I was just reminded of the first time I climbed into the super late model. All the gauges are mounted down by the left knee, and I wondered whether that was dumb, until I took the car out, ran a few laps on a 1/3 mile oval, and realized that if I took my brain off the track long enough to see the needles, I would crash.
The tach had a tell tale so you could figure if your gear ratio was correct, and the gauges were useful during cautions and in the pits.
As a high-schooler I had an ‘81 Pontiac Grand Prix with the 3.8 V6. Not a sporty car by any means but it did have a very complete (for an ‘80’s Pontiac) gauge package. One morning on the way to school I noticed that if I stepped on it, the gauge would dip down to near zero and then recover. No idiot lights ever illuminated. I asked my dad about it. Boy did I ever get an ear full. Check your oil boy. Bet it’s really low. I did. Wasn’t even on the stick. I secretly hoped it was toast. I hated that car. Dad had a ‘71 350 in a GMC he said we’d put in if it ever blew up. That 3.8 was so detuned from the factory that I never could blow it up. All through high school and college it soldiered on.
I find them to be very helpful. It's just information. I like both a light and a gauge- the gauge for monitoring how the pressures are doing at various temps (since I often build my own engines with questionable blueprinting). It's nice to know what cold and warm pressures are (and when the pressures start dropping as heat rises) to make sure I'm choosing the right viscosity. The light is nice for when I'm not actively watching the gauge.
A light will tell you when it's too low. But it's useless if your oil pressure is too low because the pressure spiked at 100 psi and blew the filter to shrapnel. They both have their uses.
Oil pressure gauge in my 924s was really a rod bearing ware indicator gauge.
_ said:accordionfolder said:I have an extra 1.6 miata oil pressure sender - I can send you one if you pay the (presumably) very small shipping charge.
I might take you up on that. Does it need the sender too?
I only have the sender (the big thing that sits on the intake side of the engine) - but I think this modification works for yours? You can just fire me a PM if you do want it.
https://www.miata.net/garage/opg2/index.html
Dr. Hess said:Keith Tanner said:Wiring the fuel pump to the oil pressure will also prevent you from starting the car before oil pressure builds unless it's one of those cars that uses a little toilet bowl to dribble fuel into the intake manifold. That could be desirable, but you'd want to be aware.
The locost has an accusump on it, and I also wired in a line from the starter control line to the fuel pump relay so that the fuel pump relay is energized if the starter is on. You need a diode in that line to prevent feedback.
Miatas are wired like that from the factory, sort of. The ECU turns the pump on at key on for a couple of seconds to build pressure, then shuts it off again. When you trigger the starter, it energizes the relay. Then, once the car starts and the ECU sees a running engine, it keeps the pump on.
APEowner said:In race cars I mount the gauges so that the needles should be more or less straight up and down during my scan, or, in the case of the tach at redline. Below is a crappy picture of the gauge layout in my Camaro. From the driver's seat the oil pressure gauge is front and center while the voltmeter and water temp are also easy to see. The warning lights are just below the oil pressure gauge. I can see the tach without taking my eyes off the track. I can't read the numbers without refocusing but I can tell when the needle is almost vertical and/or see the shift light peripherally.
Your eyes are also wired to lock in on vertical and horizontal lines, so the "straight up is good" works really well. I actually have my Miata street car set up that way, with a custom tach that has redline at vertical. Also, when we built the Track Dog race car I set all the gauges up so vertical was good. Looked like it had been put together by a drunkard, but it worked.
I have in-car video of a driver killing an engine. You can see the 3" oil pressure gauge (might have been 4") and the coolant gauge in the video, and you can see the engine getting sicker and sicker. But he's talking to his passenger, explaining the lines for this track. Then it goes boom tinkle tinkle. After that, I swore I'd wire the car to reroute the ignition coil through the driver's testicles if oil pressure dropped below a certain point...
Had them diagnose problems for me a few times while they were still stupid easy to fix. Clogged screens and filters, leaking fuel injectors, low level, all sorts of stuff.
Just a matter of making it easy to see, and knowing what is out of the norm as you drive.
I always had them in the race car (Mechanical), but never that critical. The most important gauge was water temp (also mechanical).
Very. End of thread.
The above is somewhat in jest. I like mechanical oil pressure gauges. They dance around more than electrical, and draw your eye because of it.
The first mechanical one I put in a vehicle scared the crap out of me. I had no idea there was so much change from idle to redline, hot to cold, etc. I watch mine like a hawk.
The brake light as oil pressure warning light is a great idea, too, though not necessarily aesthetic.
Here’s our multi-function warning light. When it starts to flicker in corners, it’s time to add oil.
In reply to accordionfolder :
If it is not gone, I need one for the Molvo!
Pete
NOHOME said:In reply to accordionfolder :
If it is not gone, I need one for the Molvo!
Pete
I might have two, but I'll have to look! I'll PM you either way.
Recently got an F250. The place I bought it from didn't change the oil. It was low enough to cause the pressure gauge to drop and the light come on the dash. I think it was 4 quarts low. Took care of that right away, and saved me quite a bit of trouble. Should I have changed the oil as soon as I got the truck? Yes. Doesn't mean I did.
NOHOME said:In reply to accordionfolder :
If it is not gone, I need one for the Molvo!
Pete
You can have it man.
I have this thing in one of my track cars and it's my fave.
Programmable with three different pressure level warning triggers.
First - red LED, pretty noticeable.
Second - blinks the LED, very noticeable.
Third - blinks the whole gauge display. Las Vegas time.
Fourth - there's a trigger wire for an external light, so I could wire up something even bigger. I thought I would need it, but I didn't.
In my other track car, I have a low oil pressure warning switch wired to a yellow semi-trailer side light, stuck to the windshield.
On Fiat 124 twincams, the pressure gauge/light combo dives alarmingly close to zero on turns if you're down more than half a quart. Seeing that means a quick pullover and a top-up from the ever-present oil supply in the trunk.
For a light I use a Aqua Signal LED Livewell Light available from westmarine.com. You can get various sensors for different psi ranges of oil pressure from any good parts store or online. The lights come in red, white, blue and I think amber. It is very bright will definitely get your attention in broad daylight have it mounted in direct view. Light requires 7/8” hole but being LED you don’t have to worry about vibration or bulbs burning out. You could use different colors for oil pressure, water temp, etc.
OEM oil pressure gauges & lights are only as useful as the manufacturer makes them. My old '06 Magnum would ding ding ding and then turn the engine off if it had no oil pressure. That's a high point, most manufacturers do no such thing.
Aftermarket oil pressure gauges are useful mostly for diagnosis, imo.
Aftermarket oil pressure lights are only as useful as you make them. If you hook them to a 3" taillight scabbed onto your dashboard, or to a shift light pointed at your face, they are useful. You can even tie them to other systems like ignition or boost control if you want to. If the light is just one pixel in your peripheral vision while you're racing and does nothing but glow behind one of your steering wheel spokes while you're taking a long sweeper ending in a rod knock, it's of dubious value.
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