Slippage with clutch when shifting at high RPM...
09-10-2012, 01:36 PM
#21
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There is no rev limiter at 5000 rpm, except for the acceleration based rev limiter and since he doesn't have gears or turbos he's not going to hit that one.
There is, on some cars I understand (I'm pretty sure Z06's, didn't know about coupes but maybe newer ones have it) a rev limiter that kicks in if the clutch pedal isn't all the way up. There is a clutch pedal switch at the top and the bottom. If the clutch switch isn't all the way up your cruise control won't work.
I've never had trouble with this switch based rev limiter nor have I seen it in any tuning I've done, but I have heard stories from reliable folks (Ranger) that it exists.
I suspect the OP's pedal isn't coming all the way up after a high rpm shift. Proper fluid maintenance should fix this.
I wish he'd do it and post up. I would like to see this be solved for him.
There is, on some cars I understand (I'm pretty sure Z06's, didn't know about coupes but maybe newer ones have it) a rev limiter that kicks in if the clutch pedal isn't all the way up. There is a clutch pedal switch at the top and the bottom. If the clutch switch isn't all the way up your cruise control won't work.
I've never had trouble with this switch based rev limiter nor have I seen it in any tuning I've done, but I have heard stories from reliable folks (Ranger) that it exists.
I suspect the OP's pedal isn't coming all the way up after a high rpm shift. Proper fluid maintenance should fix this.
I wish he'd do it and post up. I would like to see this be solved for him.
And I do have a 6-Speed (with gears if that is what you meant) and NOT an automatic. I would not DREAM of driving or owning an automatic Corvette. I very much appreciate your input and I will certainly keep you updated! Thanks again. You and teh rest have been very informative and helpful.
09-10-2012, 01:38 PM
#22
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09-10-2012, 01:48 PM
#23
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09-11-2012, 10:54 AM
#24
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That said, I am clueless as to changing the clutch fluid and dont have the correct tools or set up. I have an appointment this weekend at my buddy's garage. He will do it for about $80 out the door.
Thanks for your follow up and interest. The forum has been an excellent place to ask and have answered questions. See you on the road...(and the weather has cooled enough here in Texas to take off the roof!)
09-11-2012, 11:00 AM
#25
Tech Contributor
^^ oh I hate to see anyone pay $80 for this!!! You literally take off the cap, use a turkey baster to suck out the dirty fluid and put it in an old bottle, then fill it with new Dot 4 fluid ($4 a can), put the cap on, pump it a few times, check it, if it's clean, drive a few days, check again and if dirty change it using the turkey baster.
It's not much harder than opening your hood.
Only thing to watch is to not get the brake fluid on the paint, it eats paint. Even then, if you wipe it off really quick it's no big deal. Just don't let it sit on paint.
It's not much harder than opening your hood.
Only thing to watch is to not get the brake fluid on the paint, it eats paint. Even then, if you wipe it off really quick it's no big deal. Just don't let it sit on paint.
09-11-2012, 11:56 AM
#26
. By the way, tach on the SHO showed cut-off at 7,750 rpm, but Yamaha has always been overoptimistic with their tachs. Just ask R6 owners about their 18K rev limit that turned out to be 16,200 
. Just setting the record straight. Oh, and ALL ENGINES HAVE REV LIMITERS since many decades ago 
. I hate to see anyone pay $80 for this!!! You literally take off the cap, use a turkey baster to suck out the dirty fluid and put it in an old bottle, then fill it with new Dot 4 fluid ($4 a can), put the cap on, pump it a few times, check it, if it's clean, drive a few days, check again and if dirty change it using the turkey baster.
. Worth a try for sure.
Last edited by JCtx; 09-11-2012 at 12:00 PM.
09-11-2012, 12:01 PM
#27
Safety Car
^^ oh I hate to see anyone pay $80 for this!!! You literally take off the cap, use a turkey baster to suck out the dirty fluid and put it in an old bottle, then fill it with new Dot 4 fluid ($4 a can), put the cap on, pump it a few times, check it, if it's clean, drive a few days, check again and if dirty change it using the turkey baster.
It's not much harder than opening your hood.
Only thing to watch is to not get the brake fluid on the paint, it eats paint. Even then, if you wipe it off really quick it's no big deal. Just don't let it sit on paint.
It's not much harder than opening your hood.
Only thing to watch is to not get the brake fluid on the paint, it eats paint. Even then, if you wipe it off really quick it's no big deal. Just don't let it sit on paint.
When you first remove the clutch fluid cap reservoir, clean the cap's underside rubber bladder to prevent contamination of the new fluid. Then use a paper towel to wipe the bottom of the reservoir. Pump the clutch (with new fluid and cap on) at least 30 times and repeat the procedure until the fluid stays clear. When I first did this, the fluid would get dirty (dark brownish color) again within 2 weeks. However, after repeating this procedure several times, the fluid now changes to a very light brownish color. I started this procedure when the car was new and perform it 2-3 times a year. I have 50k+ miles on my original clutch and it performs without issues. Do a search "Ranger Method."
Last edited by Mike's LS3; 09-11-2012 at 12:10 PM.
09-11-2012, 12:16 PM
#28
Tech Contributor
For $5, including a bottle of brake fluid and a turkey baster there is really nothing to lose.
I think the OP's problem is he is revving the car up past 6200 rpm so the rev limiter is kicking in. His description of the problem seems to have morphed.
Regardless, fluid maintenance as described by Ranger years ago and linked above has been proven to be effective.
09-11-2012, 12:32 PM
#29
Melting Slicks
This problem sounds EXACTLY like the Traction Control is coming on for the 2-3 shift. As the OP said, the car dies for 1.5 seconds and then comes roaring back. That's the TC doing its thing, and I had the same exact experience many times in my C5.
I suggest that TC be turned off and some hard shifts are made. I have a hunch the "problem" will go away.
I suggest that TC be turned off and some hard shifts are made. I have a hunch the "problem" will go away.
09-11-2012, 05:53 PM
#30
SUBVETTE
Redline was 7,000 rpm, and rev limit 7,300 rpm. It's not a motorcycle engine . By the way, tach on the SHO showed cut-off at 7,750 rpm, but Yamaha has always been overoptimistic with their tachs. Just ask R6 owners about their 18K rev limit that turned out to be 16,200 . Just setting the record straight. Oh, and ALL ENGINES HAVE REV LIMITERS since many decades ago .
Well, that's NOT the right way to do it, and it only works (to a point) if you start doing it since day 1. On the other hand, that's probably what any shop would do since doing it right would be A LOT more than $80. Worth a try for sure.
. By the way, tach on the SHO showed cut-off at 7,750 rpm, but Yamaha has always been overoptimistic with their tachs. Just ask R6 owners about their 18K rev limit that turned out to be 16,200 . Just setting the record straight. Oh, and ALL ENGINES HAVE REV LIMITERS since many decades ago . Well, that's NOT the right way to do it, and it only works (to a point) if you start doing it since day 1. On the other hand, that's probably what any shop would do since doing it right would be A LOT more than $80
. Worth a try for sure.
09-25-2012, 04:59 PM
#31
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^^ oh I hate to see anyone pay $80 for this!!! You literally take off the cap, use a turkey baster to suck out the dirty fluid and put it in an old bottle, then fill it with new Dot 4 fluid ($4 a can), put the cap on, pump it a few times, check it, if it's clean, drive a few days, check again and if dirty change it using the turkey baster.
It's not much harder than opening your hood.
Only thing to watch is to not get the brake fluid on the paint, it eats paint. Even then, if you wipe it off really quick it's no big deal. Just don't let it sit on paint.
It's not much harder than opening your hood.
Only thing to watch is to not get the brake fluid on the paint, it eats paint. Even then, if you wipe it off really quick it's no big deal. Just don't let it sit on paint.
One question though, he put BMW clutch fluid that was yellow into the reservoir. Does that make a difference? The other "regular" one was reddish if I remember correctly.
Thanks for your insight and post.
09-25-2012, 05:04 PM
#32
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This problem sounds EXACTLY like the Traction Control is coming on for the 2-3 shift. As the OP said, the car dies for 1.5 seconds and then comes roaring back. That's the TC doing its thing, and I had the same exact experience many times in my C5.
I suggest that TC be turned off and some hard shifts are made. I have a hunch the "problem" will go away.
I suggest that TC be turned off and some hard shifts are made. I have a hunch the "problem" will go away.
I know what the TC does and when it does it. But, did you know (at least in my experience) that with the magnetic ride "on" to the Sport position and shifting hard, TC does not activate between 1>2 or 2>3. The car will float a little bit...nothing a bit of jiggle and compensation does not fix!
Again, thanks for your post.
09-25-2012, 05:15 PM
#33
Tech Contributor
I paid my buddy $80 and he also changed the brake fluid reservoir and evened out the tire pressure on all 4. No big deal. As it so happens, i drove teh car for a week and checked again. The fluid was black, so I went back. he changed it again (I had to pump the damn clutch while he laughed at me sweating in the car in this Houston heat). It is slightly dirty again, so i shall return for one more round and then be right as rain! I dont mind paying him the $80.
One question though, he put BMW clutch fluid that was yellow into the reservoir. Does that make a difference? The other "regular" one was reddish if I remember correctly.
Thanks for your insight and post.
One question though, he put BMW clutch fluid that was yellow into the reservoir. Does that make a difference? The other "regular" one was reddish if I remember correctly.
Thanks for your insight and post.
Thanks for your post. But my problem is at the very high end 6100RPM+. I am told that the engine has a rev limiter to save teh engine and clutch.
I know what the TC does and when it does it. But, did you know (at least in my experience) that with the magnetic ride "on" to the Sport position and shifting hard, TC does not activate between 1>2 or 2>3. The car will float a little bit...nothing a bit of jiggle and compensation does not fix!
Again, thanks for your post.
I know what the TC does and when it does it. But, did you know (at least in my experience) that with the magnetic ride "on" to the Sport position and shifting hard, TC does not activate between 1>2 or 2>3. The car will float a little bit...nothing a bit of jiggle and compensation does not fix!
Again, thanks for your post.
09-25-2012, 05:44 PM
#34
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Once you flush it out well, it stays pretty clean, but you have to do it every so often or it'll get black again. I do it before and after each track event, so sometimes it'll go a month or two without a flush and it'll still be mostly clean. I don't jump on it much on the street.
Your car has a rev limiter at 6400 to keep you from overreving the engine and bending pushrods or dropping a valve. It's a protection feature. You should plan to shift sooner and avoid the rev limiter. It's not good to be hitting it all the time.
Your car has a rev limiter at 6400 to keep you from overreving the engine and bending pushrods or dropping a valve. It's a protection feature. You should plan to shift sooner and avoid the rev limiter. It's not good to be hitting it all the time.
I will lay off the Corvette and change at a lower Rpm to be sure.[/
