stevo1970

iTrader: (1)

I know this has probably been done to death but please bear with me.

I'm about to fit a Dawes to my MY00 classic. I am ok with plumbing the thing between the turbo outlet and the wastegate actuator but as standard there is a T piece in this line. This other pipe goes to what looks like a Desno solenoid mounted on the drivers side suspension turret. With the Dawes fitted what do I do with the T'd line?

Thanks

borat52

I have a similar question too, is it better to fit this in parallel with the boost solenoid or to bypass the boost solenoid alltogether?

nickwrxstiV2

You bypass the boost solenoid altogether! I've just fitted one! Fit it between the actuator and the turbo elbow and then blank off the left over pipes with bolts. Really easy job!

Nick

borat52

I was going to do that, but for me the dawes was just to cap boost not actually set it. Then I thought if the boost solenoid isn't setting boost then how does the ecu know what boost is running and how to fuel accordingly for it? ie its expecting a certain amount of boost to be set via the solenoid but now the dawes device is giving a different level of boost.

My main problem is I don't know how the solenoid works in relation to the ecu and boost setting, I'm perfectly happy for the boost to be set solely from the dawes device but is it safe?

by the way nick, I remember that you organised the esl GB - are you using the dawes to up the boost on yours? If so are you still running your origional esl map or have you changed it? What boost are you currently running?

stevo1970

iTrader: (1)

Thanks Nick, a clear and concise reply !!

Stephen

nickyrhodes

Hi, I think the ecu reads the boost from the MAP sensor and tweaks the boost solenoid accordingly to adjust the boost. So long as the map sensor is still sensing pressure you should be free to bypass the oem boost solenoid. Doing mine in a few weeks so will see lol

nickwrxstiV2

Hi,

Yeah I organised the first GB of the ESL chips. Now the cold weather has set in mine started to overboost and spike. I put the Dawes in to cap the boost to 1.1bar. I'm still using my ESL chip as the boost comes in earlier than the stock ECU settings!

Nick

borat52

nickyrhodes
OK I understand this, and now it makes sense that this should be safe.

However what I am still wondering is that as the ECU uses the boost solenoid to control boost if left standard, and as nick correctly points out using a remapped ecu boost is brought in earlier in the rev range (presumably using the boost solenoid) then what happens when you bypass the oem solenoid alltogether?

As I understand it the dawes device is just an adjustable valve which vents excess pressure into the atmosphere once the preset level of boost has been achieved. If this is correct then surely this would bring boost in faster than normal and thus need adjusted fueling to cope.

I'm not professing to know a single thing about this by the way, I'm just trying to make sense of how the boost solenoid controls boost and how this would differ on a dawes. I have read that using a couple of T-pieces you can hook the dawes up in parrallel with the boost solenoid, and that way you have the boost solenoid behaving as normal and the dawes acts as a boost cut if the boost spikes above what the dawes has been set to. What exactly does the boost solenoid do, and how does a new map bring boost in earlier?

nickyrhodes

Hi,

I dont know a massive amount either!! From what i can gather i would say that you are best using the dawes as a cap (a search on here should give you instructions on parallel running). I'm only planning on using a dawes because i can't afford to get the apexi ecu at the min, if i could i would definately leave the ecu/remap to do all the boost control...

However, as far as i understand from reading the posts on the dawes device. The boost is brought in as early as the turbo allows due to it not bleeding any air until the target boost pressure... So maybe you would benefit from using a dawes solely, as long as you dont set it too high to cause detonation...

nickwrxstiV2

Guys, the Dawes device is not a bleed valve, ie. it doesnt bleed excess boost off in to the atmosphere. All it is, is a ball bearing loaded by a spring. The turbo elbow then sends a boost signal to the Dawes via a hose. The ball bearing is then pushed away from it's 'seat' and loaded by the spring. The boost then moves the ball bearing away and the air rushes around the sides of the ball bearing. When the set boost (adjusted by making Dawes longer or shorter) is achieved the wastegate actuator opens to allow maximum set boost to be kept!

A bit long I know but they are the principles of a Dawes, very simple really!

nickyrhodes

ah ha! Thanks for the info, i did know it worked different to a bleed valve and was better. Good job cos i ordered one yesterday lol!!

Cheers

New_scooby_04

iTrader: (4)

If you're increasing the boost using a dawes, I'd strongly suggesting getting the car checked over by someone with a wideband AFR and Det cans to make sure it's running safely.

It's cheaper than and engine rebuild!

Ns04

evander

iTrader: (1)

Fitting the Dawes on its own is fine, just dont get to carried away when setting the boost pressure. Infact fit it with the screw wound right out and take it to a tuner and get them to set max boost for you so theres no det. Im unsure of the scoobys ecu abilities to compensate and adjust the map for the boost coming in earlier so do an ecu reset and this will take care of the boost coming in earlier. But take it easy on the throttle on the first tank of gas so the ecu can do its schooling.