TheSamba.com :: View topic - Adding heat using an after market exhaust sytem.

Sat Dec 29, 2012 7:19 pm

I recently installed an after market exhaust system on a 1969 Squareback. I wanted to retain interior heat and installed stock heat exchangers. I installed the metal and paper fiber smaller fresh air tubes.

The question was how to supply the fresh air to these tubes. I was warned that operating the heat without supplying the secondary fresh air would pop the thermostats in the Warm air mixers that are attached to the body. That would result in extremely hot air being expelled into the interior.

The stock exhaust system/muffler utilizes an extra small heat exchanger that is located directly above the muffler. This supports the large metal elbows that provide the fresh air to both the small fresh air tubes and the main under car heat exchangers.

Materials used:

Original Elbows
1" PVC pipe couplings (2)
1 1/2" Rubber pipe coupling (1)
3/8" long #8 sheet metal screws (4)
2" heater hose from fan shroud flexible aluminum (2)
Hose clamps (eight)
1 1/8" Forstner Bit

Step 1 - Secure the 1" PVC coupling on a drill press. Open up the inside to 1 1/8" by drilling through the center with the forstner bit. Drill at a slow speed and proceed slowly to avoid overheating the bit and melting the pvc coupling. Enlarge the opening in both couplings.

Step 2 - Cut the 1 1/2" rubber pipe coupling exactly in half. This result in two rubber couplings the correct length for both sides.

Step 3 - Slip the now 1 1/8" pvc coupling onto the nipple of the right side elbow. The left side coupling onto the metal fresh air tube.

Step 4 - Install each 1 1/2" rubber coupling half onto the fresh air outlet of the fan housing. Be sure the rubber is warm and flexible as it has to be coaxed on as it is slightly too small for the application.

Step 5 - Slip each large metal elbow onto the just installed rubber coupling, left side and right side. Make sure to line up the smaller outlet nipples so they align with the metal fresh air tubes. Clamp both ends of the large rubber coupling securely.

Step 6 - Slide the smaller 1 1/8 " pvc coupling so that it connects the metal nipple from the large elbow to the metal fresh air tube on each side. Secure each end with a sheet metal screw. I drilled pilot holes before attaching the screws.

Step 7 - Install the 2" aluminum hose from the end of each elbow to the main under engine heat exchangers. It is easier to clamp them to the Heat Exchangers first, then cut them to length and clamp them to the large metal elbows.

The result is a sturdy installation that operates the heating system as VW intended. It is also completely reversible, does not render any of the used parts unusable, allowing them to be utilized with a stock exhaust system in the future.

This is the completed left side.

The right side.

Close up of the Rubber coupling.

Right side pvc coupling.

Left side coupling.[/code]

Sat Dec 29, 2012 8:20 pm

Slick! I like the PVC couplings.

Sun Dec 30, 2012 10:20 am

Just keep an eye on the aluminum tubing, as it gets fragile when it ages. It also likes to tear and or wear easily, and also fall off the heat exchanger end. Keep in mind you won't get the full heat that a stock muffler set up will give, since you're only using the large heat exchangers. Looks like a decent set up though.

Sun Dec 30, 2012 10:34 am

what other option is there to use other then the aluminum hose ???????

Sun Dec 30, 2012 11:40 am

Ducting from Aircraft Spruce rated up to 530 degrees.

Sun Dec 30, 2012 1:04 pm

About a month once it warms up in the desert, I will come up with a more permanent hose. Will get some flexible metal exhaust or fresh air hose. Stainless seems to an item I can order. Maybe 1 1/2" and expand the ends to fit or 2" with crimped down ends. I will post an update.

Sun Dec 30, 2012 8:31 pm

Mike Fisher wrote: Ducting from Aircraft Spruce rated up to 530 degrees.

Hey Mike, is it this stuff?

http://www.aircraftspruce.com/pages/ep/ducting/sceet.php

What diameter should be used?

Sun Dec 30, 2012 9:28 pm

That does look like the stuff, but someone else said to be sure to order the best grade Aircraft Spruce sells which is SCEET? I think it was the 2.25" I ordered, but take some measurements yourself. That is an 18" long piece in my picture.

Mon Dec 31, 2012 1:30 am

I like your solution to the getting air to the tubes. I'm using the same type of aircraft duct with an aftermarket exhaust as what Mikes pic shows. Do you think the PVC will withhold the engine temps? Just curious to know as the coupler idea is a great one for guys wanting to run heat with non-stock exhausts.

Mon Dec 31, 2012 3:24 am

montehm wrote: I like your solution to the getting air to the tubes. I'm using the same type of aircraft duct with an aftermarket exhaust as what Mikes pic shows. Do you think the PVC will withhold the engine temps? Just curious to know as the coupler idea is a great one for guys wanting to run heat with non-stock exhausts.

It's cool air blowing through those. I think it will hold up as good as any other plastic part.

Mon Dec 31, 2012 4:54 am

Does this get pretty good heat though? I'm wondering as I'd like to do the same... Not one for a quite car. In the mean time, what would you say it cost you total to do this?

Mon Dec 31, 2012 5:19 am

Yooyenkoo wrote: Does this get pretty good heat though? I'm wondering as I'd like to do the same... Not one for a quite car. In the mean time, what would you say it cost you total to do this?

There's plastic clips for the spark plug wires right on the tin, they don't melt. I don't see how the PVC would get any hotter.

Mon Dec 31, 2012 10:19 am

Yooyenkoo wrote: Does this get pretty good heat though? I'm wondering as I'd like to do the same...

If you want hot heat, use the stock exhaust set up. An alternative to adding the hoses like Brion did, would be to remove the heat exchanger thermostats, and plug the cool air inlet. This will make more heat, without having the "pre-heaters" that the stock exhaust uses.