Flex fuel/ e50 tune questions

[SavagePassenger]

I'm running a flex tune (with kit of course) up to e50 and was curious if anyone here might know or have thoughts on a couple of things:

With the fuel mix is there any downside if I go a percent or two above 50 when running ethanol? I wouldn't think being at 51% to 53% E would harm anything but was curious, trying to get my mix more exact when filling up.

Also is it recommended at all to run a tank of 93 octane e10 gas every once in a while with this platform? I've heard that with some other cars just as a safety thing, probably for the fuel system. Thanks

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[Bigjsn250]

No issue running a few percent over. Modern fuel system have no trouble with E85, especially when only running E50. If your car is not sitting for long periods of time, there is no need to run straight 93 occasionally.

 

[suicidaleggroll]

A few percent over is fine, but if you go too far you run the risk of maxing out the fuel system at full throttle. One time I spaced out while filling up and accidentally went way over before catching it. I ended up at something like E60-65. It ran fine, I just took it easy for ~30 miles and then added more 93 to bring the ratio back down.

 

[EddieNel]

Ok dumb question. Why not tune it on straight e85 and tune on straight 93? Will the computer not compensate for any blends?

 

[zrk]

Ok dumb question. Why not tune it on straight e85 and tune on straight 93? Will the computer not compensate for any blends?

You're describing Flex Tunes. You need a pretty beefy fuel system (pump and Port Injection), plays BM3 CustomROM or Ecutek for that.

 

[EddieNel]

You're describing Flex Tunes. You need a pretty beefy fuel system (pump and Port Injection), plays BM3 CustomROM or Ecutek for that.

That’s the direction I want to go. Thank you. It seems like that is the foundation for any kind of real growth.

 

[racebuild]

Ok dumb question. Why not tune it on straight e85 and tune on straight 93? Will the computer not compensate for any blends?

That would be a flex fuel tune. Set your base fuel map and with an ethanol sensor it’ll scale your tune according to the E content that it’s reading.

With stock fueling you’re gonna be limited to ~e60 depending on the tune.

 

[Dr. Supra]

Over e50, you will misfire.

 

[damnsupra]

Over e50, you will misfire.

why?

 

[racebuild]

Over e50, you will misfire.

Not true.

It depends on the tune, at e53 the hpfp is holding up perfectly fine, zero signs of crash. Logs show hpfp angle in the high 90’s, max angle on the pump is at 126… so there is room to play with.

 

[zrk]

Over e50, you will misfire.

No you wont, there's plenty of spark, you'll just run lean as fuck and melt stuff.

 

[SavagePassenger]

No you wont, there's plenty of spark, you'll just run lean as fuck and melt stuff.

By melt stuff do you literally mean spit flames? not that I'm trying to do that lol. Doing my best to get the mix as close to 50% ethanol as I can but was wondering about any downsides of being slightly over that.

 

[razorlab]

By melt stuff do you literally mean spit flames? not that I'm trying to do that lol. Doing my best to get the mix as close to 50% ethanol as I can but was wondering about any downsides of being slightly over that.

I believe he means as in, melt a piston.

 

[zrk]

I believe he means as in, melt a piston.

Correct.

 

[SavagePassenger]

Gotcha, makes sense. I was assuming running way over what the car is tuned for without the supporting parts/tuning would lead to damage.

I guess the consensus is that a percent or two over e50 until you re-mix shouldn't be an issue right?

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