If You Could Make Your Idiot Light Smarter, Would You?

[JohnGunn]

In the process of looking for an adapter to mount an oil pressure gauge I recently bought, I visited a number of sites dealing with gauges. For the first time in my life I discovered that you can buy oil pressure switches that respond at different pressures.

According to my Aspire electrical manual, its oil pressure light turns on when the pressure drops below 4.3 psi. I've heard members say that when that happens damage has already been done. At the very least, everyone says you should immediately turn the engine off and coast to a stop along the side of the road. Not the most graceful warning system.

Here is a list of warning light switches for sale on SummitRacing.com. Look down the left side panel to find them classified by pressure. They range from 5.5 up to 50 psi.

My immediate reaction was that you could pick a value that would make the warning light a lot more intelligent, by selecting one that would give you an earlier warning. I'm still considering what would be the best value for me. But in the mean time I thought I would ask you what you think of the idea. Have you ever used a value other than the stock one? What value did you choose? How many different schemes can you come up with? Which do you think would be the best for you?

Here are the ranges of oil pressure values at 1,000 and 3,000 rpm, used to determine when the pressure is out of spec and should be investigated.

With engine warmed up.
1,000 rpm: 28-43 psi.
3,000 rpm: 43-57 psi.

All but one of the switches on the Summit page would require an adapter to fit our engines. That one switches the light on at 9 psi. Would that value, twice the stock one, provide a worthwhile improvement in engine protection?

Or would you rather go all the way to installing a gauge to provide the highest level of security? Or do you think you might not notice small changes on a gauge, and that a light coming on is a better warning system for you?

[links56]

The only thing is what happens when the idiot light Burns out?

[Larry Hampton]

Yeah, drag racers use them along with gauges. They have a light just like a shift light, that comes on and they abort the run (this is how my Airplane will be set up). Now some big time guys will ignore it if its a big money race. Professionals on the other hand, have been known to drain the gear oil out of the rear end going into the final round or run only enough oil that it sucks the pan dry at the end of the 1/4 (this was prior to dry dump systems).

[Gomez]

Couldn't you use a couple differently rated switches and some resistors to make the light come on dimly if it reaches a lower but still decent pressure, but then come on full bright when it reaches "serious issue" time?

[Larry Hampton]

You could make a manifold with a series of switches each tied to a row of led's, but then you might as well run a pressure gauge. The nice ones have a remote diaphragm so you're not running an oil line into the cabin of your car.

[links56]

Yeah If you've ever had the oil line blow out while your driving you'll make sure to by the remote sender one. Trust me.

[91mcnasty]

^ I second this, I had mine blow out at about 145 ish in my charged foxbody.it's a little messy to say the least.

[fastivaca]

^ been there, done that myself

[getnpsi]

An electric needle gauge with a light as well is easy to wire up. If you are watching the road you may want something audible like a 1980 Ford pinto door buzzer. They are loud.

While on the subject I do like a light when my fan kicks on, this way i can decide to relocate sensors to make it come on sooner or later depending if this is a performance or economy style application.