I personally have a 2006 R53 that I'm doing some troubleshooting on, but my question is really on using Torque to do troubleshooting... anyone with an S of any gen likely could answer this question.
Mine is new to me (2 months) and 100k plus miles on the ticker. I've used Torque, but previously just for reading codes on cars. This is the first I've used the vacuum/boost readings.

I recently added a reduced supercharger pulley to increase the boost on a car that already didn't feel all that quick, and as I suspected... therefore didn't feel much different after installing. I'm guessing I am leaking boost. So... troubleshooting, I want to see my boost levels.

I plugged in my Bluetooth OBD2, fired Torque up, and took a few WOT rips down my street... Here's a few screenshots, a single gear pull, a one-two shift:






What I'm seeing here is almost no boost - but I'm seeing lots of vacuum.
The shape of the plot is exactly what I'd expect if it WERE boost - I get on the throttle, RPMs rise, and the boost climbs... basically to zero, though. From a vacuum. Rather than from zero to some boost level.

• Is this a Torque quirk (I don't know what the scale is, or if it needs to be zeroed like an actual scale)?
• Does this indicate my MAP or T-MAP sensor isn't reading correctly?
• Does this indicate that I do (as I suspect) have a boost leak? ...but in that case how do I have vacuum at this sensor?

Anyway - wanted to know how to read the boost chart, if it's accurate in Torque, if it's accurate in Torque given our MAP sensors... if this really is an eyebrow-raising result, or just how Torque scales on the Boost plot?

 

PS:

If anyone has a boost gauge to suggest, I do want to add one, for long term monitoring.
I'm torn on whether to plumb a mechanical one to vacuum (Like: Real readings. Dislike: Reliability risk for future leak) or install an OBD2 one.
Preferably round, since there's a nice Apex mount available that screws easily to my tachometer behind the steering wheel... but any suggestions are welcome there.

For now though, interested in understanding Torque's boost plot better so I can actually digest this result.

Thanks.

 

I would 100% go with an independent mechanical gauge. It will be much more reliable than an OBD gauge.

I am a fan of Autometer gauges, and I have their ES series boost-vac gauge in my Clubman since it matched my OEM gauges. But really, you can't go wrong with any of their options.

 

I run a Torque app gauge pack on my Android screen in my modified Nav system. That does not look like an app problem. I don't think you're getting any boost at all.

 

In my '05 the mechanical gauge and torque app seem to agree on both vacuum and boost. At idle I see about 19 in/Hg and corresponding increase into boost (up to a max of 17psi at full throttle) as revs climb. I would agree that you have a leak somewhere.

 

I don't have a mechanical boost gauge (not much room with Chrono cluster) but do use an OBDLink MX+ dongle in combo with their app and Android Nexus 7 tablet. From what I've seen online, these apps seem reasonably accurate but somewhat slow to respond vs real-time. Comments suggested activating only that one display to improve BT response time plus smaller virtual "dial" for reduced "sweep" time.

I'm at 5k' elev and typically drive from 4k'-7.5k' elev vs the OP's near sea level location. My boost seemed skewed until I understood I needed to factor elevation in baseline boost. For example, the image below taken in my home garage with ignition on but engine off correlates to my 5k' elev and then reduces even further as I gain elevation during typical driving conditions.

 

In my '06 I had, I added the Autometer mechanical boost guage.

But I agree, you probably have a leak.