mx5cartalk.com

Guys,

Car develops a high pitched whistle above 5000 rpm and is reluctant to rev out easily. Quite perky below that so wondering if it's blocked and or not flowing well.

Thoughts?

Craig

Sounds like it could be, disconnect it if the nuts arent rusted on and go for a drive.

Dann

Sounds like a plan!

i wonder what a new one would cost?

I'd just disconnect it and have a look inside with a bright torch.

You should see a uniform screen of little squares, with the torch on the other side you should still see some light (it's normal for it to have a bit of carbon in there)


If you drive with the car removed you won't hear the whistle if it's still there, you'll just hear noise. Open headers aren't quiet.




You can get a secondhand cat for fairly cheap, just look for a forum member selling a midpie with the car still in it.
I bought a secondhand 80cel high flow for I think $150

Hi,

So it kinda looks like a mesh arrangement of squares yeh, will have a look see on my days off.

Not as noisy as my old RX7 I drove to the exhaust shop with only a set of extractors!

yep.
Except instead of a flat mesh each square extends the length of the cat, like a mesh made of little square tubes.

each one is only about 1mm square, so they aren't huge, and each tube will have carbon in it, so don't expect to see through them. You'll just see points of light from the torch.

I haven't seen inside a new cat though (outside of a high flow) but all the used ones I looked at were like the above, and weren't blocked.

Sweet, thanks for the advice!