Custom stage 2 and forge spring choice

[J Eyo]

This has been done to death but I thought this may be a definitive a "stay away from" the yellow spring post. So, interesting, I switched out my 008 spring from green to yellow, running 23psi @ stage2 and the yellow completely destroyed my boost. On green it was ballistic, kicking in around 2000rpm. (rounded out a screw so couldn't change it back, will tackl that tomorrow) Going to try green and one shim as at freeway speed partial throttle I can hear it vent slightly. The result from the yellow spring was not what I expected, it really destroyed my boost below about 4000rpm then it seemed to come on ok but not hard. Dump and induction sound is severely more quiet with yellow. So definitely definitely if you are running the 008 with the revised piston, just green and only green if you want your stage 2 to be bat **** crazy on boost.

 

[<tuffty/>]

Yes... I have mentioned this many times before

I believe I have also mentioned this in the diverter valve threads in the FAQs

<tuffty/>

 

[badger5]

This has been done to death but I thought this may be a definitive a "stay away from" the yellow spring post. So, interesting, I switched out my 008 spring from green to yellow, running 23psi @ stage2 and the yellow completely destroyed my boost. On green it was ballistic, kicking in around 2000rpm. (rounded out a screw so couldn't change it back, will tackl that tomorrow) Going to try green and one shim as at freeway speed partial throttle I can hear it vent slightly. The result from the yellow spring was not what I expected, it really destroyed my boost below about 4000rpm then it seemed to come on ok but not hard. Dump and induction sound is severely more quiet with yellow. So definitely definitely if you are running the 008 with the revised piston, just green and only green if you want your stage 2 to be bat **** crazy on boost.

DV springs and boost onset & level are irrelevant.

you make conclusions from the wrong symptoms..
If DV is shut, how can it effect boost onset? think about it.

More likely it was sticking before hand and the act of opening it up to change things it then freed up and started to seal properly.

 

[J Eyo]

I don't think so, its been heavily greased and was performing perfectly before I opened it up, the act of opening it up and changing spring is what made it worse, not the other way around? How is this explained? The yellow spring definitely destroyed my boost, what other way does this effect spool. By the actual sound it was producing it wasn't opening and dumping at any point properly, would the MAP sensor pull timing/boost since its reading the remaining pressure in the system that wasn't there with the very easily releasing green?

 

[<tuffty/>]

you would lose boost/be laggy if the valve is stuck open... have seen this more than a few times and more recently on a big turbo/power build at Bills where a super size valve would stick open allowing boost to flow straight back into the TIP... ironically changed that from a red spring to a green with a shim and so far its been fine since... it was sticking... this is most likely whats happening with yours too... the lighter spring just seems to work better... I have a theory but its not easy to explain in words in a post..

If the valve isn't closing properly you will lose boost and spool... its that simple...

<tuffty/>

 

[badger5]

I don't think so, its been heavily greased and was performing perfectly before I opened it up, the act of opening it up and changing spring is what made it worse, not the other way around? How is this explained? The yellow spring definitely destroyed my boost, what other way does this effect spool. By the actual sound it was producing it wasn't opening and dumping at any point properly, would the MAP sensor pull timing/boost since its reading the remaining pressure in the system that wasn't there with the very easily releasing green?

Springs wont change boost onset.. think about it! Barking up the wrong tree fella

DV not sealing will however... obviously.. as open DV is a leak!

map sensor wont do anything.. its a map sensor.. just feeds boost info to ecu. In closed loop boost control the Requested and Target boost will try to be achieved, with and without leaks... Too big a leak and turbo not able to make up for the leak.

Springs, would not effect a closed DV.. let alone a softer spring working "better" as you say. Remember its Boost + Spring holding it shut presuming its fitted the correct way round..

 

[J Eyo]

So confused, changed back to yellow, lubed it up, bam, no boost again! What is doing this???? back to green, and again, hard boost.....wtf!! Badger 5, of course what you say makes sense, I've always thought this was the case....but in practice....the yellow is completely destroying my boost....im so confused

 

[<tuffty/>]

I believe the stiffer spring is causing the piston to pitch slightly while its open under vacuum as its not going to be open as much as it would with a softer spring.. there are a couple of o-rings in the valve an I suspect its sitting at just the right height under vacuum that when the valve becomes pressurised its enough to make it shut unevenly and cause enough of a leak to cause the symptoms you describe...

This is similar to what happened to a customers big turbo car at Bills which is now running a green spring and shim in the Forge supersize valve it has... the shim in this case makes the piston chamber volume smaller making it more reactive (less volume so less 'springyness' in the air)

Stick to the green as you do not need a hefty spring to shut any valve like this... its a return spring... boost in the top closes it, equalised pressure both sides of the piston keeps it shut... unless you are daft enough to fit the valve the wrong way of course

<tuffty/>

 

[<tuffty/>]

...I would also say the 008 probably doesn't need a shim as the piston is quite small as it is... super size needs one regardless as there is no preload on the piston with just a spring in on all valves I have ever had dealings with

<tuffty/>

 

[J Eyo]

No no definitely sitting the right way, don't want boost reacting against the bottom of the spring! Very interesting read, I may pop a shim in there to decrease volume a little (?) all in all extremely happy with my tune. A quick question since both of you guys are in here, I'm running a 3" turbo back (catless dp) i've got a mid resonator and another at the rear, it flows great, but its quite loud. If i take out the rear resonator and put a muffler in its place, how much flow restriction does this create? (especially with the tune) It will be a smallish back box as I want to keep weight down but will I be making any performance sacrifices?

 

[<tuffty/>]

If I understand your terminology correctly a resonator is a straight through box and a muffler is a chambered box of some description?...

Miltek back boxes for the S3 are chambered... these are good to mid 300's hp wise realistically... if its a decent enough design you should be ok but straight through boxes of decent design aren't loud... I have 3 straight through boxes on mine... not boomy or loud

<tuffty/>

 

[badger5]

So confused, changed back to yellow, lubed it up, bam, no boost again! What is doing this???? back to green, and again, hard boost.....wtf!! Badger 5, of course what you say makes sense, I've always thought this was the case....but in practice....the yellow is completely destroying my boost....im so confused

somethings sticking