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DRU155
09-03-2010, 12:20 AM
hiya i have just fitted an auto guage boost guage in psi.

i was just wondering if my car is ok as when idleing it sits at 20inmg vac and regarding boost pressure it sits at about 6-7psi then spikes to about 9psi when you change gear. is this ok? i have standard car other than a hks panel filter,sports cat and full 3" cat back.

please help

DRU155
09-03-2010, 12:21 AM
oh and forgot to mention its a tiptronic and i was changing manually

apeman69
09-03-2010, 12:56 AM
0.41 to 0.48bar (6-7 psi), spiking to 0.62bar sounds about right to me. I'm sure mine, when standard, was showing 0.55bar on my gauge. However, my gauge isn't exactly accurate and it reads too high e.g. 0.9bar reads as about 1.1

Hmmm.... just noticed you've got a W reg (facelift) auto. Mine's a pre-facelift with 260PS for the auto. Yours would be 280PS same as the facelift manuals, so max boost should be around 9psi (0.6bar).
Apparently the increased boost on a facelift auto (from 7psi on PFL to 9psi on FL) is only noticable half way through the rev range (according to one of Brad's cut & pastes) so, to check, why not boot it in 3rd gear up to say 6000rpm and take note of the highest boost reading you get? This should eliminate any boost spikes from gear changes that will muddy your observations.

Perhaps someone with a facelift auto would be better to advise.

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apeman69
09-03-2010, 01:24 AM
Thinking about this, perhaps your car is running on wastegate pressure (0.4-0.5bar). If true, this would indicate that there IS something amiss. Unless you do a proper test under load it's difficult to say though. I can get mine to sit at any pressure on the gauge from 0 to 1.0bar depending on whereabouts my right foot is. How were you driving it to get "it sits at about 6-7psi then spikes to about 9psi when you change gear"?
A 5th gear booting up a hill starting from a slow speed would give a good indication of the displayed max boost.

DRU155
09-03-2010, 05:30 PM
hiya i have just noticed that it is running at 8psi which seems pretty normal i hope