catted or off road H pipe

[90limited]

I am thinking of replacing the factory H pipe. I heard some were that you need to be over 300HP to really see any benefit from replacing the H pipe with after market. Currently, I have a honed intake, ported heads, 1.7 roller rockers, shorty headers, pulleys and 70mm MAS. I am getting ready to install a catback and assume that the factory cats are holding the motor back?

If I can get some gains, I will replace the H pipe. The question is should I go with or without the cats. How much will the high flow cats muffle the exhaust vs the off road pipe?

 

[justagt]

midpipe

The only reason to get an offroad H versus a highflow catted H is 1) price or 2) sound.

They will both give you almost exactly the same gains. Yes, the cats will keep exhaust volume down somewhat. Depending on how loud of a catback you are going with, I'd say if it's a daily driver get the catted H. It's nice to not have an obnoxiously loud exhaust when driving around town.

I run a catted Magnaflow H, performancepeddler.com has the best prices, I have ordered my last 3 exhaust systems through them and they offer free shipping and I have never had a problem with an order.

I think it's a worthwhile mod power-wise... even on a strictly bolt-on car.

 

[N8Miller]

do you have emissions where you live? if so, the you need to have the catted version unless your car is "exempt".
off road pipes are usually cheaper, so thats the way i would go.

 

[90limited]

No testing were I am... I am putting on a MAC catback and have some concerns that it may be to loud. That said it is not a daily driver so I guess I should not sweat it. Other issue is I would only like to replace the mid pipe once. If I go off road, there is always a chance that I will have to add cats...

Update: I just found a great deal on a catted magnaflow H... So that problem is solved.

 

[MY 85 GT]

No testing were I am... I am putting on a MAC catback and have some concerns that it may be to loud. That said it is not a daily driver so I guess I should not sweat it. Other issue is I would only like to replace the mid pipe once. If I go off road, there is always a chance that I will have to add cats...

Update: I just found a great deal on a catted magnaflow H... So that problem is solved.

You dont have to worry about The Mac Cat back being to loud...it isnt....I have full Mac everything Long Tubes..Off road H-pipe and there CAT BACK...I cant wait to tear the mufflers off and put 2 chamber Flows on WAY to quiet with the Mac exhaust.....I like loud exhaust and this sure isnt.....lol

 

[2000xp8]

No emissions testing, i'd say for sure go for the offroad pipe.
Not only is the catless pipe cheaper, but it makes more power, and certainly sounds better.

 

[90limited]

Car runs great right now, but as long as I am changing the mid pipe, is it worth the cash to replace the O2 sensors with new ones?

 

[2000xp8]

If you aren't getting the check engine light now, i wouldn't bother.
They aren't that hard to change in the car, if you have to in the future.
Just make sure to put anti-seize on the threads.

 

[Sicarius428]

Unless you are going for long tubes, I don't think it would be worth changing your midpipe. Idealy you should go for a catless when you do that.
Kevin