KB964Cabrio

Has anyone fitted one of these?

Does it make much difference to the sound or performance?

DaveK

I had a cat bypass fitted not long after I got the car. Mine was actually fitted because the cat had collapsed and the mechanic thought that was causing my idle hunting problems (it wasn't!).

Didn't notice a difference in sound or performance.

Of course - you can see for yourself tomorrow!

KB964Cabrio

Thanks Dave, i've been watching one on ebay and just wondered... I think it's going to have to be the g pipe route then...

Does it matter about emissions on MOT's or are our 90's 964 exempt from emissions testing due to their year?

Andy Roe

You don't need a CAT to pass you MOT. I think they came into force in 93. A G-Pipe is quite a bit louder, but nice!!

KB964Cabrio

Thanks Andy, have you got any exhaust mods? I'm happy with the performance but i want a deeper sound...

Andy Roe

Nope. Everything is standard, but like Dave, my CAT is breaking down, so will probably put a by-pass on when I next have it serviced.

On my C4, I did have a G-Pipe fitted, but decided to return it to stock as it was rather loud! -you could hear me coming before you could see me! I may have a Primary By-pass put on when I have the CAT done though....We'll see!

BaysideC4

I had the cat bypass installed and decided to removed it. Combined with the primary bypass it was just too loud. I had even set off a few car alarms

My Cat is getting old too and I think has developed a rattle. Has anyone upgraded their cat? or is the rule "just bypass it when it goes"?

Colin 90 C2

I'm running a cat bypass with a Gemballa primary muffler, which is essentially a primary bypass, and I think the exhaust note is just right. I also had a secondary bypass fitted but it was too loud for my wife.

My chip tuner makes a chip to address the cat bypass but not either of the muffler bypasses. I'm guessing that the cat bypass may give few more ponies.

warmfuzzies

I have a G pipe, you'll hear it tomorrow..........I guess.

It might be difficult but "round the corner" on my website has Daves, mine, Iains, and Christers cars on them, all with differing exhaust options.....

Kevin

Marc Shaw

In some of the older threads (2002/2003) there seemed to be alot of early interest in cat. bypasses but it seems like alot of guys who fitted them took them off due to foul smell and just too loud.

Any advice on a high-flow cat? I guess they are alot more expensive than a cat bypass and the 100-200 cell ones don't last long.

Marc

garrett376

https://rennlist.com/forums/964-forum/180490-now-that-s-how-a-964-racer-should-sound-cat-and-2ndary-bypass-combo.html

KB964Cabrio

Thanks Garrett, i must've have missed the additional links you placed on that thread... SOUNDS GREAT!

Cheers!

(ps, finished that new 993 style Roof today!!!!!)

TB993tt

I did a before after dyno test before and after cat bypass pipe back in '92 - only other mod was Ruf 98 octane chip and Ruf cup crossover pipe and it cost power - I don't recall how much it lost but I remember putting on a Porsche pre silencer instead of the cat and the lost power returned. FWIW

amorgan

I have the bypass pipe. it sounds great. Is there much difference by adding the cup pipe. That is prob the next mod for my car. Is there much of an improvement with performance

Pesty

This i sprobably a stupid question but do you need to have the car remapped/chiped if you bypass the cat?
Just found out I will be getting a small bonus £200 ish so I need to spend it before the misses finds out

ps wheres the best place to buy a cat bypass