Stock EEC Tuning Confusion (T4M0)

[Terrorist 5.0]

Hello everyone, I have fallen into the rabbit hole of confusion again. Here is the story so far. I took the car out one night and while sliding around I bumped into what seemed like the rev limiter. It hit at about 6200-6300. The car is fine, not worried about that, as I'm sure the engine can handle it, but it didn't feel quite right. It is hard to explain, but it bugged me enough to search for what the actual rev limiter is set to on these cars. I have confirmed I have the T4M0 computer. I searched on youtube for a clip of the rev limiter, and I was only able to find a few after looking for hours. They all hit around 6200-6300. Call it 6250. It is well documented that the Foxbody, as well as the SN95 5.0 Cobra (J4J1) have a rev limiter of 6250 RPM. But when I went to check out what the T4M0 rev limit is set to, it is reported that it is set to 7000. This makes no sense, as the engine makes no power at that RPM, and would likely destroy the stock top end, not to mention rapidly wear out the bottom end if it even lives. My only question is that how is it that the RPM limit in the computer is set to 7000 RPM, yet all 5.0 SN95's I've seen, including mine, seem to hit at 6250 RPM? It can't just be valve float. It can't be perfect enough that each one I've seen, ranging from stock to modified, worn out to mechanically sound, seem to always hit at the exact same RPM. Is there something in the stock tune I'm missing? Anyone have any answers? It seems like its only the T4M0 that is like this too. The auto computers seem to be limited at 5700 RPM in neutral, and 5800 RPM in gear IIRC (don't quote me on that but fairly confident), I can post proof or show the proof on request, I just need to figure out how.

 

[Wmac]

Think that there is a lot of misinformation out there about the OEM "rev limiter" of SN95 ecu's. Rather doubt that the T4M0 is set at 7000 rpm, all I have ever heard is 6250. No way the valve train or bottom end would hold-up.

Your info on the auto ecu is incorrect. My GTS had the W4H0 ecu (2.73 gears) and the fuel cutoff was about 5250rpm. Needed a chip to up the limiter with 4.10 gears. In stock configuration a wot shift in drive, 1/2 shift would bang the limiter every time. 2/3 shift would just touch it. And I had a jmod valve body, shifts were very quick.

Also, the factory tachometer can be very inaccurate.

 

[Terrorist 5.0]

Think that there is a lot of misinformation out there about the OEM "rev limiter" of SN95 ecu's. Rather doubt that the T4M0 is set at 7000 rpm, all I have ever heard is 6250. No way the valve train or bottom end would hold-up.

Your info on the auto ecu is incorrect. My GTS had the W4H0 ecu (2.73 gears) and the fuel cutoff was about 5250rpm. Needed a chip to up the limiter with 4.10 gears. In stock configuration a wot shift in drive, 1/2 shift would bang the limiter every time. 2/3 shift would just touch it. And I had a jmod valve body, shifts were very quick.

Also, the factory tachometer can be very inaccurate.

That’s exactly what I mean. Anybody else have any information?

 

[Musturd]

Problem is where we live next to nobody deals with stock ecus on these cars anymore unfortunately. Parm at jawanda Motorsports might still have some chips in stock to sort you out but the wait list is probably 3-5 months currently