Isuzu G-series Twin Cam

Alright so my plan's always been to go turbo on my G180W, running a Garrett GT2860RS "disco potato" in my TX sedan.

Whilst the $1000-$2000 needed to buy the turbo is still a while off, the time has come to start contemplating how on earth I'm going to mount it. I was going to get a custom exhaust header made from scratch, and budget about $500 for it, but I've been thinking there might be a cheaper way. If anyone's ever had a close look at a CA18DET/SR20DET exhaust header, they may have noticed that the ports are evenly spaced, and potentially a similar distance apart. They're rounded rectangles I think, could be wrong, but perhaps by taking an aftermarket header for one of these engines into an exhaust shop, they could modify it to suit?

How much space will I have to play with, does anyone know? I wanted to run high-mount because I'd imagine it'd have improved response, but I'm not sure about space (wheel arch, bonnet), is this an option? Could anyone have a look at these pics and tell me if they think it's possible?

http://s1.promotionsupplies.com/ebay/au ... ttop-4.jpg
http://www.nahux.com/NPOWER/PICS/MANIFO ... A-T3_2.JPG
http://s1.promotionsupplies.com/ebay/et ... 0det-1.jpg

Apparently headers like these start as low as $130...

And here's a random googled reference pic of a twincam in a Gemini:
http://www.geocities.com/zzzgeminiclubsa/DSC00041.JPG

be careful of the cheap chinese manifolds cheap stainless and even cheaper workmanship. ive heard many stories of the manifolds cracking on the welds.

Here's some info on the CA18DET manifold, I'll have to grab my twincam exhaust header for comparison...

http://www.nissansilvia.com/forums/inde ... 32567&st=0

Okay a very kind member of ns.com sent me a stock CA18DET exhaust header (at his expense!)

I've had a good look, the ports on the G180W are slightly further apart, but the consistency of the spacing is pretty similar and the shape/size isn't too far off. Unfortunately the retarded coolant outlets between the exhaust ports on G***W's complicate matters, and I don't know how much clearance there is to the guard as the engine isn't in the car unfortunately... But it's entirely possible that "runners" could be made up from the twincam head, to a CA manifold at a far lower price than that of an entire custom turbo header.

OR, as my mate suggested, buy a CA18DET stainless steel manifold, heat it up, and bend the pipes out to match? Any thoughts?

Think youd have a bit of trouble bending the stainless pipes.....

Be better of buying some stainless elbows,about $15 each,and then have someone TIG it..this is how Im doing mine.Cheaper alterative is steel,elbows like Darren uses on his manifolds are only $4.50 each,find a boilermaker and your set.

Use the exhaust manifold gasket to have flange laser cut and then its just a matter of tacking elbows together once they are in the required position.Sheel has posted a tech article on OzGem on building your own manifold.

Im lucky to work in a marine engineering shop where the shelves are full of holesaws and stainless buttweld elbows with plenty of tradies willing to help so cost will be keep waaay down.

Keep us posted on your progress!

Todd.