[samborambo]

Originally Posted by Zevflow

Many thanks John. Hope you get good use out of the parts. Have just listed a very good vacuum pump for sale on Trade-Me. http://www.trademe.co.nz/Browse/List...x?id=235432154 These are the best thing since sliced bread, even if I do say so myself. These are what we have been waiting for, to keep our EV's quiet and stopping properly. I am running one on my own EV and am very impressed with it's performance.

Damn! didn't see this in time

Anyone else got an ultra quiet vacuum pump for sale?

I was thinking of making a vacuum pump from a diesel exhauster and a small single phase induction motor. Anyone know which diesel vehicles have suitable vacuum exhausters?

Sam.

EDIT: I see you have a new auction running. I'll clear the funds with the boss/wife tonight.

[samborambo]

Thanks for the auction Rex. Bargain!

[Zevflow]

Pleasure Sam. Happy I could help you.

[evlowrider]

Yes thanks Rex! I received my Vacuum Pump today (I was the one who snapped up the first auction the other morning

Pete.

[samborambo]

Hey Rex, I've finally got round to testing the vacuum pump. It runs about once a second. I assume I need a vacuum reservoir tank inline but I'm having trouble tracking one down. Is there any adjustment on the pressure switch to add a bit more hysteresis?

Cheers,

Sam.

[Zevflow]

Hi Sam,

I made a resevoir of PVC pipe and althought it works well the pump is so grunty, it still only runs for 1.5 to 2 seconds anyway. The switches have no differential adjustment but seem to work fine. I went high tech (expensive) and used a digital pressure switch that gave me pressure reading, on/off adjustable switching and a low level alarm, hooked to a light and buzzer. Bit of an overkill, but what's a few more dollars on the plastic

[samborambo]

Did yours run-stop every second continuously without the reservior? I think the problem is the brake booster is a bit puny. It appears there's another type of brake booster for the MR2 with a fair bit more volume. I've bid on one closing tonight. I hope it fits.

[Zevflow]

Sounds like you have leak in the system (booster?). Mine only goes after a couple of pumps on the pedal but doesn't cut in any more if the pedal is continuously held down.

[samborambo]

Turned the system off, pumped the brakes a couple of times to equalise pressure, turned it back on and the pump runs for about 2 secs to create the vacuum and then begins to cycle. Turned it off, left it for a couple of hours and turned it back on again and it just cycles, no loss in vacuum so no leak.

I think there's a bit of reverse recovery in the one way check valve as it closes. It would be negligible in a system with enough volume (vacuum reserve) but I think because the booster is so small, that reverse flow as the check valve closes is enough to trip the pressure switch again, causing it to cycle.

I won the auction for the bigger brake booster. I'll report back on whether that solves the problem or not. Otherwise, I'll look at making a reservoir.

Sam.

[samborambo]

Following up on this thread, it did turn out to be a leak.

The vacuum hose supplied with the kit must be some imperial inner diameter as it wasn't forming a tight seal at the brake booster barb. A bit of plumber's tape over the barb sorted it out.

Thanks again Rex!