Dawes Device

[jon dossey]

Another advantage I see here, is that it will adjust the wastegate cracking
point.  Normally, if the wastegate is set at, say, 10psi, it may begin
opening as early as 6 or 7 psi (lets say, for the sake of discussion, those
numbers are dependant on plenty of other factors) and bleed off *some* boost
until the wastegate fully opens, totally bypassing the turbine.  In theory,
this would allow the turbo to spool up faster, because it wouldn't see *ANY*
boost until it popped the FDMBC.

.jon
93 SER + n2o

>Ummm...  I'm pretty sure that the operation you are describing is that of
>the Dawes Device.  Doesn't it vent off some of the pressure, therefore
>creating a pressure drop?  If your running at 10psi, your wastegate
>actuator
>would see 6 psi, because your bleeding off 4 psi of pressure.

>The FDMBC is just a like a blow off/bypass valve that is inline with the
>actuator.  At a certain pressure, it opens.

>That's a good point about the pressure build up due to the FDMBC.  I've
>never heard anyone mention that before, and I didn't think of that myself.