Will a cat-back like the new JDM increase or decrease power on a stock L. I've heard that on a un-modded truck, the Bassani cat-back will actually LOSE power. Also, is a cat-back ok for the stock engine without mods. Thanks, also, does JDM sell just a cat-back?

 

Struck in AZ put on the Bassani cat back when he was stock and i believe gaine around 7hp and 11tq. If he's here i'm sure he can give you the exact numbers. Cat back is $635 i believe.

 

If you add on just a cat back, they have been known to loose low end. You will get a overall hp and torque gain, but at the sacrifice of low end.

I have been there and done that. You have to get the complete exhaust to gain hp and torque through the overall powerband.

 

It completely depends on the vehicle. If you put a better muffler on ANY turbocharged car you'll gain more hp/tq. This is much different than normally aspirated. Supercharged is another story being that it doesn't rely on exhaust backpressure like a turbo.

Now, if you lose torque with JUST a catback, you're losing because a free flowing muffler doesn't have enough back pressure, by putting on a full exhaust, you have MUCH less back pressure so you certainly wouldn't gain with a full exhaust yet lose with just a cat back.

Again, Struck in AZ has the dyno graphs from stock vs. Bassani which will show the increase and where it increases.

 

My .02, if you install a cat-back on a stock truck, the only thing you should expect is a better sounding exhaust. Wether you gain or lose hp, it will be so little you'll never notice it.

If all you're looking for is a better sound, then make sure to get an open air filter on the end of your mass air meter too!