How to convert the E46 M3 to be 100% flex fuel compliant?

[Nihilation]

From what I've read the factory fuel injectors won't support 100% e85 so larger injectors would be required. Understanding that power gains would be minimal, I'm curious to know how best to go about supporting 100% e85 fuel if desired -- for no reason other than to be able to do it.

My initial guess is a combination of something like the AFD or APE x85 kit, larger injectors and a custom tune? A slightly larger fuel pump wouldn't hurt but not sure it's required for 100% e85. Is it that simple?

[heinzboehmer]

You probably want to do a fuel pump too if you're doing bigger injectors.

[DiscoWagon]

I had a conversation with HTE regarding this, he stated that the flex fuel sensors are merely a tool and not to be relied upon. He suggested that I simply go with larger injectors, fuel pump and a custom tune.

[mrgizmo04]

The problem with getting a tune is you are tuning for a static value of E85. E85 is not E85, it varies between gas stations down to as low as E50 (some may be lower? they all have disclaimer stickers). What happens if you don't have E85 available and need to get 91 to get to your next destination/checkpoint? Ethanol stations, while they have been popping up, are not everywhere.

I think a sensor like APE or AFD that senses actual % ethanol coming into injectors and piggy backs on the tune is needed. It also allows you to fill up randomly between 91/93 and E85.

I'd love to hear Hassan's take on how to deal with variance in actual ethanol content or sometimes needing to run pump gas on a single tune without a sensor. If this is for a racecar that will run strictly on race gas or E85 then no problem.

But yes, minimum what you will need are fuel pump and injectors and a tune that puts in the right flow factors and pulses for the larger flow injectors.

[terra]

It is not difficult to have a different fuel scalar that can be switched via mssmaper or sport mode. And if a flex fuel sensor can output a 5v signal, it wouldn’t be difficult to repurpose an unused input to scale fueling based on that. What I don’t know is if that’s truly sufficient.

[mrgizmo04]

It is not difficult to have a different fuel scalar that can be switched via mssmaper or sport mode. And if a flex fuel sensor can output a 5v signal, it wouldn’t be difficult to repurpose an unused input to scale fueling based on that. What I don’t know is if that’s truly sufficient.

Yeah would be interesting to hear from Paul or Hassan on the topic. When I spoke to them independently about E85 back maybe a year ago, they didn't have it available locally in their countries to experiment, but maybe they have done some remote dyno tuning of eE85 cars with/without the AFD/APE kits and have more insight these days.

[Ob917]

I think that unless you are buying your e85 in a barrel you won't be able to find straight e85 at the pump. The e85 I buy at the station seems to be closer to e70. And that doesn't seem to be a problem. I run the APE piggyback that build journal help me get.

[Nihilation]

I think that unless you are buying your e85 in a barrel you won't be able to find straight e85 at the pump. The e85 I buy at the station seems to be closer to e70. And that doesn't seem to be a problem. I run the APE piggyback that build journal help me get.

I happen to live a mile from a Sheetz station w E85 and my car is strictly pleasure/fun now so this makes sense for me.

[M3Guy]

I run the ApeX e85 kit, stock injectors & pump.

[Nihilation]

I run the ApeX e85 kit, stock injectors & pump.

And you fill up entirely e85?

[M3Guy]

And you fill up entirely e85?

Its as mentioned, the blend varies its not always 85, it can be as low as 70 depending on the supplier and season. If you're asking if I can go up to a corn pump and have filled up all the way yea. I'm mostly stock besides euro headers and mach schnell filter kit. The power gains on these kits on a complete stock M are generally around 15-25whp depending. Not a bad power gain at all for the price.

[martin.oconnor]

The ProFlex Commander is also a popular E85 unit, and has an M3-specific installation kit: https://www.advancedfueldynamics.com...for-bmw-e46-m3

Like many E85 flex kits, it analyzes the ethanol content and adjusts fuel (via the injectors) accordingly.

I just ordered one and will be installing shortly in my car.

Car is supercharged and already has upgraded injectors. I will also be upgrading the fuel pump.

For mostly stock cars, no injector or fuel pump upgrades may be needed.

As mentioned, E85 is rarely 85% ethanol and concentration varies by location and time of year.

In California E85 is typically at maximum concentration: https://www.fuelfreedom.org/buy-cali...85-good-stuff/

[Jimbo's M]

I've had the AFD kit on my car for 15 months and can't imagine going back to gas. I run stock injectors and stock fuel pump and have had ZERO issues. Normally I run in the lower E60 range, but have been down to ~e45 and as high as ~e70, but I've found between E55-E63ish the sweet spot. E63 is about 100 octane, so if I were to fill up from nearly empty, I'd use 13 gallons of E85 and 3 gallons of 91 gas. Make no doubt, the power difference is very real.

[ATB88]

So, it sounds like a flexfuel kit (AFD or APE) works great on a stock tune, but how about on a bolt on car with a custom dyno tune?

Say I have SSV1 headers, CSL airbox, and a custom dyno tune from Hassan, and it all works beautifully (I don't currently, but that's my planned path over the summer). Then I go and throw in one of these flexfuel kits. Will it just seamlessly work with whatever my tune is, or will it have the possibility of messing up what the tune is trying to do? What if I install the kit before having the dyno tune done? Can a tuner work with it and give me a good tune that will work properly with the kit across a range of ethanol blends, or will the tuner only really be able to dial the tune in for one specific fuel blend? In that case, if I just run a tank of 91, could I expect my tune to work just as well as if the tune was specifically meant for 91 only in the first place?

Running SSV1, CSL box, and flexfuel seems like a great combo if I can get it all to work together on a custom tune, but that last part seems like it could get a little sticky?

I would be planning on running stock injectors and fuel pump because I'll just be using pump e85 blend which the injectors should be able to keep up with, and both injectors and pump have FCP warranty so I don't have to worry about the cost of burning through injectors and pumps quicker than normal.

[heinzboehmer]

So, it sounds like a flexfuel kit (AFD or APE) works great on a stock tune, but how about on a bolt on car with a custom dyno tune?

Say I have SSV1 headers, CSL airbox, and a custom dyno tune from Hassan, and it all works beautifully (I don't currently, but that's my planned path over the summer). Then I go and throw in one of these flexfuel kits. Will it just seamlessly work with whatever my tune is, or will it have the possibility of messing up what the tune is trying to do? What if I install the kit before having the dyno tune done? Can a tuner work with it and give me a good tune that will work properly with the kit across a range of ethanol blends, or will the tuner only really be able to dial the tune in for one specific fuel blend? In that case, if I just run a tank of 91, could I expect my tune to work just as well as if the tune was specifically meant for 91 only in the first place?

Running SSV1, CSL box, and flexfuel seems like a great combo if I can get it all to work together on a custom tune, but that last part seems like it could get a little sticky?

I would be planning on running stock injectors and fuel pump because I'll just be using pump e85 blend which the injectors should be able to keep up with, and both injectors and pump have FCP warranty so I don't have to worry about the cost of burning through injectors and pumps quicker than normal.

Should work fine with whatever your tune is, that's why it's a piggyback system. You should only need to retune if changing injector size.