My Sierra Cossie has 380 hp setup (MSD chip etc) and I have been using the Amal valve, but the boost stability has not been good. It goes to 32 psi in 3rd, 4th and 5th and drops to 25 to 27 psi after few sec. Which is normal for t34.55 turbine, but I want to get more stability on the boost, sometimes I only get 25 psi sometimes I get 32 psi....?
I did try a new Hallman Pro manual boost controller just to see if the boost would be more stable, but now I only get 1,7 bar max. I did replace the fitting on the turbine to a smaller one (was included with the Hallman Pro).
It is very stable on 27 psi which is what I was looking for, but I never reached the 32 psi I wanted, and I really can feel I am not getting all the power it can provide.

Can anyone help me out here, why can I not get my 32 psi (2,2 bar) on the Boost Controller, when I can easily get this on the Amal valve?
Should I reduce the output fitting from the Hallman? Should I get a stronger spring for it? Or?

 

some controlers wont alow that much boost, i choose the duel sbc spec r as it can control up to 40 psi

 

Yes that is what I was afraid of - this type Hallman Pro can perhaps not tackle 32 psi? I simply dont know.....

 

if you can get the boost with the amal then its got to be your controller

 

Absolutely true, I just wanted to check if anyone had tried this Hallman PRO type.
Thanks mate.

 

never herd of it to be honest mate

 

just googled it mate looks like a bleed valve

 

Hallman manual Boost Controller is very common in performance cars. I just talked to some guys in the tuning business, and they are using this product for 4 cyl turbo cars like Subaro, Evo and MMC Eclipse, all running under 10 sec and over 140 miles/hrs on the 1/4 mile
The controller I have now, is not mounted with a stronger spring (used for 30+ psi), so now we have to get one and try again
The main difference when driving with this manual controller, was this very stable boost from this small turbine, which is quite a big difference from the ECU controlled Amal valve.

But still, it would be very useful to learn from those of you that have experience with the Hallman Boost Controller in a YB engine....