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I have been thinking long and hard about getting a JT 3" non cat downpipe for my 1996 NG900SET. I already have the 3" cat back system but what has been putting me off doing so is the VRK I have fitted. As I have read in several places that the subfrace crossbrace will snag the JT downpipe. I don't want to lose or lower the crossbrace as it works well and the car is already lowered and clearance is an issue. Now to the question I was wondering if it would be worth my while getting another standard front pipe and breaking the cat out of it so that it is just a straight through pipe. Obviously it won't flow as much as a 3" pipe but should give alot less restriction with the cat removed. Any opinions on this approach.
 

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Yes - removing the cat will remove a restriction. I know of one person who has done this on a 9-3. The cat is there to control exhaust emissions so unless your car can run within the prescribed limits without one (unlikely) then technically you should have a cat fitted.

One of the best modifications that you can do is to enlarge the size of the downpipe so that exhaust gases are not restricted as much and can escape quicker.

In between rolling road sessions, I estimate that my 3" downpipe and sport cat increased power by about 7-8 per cent. (on a 200bhp standard car that is about 16bhp

I have modified my Saab in stages and have normally rolling roaded the car in between mods. The cat-back exhaust system was good for about five per cent gain - but was marginally noticeable. The downpipe and sport cat was immediately noticeable


I would go so far as to say that if you were considering one modification only then the 3" DP is the one - even for non ECU modded cars.

Of course, it is down to personal preference - and if you prefer suspension/handling then that might preclude this option as you have described.

I have no experience of the subframe crossbrace so I can not comment - but knowing that hot exhaust gases are coming out as quick as possible and that is good for the engine then that is my choice.
 
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