1st Generation Specific (1979-1985) 1979-1985 Discussion including performance modifications and technical support sections

Trying to think up an exhaust combo...

Thread Tools
 
Search this Thread
 
Old 11-29-08, 08:32 PM
  #1  
Environmentally-Hostile

Thread Starter
 
Starfox07's Avatar
 
Join Date: Sep 2005
Location: Ennis/Arlington Texas
Posts: 1,662
Likes: 0
Received 1 Like on 1 Post
Trying to think up an exhaust combo...

I'm wanting to do a full exhaust system for my SE. I know what I want at the front and back, but don't really know what to put in between, even after reading ALOT of threads on here about it.

I want the RB header at the front, and a rotaflo muffler/tip at the rear, and, if at all possible, for it to sound similar (i know its street ported, but the S4 and S3 are pretty close) to this.

http://www.youtube.com/watch?v=xmAtykbDpuc

I do want it fairly loud, but I HATE the ball-bearings-in-coffee-can sound that I hear all too often.

I was thinking two inline style resonators and thickwall piping with 2'' diamter, does that sound good? What gauge or thickness piping would elimate the pinging/raspy sound? I believe the muffler shop i most often go to carries only 12 gauge piping, is that thin or thick?


(funny story: I went to that same muffler shop today to have a HUGE leak fixed [bolts were gone and there was no gasket between manifold and downpipe] and I warned the tech as soon as I got out of the car [i had to drive it on the rack because the kid couldn't drive a standard] that the exhaust would be really hot because it was a rotary. He didn't seem to pay attention to me but about 5 minutes later he came into the shop where i was sitting and asked me where i came from. I was like 'oh only a couple miles away, its only been running a few minutes' Him: "that ************ is HOT' )
Old 11-29-08, 10:11 PM
  #2  
Famous Taillights

iTrader: (3)
 
FirebirdSlayer666's Avatar
 
Join Date: Oct 2005
Location: Hagerstown, MD
Posts: 3,443
Likes: 0
Received 1 Like on 1 Post
Yeah you'll need thickwalled piping to keep the rasp down, 1/8" thick wall is what you'd want. I would probably go twin 2" pipes from the RB road race header back to the axle then merge it into a 2 1/4" or 2 1/2" single into the Rotaflo. I'd put a Borla muffler in each pipe.
Old 11-29-08, 11:00 PM
  #3  
Environmentally-Hostile

Thread Starter
 
Starfox07's Avatar
 
Join Date: Sep 2005
Location: Ennis/Arlington Texas
Posts: 1,662
Likes: 0
Received 1 Like on 1 Post
Originally Posted by FirebirdSlayer666
Yeah you'll need thickwalled piping to keep the rasp down, 1/8" thick wall is what you'd want. I would probably go twin 2" pipes from the RB road race header back to the axle then merge it into a 2 1/4" or 2 1/2" single into the Rotaflo. I'd put a Borla muffler in each pipe.
What kind of borla muffler? Like a bullet style or a chambered muffler?

Also, why do you suggest the road race header into two separate pipes all the way back? I'd like to spend under $500 if I can.
Old 11-29-08, 11:07 PM
  #4  
Famous Taillights

iTrader: (3)
 
FirebirdSlayer666's Avatar
 
Join Date: Oct 2005
Location: Hagerstown, MD
Posts: 3,443
Likes: 0
Received 1 Like on 1 Post
Twin pipes back to the axle actually helps with the scavenging of the exhaust. It's called a Long Primary exhaust and makes more power vs. just a single pipe. The Borla's of choice would be either the ProXS or XR-1's. If you want to do it right the first time you're gonna need to spend some money
Old 11-29-08, 11:40 PM
  #5  
MattG FTW!!!!!

iTrader: (2)
 
MattG's Avatar
 
Join Date: Feb 2005
Location: South Windsor, CT
Posts: 2,733
Likes: 0
Received 0 Likes on 0 Posts
You need an RB Presilencer

Also where you gonna get an rotoflo muffler?

PS you know im only about 40 miles south of you
Old 11-30-08, 12:00 AM
  #6  
Famous Taillights

iTrader: (3)
 
FirebirdSlayer666's Avatar
 
Join Date: Oct 2005
Location: Hagerstown, MD
Posts: 3,443
Likes: 0
Received 1 Like on 1 Post
With a Rotaflo, an RB presilencer just would'nt be enough. They aren't that hard to find Matt!!
Old 11-30-08, 12:08 AM
  #7  
Banned. I got OWNED!!!
iTrader: (30)
 
Kerebrus's Avatar
 
Join Date: Feb 2007
Location: Cali Native
Posts: 3,608
Likes: 0
Received 0 Likes on 0 Posts
I'm about to order my Rotaflo muffler from AU. Only place to get it.
Old 11-30-08, 12:13 AM
  #8  
MattG FTW!!!!!

iTrader: (2)
 
MattG's Avatar
 
Join Date: Feb 2005
Location: South Windsor, CT
Posts: 2,733
Likes: 0
Received 0 Likes on 0 Posts
Thanks that is what I thought, I hope he isnt being fooled by one of those ebay knock offs

This is what im talking about

http://rotaflo.com.au/products.php



Old 11-30-08, 12:18 AM
  #9  
Banned. I got OWNED!!!
iTrader: (30)
 
Kerebrus's Avatar
 
Join Date: Feb 2007
Location: Cali Native
Posts: 3,608
Likes: 0
Received 0 Likes on 0 Posts
I'm buying this one with the dump tip separate.

Old 11-30-08, 11:20 AM
  #10  
Environmentally-Hostile

Thread Starter
 
Starfox07's Avatar
 
Join Date: Sep 2005
Location: Ennis/Arlington Texas
Posts: 1,662
Likes: 0
Received 1 Like on 1 Post
Is this header worth $60?
http://dallas.craigslist.org/dal/pts/918952066.html

I think this will be my combo.

Racing beat streetable header, racing beat presilencer, then stock piping all the way back to the rotaflo muffler.

Does anybody know if the turndown tip is INCLUDED with the rotaflo? The pictures don't really show it.

So, used header = $60
Presilencer = $214
Rotaflo = $240 USD

Total = $514, plus shipping of course.
Old 11-30-08, 12:22 PM
  #11  
Banned. I got OWNED!!!
iTrader: (30)
 
Kerebrus's Avatar
 
Join Date: Feb 2007
Location: Cali Native
Posts: 3,608
Likes: 0
Received 0 Likes on 0 Posts
Originally Posted by Starfox07
Is this header worth $60?
http://dallas.craigslist.org/dal/pts/918952066.html

I think this will be my combo.

Racing beat streetable header, racing beat presilencer, then stock piping all the way back to the rotaflo muffler.

Does anybody know if the turndown tip is INCLUDED with the rotaflo? The pictures don't really show it.

So, used header = $60
Presilencer = $214
Rotaflo = $240 USD

Total = $514, plus shipping of course.

Where'd you get the $240 USD pricing for the Rotaflo? And in terms of the turndown tip, are you referring to the muffler I showed above?
Old 11-30-08, 12:24 PM
  #12  
NEED A MARIAH HATCH BADLY

 
StumpDrummer's Avatar
 
Join Date: May 2008
Location: Louisiana USA
Posts: 113
Likes: 0
Received 0 Likes on 0 Posts
Exhaust

Heres the setup I did on my old 82,Rx-7
RB, 4 barrel intake heavily modified
Did the racing beat header then 2 2 inch pipes
all the way out to 2, 2 inch free flow straight through mufflers cant remember the brand welded together
it Screamed and flowed like no other they barely fit
If you have to have pre silencers your gonna lose a few horses
but you can set them up to be unboltable and put a straight pipe in for fun

unless you want to go from 2,2 inch pipes to a 4 inch pipe
if you go from 2,2inch to a 3 inch your creating back pressure
that slows your engine down!!do the math!!
reguardless of what some people think backpressure does slow you down

Remember exhaust gasses on a rotary engine are still expanding about 1/2 way down you pipe!!!!

good luck

Last edited by StumpDrummer; 11-30-08 at 12:30 PM. Reason: forgot some stuff
Old 11-30-08, 12:36 PM
  #13  
Environmentally-Hostile

Thread Starter
 
Starfox07's Avatar
 
Join Date: Sep 2005
Location: Ennis/Arlington Texas
Posts: 1,662
Likes: 0
Received 1 Like on 1 Post
Originally Posted by Cbz
Where'd you get the $240 USD pricing for the Rotaflo? And in terms of the turndown tip, are you referring to the muffler I showed above?
$360aus ~ $240usd, that's what the converter said..?

Lobster tail, turn down, curved tip whatever you want to call it, does that come on the rotaflo or is it separate?

Originally Posted by StumpDrummer
Heres the setup I did on my old 82,Rx-7
RB, 4 barrel intake heavily modified
Did the racing beat header then 2 2 inch pipes
all the way out to 2, 2 inch free flow straight through mufflers cant remember the brand welded together
it Screamed and flowed like no other they barely fit
If you have to have pre silencers your gonna lose a few horses
but you can set them up to be unboltable and put a straight pipe in for fun

unless you want to go from 2,2 inch pipes to a 4 inch pipe
if you go from 2,2inch to a 3 inch your creating back pressure
that slows your engine down!!do the math!!
reguardless of what some people think backpressure does slow you down

Remember exhaust gasses on a rotary engine are still expanding about 1/2 way down you pipe!!!!

good luck

Any videos/audio clips of that setup?
Old 11-30-08, 01:01 PM
  #14  
MattG FTW!!!!!

iTrader: (2)
 
MattG's Avatar
 
Join Date: Feb 2005
Location: South Windsor, CT
Posts: 2,733
Likes: 0
Received 0 Likes on 0 Posts
Last time I looked at them the tip was seperate.

The header is an alright deal, maybe throw 50 bucks at him and see what he says. You might want to check out the for sale section on the forum, but you probably already have.
Old 11-30-08, 01:14 PM
  #15  
Environmentally-Hostile

Thread Starter
 
Starfox07's Avatar
 
Join Date: Sep 2005
Location: Ennis/Arlington Texas
Posts: 1,662
Likes: 0
Received 1 Like on 1 Post
Originally Posted by MattG
Last time I looked at them the tip was seperate.

The header is an alright deal, maybe throw 50 bucks at him and see what he says. You might want to check out the for sale section on the forum, but you probably already have.
Yeah, I can't find any. Also scoped out ebay, nothin doin. I figure the header will look like that in a year anyways, so why buy a new one.
Old 11-30-08, 01:41 PM
  #16  
Stu-Tron Get Yo Groove On

iTrader: (4)
 
Jeezus's Avatar
 
Join Date: Nov 2006
Location: Huntsville AL
Posts: 8,405
Received 9 Likes on 9 Posts
I run a RB single outlet header, 2.5 exhaust with a Borla ProXS presilencer and a Borla muffler:

http://ca.youtube.com/watch?v=XMEMkpTTLIw

http://ca.youtube.com/watch?v=V1cPD1TyY1U

Last edited by Jeezus; 11-30-08 at 01:43 PM.
Old 11-30-08, 02:12 PM
  #17  
Environmentally-Hostile

Thread Starter
 
Starfox07's Avatar
 
Join Date: Sep 2005
Location: Ennis/Arlington Texas
Posts: 1,662
Likes: 0
Received 1 Like on 1 Post
That's pretty close to the sound I'm looking for thanks! I think with EFI it would be a bit smoother too.

Call me a cheap bastard, but I just found this

http://cgi.ebay.com/ebaymotors/Parts-Accessories_Car-Truck-Parts-Accessories__TURBO-PRO-MUFFLER-SUBARU-NISSAN-TOYOTA-HONDA-MAZDA-DODG_W0QQitemZ250333450486QQddnZPartsQ20Q26Q20Acce ssoriesQQadiZ2865QQddiZ2811QQadnZCarQ20Q26Q20Truck Q20PartsQ20Q26Q20AccessoriesQQcmdZViewItemQQptZMot ors_Car_Truck_Parts_Accessories?hash=item250333450 486&_trksid=p4506.c0.m245&_trkparms=72%3A543|65%3A 12|39%3A1|240%3A1318

And its really got me wanting it. I'm mostly wanting the rotaflo for the look, and if it doesn't even include the tip, why bother? So the header I posted, the pre-silencer, all the way back to that muffler. It would be like $300 and be fairly loud, but I think with the pre-silencer, it would also sound pretty good.

Anybody know of any other knock-off type rotaflos? The one I posted is the only one on all of freakin ebay that I could find. That one is a 3'' inlet and 4.5'' outlet. I'm looking for 2.5'' and 4'' respectively if possible.

If it doesn't sound good, I can always go back and put in another inline-type muffler for pretty cheap, I want to keep everything as bolt-together so I can adjust it to my preferences.

I will make videos to let everybody know how good or shitty it sounds.
Old 11-30-08, 02:59 PM
  #18  
Stu-Tron Get Yo Groove On

iTrader: (4)
 
Jeezus's Avatar
 
Join Date: Nov 2006
Location: Huntsville AL
Posts: 8,405
Received 9 Likes on 9 Posts
The breaking up sound in the higher RPM is from the cheap camera I used.

Here is a one wheel peel video so you can hear the high end sound:
http://ca.youtube.com/watch?v=e_4uJE4v99g
Old 11-30-08, 04:15 PM
  #19  
Rotary Freak

iTrader: (1)
 
elwood's Avatar
 
Join Date: Mar 2003
Location: https://t.me/pump_upp
Posts: 1,540
Received 24 Likes on 19 Posts
New Math

Originally Posted by StumpDrummer
. . . unless you want to go from 2,2 inch pipes to a 4 inch pipe
if you go from 2,2inch to a 3 inch your creating back pressure
that slows your engine down!!do the math!! . . .
Flow is proportional to cross sectional area, not diameter. Area is equal to
PI X R^2.

Two 2" pipes = 6.28 in^2

One 3" pipe = 7.06 in^2

Therefore, one 3" pipe will flow more than a pair of 2" pipes; it will not create extra back pressure. This is probably a pretty good match.

Maybe more important for a street-driven car is that the difference in performance between a pair of 2" pipes and one 3" pipe is minimal. The difference in noise isn't -- the pair of 2" pipes will be a lot quieter.
Old 11-30-08, 04:31 PM
  #20  
I need a new user title

 
PercentSevenC's Avatar
 
Join Date: Oct 2005
Location: Yaizu, Japan
Posts: 2,646
Likes: 0
Received 0 Likes on 0 Posts
People tend to forget that, in a rotary, the header primaries alternate pulses. That's why it works to merge two 2" pipes into a single 2" pipe. Most of us are agreed that 3" is simply too big for a stock or streetported NA 2-rotor, for street use, at least. Velocity will go down, hurting both your power and your eardrums. Whether 2" or 2.25" or 2.5" is best is still up for debate.

Last edited by PercentSevenC; 11-30-08 at 04:34 PM.
Old 11-30-08, 05:02 PM
  #21  
Environmentally-Hostile

Thread Starter
 
Starfox07's Avatar
 
Join Date: Sep 2005
Location: Ennis/Arlington Texas
Posts: 1,662
Likes: 0
Received 1 Like on 1 Post
I think I'm gonna do 2.25''
Old 12-01-08, 10:28 AM
  #22  
NEED A MARIAH HATCH BADLY

 
StumpDrummer's Avatar
 
Join Date: May 2008
Location: Louisiana USA
Posts: 113
Likes: 0
Received 0 Likes on 0 Posts
Originally Posted by Starfox07
I think I'm gonna do 2.25''
oops forgot about the cross sectional thing my bad too many

starfox go with at least 2.5 for single exhaust!! you wont be disapointed
just make sure all your inlet holes on the accesories have the same diameter
inlets pre silencer muffler exct or youll just creat a choke point
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
Ian_D
New Member RX-7 Technical
6
09-06-15 10:38 PM
doritoloco
New Member RX-7 Technical
7
09-05-15 12:41 PM
FührerTüner
General Rotary Tech Support
3
09-04-15 01:41 PM



Quick Reply: Trying to think up an exhaust combo...



All times are GMT -5. The time now is 07:43 AM.