Saabscene Saab Forum - Saab Technical Information Resource banner
1 - 12 of 12 Posts

·
Registered
Joined
·
224 Posts
Discussion Starter · #1 ·
Hi everybody. I am thinking of installing a (non-electronic)boost controller on my CS Carlsson. The Dawes costs £50 here in the UK, while on e-bay similar ones can be found for $20 or so. I believe it is a simple device and can see no reason the dawes one should be better, but I may be wrong. What are your experiences? Which one should I go for? Can someone tell me how they connect in a Saab?

Thanks

Harry
 

·
Registered
Joined
·
403 Posts
Harry,

Take a look back over the 9000 performance bbs, there's loads of info about the dawes device (some by me!)

Yes their is a LOT of differance between them ie dawes is a boost controler not a bleed valve.

Cheers

Damo
 

·
Registered
Joined
·
2,599 Posts
£50 in the UK? Does that mean that Dawes only use allow you to puy it from their offical importer. Last year I bought two from Dawes in America - they were $35 or £23ish. Absolutely the cheapest bit of performance mod ever - just be careful - its easy to push things two far!
 

·
Registered
Joined
·
776 Posts
For the technically uneducated like me, can someone please tell me about the Dawes boost valve and where it fits into the scheme of things along with an Abbott Dump Valve and a bleed valve in the wastegate pipe, both of which I already have.
Is this something different to both, should I get one, where does it go etc..

I will also check out the Performance BBS for more info'.

Thankyou,
Andy
 

·
Registered
Joined
·
403 Posts
Andy

It seems that all the informative stuff that was on the performance bbs has gone, prior to the upgrade of the bbs.

I'm putting together a little web site with all this sort of stuff in it.
I'm hoping to have it ready soon(ish).

As to your main question the Dawes device works instead of a bleed valve and can take it's inputs from either the manifold (intake) or direct from the nipple on the turbo.
The easiest way is from the spare nipple on the intake manifold on 2.3 CSE's that is.

You run a pipe from there to the top of the DD and then run a pipe from the bottom of the DD to the wastegate nipple.

What is does differently to a bleed valve is:

A bleed valve just (bleeds) vacuum off from the apc solenoid so that your are fooling the apc into thinking its running it's pre-defined boost level, when actually your running slightly more.

But the boost control is still coming from the apc solenoid and is prone to spiking (over boosting) and the spin up (spooling) of the turbo is also controlled from apc (which tends to induce lag)

Where as the Dawes Device bypasses the apc solenoid altogether, and sets the boost pressure to a pre defined level that you set.
Why this is better is rather than the boost level fluctuating with the apc control, the boost stays the same.
It does this with a pressure spring and a ball bearing valve.
This does not bleed vacuum off but instead it holds it until the max pre-defined pressure is reached then activates the wastegate.

The benefits of this over a bleed valve is that the spooling of the turbo is much faster because it only allows the wastegate to close when max boost pressure is reached, this reduces lag to a minimum.

This coupled with a good dump valve will help reduce lag and increase boost between gear changes.

It also eliminates boost tail off on hard-sustained acceleration.

Basically in my opinion ever red-blooded turbo nutter should have one!

Damo
 

·
Registered
Joined
·
11,343 Posts
It seems that all the informative stuff that was on the performance bbs has gone, prior to the upgrade of the bbs.[/b]
Have you done a search? All of the previous threads bar about ten or so on the day of upgrade were retained. You are now able to search the archives for posts made before this board was upgraded.

Make sure you post the URL of your website here for others to see
 

·
Registered
Joined
·
403 Posts
/john,

I realised after posting that message that the reason why there were no referances to the above subject on the performance bbs i cos it didn't exists And all post were on the 9000 bbs - ohhps.

I will put link to my (small) website soon as it's done.

BTW the new ELK web site looks really good, only complaint - it don't work with netscape 4.79!!
I hate using MS internet destroyer

Damo
 

·
Registered
Joined
·
1,261 Posts
Steve, if it helps, the 900 LPT is basically the same as the full blown T16 but without an intercooler or APC. Therefore if you fit an intercooler (cheap second hand) and a bleed valve, set at FPT pressure you will have T16 performance for not a lot of wedge (and no APC protection admittedly)

Things are a little different on the 9000 since I think the 9000 LPT was only available during the Trionic era. However, since the boost valve bypasses the Trionic turbo functions you should get much the same result. I believe later 9000 LPTs already had an intercooler fitted.
 
1 - 12 of 12 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top