2 1/2" or 3"

[InFlames]

I was wondering what would be the difference in power between a FULL(o2 housing included) 2 1/2" and a FULL 3". Also, does anyone have any thoughts/expereince with the DSMotorsports exhaust systems?

 

[InFlames]

Any One?

 

[Low Flying GS-T]

It depends on your turbo size, if staying with the stock 14b the difference will be minimal and the price will be different. But if you have an upgraded turbo the HP differences really start to show, and most say do it right the first time.

 

[nined2tsi]

Id just go with the 3". Not that much more money and dont have to change from 2.5" to 3" later on after your runnin 12s. peace

 

[98TsiAWD]

Im looking at the RnR Racing Turbo back o2 eliminators -w- test pipes. I think I only want the 2.5" because I only plan to hit low 13's to high 12's and because a 3" -w- test pipe is LOUD. I want to be as quiet as possible. But I was thinking, does this sound like a good idea and would it still be quiet?

2.5" O2 eliminator Downpipe
2.5" Test Pipe
3" Catback

all from RnR Racing.

 

[doug]

That's the exhaust I have except mine's 2.5" all the way-- it's not loud at all, and I have the straight-through muffler on mine. Seems to flow well too-- if you're only planning on 12-13s, a complete 2.5" system is fine and will be quieter. I think there are pics of mine in the Gallery.

 

[InFlames]

Well, i went with a full 3" (inc. o2 housing). I got it from DSMotorsports. Personally its a LOT quieter than i expected from a full 3" w/test pipe, and staight though muffler.

 

[laserspeeddemon]

Good choice! A 3" turbo-back exhaust system give more Hp from the start and allows the larger turbos to spool faster and raises the peak power over all on the car then a 2.5" I know people that got the 2.5" turbo backs with a T/P. Then regretted, cause when the wanted to upgrade the turbo to either a 16g or 20g they had to spend nearly another grand for a full 3" exhaust system. Then the couldn't afford the turbo. I sorta made a compromise. My cat-back and T/P is 3", the D/P is is 3" from the cat and necks down to a 2.5" so it would fit the stock O2 housing. When I am ready. I will upgrade the turbo, 02 housing and D/P, then sell the D/P to someone who wants it for a nice price. I will sell the O2 housing and turbo as well.

 

[doug]

Originally posted by laserspeeddemon
I know people that got the 2.5" turbo backs with a T/P. Then regretted, cause when the wanted to upgrade the turbo to either a 16g or 20g they had to spend nearly another grand for a full 3" exhaust system.

There's no way a 16G needs to have a full 3" exhaust. Maybe not even a 20G, but that's a little debatable.

 

[Grizzly Racing]

heres my experience with the both.

i am running a big 16G P/C

i had a full 3" system.... it held rock solid at 25 psi.....

i then took off the 3" DP and installed a 2.5" DP/testpipe upto the 3" catback.

i changed nothing else....... it spooled a lot quicker and i gained 2mph in the 1/4...... but now my boost died off.......... it used to hold 25psi but now by the time i hit redline i am down to 20psi... and i also lost 3mph in the 1/4.......

i tried turning down the boost...... hit 20psi and then dropped to 16psi.

so my next plan is to run 2.5" off the o2 housing and also the flex section.... and then right after the flex i am bumping it upto 3"....

i'll let you know what happens when i get the chance to reweld the DP. i'm hoping this will give me the quick spool up.... and hold boost at the same time....

 

[doug]

Now, see, that was a great post-- thanks Grizz. That's the kind of hard factual experience we need to base our decisions on-- not just a bunch of keyboard racers (me included) saying do this or that based on what other message boards have said. I find myself guilty of quoting heresay from other users occasionally and I have to remind myself to be careful in doing so-- there's really no telling what's true and what's not just based on what some faceless internet unknown says that he found on dsmystery.com. Sure, not all of it is useless, probably not even most, but you can never know for sure if it's a priceless nugget of info, or poo.

OK, I'm done.

 

[laserspeeddemon]

Originally posted by doug
Now, see, that was a great post-- thanks Grizz. That's the kind of hard factual experience we need to base our decisions on-- not just a bunch of keyboard racers (me included) saying do this or that based on what other message boards have said. I find myself guilty of quoting heresay from other users occasionally and I have to remind myself to be careful in doing so-- there's really no telling what's true and what's not just based on what some faceless internet unknown says that he found on dsmystery.com. Sure, not all of it is useless, probably not even most, but you can never know for sure if it's a priceless nugget of info, or poo.

OK, I'm done.

I agree. I do the same when it comes to "quoting someone elses quote." But I got my laser in 99, and my Talon this year. I experiment on both. In fact all my cars are modded. Some of it is common sense though. A turbo breathes better with a bigger exhaust. The rest depends on what your goals are. I have different reasons for all my cars. Talon-Speed, 626-Suspension, Probe-science expirement, Laser-parts car.

 

[HighPsi91]

Several years ago when my talon was still my daily driver and slow relatively speaking... I used a complete pressbent 2.5inch Buschur system. I had a small 16g and a few other minor mods. I ran 12.5s all day long. The noise level was pretty tolerable. This system used an oval dynomax ultra-flow.

Boost would hold steady at the then set 20psi setting all the way to the revlimiter. The turbine housing and 02 housing needed some porting however to acheive that.

 

[AndyFL]

Don't skimp out when spending money on exhaust, go with the greddy evo or power extreme (80mm/tad over 3"), or if you must the HKS (2.75") Spend the money there instead of a cheap muffler/catback and you won't have to worry about being loud.