Pontiac Firebird 1967-2002 Birds of a feather flock together

Speed limiter

Thread Tools
 
Search this Thread
 
Old Jul 31, 2012 | 05:44 PM
  #1  
Kuhny's Avatar
Thread Starter
Registered User
 
Joined: Jul 2012
Posts: 12
Likes: 0
Default Speed limiter

Hey guys i have a 98 trans am that according to the door code it came with z rated tires but it wont go faster than 120 mph !
Ls1 no mods 6 speed 3.73 gears ! Whats the deal my wifes 98 t/a automatic climbs well above 120
Reply
Old Jul 31, 2012 | 07:09 PM
  #2  
N20zuki's Avatar
TECH Resident
 
Joined: Jun 2009
Posts: 856
Likes: 2
From: Elizabeth City NC
Default

If it came with Z-rated tires then the stock speed limiter should be 162mph.... If no Z-rated tires then it will be 118mph.... You may not have the stock ECM in the car and was swapped with a car without Z-rated tires.
Reply
Old Jul 31, 2012 | 07:20 PM
  #3  
ShowstoppaTransAm's Avatar
On The Tree
 
Joined: Mar 2005
Posts: 151
Likes: 1
From: Savannah
Default

A handheld programmer can fix this i believe. I just bought a Hypertech and there is a option for this.
Reply
Old Jul 31, 2012 | 09:01 PM
  #4  
Paul Bell's Avatar
That's MISTER MODERATOR
20 Year Member
Photogenic
Liked
Loved
iTrader: (9)
 
Joined: Nov 2005
Posts: 7,616
Likes: 65
From: NYC
Default

Kuhny, Welcome to LS1tech! SEARCH will be your best friend around here.

3.73 gears are certainly not stock so that car has at least that modified.

What RPM's are your turning at your 120MPH?
Reply
Old Aug 2, 2012 | 08:24 AM
  #5  
Kuhny's Avatar
Thread Starter
Registered User
 
Joined: Jul 2012
Posts: 12
Likes: 0
Default

In 5th @ 125mph "its 5mph or so off" its only around 4000 rpms or so . But i can take 1st through 4th 6000 rpms
Reply
Old Aug 2, 2012 | 08:31 AM
  #6  
Paul Bell's Avatar
That's MISTER MODERATOR
20 Year Member
Photogenic
Liked
Loved
iTrader: (9)
 
Joined: Nov 2005
Posts: 7,616
Likes: 65
From: NYC
Default

What speedometer is in this car?
Reply
Old Aug 2, 2012 | 10:19 AM
  #7  
Kuhny's Avatar
Thread Starter
Registered User
 
Joined: Jul 2012
Posts: 12
Likes: 0
Default

155 mph
Reply
Old Aug 2, 2012 | 11:03 AM
  #8  
Decadence75's Avatar
TECH Resident
iTrader: (17)
 
Joined: Nov 2011
Posts: 878
Likes: 1
From: Pearl, MS
Default

Just.... wow.

That is the rating of your tires, not the limit of the car.
Reply
LS1 Tech Stories

The Best V8 Stories One Small Block at Time

story-0

Topdon ONE vs. Artidiag 800 BT2: Which is the Diagnostic Tablet For You?

 Pouria Savadkouei
story-1

Gas Monkey Built a 6-Wheel Ferrari Testarossa With a Corvette LT4 Engine

 Verdad Gallardo
story-2

7 Most Reliable High-Performance Engines GM Has Ever Built

 Verdad Gallardo
story-3

Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin

 Verdad Gallardo
story-4

6 Common C5 Corvette Failures and What's Involved In Repairing Them

 Pouria Savadkouei
story-5

Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph

 Verdad Gallardo
story-6

Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked

 Pouria Savadkouei
story-7

Top 10 Most Powerful Chevy Trucks Ever Made!

 
story-8

Hennessey's New Supercharged Silverado ZR2 Has 700 HP

 Verdad Gallardo
story-9

Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes

 Verdad Gallardo
Old Aug 2, 2012 | 11:28 AM
  #9  
Kuhny's Avatar
Thread Starter
Registered User
 
Joined: Jul 2012
Posts: 12
Likes: 0
Default

It wont run faster than 120 mph
Its limited for some reason Ive had my automatic ta speedo buried guessing 160 mph 2.73 gears
Reply
Old Aug 2, 2012 | 11:36 AM
  #10  
Kuhny's Avatar
Thread Starter
Registered User
 
Joined: Jul 2012
Posts: 12
Likes: 0
Default

Paul Bell asked which speedo was in my ta i said 155 mph
Reply
Old Aug 2, 2012 | 11:48 AM
  #11  
Decadence75's Avatar
TECH Resident
iTrader: (17)
 
Joined: Nov 2011
Posts: 878
Likes: 1
From: Pearl, MS
Default

Originally Posted by Kuhny
It wont run faster than 120 mph
Its limited for some reason Ive had my automatic ta speedo buried guessing 160 mph 2.73 gears
163 is the limit...that is set in the computer. Not your tires. And just on a side...it is very very irresponsible to go that fast on public roads.
Reply
Old Aug 2, 2012 | 12:49 PM
  #12  
Kuhny's Avatar
Thread Starter
Registered User
 
Joined: Jul 2012
Posts: 12
Likes: 0
Default

I was on an old air strip never said i was on a public road. And if the car didnt come with z rated tires it was computer limited to 118 mph if equiped with z from factory 162 mph limit
Reply
Old Aug 2, 2012 | 01:09 PM
  #13  
Kuhny's Avatar
Thread Starter
Registered User
 
Joined: Jul 2012
Posts: 12
Likes: 0
Default

It is very irresponsible your right but your mom loved it!!!!!!!!
Reply
Old Aug 2, 2012 | 06:50 PM
  #14  
Paul Bell's Avatar
That's MISTER MODERATOR
20 Year Member
Photogenic
Liked
Loved
iTrader: (9)
 
Joined: Nov 2005
Posts: 7,616
Likes: 65
From: NYC
Default

Originally Posted by Decadence75
Just.... wow.

That is the rating of your tires, not the limit of the car.
The max speed of the car set in the PCM was determined by what tires originally came with the car from the factory. The Z rated tires were part of a package that included the higher MPH speedo.

Kuhny, if your speedometer is indicating the correct speed (EG: It reads 50 when you're traveling at 50) the PCM's ratio is correct but it's from another vehicle with the lower max speed set.
Reply
Old Aug 2, 2012 | 07:31 PM
  #15  
Kuhny's Avatar
Thread Starter
Registered User
 
Joined: Jul 2012
Posts: 12
Likes: 0
Default

Alright man i appreciate it . Which programer should i buy? to do away with this.
Reply
Old Aug 3, 2012 | 01:37 PM
  #16  
Hypertech's Avatar
Teching In
 
Joined: Apr 2010
Posts: 17
Likes: 0
Default

The Hypertech Max Energy will allow you to move the Top Speed to the speed rating of the tires. If you raise it all the way up it will take it to 255mph,which you will never see.
Reply
Old Aug 4, 2012 | 11:38 PM
  #17  
Kuhny's Avatar
Thread Starter
Registered User
 
Joined: Jul 2012
Posts: 12
Likes: 0
Default

Ok thanks guys for all the info . Check out my vids on youtube 22kuhny
Reply




All times are GMT -5. The time now is 10:32 PM.

story-0
Topdon ONE vs. Artidiag 800 BT2: Which is the Diagnostic Tablet For You?

Slideshow: We take a close look at the ONE and Artidiag 800BT2 diagnostic tools from Topdon and the reasons to buy one over the other.

By Pouria Savadkouei | 2026-05-28 11:05:11


VIEW MORE
story-1
Gas Monkey Built a 6-Wheel Ferrari Testarossa With a Corvette LT4 Engine

Slideshow: The controversial Ferrari F6 swaps its original flat-12 for a Corvette Z06-derived LT4 V8 and sends power to four rear wheels through a custom-built drivetrain.

By Verdad Gallardo | 2026-05-26 18:23:54


VIEW MORE
story-2
7 Most Reliable High-Performance Engines GM Has Ever Built

Slideshow:These GM engines didn't just make huge power, they survived abuse, boost, track days, and six-digit mileage with a reputation for refusing to quit.

By Verdad Gallardo | 2026-05-21 16:45:27


VIEW MORE
story-3
Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin

Slideshow: This heavily modified 1971 Camaro mixes classic muscle car styling with a fifth-generation Camaro interior and modern LS3 power.

By Verdad Gallardo | 2026-05-12 18:06:42


VIEW MORE
story-4
6 Common C5 Corvette Failures and What's Involved In Repairing Them

Slideshow: From wobbling harmonic balancers to failed EBCMs, these are the issues that define long-term C5 ownership and what repairs typically involve.

By Pouria Savadkouei | 2026-05-07 18:44:57


VIEW MORE
story-5
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph

Slideshow: A modern Camaro transformed into a retro icon, this limited-run "Bandit" build blends nostalgia with brute force in a way few revivals manage.

By Verdad Gallardo | 2026-04-21 13:57:02


VIEW MORE
story-6
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked

Slideshow: Cadillac didn't just crash the high-performance luxury vehicle party, it showed up loud, supercharged, and occasionally a little unhinged...

By Pouria Savadkouei | 2026-04-16 10:05:15


VIEW MORE
story-7
Top 10 Most Powerful Chevy Trucks Ever Made!

Slideshow: Top ten most powerful Chevy trucks ever made

By | 2026-03-25 09:22:26


VIEW MORE
story-8
Hennessey's New Supercharged Silverado ZR2 Has 700 HP

Slideshow: Hennessey has turned the Silverado ZR2 into a 700-hp off-road monster with supercharged V8 power and a limited production run.

By Verdad Gallardo | 2026-03-24 18:57:52


VIEW MORE
story-9
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes

Slideshow: A one-off sports car that looks like a vintage Italian exotic-but hides a C6 Corvette underneath-just sold for the price of a new mid-engine Corvette.

By Verdad Gallardo | 2026-03-23 18:53:41


VIEW MORE