Adjustable boost with a supercharger ??
Turbo Mini Forums

While plotting & planning & collecting parts for my 'charged 1150, I've got to the bit with the dump valve, and this is where my sketchy knowledge is failing me...

I know I need a relief valve between the intercooler and the throttle body to prevent over pressuring, and that that is controlled by vacuum off the inlet manifold downstream of the butterfly.
If I'm right, I set the amount of pressure dumped by altering the amount of vacuum required to lift the valve.

The question is this:
Can I control that valve to dump pressure from in the car instead of clambering under the bonnet ?
If so, would it be possible to run on low boost for pootling around and then crank it up when required like with a turbo ?

Metric is for people who can't do fractions.

Any typical dump valve should work ok.

Why do you think it needs adjustment ? Once its set to open early enough, and not leak under boost.....its a fit and forget item.

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

Hi,
No you can't, as you'll have no vacuum to open the valve once you're on boost.
Cheers,
Gavin :)

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You could jus have a pressure relif with adjustible spring pressure.


But dont relly see the benifit, its just wasting power driving the blower too fast.

The thing with superchargers is thet the amount of air they pump (and hence the boost generated) is set by the pulley sizes.

So altering the boost by dumping the air is a massive waste of energy; unlike a turbo, where you alter the speed of the compressor to make more or less boost as required.

If you can't trust yourself to just drive a bit slower, the best thing you can do is have a switchable rev limiter.

Fastest 998 mini in the world? 13.05 1/4 mile 106mph

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

Hi,
Stevie .. He wants to use the BOV to control boost pressure by opening the BOV to vent it to atmosphere.
Cheers,
Gavin :)

VEMs Authorised Installer / Re-seller. K head kits now available!

WB/EGT gauges. Click here for customers write-up

Visit www.doyouneedabrain.co.uk

My Mini build diary

It is do-able. Many dont reccomend it, but quite a few have done it with decent results.

I almost considered it myself for a while.....then figured why the hell would I want to turn it down !!!!!!

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will