Exhaust dilemma

[Omie01]

Ok, this may seem like a dumb question, but, I had a full 2 1/4" exhaust installed last year with a 340 hp engine. This year the new one should be around 450-460 hp, can I run the 2 1/4" exhaust for a little while until I can get car to an exhaust shop? Everything I am reading says I will have to go to at least a 2 1/2" exhaust. It is a full dual exhaust with h-pipe and turbos, will this be a problem at all?

 

[Bill73Ragtop]

Not gonna be an issue taking it to a shop for a new one. Aside from some increased back pressure, I'm not sure it will be an issue if you wanted to keep the old.

 

[mustang7173]

Omie1,

Check out this website. According to their information, 2-1/2 inch pipe MAX HP is 463 hp.

http://www.exhaustvideos.com/faq/how-to-calculate-muffler-size-pipe-diameter/

mustang7173

 

[Don C]

The exhaust flow depends on several variables, such as is your existing system mandrel bent? If not there will be more restriction to the flow. The number of, and sharpness of, bends affects the flow. An improperly placed H or X pipe will affect the flow. And of course the muffler can be very restrictive. Chances are your existing system will be under sized and somewhat restrictive. It will likely affect the tune, especially at higher RPMs, but even so you will notice a huge seat-of-the pants improvement with your new engine. When you get the new exhaust system installed expect to have to re-tune.

 

[Mister 4x4]

You're probably going to want to upsize the exhaust - 2 1/2" is a common and not too expensive way to go. I have a complete Pypes bolt-on 2.5" stainless kit with X-pipe and mufflers, and it ran around $450-ish - very easy to install and a minimal amount of cutting/trimming. Summit Racing has a house-brand aluminized 2.5" system with mufflers for $210-ish. Your exhaust shop may be able to beat that and offer custom features (H-pipe, X-pipe, name-brand mufflers, etc.) - all welded up, rather than pieced and clamped. (I'm still planning on taking mine to an exhaust shop and having them weld up some of the clamps and make some custom hangers)

More than likely, you're not going to hammer it or do much in the way of spirited driving with the 2 1/4" exhaust on the way to the exhaust shop. I wouldn't worry about it just for the drive over to the exhaust shop.

 

[TommyK]

All the most powerful 60's muscle cars had cast iron manifolds and 2- 1/4" crush bent exhaust systems from the factory. While you will make more power with headers and a larger diameter mandrel bent exhaust, it will run just fine. As Don C stated, it is simply a matter of tuning to whatever you have.

 

[barnett468]

.

if you are looking for max power, i would run straight thru mufflers like magnaflows . . an x pipe is also a good idea but not a necessity.

if you can afford 2 5/8", i would consider that.

your headers need to be at least 1 3/4 tubes and 1 7/8 is the max i would use.

 

[jbojo]

I vote Pypes, They installed with no mods with the exception of cutting the section that bolt to the headers to the correct length. Being a welder you should be able to do this in your shop with a couple of hours work. Pypes also offers different mufflers for what you need. I also ordered mine from Summit.

 

[Omie01]

I will have to look into those Pypes. I bought Borla XS mufflers to install but I'm thinking an upgrade to 2 1/2" would be a prudent choice.