So as of my knowledge the 03' H2 has a duel 3inch in on the muffler. I have a spare Flowmaster 40 series muffler that was installed on my old Expedition a year ago but I took it off. It has a 2 1/2in in and out. Would it be a bad idea to reduce the duel 3in to a single 2 1/2in, and then into the flowmaster? any thoughts?

Right after the muffler I would only put maybe a 10in pipe then direct it toward the ground for max reverb

 

Nate, here is the dirty basics of it (trust me I could go really in depth into how exhausts work)

The more the exhaust is open, the more gases it allows the engine to release. This is why dragsters have a completely open exhaust with just a couple of pipes coming off each port. They may not be BIG HUGE pipes, but then again they dont have to be...

Also, there is a science to exhaust sizes. Meaning that for the various size engines there is a correct size minimum sized exhaust. The more exhaust gases an engine can make, the bigger the exhaust diameter size. This is why 4 cyl engine have 2 inch, and 8 cyl have 3 inch. But thats not to say run out and put a HUGE diameter exhaust on either. Because the wrong sized exhaust will create power yes, but it will do so at the loss of low end torque.

This might help you out
Magnaflow Technology

So yes, it would be bad to bring your engine from a dual 3 inch to a single 2.5 inch. You would be choking your engine as it is trying to breathe out. You want to open exhausts up, not choke them down. And that choking would create backpressure and cause your engine to perform poorly

Hope this helps

 

Thanks alot jsbihn. I'm scraping the whole idea and just saving up for a new full exhaust

 

I don't think it would hurt power all that bad but why be that tight? How much could a new Flowmaster cost??? Less than $100 i'm sure.

 

Do not reduce the diameter from 3", I am sure that if 2.5" diameter was fine GM would have used that instead to save a buck.

My thinking is they used the bare minimum of 3" more then likely 3.5" would be a benefit.

 

jsbihn brings up some good points. Also as mentioned GM used 3" for a reason. V8's need to breath and get the exhaust out. You also don't want to go too big as many engines use a scavenging effect in the exhaust where the exhaust from one cylinder helps to pull the exhaust of the next cylinder hitting their exhaust cycle. I definitely wouldn't go any smaller than the stock size though.

 

Ya scrapped the idea all together. I love the sound of the Borla, but it so expensive I want one of of those sounds that make people go

 

I too love the sound of a nice exhaust but in something as slow as an H2 I just don't see the point really. Just my opinion.

 

Haha I was going to take my deuce also to the local exhaust shop also and have a flowmaster installed, but then decided against it. When Zombies finally arrive I want to be able to get around without attracting them all