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-   Performance Modifications for the NG900 / Old 9-3 (https://www.saablink.net/forum/forumdisplay.php?f=24)
-   -   Forge Piston Diverter Valve (https://www.saablink.net/forum/showthread.php?t=30319)

DViggen 06-23-2008 07:39 AM

Forge Piston Diverter Valve
 
I am thinking of ordering it from GenuineSaab - http://www.genuinesaab.com/catalog/p...roducts_id=463

Is anyone running one on a Viggen? Is it worth the $$? Does it change the sound of the engine when you let off the throttle in boost? Any feedback is appreciated....

Thanks,
-DViggen

GenuineSaab 06-23-2008 07:53 AM

Not really going to change the sound that much. If yours is dead go for it. Otherwise leave it till you kill the original.

DViggen 06-23-2008 08:14 AM

Any performance improvements?

stevehayes01 06-23-2008 08:41 AM

The only thing you will see is that it tends to hold boost better and looks way cooler under the hood.

I run a 6 series Forge and it was a good improvement but as Nick said if the stock Bosch is holding out then don't bother until it goes.

Baz 06-23-2008 09:23 AM

a lot of vw guys run the forge 007s in reverse. Supposedly it holds boost a little better.

Anyways, when you flip the intake ports you will get a metallic "pshwink" sound when you shift.

Ive been running mine that way for a year now and love it.

mcrowley 06-23-2008 10:55 AM

I run both the 007P on my 900 and the 006 on my 9000 that way. The boost doesn't push directly against the spring that way.

Baz 06-23-2008 12:03 PM

yep yep.
Forge doesnt say one way or another is better, but the general consensus is that running it 'reversed' is the way to go due to mcrowley's point about the spring

slspf2 06-23-2008 05:57 PM

Ya I ordered the thing over the weekend because my stock valve blew. I'm hoping the polished looks as good as I think it will...

slspf2 06-24-2008 10:13 PM

A bump on this thread because I just got my DV today... are the extra two springs merely replacements? And the extra two circular plates as well?

viggenkid 06-24-2008 10:36 PM

Quote:

Originally Posted by slspf2 (Post 464799)
A bump on this thread because I just got my DV today... are the extra two springs merely replacements? And the extra two circular plates as well?

the different springs have different spring rates for different boost pressure, you should be good with the yellow one.

slspf2 06-24-2008 10:47 PM

Ok cool, thanks. Just out of curiosity, when should I think about using a different spring? I will be at 20-22# next week.

viggenkid 06-24-2008 11:07 PM

well nick at GS still uses the yellow spring on his vig...so you shouldn't need to think about another spring. anything stiffer and i think you can start to damage the turbo.

DViggen 06-25-2008 05:32 AM

Are you sure? I think on a different forum he says that in a T7 car, they put in the green one and "forget" about it....

Hopefully he will chime in....

Quote:

Originally Posted by viggenkid (Post 464814)
well nick at GS still uses the yellow spring on his vig...so you shouldn't need to think about another spring. anything stiffer and i think you can start to damage the turbo.


Baz 06-25-2008 06:51 AM

Quote:

Originally Posted by DViggen (Post 464847)
Are you sure? I think on a different forum he says that in a T7 car, they put in the green one and "forget" about it....

Hopefully he will chime in....

Im not sure what he said, but when you go up to 20-22 psi i would recommend just staying with the yellow spring and just shimming it (with the included spacers)

GenuineSaab 06-25-2008 07:00 AM

Green spring.. :)

This is even what I run in my Viggen holding 30+ psi. ;)

Baz 06-25-2008 07:13 AM

Quote:

Originally Posted by GenuineSaab (Post 464874)
Green spring.. :)

This is even what I run in my Viggen holding 30+ psi. ;)

wow :shock:

lms 06-25-2008 09:08 AM

So I asked this before, but why does one buy a diverter valve with different springs? I understand the concept, but I have a viggen holding around 20-22 psi give or take and I have the hyperboost shorty which comes with one spring and it works great. Seems like a hassle getting one with all these springs/shims as there are many threads pertaining to what spring should one install. Then there are people like vigge who are running the stock bosch unit.

GenuineSaab 06-25-2008 09:15 AM

Nobody ever listens and thinks if they run a stiffer spring it will make more boost.. ;) It is not a problem, put the valve in and be done with it. If you want to tinker with it turn directions and that will make a different noise.

Saabeh 06-25-2008 12:30 PM

The one thing that I have never understood about running it backwards is that it is not only pushing up against a spring under boost. There is a vacuum line there supplying the exact pressure that the boost is. The reason why the spring is there is because the initial boost is not into the intake manifold yet, so the vacuum line is slower to respond.

I feel like running it backwards would be a negligible difference because of the fact there is spring tension plus equal pressures on both sides.

But at the same time, I can imagine high boost cars running backwards would be a better, safer method. Although my car is running 24psi, I have the lightest spring in the valve and it is not positioned backwards, I do not get any boost leaking from it.


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