X-Pipe hp gain question?

I have a 1999 cobra mustang.

How much HP gain should I recieve with a welded in mangnaflow x-pipe with four cats?

How much HP gain with a welded in X-pipe with hollowed-out cats?

Please let me know

Thanks,
Mike Morales
 
Most manufacturers state there is no difference in HP from catted to non-catted X pipes. The hi-flow cats seem to be very efficient. FWIW, I read an article in a Mustang Mag from a Ford Exhaust Engineer and he stated that hollowed out cats were a bad idea for performance since it screwed up the airflow somehow.:shrug:
 
Most manufacturers state there is no difference in HP from catted to non-catted X pipes. The hi-flow cats seem to be very efficient. FWIW, I read an article in a Mustang Mag from a Ford Exhaust Engineer and he stated that hollowed out cats were a bad idea for performance since it screwed up the airflow somehow.:shrug:

Probably something to do with back pressure.

catted or non catted it doesn't matter really. Power difference is so minimal between the two you'll never know the difference.
 
I also think it sound like **** if you hallowed out the cats. Also, the x pipe gain is somewhat dependant on other mods. On a stock 99 Cobra, it may net you 5-10rwhp, possibly more. Now if you were to install a supercharger on the stock Cobra and then install the X Pipe, it may give you 10-30rwhp.
 
Maybe a picture will clarify things.

View attachment 378198

The 2000 Cobra R has the same type of thing. LOOK.

Underneath.webp


HP Gain #’s please?
 
I've heared that the catted to non catted doesn't really make that much of a difference in power, but i have an off road x with long tubes so i have no cats at all and the power increase was nice. It really depends on how bad your areas inspections are. Thank god i don't have any inspection laws anymore.