High Flow Cats vs. No Cats

[CaliLifeStyle]

I was originally going to get a Bassani Off Road X pipe this spring but I heard from a coworker that off road pipes don't make as much horsepower as catted. I was wondering if this is true. I thought no cats made more power. He says off road pipes don't have enough backpressure which makes you lose power. He has an F-250 with a catted dual exhaust. He says that it makes more power with cats. Never heard of this before. Is it BS? I did a search and all I found was no cats make more power.

 

[boomshack]

Running no cats will make you lose backpressure which may lead to loss of lower end torque, but will be made up for generously in the mid to top range RPMs. Running an aftermarket midpipe with high flow cats will help you keep some backpressure.

 

[Premium Speed]

I was originally going to get a Bassani Off Road X pipe this spring but I heard from a coworker that off road pipes don't make as much horsepower as catted. I was wondering if this is true. I thought no cats made more power. He says off road pipes don't have enough backpressure which makes you lose power. He has an F-250 with a catted dual exhaust. He says that it makes more power with cats. Never heard of this before. Is it BS? I did a search and all I found was no cats make more power.

on a lightly modded GT, the gains of running an o/r pipe are minimal over a GOOD catted pipe...i have made 400rwhp with a catted h-pipe in the past

 

[quiksilver98]

Theres no such thing as a high-flow catalyic converter. The size of the cat is what makes a difference of the exhaust flow. The off-road pipe will make more hp because theres no restriction of exhaust flow. As for back pressure, Boomshack is right, you may lose low end torque, but gain hp up top. If you're running open headers, then that's more likely for you not to have enough back pressure and lose hp and tq.

 

[CaliLifeStyle]

So I guess it is still better to get an off road X pipe then. Just have to watch out for the popo.

 

[Gearbanger 101]

So I guess it is still better to get an off road X pipe then. Just have to watch out for the popo.

For the all of 2-3hp difference it's gonna make (that you'll never, ever notice), why bother. Just buy the catted X-pipe and don't worry about the Smog Police.

 

[CaliLifeStyle]

For the all of 2-3hp difference it's gonna make (that you'll never, ever notice), why bother. Just buy the catted X-pipe and don't worry about the Smog Police.

Catted X pipes are illegal in Cali anyway. Catted X's are also 150 dollars more. Smog police will bust me anyway no matter what pipe I get.

 

[Gearbanger 101]

Huh???? Why are they illegal?

 

[CaliLifeStyle]

Huh???? Why are they illegal?

California law. You can mess with the stock cats on a car unless they were damaged or your car was made before 1973.

 

[NYStang2002]

Huh???? Why are they illegal?

because of the Nazi cali emissions laws/regulation and the Nazi people that inforce them.

 

[bdcardinal]

they are not legal because it is illegal to use anything but OEM cats on a 1996 or newer vehicle. there are no CARB approved midpipes, even the one where you make the stock h into an X after the cats.

 

[Islander03GT]

however, most cops don't know how many cats a mustang is supposed to have. so get a catted x-pipe and you have a 99% chance of still not getting a ticket for it.

if the cop knows how many cats your mustang should have, it means he has a mustang and probably removed his too, and will probably let you go with a warning.

then your only problem is passing the visual on smog checks, but find a friend in teh smog business, or swap the stocker back on for the smog check

 

[stanford20]

i ran 9.4 completely stock on 1/8 track .i had the prochamber o/r h pipe installed and still ran 9.4. the h pipe was a garunteed 20rwhp but the loss of back makes u lose so much bottom end is not even funny. i just installed 4.10's the bottom end is unreal. you gain all your bottom end back and more. cant wait to get it back out there( also had eibach sportsline, k&n, and tb bored out since then can't wait)

 

[boomshack]

they are not legal because it is illegal to use anything but OEM cats on a 1996 or newer vehicle. there are no CARB approved midpipes, even the one where you make the stock h into an X after the cats.

Why you gotta do my like that bdcardinal?...WHY!!!????

 

[Mr GT 02]

Whats a good catted H pipe to get?

 

[99GTconvertable]

If you are going to replace a stock H-Pipe, I'd go with the Mac pro-chamber. I know what your thinking "It's Mac". I wouldn't normally put a Mac product on my car, That's just my preference. It loses the cats but the HP gain is great for $200. Mac claims a 25HP gain <<"Yeah right!" it's more like a 20HP gain on the dyno.

 

[Gearbanger 101]

Mac claims a 25HP gain <<"Yeah right!" it's more like a 20HP gain on the dyno.

Ummm, more like 5-7 horsepower. Sure, 25hp is possible, but that's on a full bolt on car, with forced induction. On a stock car, you're lucky to see much more than a few ponies.