Loosing throttle response!
Thread Starter
Instructor
Joined: Feb 2011
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Loosing throttle response!
hey guys, When I pull real hard on the car and hit redline or close to it, i lose all throttle response. The car pulls great until i lay off the throttle and shift then i stomp back on the throttle and nothing. I still get resistance from the throttle but it feels almost like its stalled out but it is still running. I get nothing until the RPMs run down and then bam the engine is back to life like nothing happened. What could this possibly be?
Team Owner
Joined: Feb 2003
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From: Sitting in his Nowhere land Hanover Pa
2024 C2 of the Year Finalist - Unmodified
2015 C2 of Year Finalist
the ECM has a rev limiter built in and shuts of power to the engine at a set RPM. and please learn how to shift and drive. shifting that high you done went past the max torque and hp
Race Director
Joined: Apr 2002
Posts: 10,036
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From: Anaheim CA
My ECM has the rev limiter set to 10,031 RPM (it's effectively disabled). When I first calculated the number I thought I made a mistake. I did some research online and that is indeed the correct number.
Team Owner
Joined: Feb 2003
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From: Sitting in his Nowhere land Hanover Pa
2024 C2 of the Year Finalist - Unmodified
2015 C2 of Year Finalist
GM would never warntey such a SB at that rpm and not when the red line is below 5K
Team Owner
Joined: Dec 1999
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From: Lacey WA RVN 68-69
NCM Sinkhole Donor
The LT1powered C4's have a fuel cutoff at 5850 RPM. When you hit that point, the engine will start to miss and RPM's won't climb after that. With the L98 motors, there is a limit when the stock TPI just won't flow any more air. That is typically seen at somewhere around 5000-5200 RPM.
Thread Starter
Instructor
Joined: Feb 2011
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Thread Starter
Instructor
Joined: Feb 2011
Posts: 191
Likes: 0
This. The year of your car is needed to help figure out what you are seeing.
The LT1powered C4's have a fuel cutoff at 5850 RPM. When you hit that point, the engine will start to miss and RPM's won't climb after that. With the L98 motors, there is a limit when the stock TPI just won't flow any more air. That is typically seen at somewhere around 5000-5200 RPM.
The LT1powered C4's have a fuel cutoff at 5850 RPM. When you hit that point, the engine will start to miss and RPM's won't climb after that. With the L98 motors, there is a limit when the stock TPI just won't flow any more air. That is typically seen at somewhere around 5000-5200 RPM.
When i rebuilt the bottom end I made sure to get nothing but the strongest of the aftermarket world.
Maybe I should get a shift light until I learn the feel, pitch, and sound of my engine.
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Team Owner
Joined: Feb 2003
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From: Sitting in his Nowhere land Hanover Pa
2024 C2 of the Year Finalist - Unmodified
2015 C2 of Year Finalist
wow, I had no idea. I am relatively new to corvettes. So why is there a fuel cutoff when there is also a rev limiter. I've bounced off the limiter a few times and it seems higher than 5850 rpm and It was never accompanied with the shut off. I take the vette so far up the RPM because with the way it is set up and rebuilt its strong enough to safely extend the reline and the power just never drops off like it does in all my other experiences with other cars. In my other cars roughly 500rpm before redline I can feel the torque drop off and i've learned to shift right before that so hitting the limiter was seldom done and certainly no fuel shut off was ever experienced. Since the corvette never drops power I don't have that mechanical queue and sift at lower RPM. Maybe I need a different cam... or bite the bullet and get the car tuned raising the factory limitations.
When i rebuilt the bottom end I made sure to get nothing but the strongest of the aftermarket world.
Maybe I should get a shift light until I learn the feel, pitch, and sound of my engine.
When i rebuilt the bottom end I made sure to get nothing but the strongest of the aftermarket world.
Maybe I should get a shift light until I learn the feel, pitch, and sound of my engine.
Thread Starter
Instructor
Joined: Feb 2011
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like I said GM had to warranty these engines for so many miles and years. they did not want a bunch of these cars coming back for blown engines so they put fail safe features such as a fuel shut off and a rev limiter. I thought only simple kids in rice rockets thought its fun to bounce off the rev limiter
like I said GM had to warranty these engines for so many miles and years. they did not want a bunch of these cars coming back for blown engines so they put fail safe features such as a fuel shut off and a rev limiter. I thought only simple kids in rice rockets thought its fun to bounce off the rev limiter
So i've got 19 years, worth of reving to the last possible RPM before shifting, to revise. playing chicken with the redline is part of the skill set when racing vehicles that only have torque up high. so take it easy on me lol
I'm 26 man. I am probably younger than 95% of the people here when they first got into their first v8 sports car.
Team Owner
Joined: Feb 2003
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From: Sitting in his Nowhere land Hanover Pa
2024 C2 of the Year Finalist - Unmodified
2015 C2 of Year Finalist
SBC were never known for being very high reving excpet for a select few namely 67-69 Z-28 302. Other then that they were your mid range rpm engines peaking HP around 3500 rpm.
Advanced
Joined: Jul 2013
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Shifting near the redline is perfectly ok. Like said above, stock engines are boring and looow reving, but you said you have mods on yours, so it will likely rev nicely.
Here's my 383 lt4, redline at 6600rpm, shifting at ~6500 with no losing any power.
And here's my friends +400cid small block singing and shifting at 7500rpm
with no loss in throttle response.
So, modified small blocks love to rev.
What cam do you have? And is your car to tuned to disable all the safety features related to high revs?
Here's my 383 lt4, redline at 6600rpm, shifting at ~6500 with no losing any power.
And here's my friends +400cid small block singing and shifting at 7500rpm
So, modified small blocks love to rev.
What cam do you have? And is your car to tuned to disable all the safety features related to high revs?
Thread Starter
Instructor
Joined: Feb 2011
Posts: 191
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Shifting near the redline is perfectly ok. Like said above, stock engines are boring and looow reving, but you said you have mods on yours, so it will likely rev nicely.
Here's my 383 lt4, redline at 6600rpm, shifting at ~6500 with no losing any power. Here's my 383 lt4, redline at 6600rpm, shifting at ~6500 with no losing any power.
And here's my friends +400cid small block singing and shifting at 7500rpm
And here's my friends +400cid small block singing and shifting at 7500rpm with no loss in throttle response.
So, modified small blocks love to rev.
What cam do you have? And is your car to tuned to disable all the safety features related to high revs?
Here's my 383 lt4, redline at 6600rpm, shifting at ~6500 with no losing any power. Here's my 383 lt4, redline at 6600rpm, shifting at ~6500 with no losing any power.
And here's my friends +400cid small block singing and shifting at 7500rpm
And here's my friends +400cid small block singing and shifting at 7500rpm with no loss in throttle response.
So, modified small blocks love to rev.
What cam do you have? And is your car to tuned to disable all the safety features related to high revs?
I have a 510 lift 276/290 degrees duration
And no, that is my problem. My engine is built to run high RPM but the computer is standing there with its arms crossed saying NOPE! That 1500 dollar tune is kind of daunting, especially since I want to do some body work and a new paint job soon.
I am still very new to everything corvette. This site has been invaluable.
Team Owner
Joined: Feb 2003
Posts: 54,110
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From: Sitting in his Nowhere land Hanover Pa
2024 C2 of the Year Finalist - Unmodified
2015 C2 of Year Finalist
NICE videos man!
I have a 510 lift 276/290 degrees duration
And no, that is my problem. My engine is built to run high RPM but the computer is standing there with its arms crossed saying NOPE! That 1500 dollar tune is kind of daunting, especially since I want to do some body work and a new paint job soon.
I am still very new to everything corvette. This site has been invaluable.
I have a 510 lift 276/290 degrees duration
And no, that is my problem. My engine is built to run high RPM but the computer is standing there with its arms crossed saying NOPE! That 1500 dollar tune is kind of daunting, especially since I want to do some body work and a new paint job soon.
I am still very new to everything corvette. This site has been invaluable.
