H15 FSC

these any good ,i know some of the evo guys use them,
im running my actuator direct to the compressor housing using pre-load to set the boost,
on my focus RS, is this the rigth way to be adjusting the boost or should i try a mbc

Red16

its basically a bleed valve iirc

BigErn

IIRC a bleed valve bleeds to atmosphere. Dawes is just like a restrictor valve in between actuator and compressor, you can open/close it to adjust boost it, doesnt actually bleed off. Thats my understanding anyway, but Ive not had much to do with either so I could be wrong.

ECU Monitor Enthusiast

iTrader: (1)

Crude device that should be thrown in the bin.

Use a proper boost controller and save your engine from going bang (if its set up right)

foreigneRS

not that crude - more sophisticated than a bleed valve as they hold a pressure regardless of ambient conditions.

obviously the ecu has no control though, so if you have a scenario where something has gone wrong, perhaps a sensor failure, then the ecu cannot reduce boost to protect the engine from potential damage

also, you cannot create a useful midrange torque spike with something like a dawes device

H15 FSC

im sort of doing that now as the pre- load does it, but i only get 15psi in 1,2,3rd then 19psi 4th and 21 in 5th but in 5th it goes to 15 psi stragth away then slowly go's up tp 21 psi with the revs ???

percybigun

i had a dawes device on my old mondeo 1.8TD. it wasnt really an engine worth spending Ł250 on a fancy electronic one, and it had no ECU anyway.

i originally had a normal bleed valve on it and it was OK, but i was recommended to use a dawes device instead because they are good on diesels, and it was better than the old bleed valve in that it didnt spike so bad.

bleed valves are crude, but they do work!

Chip

iTrader: (3)

Dawes device's are great, and have a resolution that most electronic controllers can only dream of.

Perfectly valid way of controlling your boost IMHO

_SpeedX_

iTrader: (1)

had 1 on my 200sx and on my rover turbo and they worked fine!

H15 FSC

got to be better than the pre-load way

foreigneRS

absolutely

Dave Henshall

i had one on my evo 6 with the ralliart sport ecu, and worked quite nicely,

no there wasn't any mid range boost spike, but it did maintain boost well right through the rev range .

Neil S

iTrader: (1)

What he said

I ran one for 3 years on my car, very pleased with it

Neil.

jameswrx

Yep, dawes is good... better than most electronic boost controllers. Mine just flies up to it's target boost with no spiking, which is more than I can say for a lot of EBC's I've used.

As others have stated they are not a bleed valve (which is crap) they are a ball and spring design and don't bleed off air. Bleed valves give very poor spool in comparrison.

Neil S

iTrader: (1)

They do actually bleed off air - there is a small hole in the wastegate end if memory serves

Chip

iTrader: (3)

Thats purely to allow them to depressurise once they have bene trigger to open the actuator, its a TINY amount of air, and its not done until after the wastegate opens, as opposed to leak like mad even before it is like on a bleed valve.

So its not really "bleeding off" air.

They are a bleed ON device, like air injectors if you want to think of them in terms other than just as a dawes device.