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-   -   sadly i have almost no exhaust restriction (https://www.rx7club.com/2nd-generation-specific-1986-1992-17/sadly-i-have-almost-no-exhaust-restriction-208734/)

andrew lohaus 07-25-03 12:56 AM

sadly i have almost no exhaust restriction
 
well, i'm probobly not the first person to try using exhaust backpressure to open the 6 ports and vdi, however i now know that it cant be done because i simply dont develop enough pressure. i took that stupid tube that feeds back from the presilencer, cut the one-way valve off of it and then ghetto-rigded some tubing to feed into the pipe that goes to the solenoids and eventualy the actuators. i bypassed the solenoids just to see if there was enough air to move the actuators, sure enough there wasnt. only when i grabed the throttle cam and yanked it all the way open could i get enough pressure to just slightly budge only the vdi valve.

the yin and the yang of this experiment:

the good: my exhaust flows so well it cant even develope the measly 3 psi needed to move those actuators.

the bad: since my idea of using free psi didnt work out i know have to have the long internal dissertation whether or not to remove the mechanical airpump and get an electric one.

OC_ 07-25-03 01:36 AM

or you could just wire them open and see how it is.

BLUE TII 07-25-03 02:18 AM

It sounds like you are testing it by revving it in neutral?

An engine will produce VERY little exhaust back pressure unless it is under load (driving). For example, a turbo doesn't spool in neutral (unless you use some form of antilag).

Don't give up untill you road test it. Put grease on your 6 port rods, if they open up the grease will be rubbed off the shafts.

Icemark 07-25-03 09:52 AM

exhaust back pressure is only created under load

andrew lohaus 07-25-03 03:56 PM

thanks i give it another try


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