Eaton M90 bypass valve

[350kmileford]

So I won an Eaton M90 on Ebay last week, it arrived today. It is in GREAT shape... as if it just came from the factory. I thin k I definitely got a deal. However, it did not come with an intake tube/bypass valve. I have searched around the next and haven't found anyone selling one.

Does anyone know of a substitute to the oem bypass valve that I could possible make? I believe they're vacuum referenced, so are they similar to a blowoff valve or (opposite) a wastegate? If there's no easy way to make one, has anyone seen a bypass valve for sale anywhere?

 

[Bort62]

I am using a toyota supra bypass valve.

You can get them pretty cheap online.

It is a BOV, same function.

Only needed if you are going blow through.

 

[350kmileford]

I would basically want a silent one, otherwise I would sound like a mockingbird going down the highway? I.e. it stays open longer, not just when the throttle is closed, as one turbo applications?

 

[Bort62]

I would basically want a silent one, otherwise I would sound like a mockingbird going down the highway? I.e. it stays open longer, not just when the throttle is closed, as one turbo applications?

The toyota valve is open whenever there is manifold vacuum. So cruising down the freeway would qualify.

To make it silent, you simply need to run the bypass line back into the air intake pre-supercharger.

 

[350kmileford]

So I would obviously mount it post-blower. So now for the confusing part.....on previous pictures, the bypass valve was mounted on the intake side of the supercharger....Am I just an idiot?

 

[Bort62]

So I would obviously mount it post-blower. So now for the confusing part.....on previous pictures, the bypass valve was mounted on the intake side of the supercharger....Am I just an idiot?

You mount it between the SC and Carb. The outlet of the valve can be run to the intake before the SC to re-circulate the bypassed air and cut down on the noise.

 

[350kmileford]

Will an engine make enough vacuum at cruising speeds?