Boost control duty cycle output details

Razathorn · Post by **Razathorn** » Sat Dec 24, 2005 2:06 am

What voltage and frequency does the boost control output operate at?

The reason I ask is because I am trying to figure out a way to hook up a high torque servo (like from radio controled cars, but quite a bit stronger) to open the bypass valve on my supercharger as a way to control boost.

The way these servos operate is they three wires -- one wire is signal, the other two are for power. The width of a pulse on the signal wire is used to determine the desired angle the servo will swing to. The servo expects to see a pulse every 20-30ms, but the time between pulses is not critical and can vary greatly -- the important thing is the pulse width.

If the frequency of the boost control output is such that I could adjust duty cycle down to 0-2 ms on pulses, I could control the servo quite easily. Otherwise, I'm going to be looking for some sort of driver to translate, and that sounds less than fun to hunt for.

Wayne

Post by **Hondata** » Sat Dec 24, 2005 10:04 am

12V, 20Hz but I think you are headed for doom. What about just using a turbo boost controller like setup with variable pressure to both sides of the bypass diaphram?

Razathorn · Post by **Razathorn** » Sat Dec 24, 2005 1:28 pm

Hondata wrote:12V, 20Hz but I think you are headed for doom. What about just using a turbo boost controller like setup with variable pressure to both sides of the bypass diaphram?

Well, I was under the impression that I really couldn't use boost to open the bypass valve. Is there some way to 'push on the other side' of the vacuum motor that opens the bypass valve? Is that what you're suggesting. That would be awesome.

At 20Hz, it seems obvious I would need a secondary driver. It could be done, but I'd much rather do the boost controler style deal if you can provide some additional information.

It's possible that a 50ms pulse time is acceptable -- I guess it depends on the servo I'm working with. at 20hz, or 50ms cycle times, I'd be looking at a 1-5% duty cycle adjustment range.
Wayne

Razathorn · Post by **Razathorn** » Thu Dec 29, 2005 9:02 am

Hondata wrote:What about just using a turbo boost controller like setup with variable pressure to both sides of the bypass diaphram?

I've given this more thought and I thought of a few issues. First, wouldn't the other side of the diaphram be exposed to atmosphere? Second, if I ran methenol injection, wouldn't this cause my diaphram to be destroyed eventually by taking boost from the output side of the blower?

Wayne