ZD30 Boost

[Rumcajs]

Gotcha, RUMCAJS

Once i block the EGR i will need the dawes to control the boost spikes ?

Taking EGR out will result in higher boost pressure than normal especially in your case with free flowing 3" exhaust so YES, you'll need Dawes valve to control maximum boost and needle valve to control spool up rate (instead of ECU).

You'll be wondering why you didn't do it earlier.
It can take a bit of fiddling to get it right/be happy with but its worth the effort.
Don't forget the Provent catch can/oil separator.
Cheers

[Steve69]

Thanks RUMCAJS

So once i have the exhaust gases under control the dawes valve will be used to control the max boost ?

[Steve69]

RUMCAJS

What model Provent do you used the 200 or 400 model ?

[Rumcajs]

I use Provent 200, (Provent 400 is huge and too expensive, it is designed for large truck engines). IMHO even 200 series is perhaps bigger than needed but its hard to source others indeed P150 would be more than suitable.
Dawes valve is used to limit max boost.
Cheers

[mudski]

Heres a pic for ya mate of the vac hose setup. IF your running a needle valve to that is. If not its a little different but we can help.
Fitting Diagram.jpg

[Steve69]

Thanks MUDSKI

[threedogs]

Get small stainless steel washers to fit in the dawes valve. one at a time insert and try.
keep going till it goes into limp or over boost, then remove last washer,
you now have max boost for your engine. might need 6mm of washers IMO

The Dawes let YOU control the Boost not the ECU. along with Blocking EGR your exhaust gases are spinning up the Turbo
You'll get your head around it in no time, you just need to know what bits do what.

[mudski]

Have previously read some of chaz's threads and still a bit confused of the boost spike.
The current highest boost i have recorded is 14 psi. ( with or without the dawes valve connected)

Firstly boost spike is when you put your foot into it and your boost will suddenly go up to say for example 18psi and then quickly settle at the select level.
As for your second sentence. This concerns me a little. With or without the dawes you don't see anything above 14psi? Thats definitely not right. Without the dawes you should see in excess of 20 psi at times. Particularly when cruising. I would be checking the entire intake system for boost leaks. It is very rare, and I mean rare, to need to stretch the Dawes spring or put spacer washers in it. Doing this in my opinion isn't fixing the problem.
I'd be checking for a boost leak. Take a close look at the intercooler. Check for wet oily spots on top of the motor, under the IC. Check for oil deposits where the IC tanks are joined to the core too.

• As for spec wise, Most Patrols can get around 15-16psi before limp mode kicks in.
• Your EGT's will rise quickly, although with a sufficient air cooling system you want the temps to drop quickly also.
• I have yet to see anything in excess of 400c on my Patrol, even towing on a hot day and flogging the bejesus out of her.
• Boost level at 100k's should be around the 10psi mark. Anything lower and the EGT's will crawl up.

[MEGOMONSTER]

I max out at 15psi but when climbing Kosziosko with loaded boat in, I was at 550-650 degrees for a fairly long time but I never pushed it past that and always backed off a little. I wasn't driving by speed but by EGT gauge.

[mudski]

I max out at 15psi but when climbing Kosziosko with loaded boat in, I was at 550-650 degrees for a fairly long time but I never pushed it past that and always backed off a little. I wasn't driving by speed but by EGT gauge.

Hehe. I do that too.