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Discussion Starter · #1 ·
Im about to buy a de cat pipe for my GTR, and ive also been offered a downpipe for little money. Is this a good start, the engine is standard appart from a 3" cat back exhaust system (made by Jasma i think). Will i have to also change other parts at the same time i.e. fuelling/timing, air filter etc. to get the full benefits, and not run into any problems. Im new to turbo tuning so am not sure what the right set of first mods should be.

Also will this make the exhaust note louder (its very quiet at the min at idle, and even above 3500rpm), because i dont want to have a very loud exhaust.

Im i right in thinking that because my car was built in 1990 (H), it does not need a cat to pass the MOT. I understand it that after 1992 (K) if it was originally equipped with a cat, it has to have one for the MOT. Is this correct, or will I have to change it back again to pass?

any advice is much apreciated.

Diabolus
 

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yes these are good mods to do. decat and downpipe should improve spool up and response a great deal.

If its really quiet at the moment, I cant see it being made MUCH louder, but there will certainly be a change in the noise with a little more of it being produced.

As the car is an H reg, you are correct in saying it doesnt need one for the MOT.

If the car is running standard boost, then you should speak to a tuner about a boost upgrade too as this will make the car 10 tens more fun than stock boost.

Regarding changing the fuelling etc, at this level of tune you dont need to change any parts and if your car is running correctly at the mo (so the timing is around the 21 degrees mark) you shouldnt have any probs what so ever.
 

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Jasma just means it conforms to the Japan Automotive Muffler Association standard (yes I know it doesn't work :p), the make will be elsewhere.
 

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Discussion Starter · #4 ·
Thanks for the info, much apreciated. I shall have to see if i can get that downpipe a de-cat then.

As for the Jasma bit, i thought it was something like that, but there is nothing else written on the exhaust appart from that, so it must be a no-name exhaust then.
 
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