Cats or no?

I'm about to do my exhaust, coat the headers and get rid of those damn rattling header heat shields. Since my car is considered classic and doesn't need to meet emissions, I was considering removing the cats. Any thoughts on this? Is there anything special I'd need to do?

Thanks!


Sent from my iPad using Tapatalk

 

I took off my cat years ago of my 84 QV, works and perform very well, sound is also better. Just remove the nuts and bolts with the springs that holds the cat and replace it with the test pipe or the HyperFlow cat. Just be aware that it will smell a little rich.

 

+1

or you can just sleeve the cats if you prefer the stock look, actually sleeving them is easier than buying or making test pipes.

 

+1

 

FWIW, removing a cat in good condition is not going to do anything useful per se as far as operation/power is concerned. I removed my 328's cat a few years ago and installed a test pipe because the "slow down" warning system quit working and there is no fix/replacement for the slow down control module. For that reason I was uncomfortable having the cat, knowing that if it was overheating, there was no warning for it. Otherwise I would have left the cat in place.

OTOH, there's no downside to removing it as far as the engine/car is concerned. As noted, without the cat you may smell some "richness" from the exhaust, especially when the engine is idling and not yet warmed up. Once the engine is at operating temp, if everything is properly adjusted and working, the rich mixture/smell will (should) disappear.

 

Excellent, thanks. Ummm, what's meant by "sleeving" the cats? If I do that, do I need to remove the overheating modules (I'm guessing that's what those 2 plugs are on the cat)?

One more thing...is it possible to remove the front header (against the firewall) without pulling the engine?


Sent from my iPad using Tapatalk

 

...
Image Unavailable, Please Login
Image Unavailable, Please Login

 

or this..
Image Unavailable, Please Login

 

HAHAHAHAHAHAHAHA!!!!!!

 

Those things in the cats are thermocouples and are very expensive to replace.


Sent from my iPhone using Tapatalk

 

i'm more of a dog person. But anyway....

 

Hah, awesome.

Ya, after thinking about it, I'll prob just remove and save if I ever re-sell.




Sent from my iPad using Tapatalk

 

Unless the CO is set, you can have an eyeburning experience. I drove without mine for about 7 or 8 years. Finally went to the Hyperflow.

You will have a more throaty sound without them. Sounds pretty cool.

 

Put a hyperflow on my 328 a couple years ago and have had no issues and the sound is a little deeper. Love it.

Sent from my SAMSUNG-SGH-I747 using Tapatalk

 

As far as sound, I couldn't tell any noticeable difference in my 328's exhaust note between the cat or the straight pipe. I'm sure there is SOME difference but it was not something I could notice in the cockpit in the time between having the cat on, removing it, and then driving again. If you could flip a switch to do an A/B comparison, I'm sure it's hearable but, at least on my 328, it was not apparent to me.

 

Stock silencer or aftermarket?

 

I have a Tubi muffler. A cat off sounds a lot different than when it's on on my car.

 

Stock - it's the only muffler I can stand for more than maybe 20 minutes!

 

BBC News - Climate impacts 'overwhelming' - UN

 

I feel ya

The reason I asked is that with my aftermarket muffler (Tubi), I notice a big difference in noise just going from the stock cats to Hyperflow cats -- especially under load. It's hard enough being incognito in a TR, and, with the combination that I have now (no precats, HyperFlow cats, Tubi), it's impossible. So, IMO, you can't generalize about how a single exhaust component change will affect the overall sound -- the whole exhaust system needs to be considered (e.g., cat vs straightpipe with muted stock silencer = probably not much difference per your experience; cat vs straightpipe with aftermarket muffler = TOO LOUD )

 

exactly...

 

Why would you want a carbed Euro car to drive for yourself if you are concerned about someone taking the cat of theirs and the impact it has on the planet?

 

Just curious

 

Ok - you kind of got me there. I'm on two sides of the fence here. Cars originally equipped with cats, and cars without - meaning, I'd keep the cat(s) on a car that was equipped as such. A Euro car would be difficult to fit cats on to, same with an early carbed car without the big diaper. Got it. But personally, if I end up with a QV - it's going to have the converter(s) in place.

But I will say that I don't enjoy driving a GTS without cats (or maybe a GTB with the windows open). I don't like the smell of unburned hydrocarbons, it's nasty, and your clothes smell like it as well. Although I have only half the displacement and half the cylinders at the moment, I put a cat back on because I was tired of the smell when driving with the roof off.


Anyway, it's just a preference. Modern cats don't have much of a performance deficit, but I can't speak on the change to the sound.

 

I have always wanted an X/19. I have even been to a few FLU annual meets. Cool little cars!