Hey All,
I’ve been snooping on this forum for awhile, researching, studying and spending a lot of time trying to figure this out.

I finally joined because I’m starting to go crazy and lose sleep over what I considered to be an easy modification.

I have an 88 Convertible. Manual Transmission.

The current exhaust is toast. From the first cat after the manifold to the bumper is rust and holes.

I would like to replace everything. Manifold to tip.
And I was about ready to buy the $1600 racing beat system till I saw it the flippant instruction of “just remove the air pump”. Hold the phone.

That sent me down the rabbit hole of researching what’s involved. Block off plates. Idle adjustments. Aftermarket pulleys.

I’d honestly like to keep the car closer to stock. Call me old school, but I respect stock sometimes.

So with that said.
Can I get some quotes/help on this?

If there’s no aftermarket manifold that works with the air pump, then screw it. Let’s move down to the down pipe. I live in a part Ohio where we don’t do EPA checks. Especially on “antique” cars.

Can I just get a straight pipe off the manifold, attach that to a pre silencer, then the Y section to the back?
Another goal is avoid check engine lights.

Thank you for your help and advice!!

 

I would recommend the Bonez Superflow System (https://www.rx7.com/store/rx7/fcexhaust.html) and the RB cat-back exhaust system (https://www.racingbeat.com/RX7-1986-...sts/16418.html). The Bonez has a presilencer and main cat with connection for air pump tube. It replaces all of your original cats. The RB cat-back exhaust has a y-pipe and both stainless steel mufflers. This combination is essentially what I had run on my NA S5. The Bonez cat comes with a silicone hose and clamps to connect the split air pipe to the cat. I didn't like the idea of cutting the flange off my split air pipe. So, I made a flange from a piece of flat stock and had it welded to the air pipe coming off the Bonez cat. Here's a photo of the Bonez cat on my car.

 

i did some testing a few years ago, and the manifold is a good fit for the engine, which is nice. (headers, off the shelf don't gain anything)
so you can run either the Bonez, or the RB down pipe https://www.racingbeat.com/RX7-1986-...rs/S16209.html
then either the converter of your choice, or the RB pre-silencer https://www.racingbeat.com/RX7-1986-...ers/16217.html
and then the cat back of your choice, RB, HKS, Bonez, etc also possible to buy the RB Y pipe, and run whatever mufflers you want

basically the stock manifold decouples the engine from any exhaust tuning, which is nice because then you just set the rest of the exhaust up so it has enough flow (or 2.75psi at the 6 port actuators)

 

Actually, what I'm currently running is RB non-turbo downpipe (https://www.racingbeat.com/RX7-1986-...rs/S16206.html), Bonez main cat p/n EX800655 (https://rx7.com/store/rx7/fcexhaust.html) and RB cat-back exhaust system. So, this would be another option, but slightly more expensive than what I've mentioned above. It's about the same noise level as that with the presilencer. Here's a photo of my system:

 

Thank to everyone for posting. I would like to say that over the past 3-4 months there has been multiple posts about major shipping issues with RX7.com. Like months go by and........ I haven't read any explanation either or, perhaps I just missed the thread? I really don't want to start any drama, I am just want to be honest about what I know.

I an in the market for either the three stock cats from RockAuto or something else. I really want a quiet exhaust to start of with, as every one of the three 7's that I have owned always had some sort of leak. My biggest concern is driving the car in to high rev's might destroy the first cat if the piece is cheaply built, possibly destroying my engine in the process.

I was considering a down pipe, a high flow cat with the air pump connection, a y-pipe with one resonator or silencer on each leg and some higher flow mufflers. Also, I can add a helmholtz resonator to kill any possible drone. Knowing now what the back pressure needs to be thanks to an earlier post, the process should be easier.

To the OP, if you decide on something besides the Racing Beat, post a clip of the exhaust sound if you can. So far I have not really cared for the sound of the racing beat. I need to do a deeper dive to find more videos.

 

This is great and helpful information! And also appreciate the hyperlinks as well!

The one major question has been answered for me. That I can keep the stock manifold and replace the rest.

I guess my next steps is figuring out how much I want to spend on this!

Again, great helpful information guys!
Thanks!

 

Here's a short audio clip of my exhaust as it's currently configured (as is shown in Post #4). My phone was maybe about 3 feet behind the rear center of car. I recorded this audio 2 days after I installed the exhaust system. Note that the squeaking that you hear at about 35-40 seconds was from a loose accessory belt.

 

Nice, I like it, thanks. It doesn't sound louder than stock from what I remember. The rumble while at idle seems more pleasant than others too.

I appreciate your time with this. My apologies to the OP for kinda hijacking the thread.

 

Accidental double post.

 

lol no worries on the hijack. This is such a help!
Appreciate the sound file and everything. I'm going to start looking at doing a downpipe/cat/Y-exhaust setup.
All the feedback has been helpful. I'll be sure to update when I finally get the credit card out and make some purchases!

 

Don't forget the gaskets and hangers. The cost for all that little stuff adds up pretty fast.

 

if you search i have posted longer things with measurements and such.
with an S4, your tuning tool is to tee a boost/vacuum gauge into the 6 port hose, and you're looking for ~2.75psi, which is what you need to open the ports.
i was able to get that with a totally stock S4, which was a little surprising.

its kind of nice because Mazda chose a good pipe size, and you can run a converter if you like.
also then the cat-back, is more cosmetic, pick the look and the sound

 

This is great information. Does anyone know a california legal catalytic? I have an old magnaflow cat that was CA legal when i bought it but looks like they dont make it anymore. I wonder if they will still accept it for smogg. Or just buy a new universal cat CA legal and weld it in.

 

Since I can't update my earlier statement about rx7.com.The buisness is moving and cutting ties with part of the related business if I read correctly. Hopefully all is well besides getting a shop set up. I asked for an update.

Information can be found in this and one other thread.
https://www.rx7club.com/rotary-perfo...1058550/page4/

 

Right you are! I even got a rough quote from RB for their straight down pipe, pre-silencer, and the Y cat back dual muffler setup. Looking at around $250 to even ship to Ohio. Ooftah!
We might have to see if the income tax return gods are nice to me!

Thanks guys