Volt gauges... ridiculously pointless or useful?

[DanielJames]

Morning all.

I've added some gauges on my track-build Integra.

So far I have Oil Temp, Oil Pressure and Water temp.

... but that leaves me one short from my pods.

So, instead of having a gaping hole there, I was looking at what else I could get and my question is, how useful would a volt gauge be?

I usually laugh when I see them being retrofitted. They look good on an Audi dashboard but that's about it.

Whats everyone's opinion on their usefulness?

Dan

[TommyBuoy]

Not sure on how useful they are, but could you not fit a stop watch / timer? Might be a better use for the hole.

Or fit a smaller pod

[Mave]

Not particularly IMHO- the oil and water help avoid breaking your engine, but voltmeter is more diagnostic. Just a distraction on a track...

[Hooli]

Fit a vacuum gauge and put a big sticker on the dash about staying in the green for max mpg

[skyrover]

A quick copy and paste from elsewhere showing how a gauge can be useful

Engine not running: Engine off voltage is at least 12V: So far, so good. Note voltage reading.

Engine not running: Engine off voltage is less than 12V: battery run down. Charge before continuing tests. Cars with electronic ignition may not start, even if engine cranks.

During Cranking: Voltage should be above 9.5V: If not, battery may not have enough capacity (too small or weakened by sulfanation or "old age.")

Increase engine to 1500rpm: Voltage exceeds engine-off voltage by more than 2V: Probable over-charging; look for bad regulator or regulator ground, or wiring problem.

Increase engine to 1500rpm: Voltage exceeds engine-off voltage by less than 2V: Proceed to Load Test

Load Test: 3000rpm with all lights, heater & radio on: Voltage exceeds engine-off voltage by less than 1/2 Volt: Charging system may be faulty

Load Test: 3000rpm with all lights, heater & radio on: Voltage exceeds engine-off voltage by more than 1/2 Volt: Charging system ok

Any rpm: Voltage regularly exceeds 14.5V. (May also blow lamp bulbs frequently, and/or tend to make battery run dry.): Probable over-charging; look for bad regulator or regulator ground, or wiring problem.

[TobyLaRohne]

fuel pressure is a good one

[Enricogto]

Lambda sensor reading?

[kambites]

Tyre pressures, maybe? Not sure how you'd measure and transmit them, though. Useful to be able to see how they vary, though.

[TooMany2cvs]

What else is driven by the alternator's belt? But the not-charging warning light SHOULD alert you to an issue with the belt coming off. If the alternator itself has a sulk, though, there may be enough being put out to keep the light from coming on - there certainly was on my Shogun, but not enough to keep the damn thing running.

What else could you put in there...
Air-fuel ratio?

[Mr MXT]

Oil pressure idiot light?

[Huff]

Voltmeters become much more useful if you are tempted to use a rather smaller or alternative lightweight battery (- easy saving of 10kg or so for a track or kit car.)

With the rather reduced capacity a voltmeter will give early warning before you fail to restart becasue you've been running the lights / idling in traffic/pitlane with not enough charge retained and so forth...

[DanielJames]

I thought AFR might be the only other useful one but I can't find a solid answer whether or not I can tap into the OEM wiring from the Lambda or if I'd have to put my own one in just for the sensor.

[FD3Si]

Wideband Lambda, EGT, or, as mentioned, fuel pressure - both useful for a track car (if you know what to look for).
Alternatively, some sort of knock gauge - there are plenty about like the Phormula.
Tapping into stock Lambda would be pointless as it's narrowband, so basically gives you nothing other than flashy lights, and swings from one extreme to the other. Wideband or nothing.

I run Oil and water temp, fuel temp, boost (it's FI, wouldn't bother on NA) and then the rest comes in via the engine management stuff. I don't bother with AFR as I don't know enough about engine tuning to know what they would represent, so they'd only distract/worry me.

[SO27]

As it's a track car, shift lamp?

[blank]

Brake disc or fluid temp.

You'd need a fluid thermocouple (can go in the bleed nipple) or a disc rubbing thermocouple but probably one of the most useful things you can monitor on a track.

[Spare tyre]

dunno how old your intergra is but wouldnt a scangauge type thingy be useful

it talks via odb2 wotsit and can display all that good stuff

Admittedly its probably not easy to read whilst on track, but does give a lot of info on all sorts

[PanzerCommander]

DanielJames said:

I thought AFR might be the only other useful one but I can't find a solid answer whether or not I can tap into the OEM wiring from the Lambda or if I'd have to put my own one in just for the sensor.

You can tap the stock O2 sensor and connect it to a gauge but it will tell you diddly squat if you are using it as a tuning aid as the vast majority of stock 02 sensors are narrow band. Get yourself a wideband AFR gauge kit complete with its own O2 sensor (and usually all the mounting hardware for the exhaust fitting. The vast majority of them also have a 0-4V or 0-5V signal out so if you have any form of data logging (SCT/Diablo etc.) you can record the AFR data and it can be used to refine the engine tune.

The wideband kits are far more expensive (over 2x the price) but they are better than an AFR gauge that taps the stock sensor.