Critical Gauges for Modified V8i with Automatic Box

[WesBrooks]

Hi all,

My barrage of seemingly unlinked questions continues!

Gauges. I've like more instrumentation than standard so that I can get a good idea on the current condition of the engine and transmission on top of the seat of your pants indicator! As a bare minimum I'd like the following:

Speedometer

Tachometer

Water Temperature

Engine Oil Temperature

Engine Oil Pressure

Fuel Gauge

As it's an automatic I'd also like to add:

Gearbox oil temperature

As it may get a winch at some point:

Voltmeter

Should gearbox oil pressure be considered or would this make itself painfully obvious by no drive or gear change? Perhaps just a tail tale light like the transfer box? Is what I've suggested missing anything obvious on the gauge side? My watch can do the job of the clock! There would be a collection of warning lights.

Cheers.

[Bowie69]

Fairly sure a voltmeter is going to be next to useless for winch monitoring, the moment you stick large load on it, the voltage will drop to ~9V anyways.

Gearbox oil temp is a good idea, stick it in the return line from the cooler, for pressure, no need to monitor really, it will be changing all the time, and as you say, it will be quite evident if it falls!

[Arjan]

It all depends on how you'd like to monitor, the budget and the idea behind it.

Voltmeter ? Good idea.

Speedometer ? Said to be required..

Tachometer ? Hmm.

Water Temperature ? Durite make a direct swop one

Engine Oil Temperature ? Durite make a direct swop one

Engine Oil Pressure ? Durite make a direct swop one but why..

Fuel Gauge ? Durite make a direct swop one

Gearbox temp ? Hmm. do you have any hard data to read it against..

However, I prefer a system whereby is all is well I do not need to look at all sorts of gauges. Less to see, less to distract.

Have Fun.

[WesBrooks]

Engine oil temperature would be monitored to indicate early signs of bearing wear so that it could be addressed with a minor overhaul, unlike the complete rebuild this engine needed even before it was stripped.

I'd be comparing the readings on the gearbox temp to the temperatures listed on the Ashcroft site. Over temp tail tell would suffice, but seeing the needle head towards too-hot would allow me to adapt my driving to avoid the need to stop and allow the box to cool. I'm expecting slow green laning and occasional towing to be tough on the autobox oil.

I'd welcome suggestions to favourite after market gauges. I prefer ones that have warning lights in them so that I reduce the number needed elsewhere and it directs your attention directly to the gauge reporting issues. Dash will be a custom kitcar style build with RDX/carling switchgear. No requirement to be a direct replacement.

Fair point on the voltmeter. I'll consider that one carefully.

[Bowie69]

Thought about a digi-dash?

Can monitor all sorts of things...

[honitonhobbit]

I'm a fan of a second water temp from just by the out flow on the rad - good sign of issues

I rarely use the tacho - only for the odd observation. I use my ears and feet

Voltmeter is a PITA - you have warning lights for charge issues

Engine oil and temp - useful. Racetech make a nice all in one unit with a capillary guage

Gearbox temp - that's what your hand is for

Fuel is useful

[Dave W]

Regarding choice of gauge, the Madman II gauge is a good option. Fits in place of the standard Defender water gauge and monitors pretty much everything you've mentioned with a few extras too. You can set alarm points for each of the inputs with an LED, external relay and/or sounder.

I haven't used a gearbox temp on mine as I have a Compushift which monitors/displays that, I let the Madman monitor the transfer box temperature instead.

Have had a Madman fitted to our overland Defender for 3 years now, so far the coolant level is the only thing it's alerted me to although as that was at the start of our lap of Australia it wouldn't have been good if it had gone unnoticed !

[Team Idris]

Voltage is handy to say if the charge light being on means you are really doomed or maybe you'll get home?

Most of mine are "why is that happening, is it because......" Gauges. Such as the fuel pressure which was more to do with a past problem than normal running.

I think the most important one is a capillary water temp gauge so you know it reads right independant of everything else.

Best thing for the gearbox we think is semi synthetic oil to maintain viscosity when hot.

Out of that lot the winch pressure gauge is the only used a lot.

[HoSS]

I used and Acewell gauge for speed, tach, fuel, water temp, very pleased http://www.acewell.co.uk/

And 2 Madman for oil pressures and temps, water levels, EGT etc http://madman.co.za/

(Digidash looks nice, but Acewell + 2 Madman was 1/2 the cost and does the more)

[Cynic-al]

I put a fuel pressure gauge in which came in very handy when diagnosing a loss of power fault.

[Tanuki]

I'd go #1 for a voltmeter - coupled with a mechanism to hard-disconnect all non-relevant-to-running-the-engine loads [stuff like winches, lights, heater-blowers] when the battery voltage drops below 13

Some Land-Rovers had a "Voltage-sensitive relay" to disable the heated rear window when the battery voltage dropped - you could use one of these to trigger an "accessories" relay?

If you stall the engine you always *need* to have enough juice in the battery to restart it.

In my serious towing experiences I've never suffered gearbox/torque-converter overheating - it's all down to driving style [shift-down early! shift-down often! Remember, lots of revs mean good coolant/oil circulation and the engine-driven fan providing airflow over the radiators.... ].

An adjustable rev-limiter (the type that cuts back the fuelling by 'missing' an injection rather than the ignition-missing variety) is another thing to consider - set it to whatever RPM your engine delivers peak-power then you can mash the throttle and let the electronics stop things getting out of hand. It worked just great on a nitrous-oxide-injected autobox Volvo 164E towcar of my acquaintance.

[WesBrooks]

It's occurred to me that the long term plans for mega squirt will come with gauges for free (ish) as per the following thread...

http://forums.lr4x4.com/index.php?showtopic=73567

I'll have yet another rethink and perhaps brush up on my GUI design!

Thanks for the feedback so far.

[FridgeFreezer]

Well thought - you can add other inputs to the MS as well using the spare IO pins to get all your data in one place.

There's always some gauge that will help spot a particular fault but beyond the basics I prefer to keep things minimalist - you can always use old fashioned methods to fault-find, or with MS plug the laptop in and see.

Due to time, money, laziness, and life getting in the way the 109 has gone for some years now with no gauges at all, only things doing much are oil pressure warning light, alternator warning light, and the fan relays under MS control - I know when the fans flip to full-speed it's getting warm, if they stay on for any time something's amiss. Fuel gauge sort of reads about right but I tended to work on miles per tank as on long journeys the GPS was invariably in use. Surprising what you can live without!

Another vote here for Acewell, very good value.