Supercharger bypass valve overide

[JNWorks]

Hi All,

I'm fairly new to the site, this being my first post, and would like to draw upon some of your impressive technical expertise if I may

I've been reading with interest the threads about the bypass valve for the supercharger. It got me thinking, is it possible to override the sc by manually controlling the bypass valve? It would be quite handy to drive my s works as though it's a regular 1.6 with the valve fixed open and at the touch of a button revert to normal operation Mad Max style with a view to having more reasonable fuel economy. I know Eaton claim the valve's only closed 5% of the time during normal driving, but I find this hard to believe given even very gentle driving only brings mpg in the high 20's.

My concern is that the reduced amount of air feeding the engine would cause a fuelling situation outside the ECU's adaptation range. I.e. it'd end up running rich or just going into limp mode. It'd be fairly easy to try by just tying the valve open, but I'd like to have some sort of idea about whether this is safe before I do. Any thoughts?

John

[Blusox]

I watch Mad Max 2 the other night too on TCM

[roland2003]

Hi, the fuelling will not cause any problem as the T map sensor responsible for measuing air pressure & temp is after the SC mounted on the inlet manifold. The bypass stays anything from fully open to almost closed until the throttle is at relativley wide opening. Amongst other things it gives a progressive throttle. If you were to strenghten the spring in its actuator it would close earlier, or weakening it it would close later. Its important that at ambient pressure there is enough spring preload to hold the butterfly shut still though. Weve played around with these quite a bit in the past.
Best Regards Roland GTT

[JNWorks]

Thanks for that.

When you say important that the butterfly can fully shut I assume you mean to be able to exploit full power? Only I'm thinking if I could have a facility to keep the butterfly open constantly then I'll be able to use the engine's higher rpm power at atmospheric pressure rather than running the sc at a lower rpm. This obviously would not be full power by a long way, but surely generating 100bhp at say 6500rpm, atmospheric is a lot more economical than doing so at a lower rpm with the sc partly on boost. Then when the mood takes me I release the valve back to its normal operation and full power's there for the taking

Cheers,

John

[JNWorks]

Well I tried it. All seemed fine up to about 4000 rpm, then the dash lit up like it was Christmas and limp mode ruled all. I assume it was because there was so little airflow going in it dropped outside the ECU map range. The emissions light's still on but I'm hoping that will right itself after a couple of drives (can anyone confirm this?) having read similar posts.

I'm sure it's possible to do a switch-able re-map to run with the valve fixed open and normally, but I think I'll just get a boost gauge instead and keep an eye on that for economic bimbling.

John

[roland2003]

..I thought it might....P1688 or P1689 is what you normally get .
Best Regards Roland GTT