Mechanical Vs Electronic Gauges

[SPGTi 2]

I will be getting oil pressure / oil temperature gauges for the 205. What is the difference between the 2 types of gauges (mechanical / electrical) in terms of performance ? The electric ones seem easier to fit and there are no oil lines to run and potentially leak, but do they perform the same as a mechanical gauge ?

 

cheers

 

Steve

[tagy 1]

I was looking into this recently and apparently the mechanical ones respond faster and are more accurate.

 

I reckon things like water temperature which won't change alot very quickly an electrical one will be fine. But for things like oil pressure/Boost pressure that go up and down quickly you may notice the difference. just my opinion never tried mechanical ones.

 

For ease of installation I am putting electrical ones in my track car, which should at least be more accurate than the standard dials..

 

[brumster 135 1 Cars]

As with anything, there are cheap gauges and expensive gauges. Get a relatively expensive digital electrical one for oil pressure and you won't find any performance difference over a mechanical one; in fact I prefer it as you can look and see a figure immediately - no waiting for the dial to drop down. And like you said, no pipe to run into the back of the dash and potentially leak (I had this happen on me once; made a RIGHT F**KING MESS!). The beauty of the electric gauges is they incorporate a warning light too, which saves you having to run a separate pressure switch and warning light fixed at a given pressure - with the SPA one, for example, you can choose what pressure you want it triggered at.

 

If you go for a decent electrical one (e.g. SPA) do not mount the pressure sender directly in the block; vibration trashes them over time, apparently. I have it on good advice, and run mine, remotely via some braided hose and it works fine and has worked fine for 18 months now.

 

Having said that, mechanical ones are a heck of a lot cheaper. Given choice of cheap electrical or cheap mechanical, I'd go with the latter provided you're happy with the tubing downside. On an expensive engine, I wouldn't skimp on anything that provides you accurate and instance warning of oil pressure loss

[SPGTi 2]

I would love a SPA gauge but the £150+vat is a bit off putting at the moment. I was looking at this GAUGE as I was talking to them at Autosport (oval racing section). The guys there seemed to have faith in them and said they were running them in their oval racers. But you know what they say, you get what you pay for.

 

Steve

[Spiky 37]

id say they are cheap for a reason

 

spend the extra and get good quality

 

what i dont like about mechanical gauges is having 100-120 degrees C oil in the cabin, if that splits that could hurt ALOT

 

[philfingers 5]

Look ok for the price steve. I got a mocal one from Merlin for £30 and another £5 for teh adaptors. I already had a hose tho.

[brumster 135 1 Cars]

£15 :-o

 

One half of me says "must be that cheap for a reason" but the other half says "worth a punt at that!". Problem is, the time you find out they're no good is the time you find out your engine has just seized

[Henry 1.9GTi 36]

I have used two racetec mechanical gauges and have never had a hint of a leak, hopefully it will stay that way. For temps stick with electric easier to install, make sure to buy the matched sender units as well.

[Cameron 16]

I'd definitely go for digital gauges.

[Miles 331 1 Cars]

Again always use and Supply the Mocal one's, Mind I do use Braded line's and not the normal plastic line but have never had a problem with either to date

[GTI6BOY 29]

Its better to go with analogue gauges as the brain proceses the data quicker. But digital looks much cooler

[Spiky 37]

i went for SPA as it has a red light to show danger and can be wired to an external buzzer/ light

[SPGTi 2]

I know the gauge I linked to is cheap, but electronics are cheap. I always try and use the oval racing guys as they always sell the same items cheaper than places that sell to other areas of motorsport.

I am not sure I agree that a mechanical gauge has to react quicker than an electronic gauge either. Surely as soon as the sender for the electronic gauge detects a pressure change this gives a voltage change that changes the value on the gauge. The analogue gauge also has to detect the change and move the needle correspondingly. I am sure that even cheap electronics with a digital display would be more accurate / sensitive than a mechanical system ???? Or am I completely off track here ??

 

Steve

[Cameron 16]

Yeah I'd have said that a mechanical gauge would be slower, mainly because the needle is usually damped to stop it flickering. However I'd also have thought that the cheaper digital gauges will be slower to react due to the cheaper electronics, kind of like a digital speedo is on a cheap car.

You won't be watching the gauge all the time so it doesn't really matter how quickly it reacts, its better that it just has a clear display so you can just glance at it when you need to.

Anyway, I'd say a digital gauge is just less of a faff, so worth going for one of those.

Edited January 12, 2009 by Cameron

[brumster 135 1 Cars]

Yes, typically needle-style gauges are damped so quick changes in pressure can go unnoticed - corner surge, for example. Catastrophic loss of pressure should still be picked up by a switch and an obvious warning light, of course, but I so much prefer looking at a digital number that's updating twice a second, than a needle. I don't want to be looking at the needle then trying to work out where it is in between 20 an 30 precisely - it just can't be done quick enough - but a digital dial is instant in that sense. Stepper-motor based analogue dials wouldn't be afflicted, but as far as I'm aware it's only the likes of Stack who use these for rev counters, not really for ancillary gauges.

 

Don't get me wrong, I'm not poo-pooing mechanical or dial-based gauges per se - it depends upon your application. Certainly a road car or track car doesn't need a £150 digital gauge unless you're very concerned about your oil pressure and engine.

[Cameron 16]

Racetech make stepper motor tachos too. I think they also make stepper motor pressure / temp gauges but I could be wrong, its been a while since I looked.

Edited January 13, 2009 by Cameron