Seight

I was wondering if anyone has fitted a catalytic-covertor bypass or replacement? They seem to be pretty cheap and if the cat does let go at some point is it worth taking this route? My car is a 1990 so strictly speaking I don't have to have the cat so I was wondering if:

1. Will it make the exhaust any noisier? (I like it standard)

2. Any improvement in power or mpg?

Thanks in advance
Alex

1990 Carrera 4. Black, lowered.

DaveK

I didn't notice much difference when I had my bypass fitted. Mine was only done because I was told my cat had collapsed.

Red rooster

Had one of these for ever!! Not a lot of difference - maybe feels a little freer at low rpm . Dont forget ,if you do this mod,to get a pipe with the Lamda probe hole and fit the Lambda probe. This will save you grief with setting idle mixture etc.
Geoff

Andy Roe

I did not notice any change in exhaust note or power. Had it taken off because it was breaking down like Dave's above.

Heirsh

No difference in exhaust note noticeable here. I got the so-called euro premuffler that does have some muffler qualities to it. Basically some holes in the middle pipe leading to a larger od outside pipe. Plus it looks like a Cat.

Not sure about mpg. Comparable. Been getting 26.5 (us) lately when i keep my foot out of it.

I do think it has a tad more power, but nothing definitive.

One thing to take note of is the ox sensor works better in the cat because of the increased temperatures. You can smell a rich mixture much easier without a cat also.

Also I think the cat can mask smoke coming out of your engine (burned oil).

Wachuko

Cheap as inexpensive? From where??

The only one I have found is the FABSpeed




for US$375.00 (unless that is what you call inexpensive )

Andy Roe

I've got the Danske pipe fitted. £220, with O2 sensor fitment. You'll probably also need to replace the O2 sensor at the same time as they are very hard to remove from the CAT in tact.

Greg_L

I too replaced mine as the cat collapsed - although i wanted to do it anyway. The specialist only had the non-O2 type, but if i did it again, i'd go for one with the sensor. The car runs great, but smells a little rich.
I might have been imagining it, but i thought the bypass added a slightly bassier sound to the exhaust note.

Wachuko

I placed an order for one from Fabspeed (just got off the phone with them). They give Rennlist a 10% discount I just could not wait to get rid of that piece of rusted crap that I have there... plus I had a new Oxygen sensor that I was going to install... so now it goes in with the new pipe...

<Please keep me away from this place... it is hurting my credit card>

Seight

Thanks for all your responses....

By cheap I mean cheap. Check this link on ebay, it has the mounting hole for the lamda sensor too....

http://cgi.ebay.co.uk/CAT-REPLACEMEN...QQcmdZViewItem

What d'ya reckon?

Cheers
Alex

1990 Carrera 4. Black, lowered.

Wachuko

WOW!!! That is cheap!!... even if it is not stainless steel... just paint it to protect the metal and be done with it.... wow...

That reminds me that I paid 374.00 for mine

In the words of a famous philosopher…

“Stupid is as stupid does…”

DarrylH

Just out of curiosity, do people refit their cats to pass emissions tests? Or are you in jurisdictions where there are no such tests? Or are the cars so clean they pass anyway?

DaveK

Mine allows an O2 sensor to be fitted, and originally I did have one fitted but it was removed when I had the car chipped by JZ soon afterwards. I returned to the stock chip when I had the car service earlier this year and was planning to have the O2 sensor fitted again. However, JZ advised against it - they said that if I didn't have any running problems now then leave it alone. I commented on it smelling a bit rich at idle and they said that they felt 964s ran a bit lean with the O2 sensor anyway and it was better as it was.

In the UK, only cars after 92 need a cat - cars older than that don't need one and are tested as if they don't have one, and we pass OK.

Marc Shaw

We have no emissions testing (ever) in NB.

Marc

DarrylH

Funny country, innit? I just checked Ontario's requirements - never bothered before

"Drive clean regulations require testing every two years for vehicles beginning in the third calendar year after their model year, up to and including the 19th calendar year after their model year."

So I guess I can't do much until 2010. I wonder if my cat'll last that long...