Best way to convert to flex fuel??
 

I know it's been out there a few times throughout the years. and seen a few options.
Stand alone (reliable?)
2004 c5 pcm?
Tahoe pcm?

I understand the simplest way would be just to run e85 all the time.

i installed a a@a supercharger to keep drivability close to stock as possible. I want to take it on long trips and not worry about having to filling up with e85.
It's a 01 c5
thanks for the help!

ShorTuning can do it with the stock pcm(he locks these pcms to protect his binary coding). You have to modify the binary in the c5 OS, you cant just segment swap. You would also need to swap to a p59 PCM. Or an aftermarket ECU like Holley or Haltech.

I tuned my 01 for full time Ethanol duty. I like to switch to a Holley dominator this winter, but Id also like to crank up the boost lol

Standalone. From what I understand you can get Flex fueling to "work" using an OEM PCM but it doesn't offer all of the benefits of flex fuel because you can't alter ignition timing based on fuel composition. I may be wrong on this, I didn't spend much time looking into the OEM PCM before deciding to go standalone.

any standalone You recommend?
of course I want the flexfuel for timing based on the fuel.

Whars the difference from a holley and a 04 c5 pcm?

Actually even the oldest flex fuel PCM, "411" can do that, vary timing and a/f ratio based on content sensing.

I found an 2002 "411" pcm from a Tahoe
https://cimg3.ibsrv.net/gimg/www.cor...cc558be180.jpg

This computer can command up to around 180-200lb/hr fuel injectors without having to be "fudged" for airmass calculations.
Its a gen3 computer so rear-camshaft sensor was used
Full 2-bar map sensor + flex fuel compatible simultaneously.

It was $35 in the junkyard and they had 10 of them there. I put this one behind a 5.3L + 4l80e + S364

I'm using the Haltech Elite 2500 and loving it so far. I'm just learning to tune on my own with Bret's(Blownbluez06) help but the Haltech unit seems to have everything I could ever possibly desire.

But isn't the problem finding an OS that is compatible with the C5? Again, I could be wrong but I thought that you could have basic AFR corrections based on fuel composition but not ignition timing in a C5 using the OEM flex fuel tables.

Well, i don't look at "C5" or what kind of car it is. I have a Nissan for example.

All that matters if whether or not you can plug the computer into a harness, and whether or not that harness will fit your engine. And most GM V8's after 1998 are modular in the sense that, even if a sensor didn't plug in directly, either A: It would still work with the right plug soldered on, or B: the right sensor would probably fit the same hole as the old wrong sensor.

You can def adjust timing, otherwise I don't think it would be any good.

Haltech is supposed to have flex fuel ability? Haltech should have everything.

So if I wanted to go to flex fuel on my C5, I could swap in a flex fuel PCM? (I'm still learning about the LS engines, haven't really modded my vette other than heads and a cam when I had to rebuild the bottom end).

Haltech does have flex fuel ability and it literally does have everything I can think of.

Pretty sure it does matter what vehicle it is going into or else you would have seen far more flex fuel C5's out on the streets. Doesn't the PCM have to communicate with the BCM, EBCM, etc to make it all work together?

I found a slightly older thread with some more technical data in it here.

I just also found a piggyback control box when I googled C5 Flex Fuel.

You have no idea what you're talking about and you're spewing false information.


OP You need to use a 04 (P59, NOT A p01 99-2003 C5 PCM) if you want to use flex fuel with an OEM pcm. It has be tuned by someone like James Shor of ShorTuning becuase there are hard coded parameters that have to be changed that Hp Tuners or EFI Live cannot. It is a lot more than swapping a pcm.



When talking about just segment swapping the fuel segment from Tahoe to C5 OS

If I wasnt a tuner, I would have ShorTuning do this for me. Like I said, he locks the tunes to protect his hard work with binary coding he proformed to make it work. I dont blame him.


About 2 to 3k LOL. Holley (and others) are way more capable than the factory stuff but they cost a lot more and youll have to do a lot of wiring yourself unless you send your wiring harness out along with the holley to someone like Brett (blueblownz). If you just want flex fuel, I wouldnt buy a standalone just for that.

Cordes does the c5 ecu swap but I don't know what drawbacks it has like some people listed here.

Just be careful about inspection. Ours requires an odb2 read so I'd need to keep the stock pcm wired up in parallel with an aftermarket. If it wasn't for that I'd be swapping to an aftermarket ecu asap.

all I said was if the ecu fits a harness, and the harness fits the engine,

then the ecu can control the engine.

That is not false information. It is true for every engine in the world.

I have no idea whats in Corvette. but I deal with swaps, lots of swaps. If you brought me a vette and a computer and said make this work, I would figure out what was needed to make it work, and compare that with other option to find the most practical solution. There was a question about flex fuel and gen3 stuff so I thought I would point out the availability of a $35 ECU solution that works well for gen3 applications, in general. Whatever you need to do to "convert it", could be as wild as changing the whole engine, or writing digital processor code to control in-car electronics back to factory specs, is up to your researching.

That IS false information. You cannot do that on a c5. Even if you could, why would you tell him to get a tahoe pcm when you can flash the OS (which wont work) on his current p01 controller? You deal with swaps, lots of swaps so you should know that.


Then why comment?

That is what the OP is doing and your lack of knowledge is going to send him down the wrong path.

This is Corvette Forum... the chassis is relevant to this conversation.

This is irrelevant as it doesn't apply to this car.

O yeah good point!! Trying to keep the car as smog passable!!! Guess aftermarket ECU is out of the question.

sounds like the easiest solution for me would be buying a stand alone kit.

O yeah good point!! Trying to keep the car as smog passable!!! Guess aftermarket ECU is out of the question.

sounds like the easiest solution for me would be buying a stand alone kit.

proflex seems to be the only one coming up.
But it sounds like it's not connected to the computer at all so the timing won't got up or down depending on ethanol level? Am I missing something?

exactly I see that it will only make it work. Will up the injector pressure to compansate for the Percentage of e85 in the fuel. Does not look like its connected to the timing at all.