dtsol

I feel like my '08 has become less "punchy" when accelerating. I first noticed it on a highway onramp, and it feels like a general condition. l know our cars aren't known for being fast off the line, but when I bought mine 2 years ago, it felt more responsive. When I bought it I changed the plugs, had the valves adjusted, changed the oil and filter, and changed the differential oil; other than that, I haven't done any maintenance. I've put around 3500 miles on it, mostly mountain twisties, with some around-town and occasional highway driving as well. Any suggestions as to what might be hampering my car's spirit?

windhund116

How many miles are on the clutch?

dtsol

I bought the car at 100K miles with no history other than Carfax, and there’s no clutch work in the records, so I don’t know if it was ever replaced. But as I was going through my records, I saw that right after I bought it I had the master and slave cylinders replaced and had the system flushed and bled. I did all that because the shop said the fluid that was in there was very dirty and things were all sludged up.

windhund116

The clutch disc may be the original one. How's the feel on downshifts? Positive bite or not?

This video may help.

dtsol

Thanks for the video link. I tried the tests:

• The car stalled trying to start in second, both with and without the handbrake
• I’m able to get the car moving in 1st without using any accelerator, although it does rattle a little

But the “not as responsive to the accelerator in higher gears” he describes does describe what I’m experiencing.

windhund116

Sound like you need (at least) a new clutch disc. Do you have a good S2000 mechanic that you can trust? Maybe, have him/her look at it.

B serious

There's probably nothing wrong with your car since you didn't mention a check engine light.

If the weather has very hot when you're driving it, it may just be heat soaked or something.

Save the Manual Wagons!

What other car(s) do you own? When I had a ~300whp WRX, I got used to the acceleration. When I pulled my Mazda6 wagon out of winter storage, it felt sooo different. I actually thought it was broken. Nope, it just had half the power and no turbo rush...

+1 for hot weather. What air intake do you have? Some aftermarket ones can be sucking very hot air.

How could a clutch have anything to do with this, and why are you recommending a new one? It's a big expensive job and almost certainly not the cause.

If it's slipping, it should be obvious as the engine revs but the car doesn't accelerate accordingly. Here's a better test: when driving the car, get up to about 5000 RPM in third gear. Hold it there for a moment or two, then floor it. If the RPMs shoot up but the car doesn't lunge forward, it's slipping. The tests in the linked video are for when the clutch is completely gone. He's holding the car stationary with the parking brake while the engine idles in 2nd gear. If your clutch was that bad, you would know...

Save the Manual Wagons!

Here's a way to test your car's acceleration. Accelerate in third gear at full throttle. At the exact moment the car hits 60 MPH, start your stop watch. Time the run from 60 to 100. It should take 9.6 seconds. This is plenty of time to determine if the car is up to snuff or not. And it removes any variables like trying to do a redline clutch dump launch. Anyone should be able to repeat a 60 - 100 test. Assuming you have, uhh.....a closed course to do it. Make sure it's flat and with little wind, and/or do a two way average.

https://www.caranddriver.com/reviews...ake-road-test/

Chuck S

I assume you'll need to shift gears 'cuz the top speed in 3d gear is 91 in the AP1 and a mere 80 in the AP2 cars when the rev limiters shut the engine down. 4th gear maybe?

A slipping clutch should be obvious as the revs will climb and the speed won't.

Lots of possibilities. Stale or bad gas? Mouse nest in the air cleaner (it's happened)? Former girl friend jam a potato in the exhausts?

-- Chuck