Taking out the speed limiter
 

what do i need to do to take off the speed limiter in my 1990 iroc-z? she only goes up to around 120 and just stops after that:cry:

also, is there also a way for me to change the shift points on my car through the computer?

I think there is a tech article over at thirdgen.org about this. I have an 84 Z so I dont have to worry about it :D

Why does this sort of thing make it as a tech tip? All it is would be a simple bypass of this that or the other. Wanna enrich your fuel curve? Dump more pressure into the injectors. Never mind that you are fattening it up all over and not the place you need it most. Wanna get over the 120 mph limit, cut a switch. :rolleyes: :rolleyes:

Has anyone thought of doing it right from the get go? I mean, it is controlled by the ECM right? Get the right chip that has no limitations. If they car did not come with Z rated tires, it has the limiter. Get one without the limiter. Better yet, get a custom programmed chip that will improve performance and at the same time not have the limiter.

I am personally biased against cutting the harness unless you have no choice. Each splice is a weak spot. Someone will use a cheap butt connector instead of taking it out and soldering and it could cause problems in the future. Do it once and do it right. You will not have to do it again.

where could i get a custom chip from? i dont know squat about eprom tuning on a 3rd gen... :( lol

Me thinks you need that annoying little valve in the gearbox ripping out ( the one that kicks the box down....then up.....then down etc.) and replacing it with a B&M valve. That could be your problem.

I doubt it. That is the mechanical part of the tranny. AFAIK, the only thing the ECM controls is the lockup when the tranny is in OD.

www.fasterproms.com will do a truely custom chip. They did it for me where they burnt it to my specs, had me take some readings, reburn, take more readings and do a final burn. Truely custom to your car not something where they guy advances the timing and a couple of things and sells it to you as a custom chip. If they don't make adjustments, it is off the shelf and not custom. That is the rule I go by. Lingenfelter will drill a hole into your pass side exhaust header and take readings and drive the car. Took me quite a few hours to do it at his shop but I wasn't complaining. Took a long tour of the place.

Did any Iroc-z's come with a limiter?



Mine keeps going and going until I take my foot off the gas in my 86 IROC-Z

I think '86 still has the mechanical speedo so you won't have a limiter. Maybe I'm wrong?

-Rippin

AFAIK, if the car did not come with Z rated tires from the factory, it has a limiter.

True, but only the years they had computers in the cars (~'87+) right?

-Rippin

I was under the impression that all of the iroc's came from the factory with z rated tires which is why they dont have speed limiters....maybe thats only for the 350's??? ive topped 120 before (not by much but it was my choice not the computer). When you hit the top speed what happens? I believe that the computer basically causes an occasional miss so your car cant go any faster? Maybe something like your coil isnt strong enough up top and is breaking up? You might have a mechanical problem not a computer problem.

AFAIK, the computer will not lety you go past it. Just like a rev limiter. It will get there, let it drop till it is a little below and then go up to that point only. Not sure, never had it before but this is what I heard.

Aklim's description is right... you'll hit it, it'll almost act like fuel cut, you'll drop down 5 MPH or so, she'll rocket back up...cut, repeat. heh. Very obnoxious. Never experienced it in a thirdgen before.

Good luck man. :)

is there any way i can set it to 140 or higher instead of 120? raced a stealth r/t on the street (didnt sound stock) and i had about a car on him but when i hit 120 the damn mother f*cker passed me and made me look stupid, lol