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So the guy who rebuilt my engine also swapped my SA exhaust system to a FB one, so no more thermal reactor because my old exhaust system was leaking + lower temps. I'm now learning that I should NOT be hearing any noise coming from the engine bay. but my car definitely makes a noise at the engine bay area. I noticed today that my car has a beautiful low-pitched rumble from the exhaust when I parked it in the grass ( and was 80% quieter) with the only sound coming from the fan, and the tail pip. So now I'm certain there's a gnarly exhaust leak making my car sound like a 4 banger. What are the gaskets I need for the exhaust system now that it's a FB system? I have a feeling he just bolted on a FB exhaust he had laying around without changing the gaskets and the exhaust is just leaking . I have a partially stripped carb and no emissions equipment.
P.S. don't laugh at me. I don't exactly have other cars to compare what the car should sound like. Also, my muffler has an M symbol on it, is this OEM or aftermarket.. I'm going to have a word with my mechanic if it turns out he put some aftermarket **** on my car.
You would need to confirm what parts of the newer exhaust are installed. Did they swap the entire exhaust? There are a few air pipes and cats.
For the gaskets between the majority of the connections, these are the ones. I had to order mine from Amazon. These are general gaskets for most like exhausts.
Fel-Pro 60620 Exhaust Flange Gasket
Last edited by KansasCityREPU; 03-28-21 at 06:40 PM.
You would need to confirm what parts of the newer exhaust are installed. Dod they swap the entire exhaust. There are a few air pipes and cats.
For the gaskets between the majority of the connections, these are the ones. I had to order mine from Amazon. These are general gaskets for most like exhausts.
Fel-Pro 60620 Exhaust Flange Gasket
As KC says, many of the exhaust parts are NLA. You do need to identify what parts / system you have. Here are some pages from the manuals you can find from Fox here on this site. First, the SA diagram, from the head pipe back.
Next is the FB:
This is the thermal reactor that bolts to the side of the engine on the SA system:
Here's the FB manifold:
An overall pic of the SA system, head pipe to muffler:
The FB parts are much lighter, and possibly easier to find used (more FB's than SA's). Do you need emissions testing where you live? Because if not just get an aftermarket exhaust. It's the easiest and "#1 on the list" way to free up power in an RX7. I registered my car as Classic and don't need any emissions testing any more.
I don't remember what the heat shields looked like on my stock manifold... the exhaust was the first thing I threw in the scrap pile. I know without the tin shields there's a very visible difference between the SA Thermal Reactor and the FB log manifold. Not sure what you have there.... prolly an FB manifold.
Ive only had '85 12A FB's, but here's the bottom of my stock muffler...
But why would the shop replace your stock SA exhaust with a stock FB exhaust? Was yours rotten or do you think they just messed up and gave you the wrong parts from the pile? Does this shop specialize in 1st gen RX7's and just have lots of full exhaust systems laying around?
For what it's worth the FB manifold is a better choice than the boat anchor thermal reactor, unless you're trying to stay all-original.
I don't remember what the heat shields looked like on my stock manifold... the exhaust was the first thing I threw in the scrap pile. I know without the tin shields there's a very visible difference between the SA Thermal Reactor and the FB log manifold. Not sure what you have there.... prolly an FB manifold.
Ive only had '85 12A FB's, but here's the bottom of my stock muffler...
But why would the shop replace your stock SA exhaust with a stock FB exhaust? Was yours rotten or do you think they just messed up and gave you the wrong parts from the pile? Does this shop specialize in 1st gen RX7's and just have lots of full exhaust systems laying around?
For what it's worth the FB manifold is a better choice than the boat anchor thermal reactor, unless you're trying to stay all-original.
My old muffler was close to being clogged and had alot of heavy rust. He charged me 200$ for the new used one off a FB a guy was parting out .
Sure looks like a finned FB manifold to me, poking through the hole in your heat shield.
So assuming I have a entire FB mani' and exhaust pipes / muffler . What are all the Gaskets I need. While im at it i should probably dunk it in some evaporust
Muffler , is this stock ? Sounds great when parked in the grass , the lawn mower sound comes from the engine / under car .
"M" = Mazda. "8871" = SA RX7 model, so this seems to be an SA-style muffler, based on the image. As Banzai illustrated, the SA muffler's forward (toward engine) pipe out of the muffler is longer, going OVER the axle. The FB's leading pipe is shorter, with the joint to the exhaust center pipe right at the back of the muffler...
We need to see wider shots of undercarriage (so we can see the whole exhaust). Can you put it up on a lift and drop some photos?
"M" = Mazda. "8871" = SA RX7 model, so this seems to be an SA-style muffler, based on the image. As Banzai illustrated, the SA muffler's forward (toward engine) pipe out of the muffler is longer, going OVER the axle. The FB's leading pipe is shorter, with the joint to the exhaust center pipe right at the back of the muffler...
We need to see wider shots of the undercarriage (so we can see the whole exhaust). Can you put it up on a lift and drop some photos?
Stu A
80GS
AZ
I can't get it under a lift but I sure can crawl under it to take some more pics.
Also, what is the difference between the 79-80 RB kit and the 81-85 kit ?
I also see you have a block off plate for a ACV. This means you also do not have an air pump. There are a couple of pipes that supply air to the cats and a return pipe that could be causing the exhaust leak sound. Ensure those air pipe inlets are closed off.
I can't get it under a lift but I sure can crawl under it to take some more pics.
Also, what is the difference between the 79-80 RB kit and the 81-85 kit ?
There are mounting point differences under the different 1st gen series (S1, S2, S3). I only know this because my new RB streetport systems shows where to mount to the vehicles and they are different by year. There are plumbing differences like KC said, and emissions differences regarding cats and air piping.
Here's what I'd do....
Drive the front up on ramps (or jack it onto jack stands). Set parking brake. Crawl under and check every connection point. See if any nuts or bolts are loose, wiggle it around, just see if you can feel anything loose or see any open pipes or hoses. As someone said earlier, there are metal lines from the engine manifolds down to the cat and maybe one isn't connected. Are the rubber hangers attached, including the two rubber donuts that support the center section?
Nothing? Okay start the engine and crawl around it again. Where is the noise coming from? Can you feel puffs of exhaust coming out of that noisy connection?
Here's what I'd do....
Drive the front up on ramps (or jack it onto jack stands). Set parking brake. Crawl under and check every connection point. See if any nuts or bolts are loose, wiggle it around, just see if you can feel anything loose or see any open pipes or hoses. As someone said earlier, there are metal lines from the engine manifolds down to the cat and maybe one isn't connected. Are the rubber hangers attached, including the two rubber donuts that support the center section?
Nothing? Okay start the engine and crawl around it again. Where is the noise coming from? Can you feel puffs of exhaust coming out of that noisy connection?
Now go fix it.
I'm trying to find out if this is a FB setup, a SA setup, or some Frankenstein set up There are only two hangers holding this thing up. I need reference pictures to compare, I don't have any way to raise the car ATM. Also, it seems there are hooks that are not attached to anything .
Actually, before i do anything I'm going to record my car's sound and you guys can tell me if something sounds off
Sorry, I thought you were trying to figure out where the exhaust leak/noise was coming from. It looks like a complete system so after you figure out what it's off of, you can find and fix the leak.
In post #4 Bansai gives you some great pictures of the 2 different exhaust systems. The manifolds are a dead give away- the early Thermal Reactor is a big round pig of a thing that ends in a 3 bolt triangle connection to the first cat. The FB manifold is smaller and squared off with cooling ribs, and ends in a 2 bolt connection. I know it's hard to see yours with the tin shield but the connection at its back side is a dead give away.
Just looked at your pictures again,... you definitely have an FB manifold and pipe leading to the cat/cats. I can't remember if FB's have 2 small pre-cats before the main, but your last cat (in your picture) is FB.
On FB's the pipe right after the cat has a hooked rod sticking out each side, with rubber donuts hanging it from the body to support the weight of the exhaust. Both manuals and autos have this coat hanger looking thing, but I don't see it on yours. Maybe he replaced your manifold and cats because they were in bad shape, and left everything from there back..
Have you talked to the mechanic yet? I'll bet he could have answered all your questions by now.
Sorry, I thought you were trying to figure out where the exhaust leak/noise was coming from. It looks like a complete system so after you figure out what it's off of, you can find and fix the leak.
In post #4 Bansai gives you some great pictures of the 2 different exhaust systems. The manifolds are a dead give away- the early Thermal Reactor is a big round pig of a thing that ends in a 3 bolt triangle connection to the first cat. The FB manifold is smaller and squared off with cooling ribs, and ends in a 2 bolt connection. I know it's hard to see yours with the tin shield but the connection at its back side is a dead give away.
Just looked at your pictures again,... you definitely have an FB manifold and pipe leading to the cat/cats. I can't remember if FB's have 2 small pre-cats before the main, but your last cat (in your picture) is FB.
On FB's the pipe right after the cat has a hooked rod sticking out each side, with rubber donuts hanging it from the body to support the weight of the exhaust. Both manuals and autos have this coat hanger looking thing, but I don't see it on yours. Maybe he replaced your manifold and cats because they were in bad shape, and left everything from there back..
Have you talked to the mechanic yet? I'll bet he could have answered all your questions by now.
He's on vacation in Puerto Rico and id rather not bother him. I did pay him to do a full exhaust system swap and I'm not too happy to find out there's a SA muffler on it but then again maybe he did swap my muffler to a SA one for whatever reason. I'm not too upset I paid 200$ for the removal, install and parts, and the old system was rusted together ( he showed me where he had to cut through). I'm just fixing all the small issues the car has and would like it to be quieter. The only real issue my car has right now is the right light won't pop down/up . Everything else works as it should.
Looks like an FB system to me. Since your car is an SA, the chassis would be setup with mounting points to hang the SA system. Your mechanic must have grafted it up in there. Based on the illustration in the parts book, maybe from an 83. The muffler looks similar.
You should be able to find the leaks origin by starting it up and crawling underneath.
Looks like an FB system to me. Since your car is an SA, the chassis would be setup with mounting points to hang the SA system. Your mechanic must have grafted it up in there. Based on the illustration in the parts book, maybe from an 83. The muffler looks similar.
You should be able to find the leaks origin by starting it up and crawling underneath.
After looking at that picture, I'm confident it's an 83 system now. So now onto the gaskets, how many do i need ?
I think on the stock exhaust you have there are 4 gaskets.
1) Large manifold to engine gasket (same gasket works on iron manifold or aftermarket steel header).
3) 2-bolt football shaped gaskets for joining pipe sections together.
Before you start buying gaskets and paying shipping, find the leak. It could be as simple as tightening a bolt.
For the bigger connections, like your post 16, use Fel-Pro 60620. You'll need to count the connections. I had a hard time finding them until I found the correct size. I ordered from Amazon. You might order one just to confirm first.
03-28-21, 01:36 AM
