Here is the difference between the full-race manifold and ATP's log manifold on a vw 1.8t engine. Just thought you honda guys would want to see the data comparing a log manifold to nice tubular merge collector manifold.

Note: these numbers are from a superflow engine dyno, so they are crank horsepower numbers. Both runs are at 23.5 psi on a GT30R .82 a/r

More info here:
http://forums.vwsport.com/viewtopic.php?p=116137#116137

 

they did the same dyno test on jeff's white hatch. they have a video of a dyno with a log and equal length mani. and the results were around a 50hp diff.

 

this is a repost

 

what causes it to make more power over a log?...i know they help with spike/lag or whatever

 

A nice merged collector and actually being tuned to a helmz holts frequency would be my guess.

Also, this isn't a repost. This is a follow up on the last post. These results are from the race gas tune at higher boost.

Here is the same engine with even more boost. 29 psi I think on c16. This was the last pull of the day and more tuning will be done tomorrow.

 

Thx for going through the trouble to show us info. Nice 1.8T btw.