Cylinder Head Temps, My Experience + lessons learned Options

[rwilner]

I drove down to Chris Foley's shop to get his shift linkage installed this weekend. At the charlton plaza on I-90, I stopped to fill up. I usually put premium in the 914 but this time put regular in because it's what I put in my other cars and I was on autopilot. Oh well, I thought...let's see how she runs on 87, maybe I'm wasting my $$ on the good stuff.

Before the fillup, I was running between 300 and 325 F in 5th gear around 70-75 mph.

After the fillup, I was running between 380 and 400! (IMG:style_emoticons/default/ohmy.gif)

I spent the rest of the trip in 4th gear at no less than 3500 rpm to try and keep the head temps down. When I got to Chris' shop, we put the car in the air and drained out 5 gallons. I replaced them with 93 octane before getting on the highway for the ride home. My cyl head temps were back down to 310-350 for the return trip.

Here's what I learned:

• A cylinder head temp sensor and gauge are critical to know what's happening in your engine and should be on everyone's short list. Without it I would never have known of the dangerous operating conditions for the engine. The aircraft spruce gauge/probe are short $$ and a quick install.
• The state of tune has a major impact on running temps (duh). I am still tuning my car with the microsquirt and it's clear I have work to do.
• Higher octane gas makes your car run cooler.

As always YMMV but thought I'd share my experience.
Rich

[McMark]

I like this one. It's got 4 CHT + oil pressure + oil temp + other features.

(IMG:http://www.914world.com/bbs2/uploads_offsite/www.aircraftspruce.com-419-1331824997.1.jpg)

[ChrisFoley]

I like It's got 4 CHT + oil pressure + oil temp + other features.

The MGL instruments are interesting. I'd like to see one in use to compare it to the ones we've been selling. There are a lot of factors I consider when choosing cockpit instruments, especially how quickly I can get the information I'm looking for without being distracted from the road.
The criteria which make a gauge useful in an aircraft are different from an automobile.

[McMark]

I like It's got 4 CHT + oil pressure + oil temp + other features.

The MGL instruments are interesting. I'd like to see one in use to compare it to the ones we've been selling. There are a lot of factors I consider when choosing cockpit instruments, especially how quickly I can get the information I'm looking for without being distracted from the road.
The criteria which make a gauge useful in an aircraft are different from an automobile.

I have one in a customer car. He loves it. Because the CHT is a bar graph, you can see and compare all four values in an instant, once you're used to what 'normal' looks like.

[falconfp2001]

I like It's got 4 CHT + oil pressure + oil temp + other features.

The MGL instruments are interesting. I'd like to see one in use to compare it to the ones we've been selling. There are a lot of factors I consider when choosing cockpit instruments, especially how quickly I can get the information I'm looking for without being distracted from the road.
The criteria which make a gauge useful in an aircraft are different from an automobile.

I have one in a customer car. He loves it. Because the CHT is a bar graph, you can see and compare all four values in an instant, once you're used to what 'normal' looks like.

that would be nice having a bare graph to compare all four cylinders. Does it flash the graph at a set high temp? That would be the best option on Chris's Gauge, showing the hottest cylinder at all times.