Re: Vacuum Source For Turbo Cars

["jtrealtywebspannet" <jtrealty@xxxx>]

There is nothing inside the vacuum tank, it is just a resovoir for 
vacuum. There may be a check valve to lock the vacuum in from the 
engine. The vacuum resovoir is not for the power brakes, it is meant 
only to prevent the A/C actuaters from moving during short periods of 
low vacuum such as when in a non-turbo car you accelerate and the 
vacuum goes low for a short time. Increasing the size of the vacuum 
tank will allow longer periods of low vacuum before the actuaters 
move from lack of vacuum. You can experiment with different size tanks 
to get the response you need. A large metal coffee can makes a good 
tank or go to a junk yard and pick one out that looks right. A good 
place to hide the vacuum tank might be on top of the fuel tank by the 
fuel pump, it doesn't have to be near the motor.
You need a steady source of vacuum for the brakes and the A/C. For 
the automatic transmission it uses the vacuum for determining the load 
on the engine so it can shift a little softer. A steady source isn't 
what it wants. To get it to work right is more difficult than using 
tanks or an electric vacuum pump. You really need a valve to control 
the vacuum to the modulater in response to engine load if you want to 
soften the shifts. This isn't required on a 5-speed.
David Teitelbaum
vin 10757


--- In dmcnews@xxxx, "Marc A. Levy" <malevy@xxxx> wrote:
> I suspect this valve is broken in my car, because the AC vents close 
as soon as I have even minimal boost. Before Memphis, I did not have 
time to bother with such a trivial item and since Memphis, I don't 
have the motivation to work on it!
> 
> What is inside of the vacuum tank? is there anything mechanical in 
there to keep the vacuum consistent? or is it just a empty tank?? 
Mine is no longer in the pontoon (the intercooler is there now!) so I 
don't have a lot of space for a larger one. How critical is a small 
increase in size for vacuum reserve?
> 
> 
> > -----Original Message-----
> > From: Stragand, Dave [mailto:dave.stragand@xxxx]
> > Sent: Tuesday, August 13, 2002 9:58 AM
> > To: DMC News (E-mail)
> > Subject: [DML] Re: Vacuum Source For Turbo Cars
> > 
> <SNIP>
> > If you're 
> > still having problems, check out the anti-reverse valve 
> > leading from the manifold to the vacuum canister in the 
> > pontoon. It should only "allow vacuum" one way. (If memory 
> > serves, it's black on one side, white on the other, and about 
> > the size of 5 or 6 half-dollar coins stacked together. You 
> > can also simply use a larger vacuum tank out of just about 
> > anything in a salvage yard. It's hidden deep in the pontoon 
> > anyway, so what it looks like doesn't matter.
> <SNIP>