Every owner of a modified car wants to know what's happening under the hood. Many modern cars give access to lots of information, but a series of auxiliary gauges can support the car's main instrumentation in relaying information quickly to the driver. However, it can be difficult to place extra gauges tidily inside the car. Fortunately, there are plenty of options, with A-pillar, steering wheel cowl and vent gauges being the most popular.

Recently, we found a new product from P3Cars and, after watching the excellent 2min fitting video on p3cars.com we decided to have a go ourselves - after all, if it only takes a couple of minutes to explain how to install it, how hard could it be?

The gauge plugs into the car's OBD2 port and reads information directly from the sensors, giving you accurate, instantaneous readings. It can display turbo boost/vacuum, temperature for coolant, intake air and exhaust gas as well as speed, RPM with a shift-light, throttle position and battery voltage. There's also a 0-60mph timer and it can accommodate up to three analog inputs for additional sensors. It can even read fault codes and reset them if needed.

The gauge comes in left- or right-hand drive versions for different markets and the display color is matched to your vehicle's interior lighting. You can order it pre-installed into an OEM vent ($449), or save some money and install the gauge yourself into your existing vent ($389). Either way, it fits neatly with simple connections and will give you instant readouts or record peak numbers plus 15sec of data for review.

Perhaps the only thing missing from this box of tricks is an oil temp reading, which we consider useful information for the driver. But otherwise the P3Cars gauge appears to be a clever piece of kit.

At present it's available for a range of BMW, VW and Audi models, such as the A3, A4, TT, R8 1, 3 and 5 Series plus the GTI, Golf, Jetta, Passat, Tiguan and more. The full list is at p3cars.com

To ensure we got it right, we enlisted BMW tech Derek Vieira. He works at a local dealership and has helped with all our previous BMW projects, ensuring we do things by the book.

The parts supplied included the P3Cars gauge pre-installed into an OEM vent, control box and OBD2 plug. The tools required were a plastic blade and small screwdriver or pick.


To be honest, you could skip this and visit the company's website listed above to watch the video. However, we'll recap to give you an idea of how simple it is:

In use

The P3Cars gauge is ready to go straight out of the box. There are two small buttons on the display panel, with the left one accessing the peak recall or 15sec of data playback. The right button will display the current mode or allow you to scroll through the menu to the reach the desired information.

The buttons are placed above the display, meaning you obscure the readout when pressing the buttons. So you need to remove your hand each time to identify what parameter was selected.

In the set up menu, you can switch between English or metric units and ensure the device is set for your engine - the F30 gauge fits our 335i as well as the 328i and 320i, for example...

We've not encountered any fault codes on our car, but they will be displayed as a four-digit code when you start the engine. These can be identified on the company's website, and reset if desired.

With our recent engine software upgrade and dyno sessions, it's been helpful to read boost and EGT, with the adjustable shift light being another handy option. It's certainly a useful tool for modified car owners.

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