Boost Gauge Installation

[webng]

Can anyone with a Series 2 with a boost gauge take a picture of the engine bay where the vacuum hose is cut for the t-piece connection please. Installing mine this weekend (today!) and would like to be sure before i start slicing and dicing!

Thanks!

EDIT: Ok, now I'm trying to wire it to the lights, but only when i turn the spots on.

Edited August 31, 2007 by webng

[munchstagea]

There is a spare nipple on the back of the inlet plenum (on the S1, probably on the S2 as well?) That is where mine is attached. There is one at the font too but that is further away from the gauge of course...

[66yostagea]

The connection on the back end of the plenum has a black rubber cover. Take it off and fit the gauge hose here.

[webng]

Thanks for that. I ended up putting it somewhere else, with advice from a mate whose gauge was conected the same way. But where i have it at the moment doesn't show back pressure vacuum (before throttle body or something), only boost, which is accurate (7/8psi). I'll move it to the hose from the plenum instead, now i know that's better.

Can anyone explain to me how the back pressure vacuum works? And why i need to see it on the gauge. Less vacuum is better or worse?

[webng]

Can anyone explain to me how the back pressure vacuum works? And why i need to see it on the gauge. Less vacuum is better or worse?

The hose that came with the Autometer gauge (hard white plastic one) wont go over the extra nipple from the plenum, it's a pretty small internal diameter. Is there some rubber attachment I can get that will connect the 2?

Anyone with the back pressure explanation?

Thanks.

[darrinspencer]

The hose that came with the Autometer gauge (hard white plastic one) wont go over the extra nipple from the plenum, it's a pretty small internal diameter. Is there some rubber attachment I can get that will connect the 2?

Anyone with the back pressure explanation?

Thanks.

Cheap quick fix is to use some 3-4mm vacuum hose about 5cm long

Push it over the nipple on the plenum and push the hard plastic autometer hose in the end of the vacuum hose. Fix with cable ties

[webng]

Cheap quick fix is to use some 3-4mm vacuum hose about 5cm long

Push it over the nipple on the plenum and push the hard plastic autometer hose in the end of the vacuum hose. Fix with cable ties

Ahhh... good idea, might look dodge though hey. Any idea if the gauge connected to that nipple will show vac as well?

[darrinspencer]

Ahhh... good idea, might look dodge though hey. Any idea if the gauge connected to that nipple will show vac as well?

If you do not want to see the join, run the rubber hose back to the firewall, and then the lastic hose from there

If you are connectiong to a nipple or hose from the inlet plenum, ie after the throttle body, then you will see vacuum.

[webng]

...

If you are connectiong to a nipple or hose from the inlet plenum, ie after the throttle body, then you will see vacuum.

What exactly does boost vacuum show? Is it surplus air for the turbocharger?

[munchstagea]

No vacuum is not surplus air from the turbo,

Vacuum is how a normally aspirated engine works, the piston pulling down in the cylinder draws the air/fuel in - like a vacuum.

The turbo helps this along be forcing (forced induction) more air into the combustion chamber.

These links might help make things a little clearer:

http://auto.howstuffworks.com/turbo.htm

http://auto.howstuffworks.com/engine7.htm

Couldn't find anything totally vacuum specific but I'm sure it is in there somewhere or someone else will have a better answer for you.

Cheers

Luke

Edited August 31, 2007 by munchstagea

[webng]

Thanks for that, so if my understanding is right, the more the vacuum, the better, more effecient your engine right?

[Tangles]

I hope so, because I see -1.0 on my boost guage

then I see +1.0

[munchstagea]

You have a very balance rb there Brendan!

Yeah the more the better, but turbo engines run lower compression ratios so they won't have as much vacuum as an NA.

[pixel8r]

Ahhh... good idea, might look dodge though hey. Any idea if the gauge connected to that nipple will show vac as well?

yes. yes it will.

[webng]

yes. yes it will.

Thanks for the replies guys. Now I'm trying to wire it to the lights, but only when i turn the spots on, so i can choose to have it off even with the main lights on. I tried to find the wiring under the dash/steering wheel but it all looks pretty crazy under there. Should I remove the whole steering wheel to have a look?

Another option is to wire it to the old Japanese card/toll reader thingy and put a switch there to turn the boost light on and off. Don't really want it on all the time, prolly blow te bulb quick smart.