[Biturbos4] Bum Turbo??? Help me with the Gutless Wonder!

j y jimnetpa at yahoo.com
Thu Sep 1 14:11:44 EDT 2005

well...if I get a reading at 2500 rpm of 2.2 MBAR that's really not the boost that the ECU is recording. It's actually recording 1.2 MBAR @ 2500 rpm. It's impossible for GIAC-X chips (or any other mass mkt S4 chip) to produce 2.2 MBAR of boost - even with spikes. In fact, that much boost would destroy the avg S4 engine that was not internally modified (cams, rods, etc.). 
>From my trolling of the posts on AudiWorld, the vast majority of the posters subtract 1 BAR from the reading that VAG-COM shows for a given rpm. This is a generally accepted practice in the B5-S4 forum of AudiWorld. If you have a different method - please share it with the group.

Steven Lin <steven at juniper.net> wrote:
j y writes:

> Thanks for the clarification, and accuracy.
> For the un-informed, to calculate your boost from VAG-COM readings, you MUST take your given MBAR at a given RPM and subtract 1 BAR (14.7 psi - atmosphere) from that nbr. 

Technically, shouldn't you be subtracting the pressure at idle from
the pressure at boost?


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