Running crap after new zorst.

[FATGTS-R]

Hi Guys,

Had a new zorst fitted to my RB20. 3 inch from rear housing to muffler.

Old zorst had 2 inch dump and melted cat.

It now is running like a pig at low rpm >3,000rpm. When she comes on boost it breaks free from the strangle hold and flys.

It misfires at idle, when the high idle warm up is done it will stall if I dont keep blipping the throttle. Some people say to have your car tuned after a new zorst ( which I am getting done anyway ) but is it possible for it to run this poorly after a zorst change? It idled perfectly before and didnt miss a beat, now if its not on boost its a bastard.

Please help, I hate gremlins.

[caminperth]

Possible damage to the oxygen sensor? Thats the only thing that would've been messed with on the exhaust right? Unless yours has a sensor in the cat like some R33's do. Have a look under the car in about the middle of the passenger's seat. If there's a grommet in the floor and nothing sticking out of it, check uder the carpet - you may find a wire going to nowhere.

I'm not sure if either of these things could be causing your problems, but they are the only sensors I know of in the exhaust..

[Warpspeed]

All the exhaust back pressure will now have gone away, which means that the ignition timing and fuel mixtures will be way out. Get it tuned properly and it will go better than it did before EVERYWHERE.

There is a lot of BS around that engines need back pressure to run. That is simply not true, but just changing the exhaust as you have done, can just make it seem that way.

Get it tuned, and it will be fine.