Downpipe to exhaust...

[davef]

Guys
First let me say, that I am still new to this stuff, so forgive a little ignorance on my part. I want to change to a 3 inch downpipe (from original). I will be eliminating the cat and putting on a new exhaust system, with electric cutouts in between. My question is, do I need to match my exhaust to my downpipe? Exhaust system that I would prefer is 2 /12 inches. Downpipe is 3 inches. Everything that have read and heard is that a 3 inch exhaust is pretty loud. I would prefer to try to keep the noise level down to a factory stock rumble if possible ( except for when I release the cutout of course :biggrin

You guys have been steering me in the right drection so far, so "if ain't broke......."

 

[Pittsburghkid]

You don't have to match the exhaust to the downpipe. However a larger exhaust will expell more exhaust gasses which leads to more horsepower, hence the reason for going to a larger diameter downpipe and eliminating a restrictive cat. A 3" exhaust doesn't necessarily mean it will be louder. The sound of the exhaust depends on what type of mufflers you go with. However DO NOT get an exhaust with baffled mufflers. They create a backpressure not needed on boosted engines and will only rob you of power. You want to get a straight through muffler design no matter what size exhaust you go with.

 

[davef]

Any recommendations?

 

[Pittsburghkid]

On? Mufflers? Exhaust Size? Downpipe? I need the specifics my friend.

 

[davef]

Sorry. Need recommendations on muffler. If a 3 inch exhaust is not prohibitively loud, then great.

 

[Pittsburghkid]

Well my friend put this 2.5" exhaust on from cottons. It's not loud and he loves it. He said ne noticed a significant gain going from a flowmaster to this.

2.5" Dual Exhaust, stainless steel, Exhaust, EX100SS | Cotton's Performance Buick Grand National Parts & Service

Thats the whole thing but you can get those mufflers from anywhere. He also sells it in a 3" for a little less because the pipes are aluminum and not SS.

I purchased this exhaust but have yet to put it on my car. I hear its not excessively loud for a 3" but won't know for sure til the weather clears up for me to put this on.

STAINLESS CATBACK EXHAUST

I think those mufflers only come with the full kit but you'd have to ask Mark if they sell just the mufflers.

There's the old standby of the Hooker mufflers which alot of people had on their cars (including me) from the 90's but they have a very deep throaty sound which you don't want.

There's also Dynomax which is also a straight through muffler. I haven't heard these on a car and haven't heard anyone say what they sounded like, but they are a quality muffler.

http://www.dynomax.com/mufflers.php

As long as you stay away from a baffled muffler like flowmaster you should be fine.

So it's now basically up to you as to how much you want to spend but if your looking for quiet performance and just a muffler purchase and not the enitre exhaust system i'd recommend the magnaflow which should bolt right up. Or if moving up to the 3" either kit should be fine.

 

[davef]

Thanks. This is a good starting place.

 

[davidf]

I bought a "Pypes" 2.5 stainless system from Kirbans. Less than $400.00 to my door.
1986 1987 Buick Regal Grand National Turbo T T-Type GNX PYPES PERFORMANCE DUAL EXHAUST SYSTEM (Non-Polished Stainless Steel) #6996
$388.95 to be exact.

 

[davef]

Did you connect it to a 3 inch downpipe?

 

[davidf]

Yes. I believe most DP exits are similiar. I have ATR 3'.