It's a delicate balance for sure. I mean there is a certain point where a small/short runner manifold will certainly choke and engine, as well as create (as stated) a huge difference in backpressure ratio on the motor...this will damage the motor for sure!
However you need to look at the smaller .64 t28 housing's flow ability. Certainly could the exhaust travel to the turbo more efficently with tubular? Yes...however you're still necking it down to a small housing, that won't be able to use the manifolds advantages...
Now enter my manifold, which flows a perfect amount for the turbine housing, and along with being extrude honed, helps increase velocity...at the same time, the coating also helps contain heat energy...this is big WIN for turboc cars and response junkies, as it helps spool the turbo faster. Are there downfalls to this setup? Yes...I'm sure the back pressure ratio is almost unsafe on the top end, but then again I'm not spinning to 24-26 psi either because of that (only 20). YOu also fight compressor/turbine efficiency issues in general up there, so it works out in the end.
Kalypso wrote:having an exhaust manifold of equal length... is less important then Heat retention on a turbo charged engine, correct?
http://www.majorleagueduning.c...t.htm
EDIT:: during my travels this fabricator said...
The thing with LOG manifolds such as a 3 piece manifold is that they create excessive pressure, what I am trying to do get rid of the whole pressure (PSI) mentality and get going on a flow mentality. My experience with diesels comes from vw and mercedes diesels, I found that increasing flow, while decreasing pressure, gives more power, better fuel economy, lower egt's, lower peak cylinder pressures, etc.
so the war continues
Modified by Kalypso123 at 7:25 AM 7/31/2008