Wanting to take the car on more road trips, however the constant fumes that fill the cabin is fatiguing after an hour+

I've been doing some research, seems that replacing any weather stripping seals can greatly reduce the intake for fumes. How about installing a cat? Anything I should know about this? Currently is has a straight pipe which it came with when I purchased it.

The little diagram below showing how I believe the fumes are entering the car at high speeds.


You can see in the second image how the fumes blow back into the rear.

Looking for more thoughts and insights.

Also, if I were to buy the replacement weather stripping from rock auto has anyone else had success with the Fairchild brand on an early SA model?
More specifically the rear hatch seal : https://www.rockauto.com/en/moreinfo...1192227&pt=793

Thanks in advance!

 

step one is to seal up all the holes in the back and bottom of the car. shift boots, rear hatch seal, tail light seals, any open bolt holes, etc etc etc

step two would be to put a cat back in it, ideally you'd want to have the air pump and ACV and all the other stock emissions stuff on there. when its all working these cars run really clean.

 

First off, that diagram is stupid. Air doesnt flow backwards over the top of the car - it just can't. BEHIND the car, where there's a low pressure area, sure - and that's where you're getting any exhaust fumes coming inside. It's from your tail light housing gaskets. This is a known problem when they get old and crusty and deteriorated, because the exhaust gas from the muffler comes up the rear bumper and is concentrated in that bubble of air coming off of the rear glass. Note that the air going over the car is laminar flow, and maintains its direction due to inertia.

Replace the rear tail light gaskets and you'll fix 90% of the fumes in the cabin. The catalytic converter cleans up what might seep in from other places and will account for the other 10%.

 

Wow this is huge info, I'll disassemble the lights tonight and have a look. Is it possible to fabricate custom gaskets myself? Seems like this isn't a very readily available item and the tail lights for the SA seem to be slightly different than the FB in terms of their exterior design. Maybe how they mount to the body is the same though?

 

You might be able to use butyl tape.

 

Yea these seals have definitely seen better days…

The butyl tape seems interesting, but seems like a type of permanent solution. But I don’t know enough about the product, just seems if I needed to service the tail lights again i would have to remove all the butyl tape and reapply new tape.

 

Butyl tape or rope is not a permanent solution as far as never being able to get the lenses off again. It's nice because it doesn't dry out or crack and it's not a permanent bond. You can pull them back off. It would be a low cost solution until someone makes new ones out of something like silicon rubber. Butyl is playable like a putty and never dries out.

 

Alright I'm sold, thanks for the advice!

 

I ordered new one’s from Australia, from a guy name Fibremaz. I found him on the Australia rxclub site. Also this company in Australia sells them too and other new items for these RX7s.

PACPERFORMANCE.com.au

 

There has to be something up with the rear hatch seal, tailight seal, or other. Maybe something with the side vents (these vent the cabin).

I daily drive my FB in the summer.. it is streetported with a Dellorto side draft and a full RB Streetport exhaust system and I have not experienced any fumes in the cabin.

 

maybe a exhaust leak ? Same here . I have new seals all around minus my hatch seal .

 

Yea my plan is to do the seals first. I don't feel there is a leak because i don't hear anything, and I'f i'm working on the car while running, I don't get the exhaust smell up front at all.

I suppose I'll still take a look if the seals don't resolve anything.

What about these vents near the back? Any idea what they are for or where they lead? Is it HVAC stuff?

 

they just lead to behind that panel, which is where the tail lights, and inside of the quarter panel and such.

 

Fix your exhaust leaks also. When I had a full custom exhaust build 90% of my fumes went away. Also, a spoiler helps.

 

Judging by your taillights, you have a 79 or 80 which came with a thermal reactor and not a catalyst.

depending on your current exhaust situation, you could add a metal substrate catalytic. I got one from GESI. It does not have an air feed so no air pump is necessary. The metal substrate should hold up to rotary heat.

 

Interesting, you'd have to give me some more details, would it look similar to this?




How would this effect power? (these cars are already slow as it is lol)

 

You have an exhaust leak. I have never had any smell in my cabin even when I had no tail light seals and blown out door seals. I still don't have smells and have no kittys to clean the exhaust.

Your leak is almost guaranteed to be at or past the converters . My old old exhaust pre engine rebuild once blasted a huge smoke cannon and 40% of it came through from the passenger tail light area. That exhaust had holes everywhere.

 

yes, like this. These are high flow units. I have one on my car. These would not hamper performance in any discernible way. The issue was whe I bought mine they were behind in manufacturing. It took some doing to procure one.

 

+1 on adding one of the metal core cats. I had one on my FD. No noticeable difference in power. Very noticeable difference in stench. Various companies make them. Magnaflow etc. 300 cell should be fine.

 

Alright, just got it back from muffler shop and team exhaust leak is the winner. There seems to be a major leak coming from a pipe attached to the thermal reactor area pictured below.

Unfortunately the shop didn't know exactly it's function, so they couldn't comment on how to fix it. They said they could just grind down the flange and weld it all together.

Wondering if I can remove the pipe completely and cap it? Or if I can replace it? I'm not looking to do a big overhaul on the exhaust either right now.

 

That clamp is where the Air control valve (ACV) conduit connects to the thermal reactor. Is the clamp tight? I highly doubt any air escaping from this connection is the reason for excess exhaust fumes in the cabin. Unless you run a header, you need to keep the ACV and air pump (right above this connection) I would not recommend welding this joint. I've owned an SA since new (44 years and counting) I've never had any reason to alter this connection. I'd find a new muffler shop first.

How is the integrity of the rest of your system? Any rusted thru holes in any of the pipes, connections or heat exchanger? I've saw leaks from small holes in the headpipe (up front in the system) migrate down stream, the length of the vehicle, channeled by the heat shields to the rear of the car, where it might be drawn in.

 

Hmm, its a pretty big muffler shop in the city, so they seem reputable, and there were some other vintage cars there today as well. Would there be any reason for them to lie about it to me? Or you think they don't have the proper equipment to accurately test for exhaust leaks?

 

That joint isn't super tight to begin with. There isn't much you can do to improve its integrity except to weld it up or design a flat flange for both sides and use a gasket. It's not the source of exhaust in the cabin though. You can take it apart and see if it is rusted.

 

I'm sure they are well equipped and do many things well. No one said anything about anyone lying or being dishonest. To just weld up a joint that was engineered and installed on hundreds of thousands of vehicles because their sniffer detected a leak sounds like stabbing in the dark to me. It's your car, do as you wish.

 

Yea I get where you are coming from, its a straight pipe from the thermal reactor all the way to the muffler at the back.. I'll got to another shop in the area and get a second opinion. I'll how him the outlined area, and explain as KansasCityREPU and Banzai had mentioned, that the exhaust doesn't run through this pipe, so there shouldn't be a reason for there to be a significant leak coming from there.