When to switch to a stand alone system

9397SVTs

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Hi. I'm asking for opinions on when it becomes necessary to replace the factory ECM with an aftermarket system.

I have a '97 Cobra with the LLX4 ECU. The car has been tuned with an SCT chip and uses a Diablo MAFia.

The engine is +.020 w/ stock stroke. (283)
Ported "C" heads w/ FR500 valves and valvetrain
degreed '04 Mach 1 cams
Manley rods, CP pistons (9.0:1, I believe)
Sullivan U/L and 1" spacer
BBK twin 62mm TB
twin 61mm turbos (old HP kit) full 3" exhaust, dumps at axle
120# injectors (Accleronics injector driver)
3 255lph pumps(Fore hat in 03-04 Cobra tank)
-10 feed, -6 return, aftermarket rails, Weldon FPR
MAF in 4" tube w/ honeycomb before sensor

Car runs on E54 only.

Drivability is great. Cold/hot start is great. Idle is great. Basically, it's like stock.

Here's the reason for the question. The car makes 880/793 SAE @ 22 psi and 19* of timing at 6500 rpm. I have been considering changing camshafts and adding a few more degrees of timing. I'd like to turn about 7500 rpm, as I think this is where the Sullivan would rather be.

I am thinking that I may be at the limits of the factory ECU in terms of speed/ability/reliability. Do you think this is safe or wise?

This is strictly a street car, so it's not seeing WOT all of the time.
 

9397SVTs

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I'm surprised by the lack of responses. Between here and another forum, the question has had nearly 300 views. Not a single response addressing the factory ECU. I guess I'll have to contact known tuners by phone and solicit their opinion.

I was hoping that there would be at least one Ford engineer here that could provide some insight.
 

cj428mach

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Id get in contact with decipha.

Fyi Megasquirt is in beta testing for a plug in play ecu for 96-04 mustang.
 

01yellercobra

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Probably because a lot of us are still on the stock ECU. I don't think there's a specific point of needing to switch. For me personally I've decided that when the time comes to get dumb again (and it will) I'll switch to a stand alone as I like the idea of having flex fuel capability.
 

gt347mustang

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Will the stock ecu work? Yes.

Will an aftermarket dedicated racing ecu work better and be safer? Yes.
 

Weather Man

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Stand alone ECU/display is not a cheap deal, and few do it unless race car.
 

ShootyMCstabby

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I have read in my quest to find the answer. Remember reading somewhere between 1000-1200RWHP. I don't remember if the coils(spark loss) can't keep up or the ecu.

Seems like its more of a convenience to switch over. Once people are in that power range. As I can't really find/remember a thread of the ecu being a issue. Besides the spark loss. Maybe it was a safety issue. Trying to save your investment knock sensors when going turbo and what not.

I am running 25# w/ 22* timing on a 3.4l w/e85 very close to your #'s (#'s with the magnum). Running a KC and a/c on full. Car/ecu and stock coils never missed a beat. I don't feel then need to change out the ecu for say a holley dominator set up just quite yet.
 

DSG2003Mach1

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you might get a better response in the NA SVT facebook group, there is also a Mod Motor w/ Holley EFI group.

these aftermarket units arent as constrained to race cars as they used to be. With these systems you can run low impedance injectors that cost waaaaaaaaaaaaaaaaaaaaaaaaaaaaay less than our high impedance ones, that alone pays for a big chunk towards the aftermarket setup. A set of big ID's is 1k+, an equivalent set of low impedance injectors are 200-300 from what I was reading
 

smashedheadcat

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I don’t think there is a perfect answer here. I was sick of doing work arounds for everything when using the factory ecu. Here’s a few examples:

ID1300 injectors.... scale everything in the ecu back.

BA2800 MAF (with a mafia), scale all that crap again.

Spark issues? Gap the plugs as tight as possible.

Worried about your AFR? Run 2 widebands, add knock detection, or run e85....

I just got sick of messing with it. A Holley ecu can run any injector and lets you ditch the MAF. If you have spark issues, your aftermarket ecu can support a plethora of upgraded ignition systems. Knock sensing and flex fuel capabilities are easily supportable as well.

They are not cheap, but if they save you a shortblock, it’s paid for itself.
 

9397SVTs

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I am using a boost-a-pump to increase voltage to the coil packs. I haven't had any spark problems.

I'm not on Facebook.

I'm already running low impedance injectors.

I don't mind spending the money. I just want to be sure that there is some necessity.
 

DSG2003Mach1

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I just really dont remember what I read about the RPM limits of those computers. Have you tried looking around over on Modular Fords? It's not very active these days but a lot of serious tech over there
 

smashedheadcat

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That's great. You've done the work arounds that I did not want to do (or keep doing). As I mentioned previously, it is this type of work-around that made me switch to an aftermarket ECU.

If you're looking for the hardlimit for when the ECU simply cannot keep up, I think you're looking at somewhere in the 7500+rpm range. You can scale around the airflow limits at the cost of resolution, but RPM is where you find the wall.
 

decipha

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the stock ecu is only limited by your tuners personal competency

with that said on those older slower ecus such as yours Id say any more than 1200rwhp or so and your tuner is more than likely not gonna be happy as it gets tedious keeping it streetable
 

9397SVTs

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Thanks for the replies.

The factory ECU seems to be mostly rpm limited, even though it is slow compared to other factory offerings. If I keep it 7500rpm and below, it should be fine with my set-up. I've received a few responses from people I've emailed and this seems to be the case.
 

9397SVTs

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the stock ecu is only limited by your tuners personal competency

with that said on those older slower ecus such as yours Id say any more than 1200rwhp or so and your tuner is more than likely not gonna be happy as it gets tedious keeping it streetable

If I used the Moates QuarterHorse and Tuner Pro, would I be able to tune on the fly and datalog? Is there a provision for flex fuel or would it be 2 separate tunes? The website does not show my ECU strategy as being supported.
 

decipha

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what website?

yes you can realtime tune no problem. I have datalogging disabled for non remote tunes. If you want it I'll give it to your for $200.
 

9397SVTs

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I was on Moates website and bouncing around the different links. I went and rechecked what I thought I read. I was wrong.

Does or can it be set up for flex fuel?
 

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