coalburner400

Alrighty... I'm curious about something and figured I'd open it up for discussion.

When using an MBC (manual boost controller) you are increasing the amount of pressure needed to actuate the waste-gate. With the ball/spring MBC's you create a check valve effect that only allows the air to go into the actuator, but not back.
With the gated MBC you delay the actuator in activation and deactivation.
With the double ball/spring you will have a way of bleeding off some of the pressure, but still the actuator is going to be partially active.

A bleeder is supposed to cause spikes but does address the response issue.

The question I have is how much will this delay in response (particularly the return of the waste-gate to the closed position) effect performance on a 325 HP 28 PSI application?

I was thinking one would have to purchase 2 MBC's, one to control boost, and the other to allow deactivation of the actuator. Am I missing something here?
Is there an inexpensive single unit that has a check/relief valve?

RowJ

I think you are over thinking this.
The wastegate does not know there is a MBC there. All it knows is when there is enough pressure for it to open.
With the MBC you are simply delaying the normal operating procedure of the WG.... not changing how it works...nor working it under higher pressures.
Example:
Without MBC... Boost gauge reads 40 psi, WG opens at 40 psi
With MBC... Boost gauge reads 45 psi, WG opens at 40 psi. (to the actuator)

I have run a MBC at 500 hp and there is no delay in response or any changed effect in the WG operation.

RJ

coalburner400

Yea... I figured I was over-thinking things and that is why I posted this one.

Thanks for your response. Not to spread the "cornfusion" but how does the preasure leave the actuator? Its just a diafram, no where for the air to bleed back... Again, the overall answer is that you don't experience any delays or spikes.

If you don't want to entertain the question, I'm alright with that. I hate to be annoying but I'm just trying to understand - simply for the sake of understanding. Thanks again for your response RJ.

rockjeep73

The MBC that I have has a small bleed orfice on the outlet side of it, this is where the pressure from the actuator is released once the boost falls below the set level.

RowJ

Actually a good question... and I don't know. I always assumed it just bleed back to the compressor if not maintained... but not sure.

RJ