So, question to any of you folks out there running boost and the associated gauges. (Also directed at the reps from Descendant and PTuning if they are around)

What do you prefer and why?

Gauges that tie into the ECU of the car and are purely electric/digital?

Gauges that run to the boost line (oil, etc etc) and tap in there?

I'm looking for pros and cons, since there are more varied options on a digital gauge, like one gauge that can measure boost, air, oil, etc etc...

 

Digital gauges are the best to use for accuracy and speed(refresh rate, etc).
Mechanical ones tend to be inexpensive though...

Its a matter of opinion.
I have used both on my various cars, I tend to like the feel of mechanical guages for things like boost, oil temp, etc. but things like a wideband O2 gauge, would just be retarted to try a mechanical one... its pretty much go digital or GTFO on some gauges...

 

"Imho, there's no definitive answer to this.

A mechanical boost gauge requires the pressurized air to be sent through the firewall to the cabin. If the tubing is rigid enough, does not present a noticeable restriction (think of the extreme where you use a 1mm diameter tubing, or tubing with a very rough inner wall, for example), and at the same time not being too large (say, 2 inch diameter, which is absurd of course); then it is all up to the accuracy and precision of the pressure diaphragm and dial mechanism on the gauge. For that, the quality/make of the gauge itself is probably the only factor.

An electrical boost gauge uses a locally mounted pressure transducer (in the sender unit), which may be the diaphragm-based system. While I don't know about pressure transducer used in electrical boost gauge, I know that there are various kinds of pressure transducers used in the industry. Each have their own advantage/disadvantage, but any one of them should probably be sufficient for the kind of pressure levels and rate of change that we may be interested in. Aside from whether or not the pressure transducer is calibrated properly, there is also an issue of the electrical wiring. If the wiring is done using the proper gauge wire, and proper grounding, then the reading should be accurate/precise as well.

I'm sure an electrical boost gauge with a poorly calibrated pressure transducer or poor grounding can perform worse than a so-so (and usually less expensive) mechanical boost gauge. The opposite can be true too.

Imho, mechanical boost gauges' main advantage is the price, while the electrical boost gauges' advantages are probably ease of installation (no thick tubing through the firewall, no thick tubing tethered on the gauge), and the possibility of adding a memory unit (to store peak boost etc and display later).

Quote:
It seems to me that a Mechanical would be most accurate as it is reading actual pressure, ..

While I personally chose mechanical gauge, I'm not sure I agree with the opinion that mechanical gauges are more accurate because "they read actual pressure". None of them do, in a way. Mechanical boost gauge converts air pressure into diaphragm deflection, then through the dial mechanism, turns it into the dial needle angle. Electrical boost gauge converts air pressure into diaphragm deflection (of the sensor), and then converted by the transducer into electrical signal. The electrical signal is converted into needle angle on the gauge."

An insightful post from http://forums.nasioc.com/forums/showthread.php?t=335319

 

I actually stumbled across that post on NASIOC, so many modded subarus over there, figured there would be some gauge info running about...

So the basic run on both, either one taps into the boost line, and measures pressure to a diaphragm which then converts it to needle movement or a sending unit that creates needle movement.

Now, here's a third option, not sure if there are individual gauges that plug into the ECU, but I've seen complex units such as this:

http://www.p3cars.com/guides/MK5-6%2...ll%20Guide.pdf

Looks damn sharp and seems like the install is much easier than running tubes through the firewall, BUT would it be worth it?

 

^^Wow that does look pretty stealth!