Notices
Series I Aftermarket Performance Modifications Discussion of power adding modifications

3in compared to 2in exhaust

Thread Tools
 
Search this Thread
 
Rate Thread
 
Old 06-22-2011, 05:31 PM
  #1  
Gimmie that Bitch Cannon
Thread Starter
 
TrickWilliams's Avatar
 
Join Date: Jun 2011
Location: Minnesota
Posts: 249
Likes: 0
Received 0 Likes on 0 Posts
3in compared to 2in exhaust

Im in the process of making my own custom 3 in exhaust all the way back, but today I was having second thoughts. 2.5 is usually big enough for a turbo set up, which is in the near future. I'm finishing the 3 but I just wanted to know what you guys thought and why. Pros cons, you know. Thanks a lot.
Old 06-22-2011, 05:39 PM
  #2  
SARX Legend
iTrader: (46)
 
9krpmrx8's Avatar
 
Join Date: Jan 2007
Location: San Antonio, Texas
Posts: 33,784
Received 452 Likes on 366 Posts
TX

Originally Posted by TrickWilliams
Im in the process of making my own custom 3 in exhaust all the way back, but today I was having second thoughts. 2.5 is usually big enough for a turbo set up, which is in the near future. I'm finishing the 3 but I just wanted to know what you guys thought and why. Pros cons, you know. Thanks a lot.

Most will say 3". But honestly on a NA car I kind of regret going with a 3", my car always ran stronger with the stock exhaust than it has with my HKS and now with the Turbo XS 3". But I'm installing a turbo kit so I will utilize the 3" now. I personally thin the engine needs the smaller diameter piping. I also have the BHR midpipe.

Last edited by 9krpmrx8; 06-22-2011 at 11:12 PM.
Old 06-22-2011, 05:52 PM
  #3  
Gimmie that Bitch Cannon
Thread Starter
 
TrickWilliams's Avatar
 
Join Date: Jun 2011
Location: Minnesota
Posts: 249
Likes: 0
Received 0 Likes on 0 Posts
That's what I've heard but I've never felt it. My s13 na 3 in straight back I felt more power. But I wasn't sure on this 8. I think I'm going to do it anyway though. It's almost made up and it will get utilized within the year, if stuff goes as planned
Old 06-22-2011, 05:56 PM
  #4  
Gimmie that Bitch Cannon
Thread Starter
 
TrickWilliams's Avatar
 
Join Date: Jun 2011
Location: Minnesota
Posts: 249
Likes: 0
Received 0 Likes on 0 Posts
Originally Posted by 9krpmrx8
Most will say 3". But honestly on a NA car I kind of regret going with a 3", my car always ran stronger with the stock exhaust than it has with my HKS and now with the Turbo XS 3". But I'm installing a turbo kit so I will utilize the 3" now. I personally thin the engine needs the back pressure from the smaller diameter piping. I also have the BHR midpipe.
Do you like the sound though? What's under there for the turbo xs? One resonator and muffler? What I'm fabing up will be straight all the way back..I know it's goin to be loud. If I don't like it what's the best sounding resonator or cutback I guess to tone it down a bit?
Old 06-22-2011, 05:59 PM
  #5  
SARX Legend
iTrader: (46)
 
9krpmrx8's Avatar
 
Join Date: Jan 2007
Location: San Antonio, Texas
Posts: 33,784
Received 452 Likes on 366 Posts
TX

Originally Posted by TrickWilliams
Do you like the sound though? What's under there for the turbo xs? One resonator and muffler? What I'm fabing up will be straight all the way back..I know it's goin to be loud. If I don't like it what's the best sounding resonator or cutback I guess to tone it down a bit?

I loved the HKS (single side, one muffler) with the SR motorsports midpipe and the BHR. The Turbo XS is too loud, it has two mufflers in it. I am getting a resonator welded in before the turbo build is done.

If you are doing straight back you are nuts. The HKS was loud but sounded great, the Turbo XS is loud in another way and doesn't sound great. Every muffler and resonator will sound different.
Old 06-22-2011, 06:23 PM
  #6  
Gimmie that Bitch Cannon
Thread Starter
 
TrickWilliams's Avatar
 
Join Date: Jun 2011
Location: Minnesota
Posts: 249
Likes: 0
Received 0 Likes on 0 Posts
Nuts yes, it will be done and I know it's gunna be crazy but after it's done I'll weld what I need to underneath till I have the sound I like. I get exactly what I want and it's cheaper then an exhaust kit.
Old 06-22-2011, 06:58 PM
  #7  
Registered
 
jayscoobs's Avatar
 
Join Date: May 2010
Location: Bay Area, CA
Posts: 347
Likes: 0
Received 0 Likes on 0 Posts
3 inch for turbo applications, 2.5 for NA, you lose low end a little but you gain it up top I believe. Complete straight pipe is like open header. Crazy loud. Im running a single exit with a test pipe, its loud but not too loud to me.
Old 06-22-2011, 10:05 PM
  #8  
Wheels, not rims!!
iTrader: (8)
 
SayNoToPistons's Avatar
 
Join Date: Apr 2005
Location: LA
Posts: 6,527
Received 67 Likes on 56 Posts
I have a feeling that you have no idea what you are getting into.
Old 06-22-2011, 10:12 PM
  #9  
Gimmie that Bitch Cannon
Thread Starter
 
TrickWilliams's Avatar
 
Join Date: Jun 2011
Location: Minnesota
Posts: 249
Likes: 0
Received 0 Likes on 0 Posts
Originally Posted by SayNoToPistons
I have a feeling that you have no idea what you are getting into.
I acually have it done now. thanks for your concern. just ordered an turbo xs dual resonated midpipe and exotic speed rear muffler. ill have to refab some of what i have now but i think ill like it. midpipe 3 in to the exotic speed rear R1-T muffler.
Old 06-23-2011, 12:50 AM
  #10  
I HATE SPEEDBUMPS!
 
monchie's Avatar
 
Join Date: Nov 2007
Location: Las Vegas, NV
Posts: 8,549
Likes: 0
Received 7 Likes on 6 Posts
Bigger is always better, zoom zoom!
Old 06-23-2011, 10:13 AM
  #11  
SARX Legend
iTrader: (46)
 
9krpmrx8's Avatar
 
Join Date: Jan 2007
Location: San Antonio, Texas
Posts: 33,784
Received 452 Likes on 366 Posts
TX

Originally Posted by monchie
Bigger is always better, zoom zoom!

Wrong (as usual). An exhaust that is too large can hurt performance.
Old 06-23-2011, 10:18 AM
  #12  
Registered
iTrader: (15)
 
paimon.soror's Avatar
 
Join Date: Jun 2010
Location: Between Cones
Posts: 7,560
Received 25 Likes on 23 Posts
Originally Posted by monchie
Bigger is always better, zoom zoom!
God damn you fill every thread with nonsense ... do us a favor and stfu...

While you are doing that read up on the importance of flow capacity and its relation to velocity. I am not talking about car velocity, but the velocity of the exhaust.

In a perfect world an exhaust would be engineered to fit the power band of the vehicle. Most cars utilize a midrange power band, therefore the exhaust is sized to that spec. One could ideally increase the affect of their low range power band (1k - 3k) by opting for a smaller exhaust diameter, however, as you approach midrange to high range, the backpressure created by the lack of flow and the increase velocity would cause you to lose power

If you get too large of an exhaust, the velocity would decrease at a lower rpm band as your flow diameter has increased greatly...sort of like having a large diameter garden hose vs a small one. In retrospect, the higher end rpm range would "benefit" due to the increased flow capability at that velocity.

Last edited by paimon.soror; 06-23-2011 at 10:21 AM.
Old 06-23-2011, 12:40 PM
  #13  
Banned
iTrader: (1)
 
Dan@Assaultech's Avatar
 
Join Date: Dec 2009
Posts: 1,887
Likes: 0
Received 0 Likes on 0 Posts
2.5" is ideal and still plenty large for an RX8, 3" is a bit excessive unless you are making pretty good numbers.
Old 06-23-2011, 09:50 PM
  #14  
Gimmie that Bitch Cannon
Thread Starter
 
TrickWilliams's Avatar
 
Join Date: Jun 2011
Location: Minnesota
Posts: 249
Likes: 0
Received 0 Likes on 0 Posts
Originally Posted by paimon.soror
[SIZE="3"][SIZE="5"]God damn you fill every thread with nonsense ... do us a favor and stfu...

While you are doing that read up on the importance of flow capacity and its relation to velocity. I am not talking about car velocity, but the velocity of the exhaust.

In a perfect world an exhaust would be engineered to fit the power band of the vehicle. Most cars utilize a midrange power band, therefore the exhaust is sized to that spec. One could ideally increase the affect of their low range power band (1k - 3k) by opting for a smaller exhaust diameter, however, as you approach midrange to high range, the backpressure created by the lack of flow and the increase velocity would cause you to lose power

If you get too large of an exhaust, the velocity would decrease at a lower rpm band as your flow diameter has increased greatly...sort of like having a large diameter garden hose vs a small one. In retrospect, the higher end rpm range would "benefit" due to the increased flow capability at that velocity.
Settle down settle down. Thanks though good ****
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
arexatemate
RX-8 Parts For Sale/Wanted
6
10-28-2019 08:16 AM
mdl0209
Series I Trouble Shooting
14
05-23-2019 05:46 PM
fourwhls
RX-8's For Sale/Wanted
7
02-20-2019 05:16 PM
fc2se
NE For Sale/Wanted
2
06-01-2016 08:55 PM
Jb4ker96
Series I Trouble Shooting
0
09-27-2015 10:06 PM



You have already rated this thread Rating: Thread Rating: 0 votes,  average.

Quick Reply: 3in compared to 2in exhaust



All times are GMT -5. The time now is 04:44 AM.