I recently just installed a 70mm test pipe onto my otherwise stock exhaust system. My plan was to get a 70mm single and call it a day; but I can get a good deal on a 60mm single. So is there any negative effects from running a 70mm tp to a 60mm exhaust?

thanks

 

yes it would bottle neck and cause alot of turbulence in the exhaust system

 

 

what about running a 63 testpipe into a 70 exhaust? Same problem?

 

alright thanks...thats kinda what i was thinking

...aznives i would think that would have less effect than going bigger to smaller

 

Small to big is fine. Big to small is a no no.