Geoff Raicer

iTrader: (7)

my opinion:

ideally, you want things VERY hot and VERY high pressure before the turbine, and VERY cold and VERY low pressure after the turbine.

The hotter and higher the pressure before the turbine and the lower and colder after means turbine efficiency will be maximized.

The true purpose of a long runner is not so much to "position" the turbo, or look cool but more than anything else, to isolate the combustion event from the pressure reservoir/chamber/plenum that occurs at the turbine inlet. On an undivided 4-1 application (like these) which use an undivided t3 inlet (most people on here are running this setup) a properly designed manifold will ensure that when the exh valve opens, ALL exh/unburned hydrocarbons/hot gasses and crap leaves the cylinder and is replaced with 100% fresh clean air and fuel.

Runners should never be measured by "length" as measured via a tape measure, rather by pressure drop.

I have been working with a graduate student at ASU on his Master's Thesis. We just finished a paper which will be published by SAE (society of automotive engineerings). Ill link you guys to it once we get them online

trinydex

iTrader: (12)

do you guys measure pressure drop in diameters away from the pressure source? i tend to see that's popular in engineering terminology. just wonder about how many diameters we're lookin' at for your style headers.

but that is a very good point... to efficiently clear the cylinder you would need a certain critical pressure drop after the head.

EVOlutionary

iTrader: (38)

If any of you guys have seen under the hood of John Shepherd's race car, I seem to remember it having an extremely long header leading to the turbo which was positioned in the front passenger side of the nose. Sorry if my memory is foggy, but that was at the DSM/EVO shootout last year and I was still recovering from the night before. I am pretty sure it was Shep's car that they had in front of Buschur's shop.

I am sure if he could make more power using a manifold similar to stock size, he would. I am sure it is not there to "look cool".

EVOlutionary

RyanB@VelocitySource

I know its been awhile since anyone posted on this thread but I finally made it to the 1/4 last night so I got some results with my setup. here is a link to my best run https://www.evolutionm.net/forums/sh...d.php?t=229161 this run was on 93 oct., 20 lbs of boost, and it was about 60-65 degrees out. I don't know that my results show that my manifold design is any better than anyone elses but it definitely was not below average.