Fabricating a Turbo Header

[VWRacer]

Sooner or later I am going to have to fab up my own exhaust header, whether I put this engine in the CSR or build a Rabiit GTD for NASA's 25 Hours of Thunderhill. Anyway, there is a terrific DIY Turbo Header page on Simple Digital Systems's website.

I recommend you load the page, then save the entire page as an html document. (To do that, open the page then click File > Save Page As from the pull-down menus.)

Cheers! Stan

[moTthediesel]

Stan,
I've seen that page before, that is good stuff!
I seriously thought about making a header like that when I put the turbo on my Toyo 3B diesel. In the end though, I got lazy and took advantage of the fact that the 3B manifold can simply be flipped over to mount a turbo forward and on top. No equal length exhaust tracks that way, but simple and stout.
With a 3.4L diesel in a 4600# truck, I'm not going to be doing a lot of racing anyway!
Check out the Hobart Welders board -- they often have turbo manifold construction info --
http://www.hobartwelders.com/mboard/    

[fspGTD]

Great link Stan!  That info should come in handy if/when I go at making a custom long-runner intake manifold.  I was wondering how to weld all of the tubes without them getting in the way of each other - makes sense to just tack-weld them and remove them and weld them up individually before attaching them to the flanges at the very end.  How do you think they hammered the square shape into an 8-sided... "very carefully" or just use a really big hammer, or what?  Interesting construction method.

[VWRacer]

How do you think they hammered the square shape into an 8-sided... "very carefully" or just use a really big hammer, or what?

If you look carefully at the photo, you can see grinding marks. My guess is that they notched the corners, then welded in some small triangles to "round" the corners. Afterwards, the builder ground down the welding flash.

If you have a gas welder, you could heat them cherry-red with a Rosebud, then hammer them to shape, but I think that welding in the triangles is better. Plus, the beauty of a MIG is that you can "gap fill" where needed to ensure a tight seal.

[DieselsRcool]

Yeow! That's a butt load of work. Think it is that much better than a cast iron stock manifold?

[BlackTieTD]

i believe you'd only really want to go through that much work if you were turbo'ing an NA engine and a factory manifold was not available for that application... you'd have no choice but to make one.

you're right, seems like a lot of work when the factory manifold works just fine. its a little overkill to make a custom manifold for a vw TD or TDI unless you have a pretty serious engine setup, race prep, track car, dyno queen, etc etc and you're putting a lot more air through the engine than what the factory intended.

[VWRacer]

You are quite correct, Black Tie. Most folks will not have to build a new manifold. In my case, I may be putting this engine into my CSR, which cannot accommodate the Quantum's (or a Rabbit/Golf's) exhaust manifold. If we decide to go with a Rabbit, I can get any number of rollers around here for well under $500, but they are all gassers. Again, the Q's manifold won't fit. So in any case I face this problem.

Also, we already know that the stock manifold is not ideal, so buying a TD's manifold is not the best plan for a racing application, either.

Besides, who can resist the aura of your own custom turbo manifold?  :wink:

[laser030]

IIRC, I recall reading that the head patterns are the same for 1.6 Diesels and 1.6 32V GTI engines.  You could pull the headers off a 32V and weld just a flange on.

[VWRacer]

Well, I don't know about the 32V 1.6 GTI (I'd like to have one of those, BTW... ), but the 8-valve manifold should work. Here are a couple of pics from one of my spare engines, in this case an '83 GTI 8V engine.





The GTI manifold appears to be a direct bolt-on, and fabbing a flange would be simple, so I guess I could take this approach. If I have time, though, I will almost certainly build an SDS-style tubular header. The stockers work fine at stock RPMs and boost, but tubulars make more and quicker boost while allowing the turbine section to run cooler with less back pressure, which will be critical to getting the engine to last 25 hours... :?