Rkreigh

I'm interested in exploring options and getting feedback on a solid setup for the C5 to run flex fuel.

I remember reading info on a vendor that was able to repin a different ECM from another GM vehicle that could run flex fuel and still run the gauges, tranny, ect.... Not sure of the cost, I think it was Vengeance as I remember.

The other option I have (which I know will work, but not cheap) is a Haltech S2000 with the flex fuel sensor. Are there recommended vendors near Alex VA that are VERY good with the Haltech install and tuning. I've heard Anger Management is experienced but I'd like to hear feedback.

I've already got the Haltech, but I'd sure like to hear more about retrofitting a GM ECM.

nullpointer

Free bump, I would love to hear options for the retrofitting of a GM ECM.

FEAR LS

It could be done, but anything can be done if you are willing to spend the money.

The PCM would have to be from a flex fuel capable vehicle as you had already stated, in addition you would have to ensure the ignition system on that pcm isn't setup for a 58x reluctor vs the Gen III 24x. As well as the crank and cam position sensors. Whether it was data that needed to be input or wiring/conversion or both.

These are things just to think about, I haven't done one before. Although I know I'm fully capable, just don't have the budget at the moment to convert mine.

The above is extra, meaning not including the fuel system upgrades it would require. (Pump(s), lines, injectors, etc...)

Pekka_Perkeles

Go with the other options.

Things/acronyms as P59, segment swaps, etc. are too much for average enthusiast to consider.

Cordes Performance Racing

We have done it, it's not as hard as some think but it does take a little time and know how. We offer it in house only though. but It is doable with a gm c5 pcm.

Rkreigh

tell us more! What are the costs involved? Stereo, gauge, and AC all work ok? Any downside?

Like to do the fuel system and the ECM upgrade at the same time.

Thanks for responding!

C5Natie

Agreed. It can be done with a later C5 ecu.

regorih

2004 PCM are flex fuel capable

Pekka_Perkeles

But are they (capable) as such, or is there need for some tricks? Apart of changing the values/settings of course.

Here's some screen shots of 2004 Z06 PCM (P59) with flex fuel settings (sensor and spark advance):

Cordes Performance Racing

yes it's an 04 pcm you have to do but there is some re wiring in the harness that has to be done, and I don't mean just putting in the flex fuel pin.

slow ride

Ok, so after that is complete will the cars run basically perfect from e10-e85, etc? Do you guys use HPT or EFILive?

Smoove

Holley Dominator V4 software now has it.(obviously non GM ecu).

Nate B

Another option is a stand alone controller. We're working on getting it setup and testing on my c6z right now and will be making a harness to run on the c5 as well. As long as your pump gas 93/91 ocane tune is correct and your fuel system will be able to keep up, this is a simple plug and play controller and takes about 5 min to install. It uses a gm flex fuel sensor and corrects fuel trims according to ethanol content.

Here's a dyno graph from a 06 c6z test car we are doing. The car is already setup with flex fuel (pined the factory pcm) so we have a comparison for the c6 market. The red line is the 93 octane tune, blue line is with flex fuel turned on, factory pcm adjusting for ethanol content, green line is the stand alone flex fuel controller running on the 93 tune only (flex fuel turned off on factory pcm. Even on the test car it picked up a significant amount through the mid range over the factory corrections. On the later pcm's 09+ have a flex fuel PE table you can fine tune and achieve similar gains however the earlier pcm do not have the ability which is why the stand alone picked up so much.



We have been using these controllers on Mercedes with great success. The Mercedes like the c5 do not have a flex capability in the factory pcm.

Pekka_Perkeles

Very good to have options to choose from!

Standalone controllers don't change ignition timing with WOT or part throttle and may not help cold starts (depending on device, of course), but hey, not everyone needs these functions.

JT FRC 00

Yessir you are correct. Nate is working on trying to get one setup for C5's so hopefully I'll be able to try it out and see how it works. In the process right now to get some injectors ready so I can make the swap.

Rkreigh

so one of the things I'm wanting to try is 2 sets of injectors. I bought one of the "sniper style" sheet metal intakes so I can do the following and love to hear some feedback.

I have a Haltech S2000 with flex fuel sensor

127 FIC "primary" injectors" with intank Bosch and external booster pump (thinking another bosch 450)

the "sniper intake" will have another set of bungs welded up (as high as practical for the second set of injectors)

I'm going to use 80 lb injectors for the 2nd stage injectors running pure meth. I already have a dedicated 3 gal tank in back, so I'll use another bosch pump from the tank with another fuel rail and return line.

This is complicated, but for a reason. I really want to run e85 "on kill" with the ttix kit, but it's still hard to get locally. so having the "direct port meth" all under control of the haltech will allow me great flexibility to still run high boost when E85 is unavailable on the road.

Many of you may remember the old "wheel to wheel" dual fuel project where he used another "standalone" ECM to just drive the second set of injectors. (dual rotex superchargers on a SB in a nova

I realize the implementation and tuning on this will be very difficult, so I'm looking for a really solid Haltech tuner on the east coast.

Thanks!

etekberg

Complexity is the enemy of reliability. KISS

I wouldn't do it, but it certainly sounds cool

Podium

Like what? Can you not just hook up the sensor harness and enable the flex fuel in the tune?

Cordes Performance Racing

no you cannot.

wilson34

Other than changing the wiring for the O2 sensors and hooking up the flex fuel sensor there is nothing else that I am aware of.

Is that correct?