camajo

iTrader: (3)

qq with dual wastegates.

If I want to run a max of say 18 psi, then I would set each wastegate to 9 psi totaling 18 between the two?

Seems obvious but I want to confirm there isn't some funny business going on with the air pressure that I don't understand.

Grinch

iTrader: (2)

I would think you set each gate to 18psi

camajo

iTrader: (3)

But isn't the air pressure a singular force trying to compress both spring simultaneously. I cannot envision how one waste gate could open at 9 pounds within the same airspace as a second.

peejay

You could have 20 wastegates and you'd still want to set each one to the boost pressure you want.

camajo

iTrader: (3)

Explain how that works for me. I'm thinking in terms of having one spring between my hands compared to two or more. The more Springs I add, the more difficult to compress.

KNONFS

iTrader: (14)

As already posted, your wastegate spring on each wastegate needs to at the boost pressure you want. I am running dual 38mm, and I run 9psi springs on each wastegate; MAX boost pressure is 9psi (no boost controller at the moment, and not counting boost creep)

C. Ludwig

iTrader: (27)

How exactly does a posi-trac rear-end on a Plymouth work? It just does.

Monkman33

iTrader: (28)

Pressure is pressure. Psi is pounds per square inch. So having two wastegates in separate places will only serve to lessen the amount of exhaust gasses needed to leave through them to maintain steady boost pressure.

Having two separate wastegates is not the same as adding two springs in one hand. It's more like a spring in each hand. Same pressure to squeeze each one.

camajo

iTrader: (3)

I guess the term 'psi' is key? Its pounds per square inch not pounds for the entire enclosed air space. That's how you get the spring in each hand?

Just to complicate things a tad... a twinscroll manifold requires a wastegate on each side right? i.e. the airspace for rotor 1 and rotor 2 are exhausted into separate air spaces so if the wastegate was only on the one side, the other side would have no protection to dump the excess pressure?

Sorry if this is too 'in the weeds' for some, but I like to know how things work.. not just that 'it works'

fendamonky

iTrader: (6)

No, having a divided manifold does not *require* two wastegates. However people are leaning more towards dual wastegate setups because they are more efficient.

Vicoor

Static pressure in an enclosed system is equal throughout the system. Since the opening pressure of the wastegate is a function of the area of the diaphragm divided by the force of the spring that sets the pressure that will open the wastegate and since they both have the same pressure applied to them they will open simultaneously.

Vicoor

The previous post was from my cell phone and not very well articulated so I'm going to give it another go.

Like I said before, static pressure is equal throughout the system. So each wastegate diaphragm has the same pressure applied.

The only difference between one or more would be the volume of the system, which would require more time to "inflate" to the set pressure and therefore would slow the responsiveness. Now because the volume is still pretty small you may not notice the difference outside of different PID values to tune the system.

look at it this way,

you have four tires that are inflated to the same pressure, if you were to connect a tube that joined all four together, the pressure would still be the same.

camajo

iTrader: (3)

Thanks for all of the replies guys. It makes sense now.