Mechanical vs. Electrical gauges

I am looking to purchase some gauges (oil press, oil temp, water temp). I was wonder the advantages/disadvangates of mechanical and eletrical gauages.

courtneyb

IMHO, mechanical gauges in a street car are a Bad Thing. If you use a mechanical oil pressure gauge you actually have to run a piece of tubing (full of oil) from the engine to the gauge. This means that if the gauge breaks or the tubing gets punctured, you can end up with oil all over the interior of your car. I know. I had this happen on my 1969 Mustang when i had a mechanical gauge installed in it. There are devices you can buy which will allow you to run a mechanical gauge without running actual oil and fuel directly to the gauge but, why? It's so much easier to just use an electrical gauge. With electrical gauges you only have to run one wire (assuming your gauge pod is grounded and powered) from the sending unit and that's it. Much easier to install and less mess and fuss. I'm not sure but i think that mechanical gauges are primarily designed for racing applications. Personally, i would steer clear of mechanical gauges.

-Grant

Not to mention the electronic ones have neato features like storing peak boost/oil pressure, temp, etc.. you can recall the peak values by the press of a button. Some even let you set warning modes. For example you could set your boost gauge to beep and flash an LED when you reach a certain PSI.

Mechanical gauges usually have a 270 deg sweep whilst electrical gauges usually have a 90 degree sweep. This gives the mechanical gauges better resolution. Also, mechanical gauges usually are more responsive than electrical gauges.

But, usually isn't always.

My SPI electrical gauges have 270 degree sweep. Unfortunately they don't make them anymore. I've heard there are other electrical gauges with 270 degree sweep.

Mechanical gauges can be messy. They certainly are a bit more of a PTIA to connect. The compression fittings usually used to connect them can be tricky for a first timer as well to figure out just how tight to connect them. Tighten the fittings too much and they will leak as much or more as if you didn't tighten them enough. SS braided lines can make this a non-issue though.

Electrical gauges tend to be more expensive as well and you sometimes have to buy the sending unit separately (such as with VDO).