SSI Exhaust System Install

[dkirk]

I did my obligatory Forum search on this topic and can't seem to find what I'm looking for.

Car - 1988 911 Carrera coupe with factory exhaust/heat exchangers.

I'm thinking about upgrading my exhaust system to the SSI stainless headers/heat exchangers using a Dansk 2-in, 1-out performance muffler. I've been lead to believe that the engine compartment heater blower motor has to be eliminated due to the inlet air ducting to the heat exchangers has to be altered. This bothers me a bit as I'd like to keep this blower as it does provide a boost in cabin air flow, plus I don't want to alter the appearance of the engine bay.

Question - has anyone done the SSI conversion on an '87 through '89 and found a way to retain the engine compartment heater blower motor? If so, please explain and post pictures of your solution.

[gtc]

Here's a thread that addresses the issue.
Air Control Tube SSI Heat Exchangers Conversion

If you want to keep the heater blowers, I'd go with these B&B headers, which have the heater box inlets in the proper location for the 3.2 crossover tube, and as a bonus are sized better for the 3.2 engine. You will want to make sure the new muffler has the indentation for the heater tube.... most do not, since the early cars did not have these tubes.

https://www.bbexhaust.com/shop/porsche-911-header-with-heat-exchanger-fpor-0401/
https://patrickmotorsports.com/collections/exhaust-turbocharger/products/exh-fpor-0401

Edit: One thing to consider though, is that the B&B heater boxes are not as good as the SSIs.

[tirwin]

I just installed M&K headers (with heat). 1.63" primaries which you'll need for a 3.2. 1.5" SSI will be too restrictive.

I think you'll need to backdate the oil lines. Not sure about the heat on a 3.2 I didn't have to backdate heat on my SC.

Check with Brian (Rarlyl8) at M&K on the sizing but this is what they look like.

I also went with his 2-in/2-out active exhaust.

[tirwin]

Pics of the muffler. Ignore the ugly bumper. I'm working on it and getting ready to paint it.

[boyt911sc]

Tim,

What are these two (2) devices in your new muffler? Just curious.



Thanks.

Tony

[wildcat077]

As Tim mentioned , SSI's are a little too small in diameter for a 3.2 ... more suited for a 3.0
There's plenty of reading on the subject.

I had installed Fabspeed headers on my 89 and was able to retain all the heating bits with no changes to the look of the engine bay.Best part about those is that they also fit with the 95 3.6 i since installed in my car.
The Rarlyl8 exaust items are a piece of art, albeit expensive but super nice and well made !

[tirwin]

Originally Posted by boyt911sc

Tim,

What are these two (2) devices in your new muffler? Just curious.



Thanks.

Tony

Tony, good eye.

They are vacuum pots that are connected to manifold vacuum. When the engine is at idle, the manifold vacuum keeps the two side exhaust ports closed. When you get your foot in the gas, the manifold vacuum drops off and the two extra side exhaust outlets open. It's 76db at idle and about 90 db when you get on it. About 2.5x as loud.

If you use it with a later SC ('80-'83 has the two vac lines to the distributor?), you have to disconnect and plug the blue idle retard vac line. The retarded timing affects the manifold vacuum and it isn't enough to fully close the side outlets.

Edit: The turn-down pipes aren't pictured.

[kbken62]

Originally Posted by tirwin

I just installed M&K headers (with heat). 1.63" primaries which you'll need for a 3.2. 1.5" SSI will be too restrictive.

I think you'll need to backdate the oil lines. Not sure about the heat on a 3.2 I didn't have to backdate heat on my SC.

Check with Brian (Rarlyl8) at M&K on the sizing but this is what they look like.

I also went with his 2-in/2-out active exhaust.

I have the same setup on my 3.2, now 3.4. It does require backdating the heat. Luckily I had my 2.7 tins. Also the heat exchanger portion required some clearancing to get to valve cover nuts. You will require removal of headers to access lower valve covers.

Someone also asked what the two devices On the side of the muffler where. They are vacuum actuated valves that open, making it a 4 out muffler.

Hope that helps.


Sent from my iPhone using Tapatalk

[tirwin]

I'm still playing with the orientation of the side outlets and the valence but this gives you an idea.

[tirwin]

Originally Posted by kbken62

I have the same setup on my 3.2, now 3.4. It does require backdating the heat.

I didn't have to backdate the heat on my 3.0. Maybe there is some other difference.

But I will be backdating the heat in the future anyway.

[AndrewCologne]

This is a very nice setup!
But I see the heat exchanger tubes are verrry close to the ground.

BTW: With the music that exhaust produces, here many e-bike addcted neighbours would start a camaign and a crowd of screaming kids would stay in front of your house (not only on friday):-)

[tirwin]

Originally Posted by AndrewCologne

This is a very nice setup!
But I see the heat exchanger tubes are verrry close to the ground.

BTW: With the music that exhaust produces, here many e-bike addcted neighbours would start a camaign and a crowd of screaming kids would stay in front of your house (not only on friday):-)

I think it’s just the picture. Believe it or not there is more ground clearance than with the stock heat exchangers. I was really worried about that but it’s not an issue.

My old muffler was 90db at idle so this is an improvement. I can take it easy in the neighborhood, which I couldn’t do before. There are so many people with aftermarket exhausts on their Mustangs/Challengers/Chargers that nobody cares about me. It really depends on where you live here.

I saw a post on the local cars and coffee group where a Mustang owner posted that a neighbor left on a note on his car and had filled his exhaust with a can of spray foam insulation!

[dkirk]

A big thanks to all the links, suggestions and advice. I've got some studying to do.