[Rapson]

I have been looking to put some EGT and Boost gauges in the Patrol and dont know what the difference between mechanical and electric gauges are.

Inparticular I am looking at the Auto Meter gauges, Cobolt 6144 EGT and 6160 Boost. If the boost gauge works on pressure what is the difference between mechanical and electric...apart from double the price?

 

[Ray!]

Electric gauges have a sender/measuring unit at the point of measurement, which converts the mechanical signal into an electrical signal at the gauge. A mechanical gauge has the measurement point in the gauge. For example, an electric oil pressure gauge has a sender unit at the oil reading point (usually somewhere near the oil filter) and that translates into an electrical signal for the gauge in the dash. A mechanical oil pressure gauge sends that actual oil, via an oil tube, to the gauge.

Electric gauges are easier and safer to install, as all you have to pull through the firewall are wires, and there are no nasties going into the cabin should a mechanical line fail. Hot oil spraying into the dash and cabin, aka old Mini Coopers, is something you'd best avoid. Electrical gauges can also be easier to install, as there aren't the issues with swage locks/fittings leaking etc, aka my previous ARB airlocker.

Cheers

Ray

 

[Rapson]

Thanks for that Ray, very well explained! I shall be leaning towards an electrical gauge set up now, Cheers!

 

[geeyoutoo]

Electric gauges have a sender/measuring unit at the point of measurement, which converts the mechanical signal into an electrical signal at the gauge. A mechanical gauge has the measurement point in the gauge. For example, an electric oil pressure gauge has a sender unit at the oil reading point (usually somewhere near the oil filter) and that translates into an electrical signal for the gauge in the dash. A mechanical oil pressure gauge sends that actual oil, via an oil tube, to the gauge.

Electric gauges are easier and safer to install, as all you have to pull through the firewall are wires, and there are no nasties going into the cabin should a mechanical line fail. Hot oil spraying into the dash and cabin, aka old Mini Coopers, is something you'd best avoid. Electrical gauges can also be easier to install, as there aren't the issues with swage locks/fittings leaking etc, aka my previous ARB airlocker.

Cheers

Ray

I agree with the philosophy re oil pressure gauges, but for EGT and Boost, there's plenty of room to pull them, and for the average person, it's easier and no danger.

 

[dull]

Worth noting that mech oil and fuel pressure gauges are actually illegal if installed inside the cabin.
It's an easy defect for Mr. Plod.
Cheers.

 

[bert]

so is a volts and or amps gauge mechenical then?

 

[Ray!]

I agree with the philosophy re oil pressure gauges, but for EGT and Boost, there's plenty of room to pull them, and for the average person, it's easier and no danger.

Actually, EGT gauges are all electrical. The dissimilar metals at the probe, when heated, create a current that is amplified and sent to the gauge, whether digital or analogue. Boost gauges can be electrical or mechanical, but the mechanical ones can be more problematic, needing airlines into the cabin and venturies at the measuring point to dampen erratic dial movement.

Cheers

Ray

 

[geeyoutoo]

Actually, EGT gauges are all electrical. The dissimilar metals at the probe, when heated, create a current that is amplified and sent to the gauge, whether digital or analogue. Boost gauges can be electrical or mechanical, but the mechanical ones can be more problematic, needing airlines into the cabin and venturies at the measuring point to dampen erratic dial movement.

Cheers

Ray

The dampening factor of the "mechanical" boost gauge often depends on the quality of the gauge, my Autometer had no such issues.

You are correct Capillary style gauges are ofcourse one of the earliest types of "sender".

 

[Dhuey85]

so is a volts and or amps gauge mechenical then?

No Volts and Amp gauges wouldn't be called mechanical.

 

[MikeH]

Poorly installed amps gauges cause a lot of fires.
If you use one make sure it has a "remote shunt"
I prefer not to use them at all. all of the power from your alternator goes through it, its one more thing to fail. Volts is not as useful but you can still work out what is going on and its a hell of a lot safer.

I like to use a mechanical temp gauge, it works when the ignition is off.