Stupid question about speed limiters...

I am a little bit confused about the speed limiters on Z28s. My '94 had no limiter, but on my buddies '97 it cuts out at about 125. So I was figuring they put them on starting sometime in the mid 90s, but then today i was driving my '99 to work and got up to 140. So anyone know why some Z28's have them and others don't?

My old 1991 305 TPI Z28 had one but my current two 1991 350 Z28s don't. The dealer told me it depends what tire came with the car.

where the hell do you live and go to hit 140 going to work...

The speed it is limited at depends on what the factory tires were rated at as far as I know. So if the car came with 125 mph rated tires, that's where the speed limiter is set.

Live in San Francisco. I usually leave at 5am and there is absolutely no traffic on the Bay Bridge that early. Its about 5 miles long and 5 open lanes... theres plenty of room.

Why wouldn't they just sell 160 mph rated tires on all '93 and up Camaros?

Because 160 mph rated tires would cost them more money and arent nessicary.

their nessesary if you plan on driving your car to its full potential.

yup, it was the speed ratings. cars ordered with the performance tires were not speed limited. It was a marketing plan for GM to make more money by sales of Performance Tires.

I was wondering why my car cut out at 120, but it started shaking really bad at 117, cuz of the tires?

Is that the big orange bridge?

Shaking as at high speeds can be the tires but its also common for a steel driveshaft to cause this because they arent made as well as the high performance aluminum versions.

Most people who buy cars from the dealerships drive them on the road and therefore cant legally drive them to their full potential. ITs just another way to try and keep dumb kids from taking corners at mach 1 and smearing their faces across the windshield and leaving pieces of the head for the emergency crews to deal with.

tire size and characteristics are only part of it. some cars may have higher limiters due to their application also. ie. if you got the b4c police package, those limiters are ususally set around 140-150 (my friends 9c1 caprice is 154). also it depends on who owned the car before and the engine setup. if its all stock there should be a limiter at around 100. someone could have reburned the ecm to have a higher limiter, others may have and engine not computer controlled, so it really depends.

tire size and characteristics are only part of it. some cars may have higher limiters due to their application also. ie. if you got the b4c police package, those limiters are ususally set around 140-150 (my friends 9c1 caprice is 154).


B4C has no limiter. It is all about the tire rating for all 4th Gens. when I say no limiter, I am bluffing..LOL..The cars with 'no limiter' are actually set to 255mph. However, with the drag coefficient and horespower the cars cann not go that fast. I think most LT1's (that have been dumb enough to try) can go close to 160 with a couple bolt ons.

Is that the big orange bridge?

No, thats the Golden Gate Bridge. I'm talking about the Bay Bridge. Its what connects Oakland to San Francisco. Its about twice as long as Golden Gate.

eh.. other side of the country heh

This is the skinny:

If your 94+ came with Z rated tires your speed limiter is set to 160 MPH.

If it came with the R rated tires your speed limiter is set to 117 MPH.

This is the skinny:

If your 94+ came with Z rated tires your speed limiter is set to 160 MPH.

If it came with the R rated tires your speed limiter is set to 1117 MPH.
1117mph WOW i want those tires... what are you talking about? do you mean 117mph?

I corrected my post as you posted yours, it is 117 MPH

ok, haha i beat you on it, i posted faster...

If your 94+ came with Z rated tires your speed limiter is set to 160 MPH.


Nope, it is set to 255

I'm talking about the Bay Bridge.

The one that collapsed in that big assed earthquake is the bay bridge!

I used a Hypertech programmer and set mine at 168 or so, but can't seem to do past 147... not that it's a big deal or anything. I know it has the power, just won't go past it for some reason.

I used a Hypertech programmer and set mine at 168 or so, but can't seem to do past 147... not that it's a big deal or anything. I know it has the power, just won't go past it for some reason.

Really, thats interesting... I am curious now. if you go to www.f-bodyhideout.com they have a video of a stock camaro going 155

Nope, it is set to 255

Sir, you obviously (sp) do not know what you are talking about. The TSL(Top Speed Limiter) is set per federal regulations (I do not know the regulation number), that the top speed of the vehicle can not exceede the tires rating. If you have a Z rated tire, with a Y next to a number off to the right of the tire size, the tire has been tested to 165 MPH.

If you take the above statement to be true, HOW CAN THEY SET THE TSL TO 255 MPH? that would exceede the tires speed rating.

If your TSL is set to 255 MPH, it was altered from the origional setting by LS1 edit or an HPPIII.

JMHO

Gurrzt,
Do me a favor and E mail Bryan at PCM for less or any other PCM programmers that do LT1's. they will tell you that LT1 cars without Speed limiters are set to 255. I have reprogrammed enough LT1 PCM's from stock to know what I am talking about..LOL. Let me see if I can save a screen of a stock program when I get home. I know I have a 95 stock program and a stock 94 program (different Transmission programs). Fact is, the LT1 did not have the power to go above 160mph in it's stock configuration due to weight and Drag/aerodynamics.

From camaroz28.com:
post about speed limiters, Injuneer sets em straight VIA madwolf post (http://web.camaross.com/forums/showthread.php?threadid=257473&highlight=limiter+255)

another post from Madwolf (http://web.camaross.com/forums/showthread.php?threadid=183005&perpage=15&highlight=limiter%20255&pagenumber=3)

another, but from RSKrause (http://web.camaross.com/forums/showthread.php?threadid=146323&perpage=15&highlight=limiter%20255&pagenumber=2)
in case you do not know, Madwolf is a Programmer for our cars
www.madz28.com is his site.

These articles are all the same stuff just on diff F body websites:
http://www.f-body.org/tech/4th_gen.htm
http://camarossworld.com/Specifications/
http://www.pontiac.sk/history.php
in all those articles under the 1993 year it says:
The base tires were the Eagle GA with an S speed-rating. Any cars with these tires included a 105 mph speed limiter. The base coupes only came with the GA, but the V8 cars could be ordered with the Eagle GS-C (QLC) Z-rated high performance tire, which did away with the speed limiter entirely.


Since OBD-II tuning software is still too much $$$ the info I know of PCM controls on these cars is for OBD-I. GM did incorporate a 160mph limiter (or near there) for the OBD-II cars (1996+), but top speed on the OBD-I cars was set to 255 with Z rated tires.

play nice...

Deadcarny:

You are obvioulsy more educated in these matters than I am. I stand corrected.

I do know my 2001 had the TSL set to 165. I previosley owned a 1994 Z28, however I never altered the vehicle.

Thanks so much for the information.

No prob man. I have been messing with these cars for a few years now, so I have a lot of useless info in my head...LOL