After much searching on the subject I bit the bullet and went for an electronic boost controller rather than the manual option, but still decided on the cheap option and went for the PIT BCU+. Had it installed by WRD at the weekend, and there were a couple of minor problems with the kit provided (insufficient hose and wiring, and lack of mounting bracket for the solenoid) but otherwise installation went OK.
I've now had time to have a proper go at setting the unit up but am having some weird stuff going on. The adjustable settings are as follows:
Set Boost - the target boost level in psi (separate LO and HI settings).
Gain - controls how quickly wastegate opens and closes (0-100% where 100% is quickest opening/closing, and there are separate gains for the LO and HI boost). The manual says this should be set low and gradually increased until the destination psi is reached.
Start Boost - psi below Set Boost at which the wastegate opens (e.g. if set boost is 9psi and start boost is 2psi, wastegate starts to open at 7psi).
Warning level and limiter (I've set these to 14.5psi and 90% of set boost respectively).
I've temporarily set the high boost to 0.00psi/zero gain, which as I understand it will effectively turn the unit into a boost gauge and not control the boost. In high gear, uphill at WOT I get stable boost readings from 5.9-6.1 psi which I assume is stock boost on my pre-facelift auto Leggy.
I've currently got the low boost set at 9psi, and I have tried runs up and down a nearby dual carriageway (up being uphill!), adjusting gain at 5% intervals, but I can't get a stable boost level above the stock boost level. The best I've managed is to hold 8-9psi on partial throttle in 4th, but at WOT the boost spikes to 11-12psi and then falls back to ~6psi. Even weirder, I've set the gain to 20% and the start boost to 0.5psi (i.e. wastegate shouldn't start to open until 8.5psi) and in high gear at WOT the stable boost obtained drops to 3.9-4.1psi. I didn't think it was possible to go lower than stock with a boost controller but I seem to have managed it!
Anybody got any idea WTFIGO??
Cheers,
Ade