Exhaust

I can buy an exhaust from somebody who's also got an Alfa Romeo engine in his beetle. But, the exhaust is not yet available. While waiting I want to start building my own exhaust. When the other one comes in, before my own is finished, I will use that one.

I want to try to build an exhaust with this "spaghetti" exhaust which is originally meant for a beetle engine:

Here is a mock-up under the car:

It's obvious the lower pipes have to go, but that's not a real big problem as the exhaust ports of the Alfa engine are at the bottom of the engine instead off on the sides like with the beetle engine. Because of that I don't need the lower pipes. The lower pipes are there to make all the pipes in the beetle engine layout the same length. Where the 4 pipes meet, the upper two pipes must be connected to the rear exhaust ports, and the lower ones to the front exhaust ports. It's time to buy a welder and learn how to weld...

edit 11-02-2007:I ordered a welder, but haven't got it yet. I allready started on cutting up the standard Alfa exhaust manifolds I have. I've got two:

The left one came with the engine, the right one I bought additionally.

I cut up the left manifold, and I cut two pipes from the VW beetle spaghetti exhaust. This is, roughly, my plan:

The front two cylinders will go directly to the two cut-off pipes of the spaghetti exhaust. The two rear cylinders will go the the long pipes of the spaghetti exhaust. The pieces of the Alfa manifold will have to be cut up to make them reach the spaghetti exhaust. I might even have to cut up the other Alfa manifold too.

edit 18-02-2007: Yesterday I was talking to my neighbour about this project. I told him the only thing left to do was the exhaust. That reminded him of this motorcycle silencer he had lying around in his garage... It came from a Suzuki 750 cc (he thought) race bike. He said that I could have it if I mounted it on the beetle! Here it is:

It's good to have nice neighbours... :-) It's a nice alumium silencer with a very big diameter port on the intake side. I will have to make a triangular plate to weld the exhaust pipe on to it.

I want to hang it under the rear apron pointing to the left and a little downwards.

edit 10-03-2007: After practising a few hours with my new welder, I started welding on my manifold. So far, I've got the tube for one cylinder finished:

First I'll do the two most forward cylinders, and then I can measure those tubes and use that length when I create the tubes for the rear cylinders.

edit 18-03-2007: Welded on the two tubes for the left cylinders, it was quite a puzzle to make all three tubes of roughly the same length:

The beetle exhaust proved to be very thin walled and rusty, lots of holes appeared when I welded that metal. The solution for this was to weld in tiny pieces of metal, to cover the holes. An experienced welder will roll on the floor of laughing when he sees my exhaust... But I probably will cover it with heat-isolation tape so almost none of the welding will be visible. I want to use the isolation tape, because the exhaust is right under the distribution belts and (plastic) tensioner wheel.
I still have to weld up some of the seams in between the bits of tubing in this picture.

edit 25-03-2007: Welded on the last tube, and grinded all the welds down. Some holes appeared after grinding, which I rewelded.

I still have to paint it.
Here it is mounted on the engine:

edit 01-04-2007: Made two flanges, one for the motorcycle silencer and one for the 4 in 1 header:

They're made out of a 6mm thick 10 by 20 cm steel plate, the holes in them have an aprox. 45 mm diameter.

edit 04-04-2007: Bought some shiney exhaust bits:

Four 90 degree bends, 2 metres straight pipe, a flexible piece and some suspension rubbers.

This is how I am planning to mount the silencer:

From the back of the silencer there will be a 180 degree turn, so the exhaust tubing will point to the back of the car. In the following piece of straight tubing will be the flexible piece. At the back there will be a 90 degree turn to the drivers side ot the car and then a 90 degree turn towards to front. There it will meet the header, in the middle of the car.

edit 10-04-2007: I finished the brackets for the silencer. It is a bit hard to see in the next picture, but is is supported on three places. The original bracket is used to bear the full weigth, and a alumium strip with two attachment places is used to hold it in position. These last two are attached to the left engine brace bracket. All three attachment points are not in direct contact with the car, but it is haning on pieces of rubber to silence the vibrations.

I am quite pleased with this position. It's not too close to the tire, and it has enough ground clearance.

And I like the way it looks.

I started on the piece of pipe from the header to the silencer:

edit 14-04-2007: This is a video of the exhaust installed loosly. This is the second time I started the engine!:Video
The nuts that hold the header weren't thightend so, it sounds just like it has no exhaust...
The engine didn't want to rev up, only run idle. And after like 10 seconds it slowly died... The fuel pump is making a lot of noise, so I suspect it's worn. I am going to try another fuel pump.

edit 18-04-2007: The complete exhaust system is painted and ready to be installed:

edit 20-04-2007: Installed the exhaust:

The view from behind:

edit 22-04-2007: No real update, but I made a picture of the car from the side. It gives a nice view on the silencer:

edit 28-10-2007: The rubber I used to hang the motorcycle muffler with started to tear:

I replaced it and used 4 square pieces of iron to clamp it:

This way the forces are spread along the rubber, and hopefully it will not start to tear anymore.

edit 16-03-2009: Well, the rubber strap didn't hold. I was glad I added a piece of safety wire so the muffler was still hanging from that.

I have to find an alternative for these rubber straps. Because I wanted to fix it, I used a piece of old distribution belt to create a new strap. It's just a small piece folded together in which I drilled two 8 mm holes.

Distribution belts almost don't stretch, and they have to withstand high temperatures, so I hope this will work for a while. To be sure I added a safety wire again.