E85 conversion questions

[killerspeed3]

has anyone thought of doing (or done) a E85 setup in a MS3. What wound be the cost to have a shop to it? would the gas savings be worth it? would there be any real hp gains with basic bolt-on modifications already done to the car? any thought of who could do this ssort of conversion. any thoughts on doing something like this

 

[JohnnyT]

See: http://www.mcx7.com/showthread.php?5428-E85-tuned-and-running!!!

What would be the cost to have a shop do it? - The cost of a tune.

Would the gas savings be worth it? No - it essentially evens out because your mileage per gallon decreases. E85 has less energy than regular 93 octane meaning it doesn't burn as easily which prevents pre-ignition (and thusly detonation) meaning it takes more fuel to burn at a similar rate than regular gasoline - roughly 30% more fuel.

Would there be any real hp gains with basic bolt-on modifications already done to the car? Yes - you can run more timing allowing you to pull more power safely - pending your fuel pressures are high enough to not cut.

Any thought of who could do this sort of conversion? You - bring a gas can to MAP along with your MS3, a CP-e Standback, and the cost of a tune and they'll get you set up. Your fuel lines, injectors, and upgraded fuel pump will support e-85 just fine.

 

[mndsm]

Figure you lose 30% in fuel economy, but get 30% cheaper gas, so it's a wash there. e85 runs cooler, and the alcohol content is an additional cooling agent (sorta like running alky injection, though not as serious) so you won't run into higher temps as easily. This all lets you do what JT said.

 

[killerspeed3]

Thanks guys, sounds like a pretty simple spring project.

 

[Picklz]

As JT mentioned fuel delivery is going to be your big challenge, if you don't have an upgraded fuel pump already it might be wise choice to get one before switching to e85. Especially if you are already stage2 (Intake/tip/downpipe/etc). Are you tuned already on 91/93? Fuel pressure holding @ 1600+ right now?

 

[killerspeed3]

I'm assuming that it is stock tuned with SRI and BOV.

 

[JohnnyT]

It's simple, just costly.

$667 - CP-e fuel pump
$653 - CP-e standback
$300 - CP-e plug 'n play harness
$464 - CP-e full control flash
$300+ - MAP tune

$2,384 - TOTAL

Now, the AP may be able to work with e85 which will dramatically reduce your costs. If it can work (which you should research, or Tom will), the cost will be as follows:

$667 - CP-e fuel pump
$695 - Cobb AP
$300+ - MAP tune

$1,662 - TOTAL

On a stage 1 set-up I just don't see the potential gains to be effective given the cost associated with everything that's needed. Even on a stage 2, you won't be able to run anything higher than 20psi safely even if you add meth. However, at any higher-than-stock boost pressure you run, it will be safer compared to a 93 octane set-up so that, to me, is your biggest advantage.

Let us know what you decide to do...

 

[mndsm]

And all of those prices are assuming you buy either item brand new. Expect to pay full boat for the fuel pump- but the APs are reguarly seen @ 400$ on the used market, and Standbacks can be had in the 4-500$ range.

 

[concealer404]

Are the injectors on these things really big enough to deal with the increased amount of fuel that the motor will be injesting?

I thought about converting over (completely different car, mind you) but i found that i would have had to move from my current 440s to close to 600s. And that ain't happening without a standalone in my case.

But beautiful things happen when you can tune your factory ECU i guess.

 

[mndsm]

DISI injectors are silly oversized for the car. Even at WOT, on stock fuel, they're only flowing like 50% of duty cycle. Even the standing record car (500 something horse) is on stock injectors and not running into any problems.

 

[concealer404]

That's no fair. My car if you run megasquirt on it and log, even with a stock map, stock EVERYTHING, the injectors will hit just about 120% duty cycle. Doesn't seem to bother the car any, though.

 

[JohnnyT]

Injectors are one of the few things they got right on this car.

 

[niterydr]

I can vouch for the injectors being grossly oversized, but that may be from a longevity standpoint. Direct Injection is relatively new and who knows what will happen regarding how the injectors will stand up to extended usage. I know for a standard injector, running them at a sustained 90% + duty cycle will really shorten the life, I am not sure if that threshold has been published for the DI vehicles.
Also remember, if your system says you are getting over 100% duty cycles, you are most likely not getting more than the 100% fuel. That means your injector is now spraying into the next suck-squish-bang-blow cycle, not good for power, engine life, emissions, etc.