Cylinder Head Temps, My Experience + lessons learned Options

[ChrisFoley]

Not sure we need egt info like you would on a Lycoming engine, right? That might be going a little too far. I do notice that Chris sells these things. Probably wouldn't hurt on a race car though.

Thanks, Warren

EGT is definitely not much value on a street car. Exhaust temps fluctuate too much with changing throttle position.
A good (single) AFR meter is fine for tuning.
CHT on each cylinder of an aircooled street engine is more valuable than you might think though.

[rwilner]

yah but......

I read innovate can send everything to your iphone...which would be cool.

rich

You need a special module to make that happen, which is $$ and my guess is doesn't work very well.

Still be cool.

I looked around...I think I can run a car off an Ipad...with no gauges now.

Rich

You can do this with mega/microsquirt -- they have an iOS compatible version which is a dashboard. You can customize the gauges however you like too.

It would be really sweet if you could rig up the steering rack to the accelerometer!

[ww914]

[/quote]
EGT is definitely not much value on a street car. Exhaust temps fluctuate too much with changing throttle position.
A good (single) AFR meter is fine for tuning.
CHT on each cylinder of an aircooled street engine is more valuable than you might think though.
[/quote]

Chris

Are you suggesting a single AFR meter and 4 cht probes?

Warren

[76-914]

FYI.......the a/c cht's purpose is to set the a/f ratio. when @ altitude you pull (lean) the mixture until the engine rpm's drop then push (richen) to 50F cooler than indicated temp where rpm dropped.

[ww914]

FYI.......the a/c cht's purpose is to set the a/f ratio. when @ altitude you pull (lean) the mixture until the engine rpm's drop then push (richen) to 50F cooler than indicated temp where rpm dropped.

Simple airplanes don't have either a CHT or an EGT guage. The mixture is leaned until the engine runs rough, then slighty richened until the engine runs smooth again. This must be done each time the aircraft changes altitude. If your lucky enough to have a CHT, it can be used, but an EGT puts it right on the 50 degree richer mark. Ask me how I know. I burnt the valves in my little Cessna because I didn't re-calibrate often enough. When I got my big Maule, I had the EGT installed so I wouldn't do that again.

In our cars, I think Chris is right, an EGT (Exhaust Gas Temperature) is a bit of overkill. I do think a CHT guage is a very useful tool with everything that has been said so far on this thread about overloading the engine on a hill. I haven't yet decided what I am going to install, but it will be something. I hate burned valves.

[ChrisFoley]

Chris

Are you suggesting a single AFR meter and 4 cht probes?

Warren

Yes.

As Rich Wilner's first post points out, without any CHT he would have no idea the engine ran so hot on low octane fuel.
And at the moment he doesn't know just how lean the mixture is because of the broken LM1.
With hi-test he was getting away with the lean mixture, but not with 87 octane.

Most everyone assumes cyl 3 is the hottest so they put a single CHT on #3.
My car has a hot #4 cylinder right now. If I had a single CHT on #3 I wouldn't know that.
Injector problems, spark problems, etc. might only affect one cylinder. With a 4 channel CHT its easy to identify and resolve problems before they become serious.

[Elliot Cannon]

FYI.......the a/c cht's purpose is to set the a/f ratio. when @ altitude you pull (lean) the mixture until the engine rpm's drop then push (richen) to 50F cooler than indicated temp where rpm dropped.

Simple airplanes don't have either a CHT or an EGT guage. The mixture is leaned until the engine runs rough, then slighty richened until the engine runs smooth again. This must be done each time the aircraft changes altitude. If your lucky enough to have a CHT, it can be used, but an EGT puts it right on the 50 degree richer mark. Ask me how I know. I burnt the valves in my little Cessna because I didn't re-calibrate often enough. When I got my big Maule, I had the EGT installed so I wouldn't do that again.

In our cars, I think Chris is right, an EGT (Exhaust Gas Temperature) is a bit of overkill. I do think a CHT guage is a very useful tool with everything that has been said so far on this thread about overloading the engine on a hill. I haven't yet decided what I am going to install, but it will be something. I hate burned valves.

Even in the simplest airplanes you can have and should have an EGT gauge. All things considered, they are relatively cheap considering the information they can give you. I have a CHT in my 914 and would like to have an EGT but I don't think it's that important for a street machine. Once the fuel air mixture is set on a car, it pretty much stays the same. It changes all the time in an airplane because of the great differences you can experience in air pressure and density. I used to adjust the mixture on the old Beech 18 by the color of the exhaust at nght. It was actually pretty accurate. (IMG:style_emoticons/default/laugh.gif)

[Elliot Cannon]

Chris

Are you suggesting a single AFR meter and 4 cht probes?

Warren

Yes.

As Rich Wilner's first post points out, without any CHT he would have no idea the engine ran so hot on low octane fuel.
And at the moment he doesn't know just how lean the mixture is because of the broken LM1.
With hi-test he was getting away with the lean mixture, but not with 87 octane.

Most everyone assumes cyl 3 is the hottest so they put a single CHT on #3.
My car has a hot #4 cylinder right now. If I had a single CHT on #3 I wouldn't know that.
Injector problems, spark problems, etc. might only affect one cylinder. With a 4 channel CHT its easy to identify and resolve problems before they become serious.

(IMG:style_emoticons/default/agree.gif) A CHT for each cylinder is the ideal setup.

[jsayre914]

With a 4 channel CHT its easy to identify and resolve problems before they become serious.

What guage do you reccomend Chris (4 channel) ??

[falconfp2001]

If you can source a CHT Gauge that will take 4 channels then here is the sensor.

http://thesensorconnection.com/category/ch...all-cht-sensors

[ChrisFoley]

With a 4 channel CHT its easy to identify and resolve problems before they become serious.

What guage do you reccomend Chris (4 channel) ??

I sell this one
I have the same one in my street car and my race car.
The gauge has several modes of operation. The standard mode automatically cycles through each cylinder so it only takes 4 seconds to see all 4 head temps.
The display shows cylinder, digital temp and a green/yellow/red bar graph for quick reference.

[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)

[ww914]

......or this one.

Simple and cheap.

http://www.aircraftspruce.com/catalog/inpa...westcombos1.php

[ChrisFoley]

......or this one.

Simple and cheap.

http://www.aircraftspruce.com/catalog/inpa...westcombos1.php

Although I use Westach probes I have yet to see one of their gauges that I like.
The analog 4 channel gauges with 4 needles are nearly useless in an automobile IMO.

[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.

[rwilner]

The criteria which make a gauge useful in an aircraft are different from an automobile.

(IMG:style_emoticons/default/agree.gif)

In an airplane you're often staring at your instruments as your primary information source, so dense displays with complex information are ok. In a car, as Chris points out, a quick glance at the instrument needs to give you the info you need.

[rwilner]

......or this one.

Simple and cheap.

http://www.aircraftspruce.com/catalog/inpa...westcombos1.php

Although I use Westach probes I have yet to see one of their gauges that I like.
The analog 4 channel gauges with 4 needles are nearly useless in an automobile IMO.

This is a 1-channel gauge with a 4-position rotary switch to select which cylinder you're monitoring.

By the time you've bought the gauge, probes, and switch, you're at (actually slightly above) the cost of the scanning instrument sold by Chris.

[jsayre914]

If you can source a CHT Gauge that will take 4 channels then here is the sensor.

http://thesensorconnection.com/category/ch...all-cht-sensors

So type J 14mm is the correct one ??

Type K seems to do more range wich is NA

(IMG:style_emoticons/default/popcorn[1].gif)

[Elliot Cannon]

The criteria which make a gauge useful in an aircraft are different from an automobile.

(IMG:style_emoticons/default/agree.gif)

In an airplane you're often staring at your instruments as your primary information source, so dense displays with complex information are ok. In a car, as Chris points out, a quick glance at the instrument needs to give you the info you need.

"Staring at your instruments"??

[ChrisFoley]

The criteria which make a gauge useful in an aircraft are different from an automobile.

(IMG:style_emoticons/default/agree.gif)

In an airplane you're often staring at your instruments as your primary information source, so dense displays with complex information are ok. In a car, as Chris points out, a quick glance at the instrument needs to give you the info you need.

"Staring at your instruments"??

Well, if its a cloudy day you might be staring at the artificial horizon. (IMG:style_emoticons/default/biggrin.gif)
I think what Rich meant is that in an airplane you usually don't have to worry about running into something if you do look at an instrument for more than a few seconds.