88 FC Right Side Drive Exhaust Mystery
 

I'm hoping someone can help me figure this one out. I picked up this sweet little N/A FC while living in Italy. It was originally a UK car, so right side drive. The exhaust is rusted to pieces, so I wanted to clean it out a bit while replacing the exhaust. I went with the RB down pipe for the N/A but low and behold, it won't fit my car. To me, it looks like the manifold is set up more like a TII, so I'm wondering if the TII downpipe would work or if i need to just get a custom pipe made from the manifold to the presilencer. I appreciate any help you guys can provide.
https://cimg5.ibsrv.net/gimg/www.rx7...817c7ea977.jpg
https://cimg6.ibsrv.net/gimg/www.rx7...362b79b4e7.jpg
N/A down pipe next to existing exhaust.
https://cimg7.ibsrv.net/gimg/www.rx7...ad14d7c34c.jpg
No idea what the pipe is coming off the current exhaust pipe.
https://cimg5.ibsrv.net/gimg/www.rx7...81ff1b73ab.jpg
Terrible drawing, but approximate measurements of current pipe.

The down pipe is only for the TII. One option would be a Bonez high-flow cat with presilencer (RX7.COM Performance and Repair Parts for RX-7 and RX-8) to replace all your existing converters. That's what I have on my 90 GXL along with the RB cat back. I've been running this setup for over 16 years now without any problems.

Thanks for the reply HotDog. Check out the pic below. I bought the downpipe presilencer combo for the Non Turbo. The problem is that the outlet of my exhaust manifold points straight out instead of down. So the NT downpipe won't work. But it's not a turbo, so i'm worried that the Turbo downpipe might not work either. I'll check out the Bonez setup and see if it may work. Any thoughts on that Turbo downpipe? think it might work?
https://cimg5.ibsrv.net/gimg/www.rx7...dab27ccecb.jpg

Well okay, the European version of the RX7 apparently is not the same as the US version. Sorry, but I can't help you. Maybe RB or Mazdatrix would be able to better answer your questions?

Hahaha.. No worries brother. It has been interesting working on this thing. No pictures i have found on the interwebs match what the exhaust looks like under mine. I appreciate the suggestion though. Cheers.

Just a suggestion, but you can always buy a US version exhaust manifold. This might eliminate some of your problems.

Looks like it has a thermal reactor as used on the 79-80 U.S. model year 7's. I would suggest contacting Racing Beat - Mazda Performance Specialists and looking into a full exhaust system from them. Best in the world when it comes to an RX-7 exhaust.

guess you can always get an extension made to mate up the two..a bit of a hassle if you want to keep the manifold..as hot dog mentioned a replacement U.S. manifold might be the simplest.

It's more money but you could just buy The Racing Beat header and call it done unless there is some law or standard that requires you to keep that stock exhaust manifold. Maybe if you're lucky you could talk to Racing Beat and explain your situation and they'd take the downpipe back and give you credit toward their header. It may not be worth the cost of shipping back to the U.S. though.

Thanks for the ideas fellas. I'm not tied to this manifold for any reason than it was already there and well.. i didn't want to have to mess with the pain of removing it. I talked with RB and they said that they would take the return for credit not problem, but I'm starting to lean toward finding a US spec manifold. Ebay shows them for an average of $75. I didn't want to really go the header route because of return vs cost. Anyway, I'll let you guys know how it goes. Much appreciated.

google mazdarotaryparts .. they are UK based so slightly closer .. Clive will be able to sort you out

I have loads of bits in the garage .. but im sure the are all TII bits - so no use :(

Many thanks for the heads up Grinder. I'll hit them up today and see what they say.

Cheers,

John

I'm sure you've already sorted this, but from stripping mine down already.

The cars have a thermal reactor like the old school FBs, due to our emissions laws being a little more lax at the time.
If you are going to remove it with the engine in place, all I can say is good luck! The bolts are almost inaccessible, and some are hidden behind the heatshield so you need to remove that first. The second pipe you can see leading back goes into side of the intake manifold and I believe is used for the Anti Afterburn system or whatever its called.

If you google Rx7 training manual, its about the only place you can find info on UK spec Rx7s. They're listed as 'Except Australia'.
https://cimg9.ibsrv.net/gimg/www.rx7...6681c8c6ac.jpg

DevilX,

That info is worth a million. I have been trying to figure this F'ing thing out and having zero luck. Then here you are with all the info. It is much appreciated. I have never heard of a thermal reactor. Is is in place of the traditional exhaust manifold? I have heard these are a bear to remove. I'm going to make the attempt with it in the car and have a solid exhaust shop nearby that can hopefully help as well. We shall see. As for the second pipe for the anti afterburn, do i just put a blockoff plate on that? Thanks again for all the info.

Cheers,

john

The thermal reactor gets really hot and then it has air pumped into using the airpump to help emissions, or something along those lines. I'm not familiar with the exact details.

I made a block off plate from aluminium and bolted it over where the pipe attached. I also dumped the air pump and associated bits and blanked them off as well. I left the Anti After Burn Valve plugged in but blocked off the connections with rubber end caps.
There's full vacuum diagram in the training manual.

We're quite fortunate in that our 6-port system is actuated by vacuum from manifold rather than positive pressure from the exhaust or the air pump, so its much easier for us to change the exhaust and still have a working 6 port system. On the downside we have a distributor based ignition system.