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copbait73 copbait73 is offline
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Join Date: Nov 2003
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Originally Posted by Speedy Squirrel View Post
That'll work! If there was a way to weld three 30mm tubes to each side of a standard mini-foot flange, I wish they would show it, as that would be the ultimate. Your concept is darn close.

There's too much talk about scavenging on this thread. Forgetaboutit. Pulse conversion is where it is at for big boost. Man, BMW re-did their V8 for turbocharging last year. Changed the heads, cams, cam drive, and manifolds just to get short turbo manifolds on the INSIDE of the V. Unbelievable.

I tried to swear off this thread, but this is just too much. A production motor with cast manifolds.

I'm sure there are still some Ferrari engine engineers around from the early 1980s F1 days who will tell you how they started with that belief but finally moved the turbos from within the Vee to outboard (like everyone else) just to keep up in the rapidly escalating turbo HP race. Once that BMW engine gets to the power levels of F1, 15HP/cubic inch for a transient, road course duty cycle, I'll listen.

I had that belief at one time, it all sounds logical and pulse recover has its applications. Then I had a discussion with Ed Pink, look him up. He explained his experience with these manifolds on high performance motors and why he would not allow one retro-fitted to one of his turbo Cosworth Indy engines.

It goes like this: You blue print the combustion cycle components to make all cylinders operate under the same conditions, at all times. This doesn’t just mean the block related components but the air system also. When you’ve made every effort to achieve this you can reliably pull high HP. As it relates to exhaust, his comparative testing (yes he tested log manifolds that were the previous standard on turbo Indy motors) showed anything less than equal primary pipes (whatever length) gives you misfires on random cylinders at random RPM and misfires become more critical and damaging as power density increases.

I’ve witnessed and done many things demanded of a turbocharger and engine that took away from ideal power production. This is more the norm than the exception. Only BMW engineering know the numerous reasons they moved the turbos here but my prediction is like Mr. T said: “Pain”.

Last edited by copbait73; 01-14-2010 at 09:16 AM..
Old 01-14-2010, 08:47 AM
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