1994 Mustang RPM liniter
08-02-2017, 10:39 AM
#1
Thread Starter
Join Date: Oct 2008
Location: Illinois
Posts: 17
1994 Mustang RPM liniter
I have had a 1994 and 1995 Mustang GT, both cars appear to have a 5500 rpm rev limiter. I have a 1994 Mustang GT 5 spd now and I am leery about doing performance mods if the car won't go over 5500 rpm.
I have researched and can't find anything specific on how to resolve this issue? I read one issue might be the fuel pressure is getting dropped to cut the rpm off. Im looking to put a cam and aluminum heads on the 1994 GT and don't want to be limited to 5500 rpm. I also had 1993 mustangs and never experienced this problem, the 1993 was modified and would pull to 6500 rpm. Any help would be greatly appreciated.
The 1995 Mustang GT I had before was supercharged. Motor could easily pull over 5500 rpm but would stumble after 5500. I had a computer chip programmed and it still didn't resolve the problem. Any help would be greatly appreciated.
I have researched and can't find anything specific on how to resolve this issue? I read one issue might be the fuel pressure is getting dropped to cut the rpm off. Im looking to put a cam and aluminum heads on the 1994 GT and don't want to be limited to 5500 rpm. I also had 1993 mustangs and never experienced this problem, the 1993 was modified and would pull to 6500 rpm. Any help would be greatly appreciated.
The 1995 Mustang GT I had before was supercharged. Motor could easily pull over 5500 rpm but would stumble after 5500. I had a computer chip programmed and it still didn't resolve the problem. Any help would be greatly appreciated.
08-02-2017, 03:05 PM
#2
5th Gear Member
Join Date: Jul 2012
Location: ohio
Posts: 3,628
Your not hitting the rev limiter.
You're seeing mechanical valve float. The stock heads wont hold much past 6250 and sometimes even 5200 rpm can start to float them if the springs are worn, or the car sat for a long time with the springs compressed. Your rev limiter is right around 6500-7k depending on what computer is in the car auto vs manual,, the manual transmission cars have a higher rev limit. Also your stock heads do not move enough air at high rpm. I shifted my 95 manual with a cam on gt40 heads and intake at right about 6500.
You're seeing mechanical valve float. The stock heads wont hold much past 6250 and sometimes even 5200 rpm can start to float them if the springs are worn, or the car sat for a long time with the springs compressed. Your rev limiter is right around 6500-7k depending on what computer is in the car auto vs manual,, the manual transmission cars have a higher rev limit. Also your stock heads do not move enough air at high rpm. I shifted my 95 manual with a cam on gt40 heads and intake at right about 6500.
08-24-2017, 06:10 AM
#5
2nd Gear Member
Join Date: Aug 2017
Location: North Carolina
Posts: 489
All great replies. When campaigning our 1994 Mustang Gt the engine would stumble about 100 feet before the quarter mile finish line. After much time and aggravation we discovered our factory ECU, rev limiter, was causing the problem. Even with the MSD 7AL-2, with bumped up RPM chips, the factory rev limiter could not be changed/overridden. We had to have the factory ECU completely reprogrammed in order to override the OEM rev limiter. All the other suggestions are very valid. Just one of my many war stories about drag racing.
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