Running FiST with E85 Blends - Discussion Thread

[CSM]

You're running e30 with no tune?

Yes you can do this. The factory ECU tuning will recognize the higher octane rating and bump timing a bit to get a decent torque gain and some HP.

There's a very old thread on this from ~2015 where someone documented the gains.

 

[M-Sport fan]

I was always told on here to NOT go any higher than maybe E20 on the factory tune, since anything past that was 'out of range' for the factory ECU/O.A.R. system, etc., and could cause an over-lean fueling problem.

 

[Frisk]

Hasn't caused any issues for me. the factory ECU seemed to make appropriate adjustments.

 

[FiestaSTdude]

Yes you can do this. The factory ECU tuning will recognize the higher octane rating and bump timing a bit to get a decent torque gain and some HP.

There's a very old thread on this from ~2015 where someone documented the gains.

Really? Wow, I always thought that would destroy your engine!

I was always told on here to NOT go any higher than maybe E20 on the factory tune, since anything past that was 'out of range' for the factory ECU/O.A.R. system, etc., and could cause an over-lean fueling problem.

Same.

Hasn't caused any issues for me. the factory ECU seemed to make appropriate adjustments.

Do you monitor AFR on your accessport (assuming you have one)? I’d be curious what it looks like.

 

[CSM]

I was always told on here to NOT go any higher than maybe E20 on the factory tune, since anything past that was 'out of range' for the factory ECU/O.A.R. system, etc., and could cause an over-lean fueling problem.

Nope. Most modern cars have fuel trims that can accommodate E30. It's approaching near the top of the limits but there's still some ceiling.

There was an interesting journal article in an engineering journal recently where they enrolled about 100 cars in E30 use over a couple of years. Not a single car Had any sign of detriment or damage. I'll see if I can dig up the article later

 

[Frisk]

Really? Wow, I always thought that would destroy your engine!

Same.

Do you monitor AFR on your accessport (assuming you have one)? I’d be curious what it looks like.

I’ve only had the AP for a week, but I’ll get some logs and send em to ya if you’d like

 

[FiestaSTdude]

I’ve only had the AP for a week, but I’ll get some logs and send em to ya if you’d like

Just do a WOT pull and see what you min afr value is. Mine is around 11.5 -12

 

[Frisk]

I hit 11.6 reverse idling out of the garage, but never below 12.4, WOT in various gears. There’s a chance it dropped lower and I didn’t see it, but the min value was before I left the house.

 

[Frisk]

I hit 11.5 on the way home today, fwiw