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-   -   Anybody actually using E85 as a performance fuel? (https://www.miataturbo.net/general-miata-chat-9/anybody-actually-using-e85-performance-fuel-64236/)

supramantrm 03-15-2012 10:17 AM

I built my 95 to run ONLY e-85 .I have 7,000 miles on it so far .Hard or slow starts in below 50 sometimes ,no big deal.
Poor fuel mileage ,ok,but great fun to drive even around town.
You wanna talk about fuel being inconsistent ,what about the junk we all get at 93 octane pumps regularly ,i think e-85 is more consistent .
I run a 2560 with ID 1,000`s and a 190 pump with a stainless fuel filter and a 94-95 Megasquirt ,its great .
Prior to this i had a 94 single turbo supra that made 703 at the back and ran e-85 with it on a stock upgraded computer and piggy backs ,worked great.
You won`t find a better ,cheaper or more available fuel source for a car to be driven daily ,you can`t get race fuel at the 7-11 either as far as i know!

ZX-Tex 03-15-2012 10:35 AM

7-11s? We used to have those here years ago. They were all run out of town or something.

But I digress. I know of two others here locally running E85 in their turbo Miatas and they are both happy with it. Maybe they will chime in. One of them had some issues for a few months with the local gas station running out of E85 a couple of times but otherwise they are both liking it. If it was not such a hassle to retune my 1995 BMW M3 (supercharged) for E85 I would convert it over as well. I have an E85 station right on my daily commute.

I have considered running it in my track car (LS1 Miata), though in that case I would only do it to keep the engine cooler. I am already making all of the power that my TT class allows. If I still had my turbo Miata I would definitely be running E85. I was all set up for it in fact right before I parted out the car, which I still lament.

Forget about the renewable/domestic energy source politics of it. Pragmatically speaking, it is a relatively cheap source of 'race' fuel. And like Andrew alluded, I would rather tune timing on E85 than on pump gas since, consistently, on multiple platforms, MBT seems to come well before knock.

18psi 03-15-2012 10:57 AM

Basically that's all it comes down to: cheap race fuel alternative. Not much else is going to get you 95-110oct for 4 bux a gallon

Homemade WRX 03-15-2012 02:29 PM

Savington; I know you said you added timing with a power loss. That is probably from crank angle vs pressure issue...basically you had the sweet spot for the given pressure.

Did you add more boost pressure and pull back a timing?

ZX-Tex 03-15-2012 07:50 PM

Here is a decent definition of MBT for those who are not familiar with the concept.

"Abstract—Minimal advance for best torque (MBT) timing for an
internal combustion (IC) spark ignition (SI) engine is the minimum
advance of spark timing for the best torque or, in other words,
for the best fuel economy. But MBT timing is often limited by
engine knock in the advanced direction and spark timing is also
constrained by partial burn and misfire in the retard direction. It
is preferred to operate IC engines at MBT timing when it is not
knock limited and at borderline knock limit when it is knock limited.
"

*Taken from
IEEE TRANSACTIONS ON CONTROL SYSTEMS TECHNOLOGY, VOL. 15, NO. 3, MAY 2007
"Closed-Loop Ignition Timing Control for SI Engines Using Ionization Current Feedback"
Guoming G. Zhu, Ibrahim Haskara, and Jim Winkelman, Fellow, IEEE

So the idea is, since knock is really destructive, it is better to be MBT limited than knock limited.

Homemade WRX 03-15-2012 09:02 PM

^^^correct completely!!

It also tends to be moved closer (as does knock/pre-igntion/detonation) to TDC with more pre-ignition pressure...Hence my question of adding boost pressure and pulling timing :)

At work we run usually 2-8* pending power rating and engine size but that's a different world of engines.

94mx5red 04-16-2012 06:18 PM

Great thread.

Are all injectors capable of running E85? Rx7 460 and 550's?

Here is a website that shows station locations:
http://e85vehicles.com/e85-stations.html

573 04-16-2012 08:20 PM

I started out running RX7 460's but they were operating at >90% duty cycle with 9 pounds of boost. 550's might be fine, though, depending on your setup.

Savington 04-16-2012 09:19 PM

Take the standard gasoline recommendation and multiply the injector requirement by 1.47 to get the correct E85 sizing.

Or just buy ID1000s.

Renown Performance 04-16-2012 10:43 PM

I am pumping E85 and have been for about 5 yrs now. Started off with FIC 950cc (1000cc)
This yr I am moving up to FIC 2150cc injectors.

I am a fan of E85 however I also may go get a drum or two of e98.

18psi 04-16-2012 11:04 PM

quick question: fic miata injectors: ev14?

Renown Performance 04-16-2012 11:11 PM

Yes

18psi 04-16-2012 11:16 PM

thank you sir.

sorry for off topic q

falcon 04-16-2012 11:36 PM

I have ev14's... they're basically non dead time matched injector dynamics

Renown Performance 04-17-2012 03:08 AM

Now worries 18psi.
You say your sorry, but can you prove it?
Buy a set and we will believe you. Jk.

573 04-17-2012 09:15 AM


Originally Posted by Savington (Post 865376)
Take the standard gasoline recommendation and multiply the injector requirement by 1.47 to get the correct E85 sizing.

Or just buy ID1000s.

I went with the ID1000's. I've never seen them go over 50% duty cycle with my current setup, but the car runs well and I'm sure I'll push them a bit more at some point in the future.


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