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Discussion Starter · #1 ·
Cannot get this damn thing to work..
When I set it so that I get decent boost ,damn thing spikes
when I set it so it doesn't spike ...Boost is only 1 bar...
On my bleed valve I could set it at 1.3-1.4 bar and it would be on the spike threshold..
tried taking boost pressure directly from turbo..worse spiking !
What am I doing wrong?
 

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Ive not had ne problems with mine.
although i did get the race version which is more responsive.

Have you tried running it off the intake manifod nipple ?
May be your wastegate diaphram is too weak to hold it constant?

You could e mail darren dawes in the usa - I found him very helpfull when I was getting technical info on the D device. Darren Dawes <[email protected]>

Ill try and have a think on it - see if I can come up with an explaination.

Damo
 

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Ylee,

I've just bought the race version of the Dawes and will try fitting it shortly- I'll let you know how I get on. Basically my problem is that running a 12psi T2 actuator with a bleed valve, I was happily peaking about 1.55 bar then dropping back to a sustained 1.2ish. i.e. kick you in the back acceleration.

What happened next was I fiited the Abbott intercooler and started running into big time overboost. Abbott advised reducing the preload on the actuator to a minimum which I did but still have problems. So I'm going to try the Dawes to see if it helps. I've also got a manual boost control valve to try. Basically I'm reluctant to fit either of the above because they both remove APC totally whereas I'm still having some now.

Mark
 

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Discussion Starter · #6 ·
Took the device apart ...
it is just a spring and a ball bearing !!
the pressure acts on the ball bearing pushes against the spring until the pressure overcomes the spring and it opens..simple
tried putting some air pressure from a foot pump and it opens as required
There is aalso a small hole " downwind " of the device .I guess this is for pressure release after the device has shut off...
My only thinking is there seems to be an airflow related issue ie there is not enough airflow to the actuator to open the wastegate quickly enough..so the spike has occurred before the boost has decayed..
One thing I have noticed is the cut off is a lot more gentle it is more a hiccup rather than a slam
so what to do ...
my thoughts are to try and make a high airflow design is change all the narrow bore's for larger bore ..especially the last elbow.

this will be available (shortly ) as the ylee dawes device pat pend...
 

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ylee coyote,

I know this is a daft question - but you have blocked off the pipe from the apc solenoid ?

Where exactly are you taking the vacuum/pressure from?

You could try taking it from the Y splitter at the back of the engine bay/bulkhead, this comes off the manifold and splits to the dump valve & boost gauge (I assume as it goes into dashboard area).
You may for some reason have a differing vacuum from separate sources?

Damian
 

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Discussion Starter · #8 ·
sorted...it was a flow sort of a thing
I put a bigger fitment on the upstream part.. this being a much better fit to the hosing
big cable tie to keep the hose on and bingo..no spiking ..set at 1.4 bar and thats as far as it goes..
My thought is I was losing pressure because of the mismatch in sizes..there is 20 psi on this hose !!
wot a happy man am I
 

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Congrats Ylee.

I'm going to *try* to find the best set up for mine, but probably won't do it all before the weekend. What I have to play with is:

12psi actuator
bleed valve
Abbott manual boost control valve
Dawes device (racing version)

Presently I'm running the actuator on minimum preload and bleeding the feed to it. She's no slouch, but I'm going to try to aim for more consistent performance. If possible I want to reduce the tendency for initial spiking whilst increasing the sustained boost. The spiking has been precipitated by the fitting of the Abbott intercooler which has much lower resistance. Now this in itself is no bad thing because even though I've turned the bleed down to overcome the spiking, the top end performance is definitely better. What I'm looking to restore is the total animal factor between about 3000-4500rpm.

Options to try inlcude:
1. Close bleed valve & increase preload
2. Use manual boost control only
3. Use Dawes device only
4. 2 or 3 above with some bleed
5. Bleed a *smidge* off the MAP to cure spiking

All the above have their pros & cons and I'd be grateful for anyone's thoughts/experience. I have to say that if possible I would like to retain some APC functionality because it's good protection. Options 2,3&4 clearly remove that; the others do retain some control.

The easiest to try is bleeding a smidge off the MAP sensor. I suspect it may only need less than 0.1 bar to keep things happy.

I believe the best solution is a combination of bleed valve/actuator that stays within the "safe" envelope of an unbled MAP sensor.

I'll let you know how I get on...

Mark
 
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