evo462

I just bought a 2003 Z06 with 58k miles on it. Only performance mod right now is Borla catback. After driving it awhile, I noticed a high pitch squeak or whistle when WOT over 5K RPM or so. It kind of sounds like a metallic noise, not really like a slipping belt or anything like that.

I've done some searching online and it sounds like similar symptoms are fairly common. Some have pointed to the air intake making noises (mine's stock), others the throwout bearing, things like that.

I'm wondering if it's the clutch making the noise. As far as I know, it's probably the original. The other weird thing it does is that the clutch pedal feels slightly "mushy" after a few hard shifts at WOT. So I don't know if it's slipping and the squeak is from that or what the deal is. Hoping someone else has been through this and can point me in the right direction.

I've driven a car with a slipping clutch before - a 4 door Toyota Corolla with 100 HP when I was in high school, so I kind of know what THAT felt like....as though the car was slipping back into neutral under acceleration then it'd "grab" again.

This doesn't really feel like that, but it's clearly an apples to oranges car comparison. I will also be doing a head/cam/header install on it so I'm expecting it'll be putting down about 450 to the tires after all that.

Thank you!

racebum

stock clutch just does that. the fluid needs to be flushed #1 and you need to flush it every 500 miles. lot of us do the ranger method. GM had AP limit the fluid travel in the clutch in order to reduce driveline shock. between that and the self adjusting pressure plate you wind up with a clutch that performs poorly when pushed

the whistle may be the serpentine belt. if it's old or ANY coolant or slick fluid hit the belt they will slip the faster you spin them. tensioners also wear with mileage and age. actually a very common problem as well. mine did exactly the same thing as yours. replaced pulleys and tensioners, installed a new belt, no more squeal. use a gatorback or dayco belt, they are heavy in poly. the gates belts just don't work well on these cars

evo462

Well I know for sure the belt was changed shortly before I bought it....doubt the tensioner or any pulleys were. Maybe I'll just live with it until I pull everything off for the head/cam swap and look into the pulleys then.

I guess my biggest concern was that the clutch was going bad.

Is this the "ranger method" you speak of?

http://www.rangeracceleration.com/Clutch_Care.html

racebum

yep, that's it, just something you have to do with the stock clutch

when you replace the tensioners and pulleys make sure to clean the whole area with degreaser and rinse well, also go over each old pulley and the crank pulley with a wire brush and make sure no old bits of crap are in there. you will also have to buy another belt{s} once they slip they are done

evo462

Good to know, thanks for the info!

So you mention that's something you have to do with the stock clutch - I assume that isn't required with aftermarket clutch and PP?

I had an LS7 clutch in my LS1 Camaro and it never once did any of the mushy feel or whine. Figure I'm going to have to upgrade anyway after the H/C/I.

racebum

camaro hydraulics are different, it was also a new clutch. for whatever reason they seem to get a little worse as they age. i remember driving a c5z in 2002 and the clutch seemed better, mine, which is also stock will get a little weird after a 1/4 mile run. it comes back and whatnot but it doesn't feel the same after the run as it did starting it. a minute later it will be back to normal

fluid is the big thing though, once you bleed it or ranger it 20 times or so it will get better

i have a monster stage 1 here that i plan to install at some point. just running this one till it dies or starts getting worse

RC000E

It might as well be noted, if you ever change the clutch OP, be sure to install a remote bleeder while you're in there!

evo462

Yep will definitely do that.

evo462

Well I did end up ordering some good Dot4 fluid to swap out the clutch fluid, but I haven't done it yet....been too busy installing heads/cam/headers.

After doing that...the clutch is definitely pissed off now. "Enthusiastically shifted" through a few of the gears and the clutch didn't fully reset and was kind of hard to push down. So I'm guessing the extra 110+ RWHP isn't helping things, regardless of whether or not I do some fluid flushing. I'm obviously well over the power level the stock clutch was expected to handle, but I'm going to swap out the fluid anyway and hope that gets me by for a few months until I save up for a clutch.

racebum

over powering has been the kiss of death for many a ls6 clutch.

monster usually has sales over thanksgiving or christmas. that's when i would look to order. their stage 1 or stage 2 depending on how much torque at the wheels you make would be a nice upgrade. if you hit the sale it should come in at 720-800 for the full package with new bolts, new slave, remote bleeder, billet flywheel, shipped to your door

evo462

Guess I will have to baby it for a few months....I plan to put a supercharger on it next year so I will need something that can handle another couple hundred RWHP

racebum

twin disc

start doing your research. if you're going over 500-550whp go twin, monster rates their clutches at real world numbers so if you plan on passing 550tq which wouldn't be hard FI twin discs are the way to go. the ceramic and metallic single discs just drive like complete ****