3" downpipe any good with standard catalysator? [Archive] - SaabCentral Forums

: 3" downpipe any good with standard catalysator?

31st July 2003, 03:46 AM
So, my question is, do I get any improvement (quicker spool up etc.) with changing the downpipe to 3" from Speedparts, if I don't change the catalysator? I got to have the cat for MOT's, even though mine is as "old" as -92, because it's been registered to have low emissions (my 9k is imported, originally sold in Austria), so I can't just dump the restrictive b*s**rd :o

Any thoughts, experiences on this :-?? Or should I just spend my life savings and buy the sports cat too? :o


31st July 2003, 09:49 AM
If you have the skill to do some welding you can very easy "transform" your stock cat to a sport one - just weld some 3" fittings to your original one!

To be honest most of the "sport" cat's are just stock once with larger pipes.

Yes you will get improvements with a 3" downpipe and most of all - your turbo will live a more healthy life since the temperature will go down. Make sure to adjust the base boost as it tends to go down when you install a bigger downpipe. Adjust to 0.43-0.45 bar.

31st July 2003, 11:59 AM
Excellent! :D Thanks for the info, now I must think of a REALLY good excuse NOT to order bigger downpipe from my next salary :lol:


31st July 2003, 12:17 PM
What price should I be looking to pay for a 3" down pipe? Is there a cheap place to pick them up?


1st August 2003, 12:08 AM
Speedparts are selling one for 1800SEK (around 220Eur). Of course there would shipping payment added for delivery to the jolly old England :wink:

Yeah, but keep that as a "base price", and start shopping around.


2nd August 2003, 03:48 AM
You can order the JT downpipe (the one Speedparts sell) with an adpaptor to fit on to your stock cat. You do, however, need to cut about 2 inches off the back of the downpipe that the adaptor goes on. He easiest way to check this is to fit the 3" pipe, with adaptor, and meaure how far it overhangs the cat flange, then cut that amount off. It's very difficult to get it right by trying to lay the two pipes side by side off the car because the have awkward angles etc...