Z20NET Turbo boost pressure.

**crabbitoldgit** · 25th May 2009, 15:13

Hi,
Can some of the more technically minded amongst you assist with this query. I’ve purchased one of the Opcom code readers from fleabay and have been having a play around with it. As it can read and record live data I’d thought I’d go for a spin in my Signum (Z20NET) and record some info. I’ve always been curious as to what the boost pressure my turbo is currently kicking out and according to the data produced by the reader it is producing a maximum of 176Kpa. Converting that figure gives me 1.55bar. Now my question is this, what’s a Signum Z20NET 2003 plate supposed to be producing, boost wise?

**gibbon7000** · 25th May 2009, 15:21

PM duncan (admin) m8 he knows a hell of a lot of info about the Z20NET. HTH

**crabbitoldgit** · 25th May 2009, 15:28

I'll do that. Thanks.

**benny** · 25th May 2009, 16:05

thats about 21 and a bit psi if my science is correct sounds about right to me ....

**crabbitoldgit** · 25th May 2009, 16:24

Doh, I was always rubbish at maths.

176Kpa = 1.76Bar (give or take)

1.76Bar = 25.5Psi (give or take)

**Duncan** · 1st June 2009, 20:46

I've edited your original post with respect to this thread - http://www.vectra-c.com/forum/showthread.php?t=70975 - which you may not have seen.

With respect to your question, if you're running boost of 1.76 bar on a standard 2.0T then it's somewhat higher than it should be.

A standard 2.0T runs around 0.7 bar (10psi), a BSR Stage 1 remapped 2.0T runs around 1.0/1.1 bar (14/15psi) and a Stage 3 runs around 1.76 bar (25psi) - so if you're running 1.4 bar then it's not right

(understatement). Danger of things going

with that.

However, you say that youv'e got a reading of 176kPa on the kit you were using. Without knowing where that pressure was being read from i.e. what variable you were looking at then it may well be that you're not reading the actual boost pressure.

**phill77** · 1st June 2009, 21:31

All pressure values read from the ECM transducers on my engines at work show absolute pressure values (to allow for use at varying altitude).
So if you are seeing a value of around 176kPa, with atmospheric pressure of say 102 kPa, your boost is really 74kPa / 0.74bar / 10.7PSI gauge pressure.

Phill

**crabbitoldgit** · 2nd June 2009, 10:49

Thanks for the replies lads. I feel a bit more at ease now that you have explained the magic/maths.

**Duncan** · 2nd June 2009, 10:53

Originally Posted by phill77

All pressure values read from the ECM transducers on my engines at work show absolute pressure values (to allow for use at varying altitude).
So if you are seeing a value of around 176kPa, with atmospheric pressure of say 102 kPa, your boost is really 74kPa / 0.74bar / 10.7PSI gauge pressure.

Phill

Yep, that would explain it perfectly - the reading he's getting being an absolute one - and with the correction then coming out at around 0.7 bar then that's spot on for what it should be on a standard 2.0T.