I just got a new cat and muffler with all stainless steel tubing how much of HP will i gain outta that

 

dont think its gonna give you more thatn 3 hp but your engine will run better it will breathe better,if you want to gain hp you have to look the high flow cats,and all engines got to have a little of back pressure so if you have a strait thru like magnaflow or glasspack,well you may get a little more power in the top end.

 

not enough to notice the difference.

 

you wont gain any. It will just get back the power lost from the old plugged cat

 

10,000HP

 

Only if it is painted neon green.

 

with flames

 

thread winner.

Really, right about none. I'd say a rule of thumb for a catback should be 1% of total HP. So, assuming you have a 4.0HO, that would be 1% of 195 crank HP, or 1.9CHP.

If we're talking automatic 4WD, and assume a 20% drivetrain loss (although I think it would be more on an XJ), then 1.9 - 20% = about 1.5WHP. Meaning not really any.

 

with fuzzy pink dice in the window..

 

and as stated, its more of ensuring better breathing for your exhaust system , which in turn means a smoother, healthier running engine. A sufficient intake, clean fuel system, and opened exhaust (freeing up any backflows/restrictions from the factory) will make it more responsive, not necessarily faster.

with the above, then do fuel injectors, better plugs/wires, occassionaly replace the distributor when its bad, and youre jeep is a pretty stout SUV. i bet an open air intake system (for those that dont offroad) and a clean exhaust, these XJ's sound pretty good!