[MA70-3.0GT]

In all honesty I run a bailey dump valve & experience no problem on overrun, all that happens basically is that the airflow meter has registered so much air has gone in & when the BOV opens to atmosphere it loses a few litres, hence sending the engine slightly rich for the second or so that it's open.

All that's needed to fit is to remove the stock recirc. valve, plug the hole that leads to the turbo inlet (on the "accordion pipe") with the bung supplied with the BOV, clamping it with a hose clip of course, and fit the BOV to the other hose (from the "3000 pipe" on top of the motor.). Not forgetting of course to fit the small vac/boost pipe to the nipple too.

See what you think, if it affects the running badly chances are though theres something else amiss IMO as running my Bailey unit causes no more than a small puff of black unburnt fuel from the exhaust if shutting off from high boost. (that's only an observation made by a following car after pulling full bore from 30 to 100 & closing the throttle).