Razor2001

Hi all,

I am not thinking of getting one, just curious to know how they work.

Dawes: I know you can use this to adjust the boost. If you say 'dial' in 1.3 bar does it hit 1.3 bar in all gears and basically just sit there with no taper or ecu interferance. i.e. if you set it at 1.3 bar it will hold that till redline....if the answer is yes then these things must be very dangerous....one boost level for all gears and all rpms ???? seems nutso ?

Cheers,
Ray

john banks

There is some fuzziness in its control so that it doesn't reach the same boost in every gear, won't bore you with the reasons why, but often it is not far off. If the actuator is strong enough to avoid being blown open by the exhaust gas and the compressor will handle it then it will hold boost to the red line. You can influence the boost behaviour quite nicely by changing wastegate actuator tension relative to the setting on the Dawes, so you can have a beefy midrange and have it tapering at the top.

In practice a lot of turbo setups will not hold silly turbo and engine damaging boost to the redline. If they do so easily they are usually capable of this without excessive exhaust gas back pressure or charge temperatures.

If for example you put a Dawes on a VF23, 28, 29, TD04 or 05 or MD304 it will still taper fairly sensibly towards the redline. This is because these turbos have an actuator setup that tends to help them roll off naturally at the top. VF3x may be a different matter depending on the exhausts. TD05/06 20g is a bit of a creepy monster at the top with minimal turbine clip - work in progress.

Razor2001

Thanks John, appreciate the info

Cheers,
Ray