Could a slipping clutch or low tread tires cause dyno numbers to fall off at 5400 rpm's and higher?

The reason I'm asking is because I have an '02 Z06 and once the car gets to 5400 rpm's the car peaks and the graph rolls off similar to several ls1/ls2 graphs I've seen. A stock or near stock Z06 peaks around 6200 rpms.

I have replaced valve springs and pushrods thinking it could be valve float but no luck. I have also tried replacing the MAF while on the dyno, no luck there either. My A/F is almost perfect at 13.0. I am not the original owner of the car so I'm beginning to wonder if it had an aftermarket cam at some point and was replaced with whatever they could find.

That seems a little far-fetched since everything was dead stock on the car all the way down to stock plugs. Well with the exception of a Halltech stinger. Any other suggestion or ideas on anything I could check before getting into the motor. Oh, there is no knock retard in any part of the RPM's and the car is tuned. Nothing shows up saying that it could be mechanical.

I took the car to the track last weekend and it ran a 7.96 right at 92 mph so it seems to be fine comparing to other Z06's... Just not on the dyno?? This run was made on F1 SC's with 25k on them. My 60 ft. was a 2.01 and lots of tire spin going in to second and some going into third.

 

i would say its your tune

 

Suggest you post the Dyno graph or at least the SAE rwhp and rwtq.

Your 1/8 mile times equate to approx. 12.2X quarter in my drag log, which bests the Chevy spec. So it's very unlikely that the engine is down on power.

Ranger

 

ZO6 redline is 6500 rmps and in most cases peek HP is 61-6200 rpms.

Cars that have not been tuned ( stock engine ) tend to be lower.

 

i would say your probably right about the tires-i think they have a major effect.. at 25k miles they are definitely worn out and traction is really limited-i know mine were "done" at18k and i drove the car to 22k on those tires and it was a joke-with new F1's it was like a totally different car-and SOTP felt i added back 20hp
and recently i dynoed my 01-with rear tires with 7k on them and did 373 rwh 352 tq-and my mods are limited the usual intake and cat back stuff.

 

At < 8 sec 1/8 miles and 92mph, your car runs strong and you are apparently a decent driver. Kind of odd about the dyno though. I really put very little stock in dynos except for "relative" verification of changes.

 

Thanks for the replies... I think I'll stay on the same track with my plans for the car. First long tubes, then cam, then maybe heads later. I keep saying I'll stop at the the cam.... But we all know how that goes...

Thanks again.