Backpressure/Exhaust Questions

[BlackMetal]

I've searched the forums and found other threads stating that you want as little exhaust restriction as possible. Correct? So my hypothetical exhaust system design of: 3" DP, 3" Testpipe, Y-Pipe, and custom bent pipes off the Y-pipe exiting in front of the rear tires will improve performance?

With that said, how loud is a GN with no mufflers? Stock is too quiet for me, but I don't want to be louder to the point that cops notice my exhaust.

 

[Pronto]

Backpressure after the turbo=performance killer. That's why we either get rid of the cat or make it removeable and only use it for inspections, put on a larger diameter cat back system and low restriction muffler(s). The choice then becomes how much noise do you want to hear. Single shot 3" are the loudest and stock is the quietiest. One way to keep it quieter is to use a dump pipe in place of the cat and then open it at the track for more performance. Do a search on mufflers for opinions on which is best. Most will say a straight through design works best. Most will also say that the Flowmasters are not a good match for the turbo. I have a Hooker catback and am happy with it. Exiting behind the wheel would keep it quieter. As long as you have mandel bent pipes it really isn't that big of issue.

 

[BlackMetal]

Backpressure after the turbo=performance killer. That's why we either get rid of the cat or make it removeable and only use it for inspections, put on a larger diameter cat back system and low restriction muffler(s). The choice then becomes how much noise do you want to hear. Single shot 3" are the loudest and stock is the quietiest. One way to keep it quieter is to use a dump pipe in place of the cat and then open it at the track for more performance. Do a search on mufflers for opinions on which is best. Most will say a straight through design works best. Most will also say that the Flowmasters are not a good match for the turbo.

Thanks for the response, sorry for editing my post while you were apparently replying to it. Now that I edited my post I specifically mentioned what I sorta have in mind to do with my exhaust. I just wanted to make sure I didn't spend my money and end up with bogged-down performace, so I wanted to triple check the facts about backpressure on a turbo car.

 

[Evaddave 87gn]

Back pressure

W/turbo's Zero backpressure is perfect, (pressure of air exiting turbo to outside air,) thats why so many run dumps at drag strip. However as you could imagine its really LOUD! I ran a 3" and hated it! The Drone was crazy! I am installing a 2.25 this winter. If your looking for the best performacne then check out RJCracing they have a 5inch down pipe, they also go into detail on backpressure. As far as pessure from bends at tail pipe muffler etc.. not as high as you think. Most restriction is being casued by pipe diameter. Only so much air to stuff in a 3" hole, stuff the same amount in a 2" hole, which one is at Higher pressure?

DAve

 

[Pronto]

BTW, mine did get louder when I added the THDP this fall. IMO the V-6 doesn't sound the greatest when it's louder, it's not going give that V-8 muscle car sound.

 

[BlackMetal]

Well my car is stock right now so I have no need to jump straight to something as extreme as a 5 inch DP.

So I take it if a dump tube is really loud, then the exhaust system I wanted to do will be deafening? I wanted my GN to sound meaner, not throw a red flag up for the cops to pull me over.

 

[BlackMetal]

BTW, mine did get louder when I added the THDP this fall. IMO the V-6 doesn't sound the greatest when it's louder, it's not going give that V-8 muscle car sound.

Yeah I can understand what you're saying, I know it'll only get "louder" not much "better" in terms of tone. I just wanted to bring it above the stock whisper. I thought it would give people something to look at though if I moved my exhaust to the front of the rear tires, but it's a semi-daily-driver, I don't want to go deaf.

 

[Evaddave 87gn]

Hooker will fit needs

Hooker makes a really nice set at a reasonable price, 299 w/areo chamber mufflers. These cars sound great w/this set up. I intend to use this myself.
DAve

 

[Pronto]

Then you would be very happy with the Hooker cat back, it fits great and is very reasonably priced from Buick vendors and Summit/Jegs etc. Your performance will improve immediately especially if you can skip the cat. Next get a Scanmaster!!!

 

[BlackMetal]

I guess I'm deciding between the Hooker system, the 2.75" system selling at Jaysgn.com, or the system from the group buy that is currently being organized in the "Parts for Sale" forum.

 

[sweetv6]

go with hooker i have a single shot 3-1/2 stop at rear end
with stock down pipe and turbo and it gave me .2 on 1/4
sound is great too.

IMO

Claude