What By pass valve to get?

[mgerst1]

Are you basing that off of fact or an assumption? 3rd gen Supras, 93-95 Imprezzas, 4th Gen Supras all came with 19mm valves and none suffer from "turkey" neither with the factory valve nor with our upgraded units. I've personally run the OEM 19mm valve on a TT Supra at 22psi and over 400 wheel horsepower so I'm not convinced that 19mm is too small.

There may be something unique with the MSP that going to the larger size corrects but I would be curious to see if it has more to do with running a new reference line or just ditching the diaphragm valve. Or both.

It worked for me.

 

[patty AT forge]

I assume 19mm is the size of the stock MSP valve and Forge's direct replacement piece?

Yes that is correct.

 

[patty AT forge]

It worked for me.

Yes. But if you make 3 changes at once you can't be sure which one or what combination actually affected the change.

I'd be willing to send out a 19mm piston valve to someone if they can test this for me.

 

[Viralphrame]

Yes. But if you make 3 changes at once you can't be sure which one or what combination actually affected the change.

I'd be willing to send out a 19mm piston valve to someone if they can test this for me.

What intake/hardpipe setup are you looking to test this on? My setup is fully stock but I would be willing to do this for you. The only difference from the factory setup is that I am running a dedicated vacuum line for my stock BPV from the brake booster vacuum hose.

I can understand if you were wanting someone with a tubular aluminum-walled intake to test this since the turkey isn't super noticeable with the stock airbox.

 

[patty AT forge]

What intake/hardpipe setup are you looking to test this on? My setup is fully stock but I would be willing to do this for you. The only difference from the factory setup is that I am running a dedicated vacuum line for my stock BPV from the brake booster vacuum hose.

I can understand if you were wanting someone with a tubular aluminum-walled intake to test this since the turkey isn't super noticeable with the stock airbox.

How did running the dedicated line effect the sound? If at all.

 

[Viralphrame]

How did running the dedicated line effect the sound? If at all.

If anything, the sound is a little softer. It wasn't very noticeable to begin with due to the plastic pipes and stock airbox, though.