Weird Isssue...Help!
Thread Starter
Racer
Joined: Apr 2022
Posts: 258
Likes: 35
From: Boring Green, Kentucky
Weird Isssue...Help!
My C5 has some issues going from 1st to 2 second on WOT. I get it up to 5500-6000 in 1st, then when I get her into 2nd, she falls flat on her face. It lasts about 2 seconds, them the motor picks up again. The motor doesn't stall, but the loss of power always puts my face into the steering wheel.
98 C5, heads, cam, nitrous, long tubes, and every bolt on your can think of. She dynoed at 516rwhp with nitrous, which to is kinda low to me. I had a tuner slap on the 200 shot wet kit. I thought he was going tune it as well, but when I picked it up, he said it was already tuned, so he didn't do it. Aren't you supposed to re-tune after a nitrous install? This is my first nitrous car. Please keep in mind, that this event occurs with the nitrous unarmed. The internals are forged.
I'm ready to race, but 'can't seem to wrap my head around this.
I would gladly welcome any theories, thanks!
-Tom
98 C5, heads, cam, nitrous, long tubes, and every bolt on your can think of. She dynoed at 516rwhp with nitrous, which to is kinda low to me. I had a tuner slap on the 200 shot wet kit. I thought he was going tune it as well, but when I picked it up, he said it was already tuned, so he didn't do it. Aren't you supposed to re-tune after a nitrous install? This is my first nitrous car. Please keep in mind, that this event occurs with the nitrous unarmed. The internals are forged.
I'm ready to race, but 'can't seem to wrap my head around this.
I would gladly welcome any theories, thanks!
-Tom
Thread Starter
Racer
Joined: Apr 2022
Posts: 258
Likes: 35
From: Boring Green, Kentucky
Ahhhhh, that could be it. Yikes. Big $. 
I thought it could have been a fuel delivery issue like injectors or fuel pump, but this problem occurs without nitrous. I hope you're wrong, but you are probably right. Also, shifting gears has become very notchy.
edit: I did some research, and it looks like clutch for sure. ****! Any recommendations? I don't know where to begin. I need a clutch to handle 500-600 rwhp. Would a bad clutch drop the rpms very low between shifts?
I thought it could have been a fuel delivery issue like injectors or fuel pump, but this problem occurs without nitrous. I hope you're wrong, but you are probably right. Also, shifting gears has become very notchy.
edit: I did some research, and it looks like clutch for sure. ****! Any recommendations? I don't know where to begin. I need a clutch to handle 500-600 rwhp. Would a bad clutch drop the rpms very low between shifts?
Last edited by zztopo; Aug 20, 2023 at 01:03 AM.
Drifting
Joined: Feb 2017
Posts: 1,274
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From: Tacoma WA
2024 C4 of the Year Finalist - Unmodified
A bad clutch should not drop the rpms while shifting. In fact the opposite should be true since the clutch would be slipping allowing the engine to rev higher due to the load on the engine not being fully transferred to the engine.
You mention it “falls on its face” which seems to indicate a loss of power not a clutch issue. I would do some serious troubleshooting before I considered changing the clutch.
You mention it “falls on its face” which seems to indicate a loss of power not a clutch issue. I would do some serious troubleshooting before I considered changing the clutch.
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Joined: Sep 2013
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From: Cape Coral, Florida
Just put the car in 2nd gear and with the E brake on raise the RPM to 3000 RPM and let the clutch out and see if it stalls...that's how I used to check it on my '72 Z28 back in the day...LOL !!!...if clutch is good and you have a good scan tool we can look at a few things.
Thread Starter
Racer
Joined: Apr 2022
Posts: 258
Likes: 35
From: Boring Green, Kentucky
Fiberbundle, I was pondering that late last night. Based on my incidents, it does seem that the problem is coming from the power plant itself. She really does fall on her face, with rpms disappearing when I upshift. Reason being what you said; the power essentially cuts out, but does not completely stall-out. And, the clutch doesn't bear any other symptoms, like slippage, growling noise, spongy clutch feel, or loss of acceleration with high rpm's. The clutch grabs hard and solid when rolling out in first gear.
I plan to duck-hunt a mechanic who tunes. Maybe that will help. But there are not any in my area, based on recent experiences.
I really want to thank you for responding, you have helped me greatly. Have a good day!
-Tom
I plan to duck-hunt a mechanic who tunes. Maybe that will help. But there are not any in my area, based on recent experiences.
I really want to thank you for responding, you have helped me greatly. Have a good day!
-Tom
Thread Starter
Racer
Joined: Apr 2022
Posts: 258
Likes: 35
From: Boring Green, Kentucky
Just put the car in 2nd gear and with the E brake on raise the RPM to 3000 RPM and let the clutch out and see if it stalls...that's how I used to check it on my '72 Z28 back in the day...LOL !!!...if clutch is good and you have a good scan tool we can look at a few things.
