Turbo manifold question

SiLeNcEbOnE
Club4AG Enthusiast
Posts: 50
Joined: Tue Aug 19, 2014 4:02 pm

Turbo manifold question

Postby SiLeNcEbOnE » Fri Oct 27, 2017 7:57 am

A little info about my engine.
4age bigport stock head. 11.0 comp pistons, stock size not oversized. precision 6262. ARP all around.
In a starlet fwd. Just to drag race. not street intended. Looking to make around 300hp.

I was on the lookout for a manifold to purchase.
I found one that was on sale.
However the runners were smaller then what my friend had let made for his engine build.

See pics for comparison.
Image
Image

The one on the 20v engine is the one my friend has.
The bottom pic is the one for sale.
As you can see the runners are smaller or lets say thinner.
After measuring the runners, they are the same size as the exhaust ports on the head.
While the one on the 20v is actually bigger then the exhaust ports on the head.
Now I understand the difference.
But what would be better for me to run?
I don't want to buy a manifold and then have it be some kind of a restriction afterwards, as I still want to get the head done after next years race season.

Any input highly apreciated

Gino1X1
Club4AG Enthusiast
Posts: 130
Joined: Wed Jun 05, 2013 10:59 am

Re: Turbo manifold question

Postby Gino1X1 » Fri Oct 27, 2017 12:41 pm

XCorrect me if I'm wrong, but.... strictly speaking, a turbo manifold/header is really not an issue restriction wise as is the actual turbo. For racing it's the norm to use an efficiently fabbed turbo header depending on the engine combo and the turbo used. For street or a street/strip vehicle, for me it doesn't matter if you want a "log" manifold or the added expense of a header for the turbo.