rancherman

Ok, after reading a lot of posts about cat deletes, or gutting, (22re) I've read a lot of guys saying these engines like some back pressure. Some guys will post that taking their cat off, or gutting it makes it 'feel' better. Chances are, my guess, their original cat was really plugged..

So when someone proudly posts that going with a 2.25 system, and a high flow cat, and a mega flow muffler, it's a real noticeable improvement?

Wouldn't the combination of the high flow cat, and larger pipe be just as 'back pressure reducing' as a stock system with the cat removed/gutted??

My stock system is working fine, and don't plan to change it. The tail pipe is gone, lol, but 'muffler foward' seems to have some life in it yet. I'm just trying to wrap my head around why there would be any difference between the two.

thefishguy77

iTrader: (1)

Its a small difference at most. Also a lot depend on the engine as well. 2-2.25 seems to be what most here like. I have read a lot of people without cats run 2" and I run 2.25 header back.

A lot of engines come some what conservative from the factory. Meaning they could use a little bit of exhaust improvement. But its a big cycle. More air out inly make a big difference if you have more air in. Now you need to get it through the engine better as well. Then more fuel and better spark and bigger valves. Its a big rabbit hole with little gains for the money.

I went 2.25 header back because I had a good new header and high flow cat from back when i had my first 85 just out of high school. Never put it on before the truck got stolen. I did notice the engine felt smoother after the exhaust but mine was old and haggard when i replaced it. I also have a freshly rebuild engine with a slightly more aggressive cam than stock as well.

These motors are just like having a pair of squirrel under the hood. You can throw tons of money at it but in the end its still just a couple of squirrels.

highonpottery

iTrader: (1)

I'd say you'd notice the improvement, but it's not going to be like night and day. Like said above - in the end it's still just a couple of squirrels, lol

On my 93 the CAT was stolen one night and because I have to deal with CA smog laws I had to re-install a new one. Of course I wanted all the upgrades with headers and high flow everything, but in reality if you look through what people say about them you may realize it's really a waste of $ for such small gains. So I chose to keep my stock exhaust manifold and upgrade to 2" in the middle of the downpipe, with a 2" high-flow CAT, then went 2.25" for the rest of the system with a high flow Magnaflow. I do not notice any improvements around town with lower RPM driving aside from a little more grunt/noise when I am on the throttle. Where I notice the gains are in highway and higher RPM driving as it's breathing easier.

I paid $500 for my exhaust, most of it was a new CAT and muffler and paying someone else....if I did it again, I'd likely go with one of the OEM replacements, like the Bosal one you can get from a lot of sources

gixxsta04

Most high flow cats will go bad much quicker than a stock one.