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

12A exhaust swap to a 13b motor?

Thread Tools
 
Search this Thread
 
Old 09-28-10, 07:05 AM
  #1  
FixinThingsThatAintBroke

Thread Starter
 
MacNeil's Avatar
 
Join Date: Nov 2007
Location: Canada
Posts: 54
Likes: 0
Received 0 Likes on 0 Posts
12A exhaust swap to a 13b motor?

Hey there, i rarely post because I almost always find what i need to know from searching the archives but today im at work and dont have the time. I have a guy down the street wanting to sell me a year old RB Exhaust system from his 12A GSL for 75 bucks, ive got a 13B GSL-SE and never had any knowledge pertaining to the 12A. can I bolt it on to my catback ( i know that the mani wouldnt fit) or do i have to fabticate/weld it on? is it a bad idea or a thrifty one considering the price?
Sorry again I could gather this info myself but im short on time im going to look at it after work.

Thanks,

-MacNeil
Old 09-28-10, 09:47 AM
  #2  
Old Fart Young at Heart

iTrader: (6)
 
trochoid's Avatar
 
Join Date: Apr 2004
Location: St Joe MO
Posts: 15,145
Likes: 0
Received 7 Likes on 7 Posts
I've seen the engine flange on a 12A header split down the middle, then spread to fit a 13B. How well it fits or seals is another question but should work with a little tweaking. More mods may be needed to mate up to the rest of the system but the price is right.
Old 09-28-10, 11:05 AM
  #3  
FixinThingsThatAintBroke

Thread Starter
 
MacNeil's Avatar
 
Join Date: Nov 2007
Location: Canada
Posts: 54
Likes: 0
Received 0 Likes on 0 Posts
What about if i just leave my stock thermal reactor on and attach the pipe from there? would it be compatible?
Old 09-28-10, 11:31 AM
  #4  
ALLROTOR

iTrader: (2)
 
85TIIDEVIL's Avatar
 
Join Date: Sep 2002
Location: Oceanside, NY.
Posts: 1,856
Received 6 Likes on 5 Posts
I've split the exhaust flange where it connects to the motor and either shortened or lengthened the longer piping an 1" depending if you're going from 12A - 13B or vise versa, pretty simple. I've never seen it done without adding or removing the inch though.

If it's a whole Racing Beat exhaust for $75 take it...! That's a good deal even if it was just the header. Any muffler shop can hang it to fit properly and you will still be saving a ton.
Old 09-28-10, 02:30 PM
  #5  
FixinThingsThatAintBroke

Thread Starter
 
MacNeil's Avatar
 
Join Date: Nov 2007
Location: Canada
Posts: 54
Likes: 0
Received 0 Likes on 0 Posts
Yea its whole exhaust system I don't have the means to fab the header flange I just want to connect it all up to my current 13b exhausts thermal reactor... Is that possible?
Old 09-28-10, 06:21 PM
  #6  
Lives on the Forum

iTrader: (13)
 
Rx-7Doctor's Avatar
 
Join Date: Jul 2004
Location: Oregon
Posts: 10,584
Likes: 0
Received 11 Likes on 10 Posts
You don't have a "Thermal" Reactor. You have a exhaust manifold. Sa's have the thermal reactor style.

You have not told us what system they are selling? What year GSL is it?

81-82 use a different muffler versus the 83-85 models. If his is for the 81-82 then you would need to change the connecting pipe between the muffler and the catalytic converter. If it is a system for 83-85 then the muffler will bolt right up. As far as the silencer goes you will have to have something made to connect between the stock exhaust manifold and the silencer, then from the silencer to the connecting pipe. Either way you will have to make something to get whatever parts you want to fit.


Originally Posted by MacNeil
Yea its whole exhaust system I don't have the means to fab the header flange I just want to connect it all up to my current 13b exhausts thermal reactor... Is that possible?
Old 09-28-10, 07:34 PM
  #7  
FixinThingsThatAintBroke

Thread Starter
 
MacNeil's Avatar
 
Join Date: Nov 2007
Location: Canada
Posts: 54
Likes: 0
Received 0 Likes on 0 Posts
Yea it's just what I was going by lol I was prety much reading it straight out of my Haynes service manual and it describes it as the thermal reactor. And the car the exhaust is coming off is a 1985 Targa Edtion GSL.
Old 09-29-10, 01:01 AM
  #8  
Old Fart Young at Heart

iTrader: (6)
 
trochoid's Avatar
 
Join Date: Apr 2004
Location: St Joe MO
Posts: 15,145
Likes: 0
Received 7 Likes on 7 Posts
The header flange just needs split down the center, then spread. If you use the stock exhaust manifold, you're losing 20+ hp. Another option is to buy the 13B header flange from Racing Beat and have someone modify the header for you.
Old 10-01-10, 11:31 AM
  #9  
FixinThingsThatAintBroke

Thread Starter
 
MacNeil's Avatar
 
Join Date: Nov 2007
Location: Canada
Posts: 54
Likes: 0
Received 0 Likes on 0 Posts
I just need a new muffler to pass safety right now so performance has to sit on the sidelines at the moment :/ I was just hoping if I take the RB 12b header off and attach the rest of the system to my stock manifold it will work and pass safety untill I pick up a 13b RB or Moza Header.
Old 10-01-10, 03:24 PM
  #10  
Old Fart Young at Heart

iTrader: (6)
 
trochoid's Avatar
 
Join Date: Apr 2004
Location: St Joe MO
Posts: 15,145
Likes: 0
Received 7 Likes on 7 Posts
There's a chance the RB system will bolt up to the cat. Get the tape measure out.
Old 10-01-10, 05:13 PM
  #11  
Moderator

iTrader: (3)
 
j9fd3s's Avatar
 
Join Date: Mar 2001
Location: https://www2.mazda.com/en/100th/
Posts: 30,832
Received 2,603 Likes on 1,847 Posts
Originally Posted by MacNeil
Yea it's just what I was going by lol I was prety much reading it straight out of my Haynes service manual and it describes it as the thermal reactor. And the car the exhaust is coming off is a 1985 Targa Edtion GSL.
if you read it, the haynes manual is for the 79, and there is an addition to the back that covers 81-85.

i suggest going to the website foxed.ca and downloading a FACTORY service manual for your car
Old 10-01-10, 06:44 PM
  #12  
FixinThingsThatAintBroke

Thread Starter
 
MacNeil's Avatar
 
Join Date: Nov 2007
Location: Canada
Posts: 54
Likes: 0
Received 0 Likes on 0 Posts
Thanks, I'll do that now.
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
Azevedo
Other Engine Conversions - non V-8
26
03-01-19 09:19 PM
Machupicchu
1st Generation Specific (1979-1985)
8
08-17-15 08:27 PM



Quick Reply: 12A exhaust swap to a 13b motor?



All times are GMT -5. The time now is 08:28 AM.