Best way to plumb a WG

[zstroken]

Curious question: Why use drive pressure at all? I realize that I have only set two of these up on my truck but I have yet to use drive pressure and have yet to have an issue, boost seems to work just fine.

Educate me!

Jim

Jim I am thinking about trying boost to the top, the only bad thing about this is IIRC the spring in the gate pops at 30psi. So as long as during spoolup you don't exceed that then you will be ok.

So theoretically if you set regulated boost at say 30 psi to the top, then 30 psi on the spring assuming the valve diamter is the same as the top of the piston that would work.


2.6" is the top piston diameter and the valve face is 1.96" so it would require a little less than 30 psi on the top to pop the gate open at 60 psi of drive. Another thing that could be put in is a flow control(boost elbow), that might help regulate how fast and slow the gate will open.

 

[seeker1056]

hmmm - it was my understanding that regulated boost plus spring pressure is what keeps the valve closed,
So if I want 60 psi regulated boost; then I use a 15 lb spring, plus say 45 psi regulated boost vs the unregulated boost to the bottom port-
anything over 60 psi to the bottom port then opens the valve and reduces the boost to the wanted 60 psi

or have i got it wrong?

 

[zstroken]

Wastegate forces

What is pushing the valve open
1) pressure on the Valve face
2) pressure on the bottom of the piston

What is pushing the valve closed
1) Spring pressure in the gate
2) pressure on the top of the piston

These measurements are on a post it at work so they might be a little off
for a 50mm gate

top of piston 2.6"
bottom of piston 2.2"(not sure they aren't the same, but I don't have my gate with me)
Rod .37"(you need to subtract the cross section of the rod to get the total area of the bottom
Then you have the diameter of the gate 50mm(1.98")

F=area*PSI

So using that you should be able to figure out what you open at

 

[milldog]

I have an E.D. wastegate, running regulated boost to the bottom port with unregulated drive pressure to the top port. I assumed that the drive pressure pushing up on the bottom of the valve and the pressure pushing down on the top of the actuator would be the same? Then it was just the boost vs. the spring pressure to determine when it opened up. But I have a 50mm wastegate and the valve size is probably closer to the actuator piston size.

Milldog, how do you like that setup? I was going to run the same setup eventually, but I wasn't sure about what specs to get on the S400.

Im loving it right now. It pulls hard and drive pressure is in check. Need to do a little more adjusting, only getting 55psi of boost. Would like another ten if possible while keeping my DP down. Havent seen over 1300 degrees yet which is nice. Last setup would get there in a blink of an eye

 

[milldog]

Curious question: Why use drive pressure at all? I realize that I have only set two of these up on my truck but I have yet to use drive pressure and have yet to have an issue, boost seems to work just fine.

Educate me!

Jim

I ran that way at first and I could only spool to 30psi due to DP overriding the spring tension. With DP to the top you cancel this out. I guess you could do it with a stiffer spring but it would be less adjustable. My spring is only a .9bar so I need to go up a bit, maybe a 1.5bar. Still going to keep regulated dp on top and regulated boost on bottom for more adjustability

 

[carfichris]

As a couple people have responded Jim, We run them that way because of the wide range of drive pressure to boost imbalances. You have drive early on to fight the opposing drive lifting the valve where as boost arrives later in the process.

 

[seeker1056]

in my case drive pressure has always been less than boost till i hit about 45 lbs boost then it is about 1:1 to 52-55 lbs boost, and about 1.1:1 to 60 psi boost

so I dont think drive pressure for the wastegate operation would work in my case

 

[loganp]

in my case drive pressure has always been less than boost till i hit about 45 lbs boost then it is about 1:1 to 52-55 lbs boost, and about 1.1:1 to 60 psi boost

so I dont think drive pressure for the wastegate operation would work in my case

But what turbo are you running? And how well does it spool? Only turbo I have ever seen do that in person was a 62/74/16 with a 38mm (I think) wastegate, and it spooled pretty slow compared to another guys 62/65/13SS internal wastegate.

 

[Signature600]

But what turbo are you running? And how well does it spool? Only turbo I have ever seen do that in person was a 62/74/16 with a 38mm (I think) wastegate, and it spooled pretty slow compared to another guys 62/65/13SS internal wastegate.

That makes sense though...a bigger exhaust housing WITH a bigger turbine wheel SHOULD spool slower...actually, with that charger, a wastegate probably isn't needed at all.

Chris