SSI's and heater duct mods

[rob justice]

Advice required on what mods have been required to the heating duct once SSI's have been installed and what works

[ChrisBennet]

Originally posted by rob justice
Advice required on what mods have been required to the heating duct once SSI's have been installed and what works

If you have a pre-84 car you don't have to do anything. (Might be helpful to post the year of the car.)
-Chris

[rob justice]

its an 85 car

[89911]

You have 2 options: 1. Backdate your engine shroud metal to and earlier year that allows you to run the heater hoses straight down to the SSI's. Cleanest way is use an early (71-72), fan housing that takes the ducts. Downside is you lose you electric blower that comes into use under low rpm. My brother is using this method on his 87 track car. 2: Modifying your present system. You need to split your duct once it leaves you enging bay differently now that the SSI's heater openings are moved from the OE boxes. Once everything is installed, except for the rear muffler, I would suggest taking it to a metal fabricator, like a good muffler shop, and show them the connections to be made.

[ChrisBennet]

When I had SSI's on my '86 I used a piece of that brown heater duct hose (like you see on SC's) to connect the left side heat exchanger to the blower. I blocked off the right side heat exchanger with a soda can and a hose clamp. Not the most elegant solution but it gave me good heat on the driver's side. Unfortunately for you, the heat would be on the passenger's side.
-Chris

[Joeaksa]

Rob,

There is a company on the East coast who takes your old duct and modifies it to split the air. Costs around $150 or so (or more) for the work and ends up being very nice.

That said, you can go to a good muffler shop and get same made for about 30% the price. The big issue is getting air to the right side HE as the room is a bit tight there. I used some of the old metalized ducting on both sides as it will take the heat and bend fairly easily.

Here are some pics to give you an idea. On the last pic it shows the duct going inbetween the motor and muffler. On the 3.6 there is a lot more room to run the duct and you will not have this on a 3.2 or smaller normal.

Hope this helps... and the system puts out enough heat to run you out of the car once you get the air flowing correctly!

Joe


This is the adapter made by the company on the East Coast.


This is a home made adapter that splits the air. Forget who sent me this picture, sorry! Could be Bill below.


This is a pic of Bill Verburgs installation of SSI's on a 3.6 showing the complete heat ducting.

[89911]

Joe, I used Bodymotion to adapt the old down tube. It wasn't pretty when it came back, in fact it had a few pinhole leaks from miswelds. If I had to do it again, I would have a custom muffler fabricator do the work. The old style is the best for simplicity, 2 tubes staight down to the SSI's. BodyMotion sent me some of the brown SC ducting to use that did not work. The stuff is not high heat resistance when it comes into contact with the muffler and burns through. I ended up using a reducer and snaking some VW flexible aluminum tubing to met with the left side. The right side is easy with a flexible silicon piece.

[Joeaksa]

89,

I agree with you but the sheetmetal to backdate the heater is not always available and if you have A/C on the car its even more difficult. You and I used the same type of tubing and it works well.

I have been thinking of making an adapter that splits the air as well as a "pancake" type tube that would direct air to the right HE as a winter project. May burn some midnight oil on this...

Joe

[rob justice]

i was going to start cutting and modifing the existing ducting tomorrow - i bolted the new exhaust together - thanks for posting the photos - i almost made a complete twat of myself - check this out!!!!!!


talk about in the nick of time!!!!
Due the cold climate - i will need as much heat as possible so blocking off one exchanger would not be much good.

[Joeaksa]

Rob,

A work of art for us 911 owners! Where you will have a problem is between the right side of the muffler and the motor and that is where you need to get creative with the ducting. The rest of the installation (heat wise) is not anything exciting.

Hope it works out and I sure like my setup. Who made your exhaust? Its not SSI I believe unless they have they started putting the oxygen sensor port on the right header. Mine is on the left hand side but on your right hand drive car it may be different.

Joe

[rob justice]

Joeaksa

yep thats what i did wrong - how lucky i hadn't started cutting!!!!

[Joeaksa]

Rob,

Thats why this board is a goldmine! Good luck and hope it works as good as it looks!

Joe

[Randy Webb]

I'm a little confused after reading these posts -- Is this a modification that is needed if I put a 3.2L motor (with carbs & SSIs) in an early car (a '73)? And what is the company on the East coast? Or is that the company that one person was not very satisfied with?

Thanks!

[Joeaksa]

Randy,

This mod can be used on any style 911 from 89 earlier if you are using the SSI or Factory 74' style heat exchangers.

It all depends on which sheetmetal you use on your motor for heating. You can use the early style sheetmetal that does not use a "booster" fan or you can go with the stock factory sheetmetal that came with your 3.2 motor and use the fan.

Porsche put the fan motor on the later model cars to improve the heating air flow when you are at low motor speeds, like stuck in traffic. It works fairly well but the motors do go out from time to time.

Backdating the system means that the only air you have going through your heater is what is pushed by the fan that also cools your motor. Its more than adequate provided you are driving and not stuck in traffic. If you are in traffic alot then I would go for the extra fan...

The company on the East Coast does a very good job of modifying the heat duct tubing but then they also charge a pretty penny for their work. If one is handy with a welder or goes to a local shop, the same tubing can be made locally for a lot less money.

Joe

[89911]

The company is www.bodymotion.com. Mike Bavarro is the owner. I also have the same exhaust as you have, a Dansk Stainless single out. Good choice and it is of good quality.

[Steve W]

Rob, you do realize you got the left and right heat exchangers mixed up in the picture don't you?

[Joeaksa]

Steve,

Kept looking at the exhaust and thought it was backwards but has been too long since I was under the car. Noticed that the oxy sensor was on the wrong side but...

JA

[andyu911]

I've tired to fit the SSI on my 3.2 today. Trial fitted and found the heating ducts are anything but bolt-on. Quickly search the site and found this great thread. One question, I have this heat shield kind of thing on the driver's side extends from the engine shroud. Do I have to modify that sheet metal? Can't wait to put it together!

Andy
'87 Carrera

[Joeaksa]

Andy,

Is this heat shield part of the old exhaust system? Seem to remember something like this on my old exhaust but it was to shield the cat converter and is not needed with the SSI heat exchangers.

Did not use anything like it on the SSI installation with a 3.2 motor.

Joe

[marcesq]

Andy:

Joe is right. The heat shield that ran along the bottom of the Cat and the cross over pipe goes out with the old system.

FWIW, I blocked off the passenger side SSI and cut the 3.2 downpipe that fed the 3.2 heat exhangers so that it is connected to the drivers side SSI and I get plenty of heat. Was out in 34 degree weather yesterday, and was toasty.

I will, in the future connect the other side, by running hose to it, but the motovation level is a little low right now after doing the rocker shafts.

FWIW.