DC350

yes, i know this subject has been beaten to death. But how do you know that your ports are opening from normal everyday driving? I have no air pump, or cats. But the vaccum hose, is connected to a nipple on the race pipe.

And the car pulls harder then before sounds a hell of a lot better, if the ports aren't opening...What am i missing?

Evan

OC_

what year is your car? i think 88 and earlyer ones work differently then the later ones. Every one says to smear white lithum grease (cuz its ez to see?) on the actuators, then go drive around and make sure to take it up to red line. then see if the grease has moved on the actuators, if its not, they arnt opening.

DC350

ohh, okay thanks man! yeah, i uses back pressude, not VDI

it's an 87, thanks!

rymnryan

iTrader: (1)

While you have the car in idle use the throttle lever on the throttle body. Slam it down really fast all the way and then release so as not to blow your engine. If they work you should see them open.

JerryLH3

iTrader: (11)

Incorrect terminology. The S4 does open with backpressure, but the S5 opens using pressure from the air pump, not the VDI valve. VDI (Variable Dynamic effect Intake) opens a valve in the upper manifold that creates a pressure wave that almost acts as "boost." Believe me, when it's working, you can feel it.

Also, I'm darned near positive there has to be a load on the engine for the ports to open (I know this is true on S5s). Therefore, revving the engine in the driveway is not going to open the ports.