Do you think there would be any benefit to running full 2.5" or 3" exhaust piping from the cats back? Or would that hurt, more then help, due to less back pressure? Seems like it may cause you to make less boost, but not necessarily lose power due to the fact the exhaust if flowing more efficiently. I dunno, I guess it could also just throw the entire dynamics off and make it run like poo. I'll be getting whichever exhaust direction I go, tuned in, which will help either way. Really I'm just tossing around different ideas and getting different opinions by those of yall more experienced in this area then I. I know with my Z06 the more airflow, the more power, but could be different with all motor NA setups vs supercharged applications.

 

I will correct for whatever exhaust opening you do on your car. The more free flowing the better, but has to be adjusted for in ECU. If it's actually beneficial or not to go to a 3", I suspect not. You will loose some boost with exhaust opening , but really it shouldn't be looked at as a loss, your efficiency just goes up and so does power. For example clogged cats will cause boost to go up , but your actually loosing power..

 

That makes sense, and for the most part what I was thinking. At the most, I'll just stick with just going full 2.5" front to back and then let you work ya magic from there.

 

Back pressure is not a thing with these motors. Think of your motor as an air pump. Boost is also not really a concern. The issue is flow velocity, not enough restriction and the air can't flow as much, too much restriction and you sort of get the same thing. Since you have a twin screw TVS blower you CAN benefit from larger intakes AND larger exhaust pipes, it just has to be a balance.

Intakes, pulley, exhaust and ECU re-map you could easily go over 600BHP/TQ

 

A lot can be said for building your own exhaust. People still comment on just how fricken awesome mine sounds. Dang hybrids try to keep pace just to hear the sweet burble of pure sex at 3k rpm. I went with take off '11 5.0 mustang cats without regret. The high flows were just too loud.

 

I have a feeling it's going to take some, try this and try that's, before I get it just how I want it lol. But, maybe I will get lucky and it end up just how I want it the first time. Sound and performance wise. It's gonna happen one way or another that's for sure.

 

Yeah, these setups are similar to the supercharged 03/04 Cobra, though they are 4.6l's. I put a nice JLT CAI, swapped pulleys, exhaust, tune, and picked up just shy of 100hp with the Eaton(heaton as they are called a lot of times) and over 100 ft lbs of torque. So I can see how those things could be a real game changer with the XKR's as well.

 

The 2007-2009 have the 4.2 with the roots Eaton just like the older Mustangs, but you are endowed with the newer TVS blower which is significantly more efficient and capable of producing much more power.

 

Agreed, it's most definitely a nice upgrade from the 03/04 Cobra Eaton, even the ported Eaton's. Though I can't lie, I do miss the sweet whine of the Eaton at WOT, but that's me. XKR's needed more cubes and bigger charger to get them moving, as they are a little "heftier" so to speak haha.