I plan on running a TSP catback or something similar at some point but im wondering if running open DP when im tuned will somehow mess up the tune with a catback on it. Thanks

 

It will make better power with open downpipe. When the catback is on the car it usually tends to run more rich. You might consider a cutout when the catback goes on.

 

And you must have a minimum of 18" of pipe after the O2 sensor or it will read very lean due to contamination with the outside air. If you are doing anything larger than a 3" pipe I would want min. 24" to get a good reading.

Jim

 

Im running the eBay turbo piping setup so the end of the piping provided is right before the axle, I dont think the o2 sensor will be a problem.