what are you running, blow through or efi, and I take it a custom turbo manifold?
Blow-thru seems to work well, although I have heard that you can actually make more horsepower with a draw-thru system. The trouble with a draw-thru system seems to me, to be that if you put a carburetor at the head of a draw-thru system, and then run that mixture through an intercooler, you have the potential for a sizeable explosion in the event of a backfire, should an intake valve hang open. KA-BOOM... Lots of combustible mixture in that induction tract...
So, in the real world of street-driven cars, the draw-thru has few takers.
Our system is a blow-thru, which is pretty popular right now, with several carb companies offering modified carbs for blow-thru applications, or there are instructionals available online, should you want to make the metering circuit modifications, yourself. Of course efi is always a possibility should you want to go that route. I don't know anything about it, so my car is carbbed..
My racing partner and I elected to have someone else do the blow-thru mods for us, we being babes in the woods around carburetors.
He (my partner) built an elaborate header for the turbo, but that is not necessarily the right thing to do. Simply sawing off the original head-pipe flange from the stock, cast iron exhaust manifold and either adding a tubing 90-degree elbow with the turbo bolted to that (with the appropriate turbo mounting flange) or, welding that turbo mounting flange to the cast iron manifold and bolting the turbo directly to it (the exhaust manifold) seems to work about as well.
The intake manifold is no problem at all, as any aftermarket 4bbl manifold of practically any design seems to work equally as well. Used ones are always popping up on here, as well as ebay. Offenhauser, Clifford, Weiand, and Aussiespeed all have been making those 4bbl manifolds for years. They are in no way, rare or hard to find... Stay away from the long-runner Hurricane manifold; it's a really good manifold for normally-aspirated applications, but not for turbos.
There is a piston company (Wiseco) that works in conjunction with a rod manufacturer (K-1), that specializes in low-compression, turbo forged pistons for the slant 6, and they come with a special low-drag ring package, and have thick crowns so will stand lots of boost before giving up the ghost... You'll need forged pistons to run much more than 10 pounds of boost.... and believe me, boost is addictive... LOL!
Turbo slant sixes and their performance potential are a well-kept secret, but more and more are being built.. One fellow on this board has a '66 Valiant turbo /6 that runs mid-tens at 127 mph... and, I think that's fast enough to have a considerable amount of fun at the strip...
Here's a video...
[ame="http://www.youtube.com/watch?v=7QzUfV8iTpQ"]Turbo Slant Six 10.74 @ 127 mph 7-19-10 - YouTube[/ame]
My contention is that if you alreay have a car with a slant six in it, rather than swapping to a V8 for performance, it would be cheaper to build the turbo six... for the same performance level.
Food for thought....
Bill
