Currently i'm using the d-series SS autochrome manifold and after seeing the post of the guy who made the top mount manifold using the oe cast manifold i have been very interested in making one to replace this ss auto bs mani. How would the top mount manifold flow compared to my "equal length" (correct me if i'm wrong) ss auto manifold? Would i be better off just buy a log manifold or just sticking with the ss auto mani? Basically my plans are to pick up a cheap ebay header and pick up a couple of 180 degree bends and fab it up. thanks for any input

 

stick with the ss auto untill your turbo falls out the bottom of your car. You already paid for it so you may as well use it untill it breaks. If you weld a shitload of reinforcements in, it will last for awhile.

As far as the cast manifolds flow, it will be quite inferiour to your ss auto one. No matter what, a factory manifold is a bit of restriction becasue of the small ports. But in my opinion, an Hf (or equivilant) that has some kind of a collector is better than a high pressure log manifold.

 

Thanks for the info. I paid $100 for the manifold, turbo, and downpipe The main reason i want to change the manifold is because i want to convert to external wastegate and i need to turn the turbocharger around so i can route the charge piping much easier. I was also considering using an hf manifold and porting the o2 housing and welding an elbow to run a wastegate. Would the hf flow better then the homemade top mount?

 

Also how would the turbo spool with a top mount manifold? vs hf?

 

your in ------- luck. Im selling my Hf with the external wastegate. It worked great for me, just not past 15 psi or so. I had an audi gate on it, put im keeping it. I'll cut the audi flange off and weld on a tial/deltagate for you.

Manifold+Adapter plate (T3) $85 shipped.

 

Wow, thats almost like winning the lottery