be due to not learning and running the car enough on E85. might be interesting to see what a fresh tank of e85 with a KAM reset does.

 

[superman07]

I don't plan on making mine a daily driver either, but definitely not a garage queen. I know the car is designed to be a road course car, but I have no history in that venue so I will probably do some mods leaning towards street\drag performance (blasphemy, I know). I've crewed for a Comp Eliminator team as well as running Super Comp in NHRA and yes, as a stupid teen many years ago I've street raced some, though I much prefer the track. I'm thinking headers, heavier rear axles, lower rear gear, a tune for race fuel, and probably a few more things ... the larger throttle body comes to mind. This car will set more than it gets driven so I'm a little leery of E85 too.

I think if you lock it in and drive the piss out of it with E85, Your good. but don't get too cute with different percentages like I was.

 

[olaosunt]

Will the flex tune adjust for race gas too?

 

[superman07]

yes, but so will the stock tune to a certain point. The best aspect of the aftermarket tunes from my perspective is the lack of emissions compliance. octane for octane they are better, but no warranty better? to each their own.

 

[olaosunt]

I heard about the stock tune adding timing and I thought it was quicker when I did per my butt dyno.

However I was disappointed when I was only able trap 112 mph with race gas when I thought it should trap 115-116 stock with 93.I wonder if it loses power running rich .
DA was only 1300 as well.

I know car is not a drag car but I would rather estimate power per trap than put it on the dyno .
That track outing was what convinced to pull the trigger on the flex tune .

I am switching my Hellion car to E85 so I have a few gallons of race gas left I plan on testing with.

 

[superman07]

When my Alc percentage has been correct, e50 plus really opened up the torque low, and of course pulled much harder all the way up. However when I have had issues dealing with a poor Alc percentage learned at idle or too quickly rich AFRs have made the top end mush. I have changed my mind today though. I'm going to go with 5 gallons full e85 and reset the KAM and see how the ecu learns from e85 at the start. then drive it like a raped ape. It seems most have little to no issues after the second or third tank.

 

[superman07]

I might go ahead and get new plugs also.

 

[superman07]

Turned out to be a vacuum leak due to a faulty UPR clean side separator. This caused issues with the deductive refuel logic and allowed the ECU infer the wrong percentage.

Filled up today and working as intended.

 

[olaosunt]

Good to hear.
I am loving my flex tune.
Per my butt dyno it picked torque below 3500 rpm for sure .
It trapped almost 116 mph in the 1/4 in almost 3000 DA with 5 gallons of E85 added to about 5 of 93 still in tanks vs the stock tune/100 octane which went 112 in 1300 DA.
Still same best ET of 12.4 since I had the stock tires (vs drag radials with the stock tune) and only managed 2.0-2.1. 60 ft times be 1.9 with the drag radials .

I have since filled up twice nclose to empty with E85 and itn feels even stronger on the top end so it may even trap higher .

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