shotgreen

Hello all,
I recently found an E85 station on my way to work and this got me thinking about switching. With the hotter temps here I'm starting to get paranoid about detonation and feel like E50 would be safer compared to 91. I already have bigger E85 compatible injectors installed and a way to easily switch between tunes. Other then new injectors, the rest of the fuel system is still stock. Just wanted to know what the minimum requirements before switching? Would also be nice to know if anyone is running E85 on stock fuel system without problems? Below is my current setup running 8psi of boost. Thanks!

List of mods:
Flyin Miata Turbo manifold and downpipe
Flyin Miata Intercooler
Garret GT2560R Turbo
Flyin Miata Clutch lvl 1
Flow Force 640cc Injectors
AEM FIC6 ECU
AEM X series wideband sensor
Flyin Miata Sway Bars
NGK BKR7E gapped to 0.032"

afm

iTrader: (3)

Lots of people (myself included) do nothing special beyond a fresh OEM replacement fuel filter. Maybe a second new fuel filter after 500 miles if you’re feeling saucy. Send it.

It’s easy to run E85 with no mythical “conversion.” The bigger question is whether your fuel system has the flow capacity to accommodate the amount of power/boost you’d like to run with E85. Which you answer by reading.

codrus

640cc injectors I'm gonna go with "no" on the fuel system capacity.

I also wouldn't run it without the flex fuel sensor and an ECU that understands it. FIC is a piggyback, right? That doesn't strike me as a great idea.

--Ian

vitamin j

iTrader: (5)

Send it. You may run out of fuel pump. Hopefully you have a MS3 that supports flex fuel. I am running EFR 6258 at 8psi on FF 640s with E85, I have increased my base fuel pressure to 60psi, however.

shotgreen

Currently my max injector duty is about 50%, this means I should be able to add 30% more fuel easily, Right? Also E85 isn't actually available in phoenix and instead it is E52 here, this means the fuel requirements are lower compared to real E85. I am using a piggyback ECU and I don't disagree that it is a bad idea but i'm confident that I can make it work. If things don't work out I can always switch back to pump gas. My main concern was that the factory FP might not be compatible but it sounds like it is? How important is the flex fuel sensor? I would imagine that the ethanol content is someone consistent? Correct me if i'm wrong on this.

codrus

I have never run E85 personally, but from what I have been told that assumption would be incorrect -- the ethanol content can vary widely.

My experience was that a 2560 at 15 psi making roughly 270 at the wheels (on gasoline) was at 80% DC on 550s. If you're only using half of your 640s then I think you've got a lot of headroom left before you need ethanol.

--Ian

shotgreen

I know that ethanol isn't totally necessary to make more power but I've had to pull a lot of timing due to high intake temps and detonation issues. I think the advantages of ethanol outweigh the disadvantages, especially in a hot climate like AZ. As long as it is safe to run ethanol on a stock fuel system then it's worth a try IMO.

Arca_ex

iTrader: (2)

I'm from Arizona as well and run my car on flex fuel.

If you want to use flex fuel with a street car around here you are going to need a standalone ECU that can utilize a flex fuel sensor to adapt to the different mixtures. Most stations around here now carry 54% ethanol flex fuel, but you'll get the occasional batch that will hit 70% or higher, and there is one particular station in Mesa that trucks in actual e85 that is 80% to 85% range but you wouldn't know unless you asked the employees or tested it yourself. You need something that will adapt to all of these on its own unless you like testing fuel every time you fill up, and if it's not what you're tuned for then you're kind of screwed and will be trying mix pump gas and flex fuel together to hit your marks.

As far as the fuel system goes, there's three more things you need to do to be safe. You've already got the fuel injectors which is the most expensive thing so that's good.

First, if you still have the stock fuel pump that thing is tired. Grab a Walbro 190HP and new sock filter.

Second, replace all the rubber lines with Gates Barricade Fuel Injection hose. It's rated for ethanol/alcohol use and won't start coming apart and plug up your injectors.

Third, replace the fuel filter with a Wix filter. They do pretty well compared to most stock replacements with ethanol. Replacing it again after the first 1000 miles of flex fuel use is a safe practice as well.

z31maniac

Shouldn't the first suggestion be to ensure your tune won't detonate when it's hot?

shotgreen

Thanks for the info guys. I don't think the NB2 has any rubber fuel lines. All the flexible fuel lines i've seen on my car are made of plastic. I'd be surprised if the ethanol actually did anything to them. Going to be throwing in a new filter and adding a flex fuel sensor later this week. After that i'm going to fill up on corn and see what happens.

sonofthehill

iTrader: (1)

The only rubber is in the tank. The OEM plastic stuff is nice PA 12, I used it in the tank instead of the rubber crap.