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View Full Version : 318is exhaust with out cat??

dwf08
08-04-2008, 10:45 PM
do any of you guys not have a cat on your car? and do you guys think that it changes anything at all or will hurt anything? someone told me that they dont run that good without is that true??
dwf08
08-05-2008, 12:31 AM
no one dont have a cat on their car or does evry body have one some one tell me something plzz
Jimmy Lewis
08-05-2008, 01:09 AM
Well, where I live, and in most places in the country you are required to run a cat if the car came with one. I've had my resonator replaced with a straight pipe, and it didn't do a whole lot. The car is louder as high rpm's, I think with no cat it would sound too raspy and a lot like a honda d-series.
nomad
08-05-2008, 02:27 AM
Does it change something? Yes
1. It will sound louder and raspier.
2. Unburned gasses and fuel escape into the air.

Will it hurt anything? Yes
1. The environment
2. Your lungs

Will it give you that 20hp you think you're missing? No
Spending money on real power mods is much wiser.


do any of you guys not have a cat on your car? and do you guys think that it changes anything at all or will hurt anything? someone told me that they dont run that good without is that true??
BMWManiac
08-05-2008, 02:42 AM
I had a straight pipe that the original owner replaced the cat with....sounds horrible and I'll be looking to add one in the near future, if not this week.
E30_318is
08-07-2008, 12:16 PM
I replaced cat. and stock resonator with Simons Tubex resonaator. 2,5" (lenght ~25")http://www.ostuauk.com/images/products/s406.jpg
The rest of the exhaust is stock.
It only sounds a little raspy when the engine is cold.
1500-4000 rpm sounds almost like stock exhaust.
4000-7000 rmp ( i have a chip) its louder but not 2 lound or like a ricer.

i was suprised how restrictive the stock cat. is, my m42 revs up much faster now. + i recycled the cat. and got 105 Eur for it :eek:.


Sorry for my English
colin86325
08-07-2008, 08:51 PM
If you remove the cat, I think a resonator or a small muffler is definitely required for a small-displacement 4-cylinder, unless you want to sound like a Honda.

I'm surprised you have ricers in Estonia. I guess no country is free of them. :(