Understanding Dump Vales and springs

[Skorchio]

I know/hope i have got something wrong so I'm looking to be put straight, this is not a "YOU DON'T NEED TO CHANGE YOUR DV SPRING" thread.

A 007p has 3 pipe connections - Top Bottom and right (ref below pic).

Top goes to the vac line, right goes post turbo and bottom goes pre turbo (according to forge).

From how the 007p looks (iv never held one in my hand and inspected it (so correct me if I'm wrong)) i guess the piston moves up and down, as in, if you stuck your finger in the bottom hole you could push the piston up.

So now my first question. If you mount this the way Forge say to it don't matter how much boost you run it never going to be able to move the piston as its pushing against the side of it? So whats the need for a stronger spring? Lets say you mount it the other way round (like the splitter is mounted), now, when your on boost the boost is pushing against the piston trying to move it up. So you think more boost stronger spring? Right? Well.. I thought about this then thought the top of the DV is getting the same amount of boost pressure pushing on the top of the piston as on the bottom, so again.. if this is the case why do you need a stronger spring. The only reason i can think of is when you come off boost and the top received vac the piston (because of the excessive boost and the vac) is slammed open (possible causing damage to the DV?). But this would not account for why you need to change your spring on the 007p if you mount it the way Forge say.

Also why the Splitter has an adjustable spring, if its receiving the same boost either side of the piston, as long as the spring has a bit of push init, why does it leak boost when not ratcheted (is that a word?) up to suite the engine?

If someone can shed some light on what i don't understand that would be great

I hope that all makes sense

Thanks
Nick

 

[mrwookie]

The spring is not so much about keeping it closed but how quickly it shuts after it is opened to save loosing boost pressure.

 

[Skorchio]

Then why would you not have a stronger spring in it all the time?

 

[mrwookie]

If you think about it if there is lots of pressure in the system to save losing it when a controlled leak occurs, DV, you want to get it shut up as soon as you can to avoid losing that pressure. The more pressure the quicker it will escape. Plus you can fit a 007p in reverse don't forget....

 

[Skorchio]

Yeh i know, in reverse its placed like a conventioan valve, but in the way forge say to mount it its not, the pressure is pushing againt the side of the piston no the bottom. But yeh i understand where ur commig from, it reduces lag?

 

[mrwookie]

Yea saves have to spool all that pressure again. Plus forge do say you can mount it either way but if you mount it in reverse it makes a noise like a strangled budgie!!

 

[Skorchio]

I like that sound Thanks mate i guess that clears it up! The spring only comes in to it when it dumps!

 

[mrwookie]

Nick if you want to try any other springs I've now got a wide collection, , so let me know and I can bring them along to the next bucks meet

 

[Skorchio]

Thanks mate, iv got my 007p comming either tomorro or friday, they have lobbed in a yellow spring which is nice of them!! Ill try them both out, but i think ill be best off running the yellow!!

 

[mrwookie]

Ok see what you reckon but i'm running a 007p with DV relocation which you have, if memory serves me correctly, and I found green better. Personnel choice at the end of the day.

 

[Skorchio]

Can you explain how they "feel" differnt? You can see mine in my Sig Pic

 

[mrwookie]

Yellow makes the car feel more responsive as shuts quicker than say the green and therefore doesn't lose as much pressure.

 

[Avant4me]

Its a balance thing. Top line has to switch from being under pressure, into a vacuum when you let off. If you have a strong spring in there and are not running increased boost, then the vacuum has to work harder to open the valve which could make the whole system slower to purge.

If you are running the system in reverse then the stronger springs are there to keep the piston shut in the face of higher boost levels. Forge do state that you should not need a different spring for standard turbo and maps as it is able to cope with these boost levels.

 

[traumapat]

also it can effect turbo life on ihi turbos. the stronger spring shuts harder but also produces back pressure that can push against the turbos spindle.

ive used a yellow on a stage 2 with good results, dosnt effect KO turbos in the same way.

 

[Skorchio]

Its a balance thing. Top line is not under pressure, its a vacuum. If you have a strong spring in there and are not running increased boost, then the vacuum has to work harder to open the valve which could make the whole system slower to purge.

If you are running the system in reverse then the stronger springs are there to keep the piston shut in the face of higher boost levels. Forge do state that you should not need a different spring for standard turbo and maps as it is able to cope with these boost levels.

Sorry but thats wrong, there is pressure in the top line, so all of what you have said in invalid. It turns to vac only when you let off the throttle and the TB closes.

Can you edit that so people don't get conflicting information please?

 

[Skorchio]

but also produces back pressure that can push against the turbos spindle.

ive used a yellow on a stage 2 with good results, dosnt effect KO turbos in the same way.

Can you elaborate on the back pressure part?

How does it differ with KO4's?

 

[mrwookie]

Sorry but thats wrong, there is pressure in the top line, so all of what you have said in invalid. It turns to vac only when you let off the throttle and the TB closes.

Can you edit that so people don't get conflicting information please?

mashoo810 as Skorchio has said there is pressure on that feed as you can splice into it for a Boost Gauge otherwise if only vac then thats all the gauge would show.

 

[Skorchio]

Also if you follow where the feed comes from, it comes from the inlet manifold, up to the 294 then on to the DV

 

[traumapat]

Can you elaborate on the back pressure part?

How does it differ with KO4's?

sadly i`m passing on comments made at jabba, so excuse my limited knowledge. if the dv closes slowly its less of a shock pressure wise than if it was to slam shut. with IHI that shock can jolt the spindle and cause damage.
a member on here running jabba mapped IHI mistakenly fitted a 007 with the wrong spring and it killed the turbo. but i think it may have been blue or stronger.
this may be part of mikes mapping style but he wouldnt do my conversion until i replaced my yellow forge spring with the green one.

never heard of it being an issue with the KO turbos. one member runs blue and hasnt had issues but i think yellows enough.

 

[Skorchio]

Ah that makes scene. Thanks for the information