Some Hypothetical Exhaust Questions....

[USMC850T]

Ok so I did my exhaust from the DP back pretty much by myself. I used 2.5" pipe all the way back, and used mandrel bends to go up around and over the rear axle. I have a veracious motorsports resonator and a generic ebay straight through muffler.

Now let's say hypothetically I wanted to quiet it down a little bit.... Could I take my 2.5" and split it into 2 2.25" or 2" bends to clear the axle and 2 - 2" straight through mufflers to keep things quieter? Would those still be able to flow what I need at 18psi? Keep in mind I have a stock DP and 2.5" going back to the muffling right now.

Basically what I have in mind is a Dual system with smaller pipe and straight through mufflers.

For the record this is what it sounds like now:

http://rochesterhti.com/850/103_3160.MOV

18 meg, don't worry about my bandwidth I have more than I know what to do with.

[Zappo]

Doesn't matter about flow. Your biggest exhaust bottleneck is the stock DP now. Your current 2.5 setup is good enough for what you have.

The setup you describe is still basically flowing the exhuast once through a muffler. It might quiet it a little, but if you are trying to run dual exhuast to only make it quieter then you are wasting your money.

[USMC850T]

It's not so much a money thing. By the mufflers are cheap and the bends aren't that expensive either.

[Zappo]

It's not so much a money thing. By the mufflers are cheap and the bends aren't that expensive either.

Dual exhaust is more of a cosmetic thing on our cars anyway, but that has been posted a lot. If you want quiet, swap the resonator for another muffler, like a 1 in/2 out setup and run your dual exhaust from that. I would think it would still be easier to split the exhuast after the axle.

[VolvoFan]

Ok so I did my exhaust from the down pipe back pretty much by myself. I used 2.5" pipe all the way back, and used mandrel bends to go up around and over the rear axle. I have a veracious motorsports resonator and a generic ebay straight through muffler.

Now let's say hypothetically I wanted to quiet it down a little bit.... Could I take my 2.5" and split it into 2 2.25" or 2" bends to clear the axle and 2 - 2" straight through mufflers to keep things quieter? Would those still be able to flow what I need at 18psi? Keep in mind I have a stock down pipe and 2.5" going back to the muffling right now.

Basically what I have in mind is a Dual system with smaller pipe and straight through mufflers.

For the record this is what it sounds like now:

http://rochesterhti.com/850/103_3160.MOV

18 meg, don't worry about my bandwidth I have more than I know what to do with.

I'm pretty sure that my 2x2.25" setup sounds quieter than if I'd left it as a single 2.5". Crunch the numbers on the diameters, and it flows just as well or better, even with a couple extra bends in there. Here's a quick summary of my setup:

3" downpipe from the turbo

3" flex joint

3" race cat

3" in, 2x3" out wye joint right about underneath the center of the rear passenger's seat... 90 degree bend to the passenger's side and 45 degree bend to the driver's side

Off the passenger's side, 3" electric cutout into a Dr. Gas "Boom Tube" that necks down from 3" round to 1.25 x 8" flat and heads straight out in front of the passenger's rear wheel

Off the driver's side, straight into TME muffler used in IPD's 2.5" cat-back.

2.5" out of TME muffler, then over the rear axle and into a 2.5" in, 2x2.25" out wye joint... one straight, and one 90 degree bend to the passenger's side that travels in front of the gas tank and bends back towards the rear of the car in a symmetrical fashion to the driver's side

Both 2.25" outlets have a Car Chemistry 3 disc insert welded inside them to quiet things down, then they each go through a Summit Racing 2.25" glasspack muffler and out through a stock C70 exhaust tip.

I'm not concerned about flow restriction, because if I really want to crank things up, it's easy to just open up the cutout and have essentially a 3" straight pipe with just a race cat restricting things.

The glasspacks alone out back were not nearly quiet enough, but the Car Chemistry inserts made it sound sweet... it doesn't drone at all, and makes a great sound when you really rev things up... sounds Porsche-like but still quiet enough to enjoy the engine/turbo sounds.

2.5" is a pipe cross sectional area of (1.25)^2 x pi = 4.9 in^2. two 2.25" pipes have a cross sectional area of (1.125)^2 x pi x TWO PIPES = 4.0 in^2 x 2 = 8 in^2!!! Almost double the cross sectional area of the single 2.5" pipe. Two 2" pipes have a cross sectional area of (1)^2 x pi x TWO PIPES = 3.1 in^2 x 2 = 6.2 in^2!!! Still larger than the cross section of a 2.5" pipe. If you're sticking with 2.5" all the way back, split it into two 2" pipes for more muffling. That's probably what I should have done in retrospect. If you're going to step up to a full 3" eventually and want no cross sectional area loss... (1.5)^2 x pi = 7.1 in^2, which is more than two 2" but less than two 2.25" so go with two 2.25" in that case. It'll be louder than two 2" pipes but if you're concerned about flow restriction that's the way to go.

Hope this helps,

-Jon

[Guest 300+_T5R_855]

Get rid of the glass paks and get a real muffler if you want to quiet it down. I use a Magnaflow with a big a$$ resonator in the back and with the 3" DP it's still loud.

[BOOSTPHREAK]

Get rid of the glass paks and get a real muffler if you want to quiet it down. I use a Magnaflow with a big a$$ resonator in the back and with the 3" down pipe it's still loud.

I would Go with a inch down pipe, then go to 2.5 inche cat to mufflers, then go 2.25inche dual mufflers one per rear exhaust outlet. Should deliver the power you want and the acoustics, at a resonable price.

[narxs70]

what about a 2.5" x 18" resonator? or two 2.5" x12" resonators? would that quiet it down without the retriction of going to 2.25"?

[socal850tuner]

I am a fan of doing 2 glass packed with 3in from the turbo back