<VV> exhaust manifold mod improved flow?

[Bryan Blackwell]

I have talked to a number of folks with turbos, and even when using  
140 heads the small manifolds worked better because the velocity was  
higher and they have enough mass to stay hot.  I might be worth the  
time to smooth the transition from the manifold to the crossover  
pipe, but other than that the stock small manifolds seem to do best.   
I think if you could make the turns smoother but keep the mass and  
cross section about the same that might be the ticket.

Bryan Blackwell bryan at skiblack.com
http://autoxer.skiblack.com/
   Corvairs: '61 Lakewood, '64 Greenbrier, '65 Corsa, '66 Corsa
   '69 Road Runner, '97 Ford F-150, '99 Neon R/T
"Why do something if you're not going to obsess about it?"


On Jul 31, 2008, at 12:40 PM, chad c wrote:

> It seems that the exhaust manifold is fairly restrictive.  I have  
> thought of cutting the end off (where the exhaust exits).  Then  
> cutting the log open long ways, horizontally.  Then having a good  
> welder weld in another 1/2 inch or so of material.  Basically,  
> increasing the internal volume.   Weld the end back on, then open  
> up the exit port to increase flow there.
>
> Probably a crazy idea, I know.  But I figured I'd ask if anyone has  
> done something similar.  And has it helped flow and performance?   
> What kind of flaws does anyone see in this idea?