To do this mod, you need to grab one of these kits from Jaycar for around $20.
Basically, it looks at the signal from the TPS, and opens the BOV for a predetermined time when the throttle snaps shut.
The assembled kit:
Pretty easy stuff; even if you've never made anything like it, you'll be right as long as you can solder, and you make sure you're putting the right components in the right way...
Slight mod here; since we don't have a TPS, this is a voltage supply for a retrofit.
The top right of the black wire is a regulated 8V supply; the two solder pads indicated by the screwdriver are terminals, one of which is spare but the track between them needs to be scratched away.
Here's the idle switch with a nicely-placed hole in the cover.
It doesn't matter if the hole's a bit big or whatever. Notice the hole in the switch itself is almost the same as the ones in some volume knobs... : )
Go the hack on the throttle spindle.
You need to make some room in the switch hole for the potentiometer shaft.
10kΩ pot mounted in place. The shaft needs to be trimmed pretty short... a single layer of electrician's tape gives it a snug fit in the hole.
For peace of mind, I went a bit OTT and dismantled the pot to remove the sticky shit (soaking in solvent won't do it) in order to free it up, but that's prolly unneccessary...
Irrigation solenoid - $40-odd from a plumbing supplies joint.
Bit of radiator hose for the curve. In hindsight, the reducer on the outlet was prolly a mistake
Inlet pipe modded to suit.
I reckon up near the throttle is prolly the go
TPS wired up:
Short black wire is obviously grounded; long black wire goes to that 8V supply, and the green wire is the signal.
BOV in place
It's powered by juice I pinched from the removable link to the reverse light switch, which also powers the the circuit itself, since it switches off with the engine.
Circuit inside a zippy box:
Green and black wires are the TPS supply and signal; red and black are power and ground (I soldered it onto the ground eyelet on the plenum), and there's a couple more for the solenoid. Once it's all together, you just tweak a little trimpot to open the valve for as long as you want (about a second or so, I guess), then you adjust another as you flip the throttle to get the sensitivity right.
BOV plumb back:
The idea with the reducer and the skinny hose was to get some velocity happening, and squirt it into the inlet of the turbo...
It lines right up...
Problem is, I can't even tell the difference with the BOV disconnected, so I guess there's too much backpressure going on, or the solenoid itself is too restrictive...
I guess my turbo's prolly having an easier time of it, at least
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