Originally Posted by andyKAIZENSPEED

Flow Control Valve: The flow is unrestricted when the pedal is pressed and the clutch is disengaged. The fluid is restricted through an orfice as the clutch engages and flows back toward the master cylinder. The orfice size controls the time it takes to fully engage the clutch. Pretty simple.

Here is a DIY flow control valve. The inlet and outlet are inverted flare to use with stock style clutch lines. A nitrous jet is seated against the inlet with a spring. The inlet fitting is chamfered for the jet to seat in. When the fluid travels from the master cylinder it blows the jet off it seat and travels around it. When the fluid travels from the slave to the master the spring and fluid seat the jet and the fluid must travel through the orfice.

Here is the explored pic:


Assembled:


Same thing, but with -3AN instead of inverted flare:



Here is the one I built for our racecar. It does the same thing, but has a line lock to bypass the nitrous jet. This allows us to fine tune the engagement at launch, but shift normal for the rest of the run.

Originally Posted by rudebwoy

drove the car today for a short move to a parking lot, took it through 3 gears, and shifts ok a little irratic like the shift of the e46 in 1st gear, but not as harsh as it was without the valve. won't be able to race it till next may.

Originally Posted by cloviskilla

Your tracks r closed till may?

Originally Posted by draggbody

i bought one of these from mcmaster-carr for $30 plus the fittings... it works well and ill be testing it at the track tonight...



it will probably just show up the catalog page, but if you search the part number it will locate it on the page for you... part# 4982K71

http://www.mcmaster.com/#4982K71