Used my industrial Dwyer differential pressure gauge, 3.58 psi range, to check some pressure drops. Stock seq'l turbos, ported efini y-pipe, greddy smic, usual intake and exh upgrades with hf-cat. Running about 9.5 psi at 7000 rpm, where max drops occured.

Used 3 measurment points:

1) hose behind y-pipe (goes up to check valve then pressure tank).
2) I made a tee, fitted in the AWS hose, for a before-TB tap at the elbo.
3) std upper manifold port.

2.9 psi drop from y-pipe to manifold ( acrosss IC + piping + TB )
1.5 psi drop from y-pipe to elbo ( across just IC and piping )

This implies 1.4 psi drop across the TB. I still have the double throttle valve, so this contributes some.

SCC measured about 1 psi across the M2's at 12-13 psi, and 2.5 across the stock IC. My 1.5 psi for greddy smic is a little higher than I had assumed.

Also measured very low .7" hg vac (-.35 psig) on top of K&N drop in, with mod'd stockbox intake. Had measured -1.2 psig a while ago, wth K&N and stock ducting to box. That inlet elbo to box limits airflow.

Will repeat measurments with stock IC next.

 

Good data....

do you have access to anymore parts to test? Rotaryextreme has a beautiful preproduction ported throttle body.....I would love to see the difference with that.

 

good point 7, get a hold of one of Chuck's bored out TB and check it.

Tim

 

nope.

search on 'dwyer' ... can get a 100" wc gauge like mine for $55. good investment for chuck?

I hate to take 12.5 at the turbos to put 9.5 in the manifold. that's about 4-5 psi excess backpressure to the exhaust ports.

 

KevinK2, how/where did you port your efini y-pipe?