Anyone know how to make a FCD for an NA? I know its suppost to be at 7800, but as soon as my buzzer comes on at 6800 the power nose dives, if im in first it literally throws you forward, it still climbs, but at about half speed. While this isnt any consern now, it will be when i switch to an s5 intake, so if anyone knows, or doesnt think its fuel cut, please respond

 

that's cause you don't have any power above that, I don't think n/as have fuel cut.

 

no power up there... shift sooner.

 

ok, thanks, i was kinda thinking hat, cus i know our torque dies up there, but its just so drastic i thought it might be fuel cut. there will be power up there when im threw with it :-)

 

My friends 86 has a very obvious fuel cut right about where your talking about. Its not just lack of power unless it has a huge and i do mean huge dive in power(like 100hp). I'm talking about 7800rpm in first or so.

 

ya it has fuel cut at 7800, since redline is 7000

 

I'm by no means condoning gettin to 7800. But it does cut off fuel.

 

Its a rev limiter not a fuel cut. It is so people dont over-rev thier engine. This is because the s4 redlines at 7k not 7800.

 

do S5 have a rev limiter?

 

i have revved stock s4 to 8000 for extremely short peiods rarely and it has never cut off.

 

well maybe that's cause the stock tach is off. I've taken my old 88 SE to 8k to once and it didn't but off either.
But in my 89 GXL at 8k my AFC shows 7.5k, so maybe that's why the rev limiter didn't go.

 

IT HAS A FUEL CUT ....some argue that it is at 8100 but some tachs are off 300rpms so put 2+2 together there ya go....

 

You should have power up to 7300-7500 RPM. I doubt that it is related to fuel unless you have an old fuel pump or dirty pick up and filter.

Typically if it is dieing before that, check your ignition system (like plugs, plug wires, and coils). It should not be down on power that much at 7000 rpm.

 

I took my s5 over 8500 once just to see if the rev limiter was there - it was..

 

I don't think so. One time when I went drifting I was a little pissed so I tried to blow the motor by over-reving. Damn needle went around or past 9K After that I was all like..."What the hell...," and let off. LOL Either that the rev limiter would be after 9 which would make no sense at all. Considering that you would want the rev limiter before redline. Peace

 

There you have it. - Some do & some don't..

 

the S5 n/a's limit at 8800 or so....

keep in mind, those of you that say they don't hit it. the limiter is controled by electrics, which suck *** in these cars. if you've gone past. it means you need to resolder stuff LOL

 

Which wire do I cut then?

My S-AFC says somewhere around 8137ish (within a couple revs or so) everytime she cuts out on me.

I have a heavily street ported S4 with S5 TII intermediate housing (also ported) and I have massive power untill she cuts out.

How do we get rid of this device? I should have power till the engine blows up and I want to be able to rev to 10K dammit!

 

Im in a different boat than anyone here. I have a heavily ported motor, and 3 main window bearings, 100 psi oil pressure regulator, etc. My motor was built to go past the 8600 rpm limit on my 90, but I NEED to disable the rev limiter to be able to use the last few hundred rpm of my powerband. I will have something to control the fuel, but the rev limiter will affect what I use to control the fuel.

 

how is that different than me? My engine is ready to wind to the limits of the e-shaft. I just need to get it to rev above 8100 and change...

 

NA's do not have a fuel cut, just a rev-limiter. Fuel cuts are used in turbo cars as a safety tp prevent running dangerous boost pressures w stock fuel systems. Fuel cut doesn't drop power when triggered...ther motor cuts out and the car feels like it hits a brick wall!! In my GVR4 I used to hit fuel cut on very cold nights w/ my big ported 16G spinning 1.2 bar

 

so, how do we get rid of it?

 

The rev limiter (8,600rpm according to the FSM) is part of the ECU's software, you can't just cut a wire. An aftermarket chip might remove it, but really, if you need to rev that high you should seriously consider an aftermartket programmable ECU. The stock ECU's maps won't safely support those revs, plus the AFM will be strangling the engine. I doubt there'd be much more power up there whatever your porting.

 

Yeah Jason is exactly right. The maps and control on the factory ECU do not support much past 9000 rpm. You need to be using an aftermarket unit like the Haltech

 

What if my car used to be an automatic and now it is a manual? The old redline was 7k; so was the limiter lower also?