Boost gauge....what should it do

[MickG]

Just had a turbo boost gauge fitted to my TD5 Disco and wanted to confirm if the following is correct, i.e. normal operation for a '99 TD5.

1. Makes 19psi of boost max and no more (gauge goes to 30psi)
2. As soon as I hit the clutch it drops to 0psi until I step back on the acceperator - at which time it rises again slowly on it's way again to 19psi
3. Would a sign of a sticking waste gate be the needle dropping back to 0 or there abouts when accelerating before it reaches 19psi?
4. What does the boost actually mean or do:eek:

Anything else to look out for and apologies for the simple questions but turbo's are a device I know nothing about......other than my car has one?

Cheers, Mick

[drover81]

1. Sounds about right
2. Sounds about right
3. Sticky wastegate = boost exceeding about 18 psi, not dropping off, or not getting to 18psi. It's either stuck closed (exceeds 18psi), or stuck open (doesn't make 18psi)
4. Boost = pressure of air being forced into the cylinders (as opposed to being naturally inducted ie no turbo). More Air + more fuel into cylinder = more power etc.

Cheers

[discowhite]

1. Sounds about right
2. Sounds about right
3. Sticky wastegate = boost exceeding about 18 psi, not dropping off, or not getting to 18psi. It's either stuck closed (exceeds 18psi), or stuck open (doesn't make 18psi)
4. Boost = pressure of air being forced into the cylinders (as opposed to being naturally inducted ie no turbo). More Air + more fuel into cylinder = more power etc.

Cheers

yep that about covers it:)

cheers phil

[MickG]

1. Sounds about right
2. Sounds about right
3. Sticky wastegate = boost exceeding about 18 psi, not dropping off, or not getting to 18psi. It's either stuck closed (exceeds 18psi), or stuck open (doesn't make 18psi)
4. Boost = pressure of air being forced into the cylinders (as opposed to being naturally inducted ie no turbo). More Air + more fuel into cylinder = more power etc.

Cheers

Thanks drover81, that makes perfect sense so I can now say I have learnt something today:D
One last questions, if mine is running to 19psi, is this good/bad/doesn't matter/could be cheap boost gauge?

Thanks again, Mick

[DEFENDERZOOK]

if youve got a switch on your clutch master cylinder.....remove the connector and go for a drive......

[discowhite]

dont think D2's have em tony.

19 psi is about factory give or take a psi.
ive been running the 90 at 21psi for over 8months now, even been at 24psi for a while, just over kill.

cheers phil

[Blknight.aus]

double check the gauge for accuracry onthe wastegate actuatro should be a number (1.305 or thereabouts) that is the actuation pressure in Gauge Atmospheres that it should be fully open at.

[drover81]

Thanks drover81, that makes perfect sense so I can now say I have learnt something today:D
One last questions, if mine is running to 19psi, is this good/bad/doesn't matter/could be cheap boost gauge?

Thanks again, Mick

No worries (what little I know, I share!!!). Only reason I know that stuff is I think I have a sticky actuator on mine (but it works every time when connected to a compressor:mad:)

I think your inaccuracy may be just the boost gauge (can't be 100% sure though)... I know VDO (decent quality) are out by about 1psi in some cases. Either way, as discowhite says, nothing to worry about.

[MickG]

Thanks guys, info very much appreciated:D

Aye, Mick