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What are the advantages / disadvantages of each? I am curious to know if one is better than the other (ie: we have 1 turbo kit with a log manifold advertised here, and another one with a 4-in-1).

I realize that the 4-in-1 will allow for faster spool up of the turbine, but is there any other advantage to it? If you have a T25BB vs a T3, the differences should almost negate each other......

 
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This might oversimplify the answer. I believe that the "log" style is easier and therefore cheaper to manufacture, but has a spool up penalty like you already mentioned.

 
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the purpose of a log manifold is to make it easy and cheap .it performs the basic function of getting the exh. to the turbo.the down side of a log manifold is the presure spike of all the exh. pulses coming together happens in the manifold instead of inthe turbo housing.this causes the manifold to run hotter and more likely to crack,loss of heat to drive the turbine,increase of back pressure at the head,and offers no scavenging of the cyliders at preboost and low boost situation.

a four to one manifold scavanges exh. out of the head at low boost and preboost just like an after market header. this allows more exh. out of the cylinder during the exh. stroke whitch allows more fresh air and fuel in on the intake stoke.the four to one also increases heat and presure at the turbo thus increasing spoolup time while reducing back presure at the head

the four to one allows you to run a larger more efficent turbo without suffering brutal turbo lag

 
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^^^ yea what he said

 
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So essentiallly what you are saying is that with a 4-in-1 header each chamber is isolated from the others, thus decreasing back pressure into the adjacent firing chambers? Or in layman's terms - a more effecient design for maxumum performance.

Thanks for the reply!

 
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Check this out, for those of the engineering mindset:

http://www.awe-tuning.com/media/pdf/...comparison.pdf

Its an excellent paper I found which describes what SFPower has said - only with photos.....

Good read...

 
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That WAS a good read. Thank you for posting the link. In a nut shell the log gets the job done, but the "collector" style is the upgraded way to do it with increased efficiency, lower spool up time, and lower back pressure.