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914World.com _ 914World Garage _ Cylinder Head Temps
Posted by: rwilner Mar 12 2012, 07:01 AM
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 $$ on the good stuff.
Before the fillup, I was running between 300 and 325 F in 5th gear around 70-75 mph.
After the fillup, I was running between 380 and 400! 
I spent the rest of the trip in 4th gear at no less than 3500 rpm to try and keep the head temps down. When I got to Chris' shop, we put the car in the air and drained out 5 gallons. I replaced them with 93 octane before getting on the highway for the ride home. My cyl head temps were back down to 310-350 for the return trip.
Here's what I learned:
- A cylinder head temp sensor and gauge are critical to know what's happening in your engine and should be on everyone's short list. Without it I would never have known of the dangerous operating conditions for the engine. The aircraft spruce gauge/probe are short $$ 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.
Rich
Posted by: Racer Chris Mar 12 2012, 10:33 AM
I'll add a data point to your observations.
Yesterday on the way home from a trade show in Warwick, RI I filled my tank with 87 octane. I was planning to fill with 89 but at the station where I stopped just before entering CT all 3 buttons on the pump were 87 
My head temps weren't significantly hotter but the engine did start rattling at 3500 rpm if I pushed it a bit going up hills.
My air/fuel mixture is a bit on the rich side right now for moderate throttle cruise so I was pretty sure the head temps would remain stable.
Posted by: Vacca Rabite Mar 12 2012, 10:36 AM
QUOTE(rwilner @ Mar 12 2012, 08:01 AM) 
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!
What kind of compression are you running, and what engine size?
On 93octane with 9.2:1 compression in my 2056 I'm always in the 370-400 range in 5th, and so am always driving in 4th on the freeway to keep temps down. Works, but not where I want to be. My area has long hills and that is part of the issue, but I still think I can tune it cooler.
Part of the reason I am going to megasquirt is to try and better tune my engine out of the red zone in 5th.
A good head temp gauge is CRITICAL if you are modifying these engines in any way away from stock. Without the gauge, there is no way I can tell from the drivers seat that my engine is getting hot.
Zach
Posted by: rwilner Mar 12 2012, 06:38 PM
QUOTE(Vacca Rabite @ Mar 12 2012, 12:36 PM)
What kind of compression are you running, and what engine size?
I have a stock GA 2.0L except for european Ps and Cs, so that puts my CR at around 8.5:1 I think.
I think a CHT is essential even for stock engines because as the FI parts age the mixture will change which will have a major impact on running temps. My car was giving me no indication of poor running except for the high CHT.
Posted by: r_towle Mar 12 2012, 07:42 PM
Observation
It was warmer on the way down than on the way back.
From charton to foleys is all long ass highway hills.
Your car is not tuned
You never answered me about last weekend.
Rich
Posted by: rwilner Mar 13 2012, 06:48 AM
QUOTE(r_towle @ Mar 12 2012, 09:42 PM)
Observation
It was warmer on the way down than on the way back.
From charton to foleys is all long ass highway hills.
Your car is not tuned
You never answered me about last weekend.
Rich
Rich
80-100 degree differentials are due to more than a few degrees difference in ambient temps...plus, I noticed the spike right after the 87 fill up.
I missed your request for last weekend?
Anyway my O2 sensor isn't working and I've given up on the innovate setup. I bought a completely different AEM setup that doesn't require goofy free air calibrations and doesn't require mounting a separate brain under my car. I'm going to put in this weekend if I can find a few hrs to get into the garage again. After that we can tune it up...until I have a working AFR gauge, we're just guessing.
Posted by: mrbubblehead Mar 13 2012, 06:53 AM
QUOTE(rwilner @ Mar 13 2012, 05:48 AM)
QUOTE(r_towle @ Mar 12 2012, 09:42 PM)
Observation
It was warmer on the way down than on the way back.
From charton to foleys is all long ass highway hills.
Your car is not tuned
You never answered me about last weekend.
Rich
Rich
80-100 degree differentials are due to more than a few degrees difference in ambient temps...plus, I noticed the spike right after the 87 fill up.
I missed your request for last weekend?
Anyway my O2 sensor isn't working and I've given up on the innovate setup. I bought a completely different AEM setup that doesn't require goofy free air calibrations and doesn't require mounting a separate brain under my car. I'm going to put in this weekend if I can find a few hrs to get into the garage again. After that we can tune it up...until I have a working AFR gauge, we're just guessing.
rich do you have an innovate a/f gauge you are having trouble with? error codes?
Posted by: rwilner Mar 13 2012, 12:49 PM
QUOTE(mrbubblehead @ Mar 13 2012, 08:53 AM)
rich do you have an innovate a/f gauge you are having trouble with? error codes?
yep.
No error codes...the LED stays on solid. I just get either full rich or full lean, all the time...like a narrow band. The gauge was showing me I am idling at 9:1 which of course is impossible, especially when I'm fairly certain I'm running lean.
I've tried 3 O2 sensors now, calibrated probably 10 times, updated the firmware, and swung a dead cat over my head at precisely midnight...no joy.
The innovate forums are littered with people having similar problems and the AEM seems more well regarded so I'm going to try it.
Posted by: mrbubblehead Mar 13 2012, 12:53 PM
QUOTE(rwilner @ Mar 13 2012, 11:49 AM)
QUOTE(mrbubblehead @ Mar 13 2012, 08:53 AM)
rich do you have an innovate a/f gauge you are having trouble with? error codes?
yep.
No error codes...the LED stays on solid. I just get either full rich or full lean, all the time...like a narrow band. The gauge was showing me I am idling at 9:1 which of course is impossible, especially when I'm fairly certain I'm running lean.
I've tried 3 O2 sensors now, calibrated probably 10 times, updated the firmware, and swung a dead cat over my head at precisely midnight...no joy.
The innovate forums are littered with people having similar problems and the AEM seems more well regarded so I'm going to try it.
i had the same problem, and did the exact same steps as you. but i finally fixed it. it was pretty simple actually if you are interested. or did you already get the aem.....
mine has been flawless since i added a time delay circuit.....mine didnt work for months. until i built the circuit.
Posted by: r_towle Mar 13 2012, 01:04 PM
yah but......
I read innovate can send everything to your iphone...which would be cool.
rich
Posted by: rwilner Mar 13 2012, 01:08 PM
QUOTE(mrbubblehead @ Mar 13 2012, 02:53 PM)
i had the same problem, and did the exact same steps as you. but i finally fixed it. it was pretty simple actually if you are interested. or did you already get the aem.....
mine has been flawless since i added a time delay circuit.....mine didnt work for months. until i built the circuit.
Yeah...thanks for the offer. I already bought the http://www.aemelectronics.com/wideband-air-fuel-systems-15/analog-wideband-air-fuel-gauge-31/. I prefer it for several reasons:
- It requires no calibration
- There is no separate brain to mount -- all electronics are integral to the gauge
- The indicator lights are integral to the gauge...not a loose LED I have to mount someplace
- it's a small thing, but you can change the illumination color, bezel, and face of the AEM gauge so it matches the VDO gauges
- All reviews and forum posts seem to indicate it's more robust
Thanks though and glad you got your setup to work.
Posted by: mrbubblehead Mar 13 2012, 01:09 PM
QUOTE(rwilner @ Mar 13 2012, 12:08 PM)
QUOTE(mrbubblehead @ Mar 13 2012, 02:53 PM)
i had the same problem, and did the exact same steps as you. but i finally fixed it. it was pretty simple actually if you are interested. or did you already get the aem.....
mine has been flawless since i added a time delay circuit.....mine didnt work for months. until i built the circuit.
Yeah...thanks for the offer. I already bought the AEM setup. I prefer it for several reasons:
- It requires no calibration
- There is no separate brain to mount -- all electronics are integral to the gauge
- The indicator lights are integral to the gauge...not a loose LED I have to mount someplace
- it's a small thing, but you can change the illumination color, bezel, and face of the AEM gauge so it matches the VDO gauges
- All reviews and forum posts seem to indicate it's more robust
Thanks though and glad you got your setup to work.
no prob, i had to get mine to work, i was damned if i was gonna buy another set up. good luck and post up your experiances with it.
Posted by: rwilner Mar 13 2012, 01:23 PM
QUOTE(mrbubblehead @ Mar 13 2012, 03:09 PM)
no prob, i had to get mine to work, i was damned if i was gonna buy another set up. good luck and post up your experiances with it.
maybe post up your time delay circuit so others that have problems with innovate can try your fix?
Also...I may just put a switch in line between the system ground connection and the ground post, which i'll throw after the car has been running for a bit...a manual "time delay"....maybe this will enable me to tune while I get the AEM sorted out.
Posted by: michael7810 Mar 13 2012, 02:02 PM
Rich- I've been wanting to add a CHT gauge for the same reason. Your story convinces me it's time to move. Which CHT gauge from Spruce are you using? I've looked at several on the website but didn't know which one to buy. Thanks,
Michael
QUOTE(rwilner @ Mar 12 2012, 06:01 AM)
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!
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 $$ and a quick install.
- The state of tune has a major impact on running temps (duh). I am still tuning my car with the microsquirt and it's clear I have work to do.
- Higher octane gas makes your car run cooler.
Rich
Posted by: rwilner Mar 14 2012, 07:15 AM
QUOTE(michael7810 @ Mar 13 2012, 04:02 PM)
Rich- I've been wanting to add a CHT gauge for the same reason. Your story convinces me it's time to move. Which CHT gauge from Spruce are you using? I've looked at several on the website but didn't know which one to buy. Thanks,
Michael
Michael
http://www.aircraftspruce.com/catalog/inpages/CHT_gauges.php-- the 2" one. You'll also want the 14mm probe and the 15 foot extension lead.
You may be able to make the 7 foot one work, I cut probably half of the 15 foot lead off...but better to have too much than too little after you go through the effort of routing the wire.
Prices have gone up a bit, looks like the complete setup is around $120...still a bargain in my book though.
Posted by: rwilner Mar 14 2012, 07:20 AM
Also, if you have a few more bucks and want to go first class, Chris sells a http://www.tangerineracing.com/engine.htm#EGTandCHTInstruments which monitors all 4 cylinders with 4 probes.
Posted by: rwilner Mar 14 2012, 07:34 AM
QUOTE(r_towle @ Mar 13 2012, 03:04 PM)
yah but......
I read innovate can send everything to your iphone...which would be cool.
rich
You need a special module to make that happen, which is $$ and my guess is doesn't work very well.
Posted by: ww914 Mar 14 2012, 09:34 AM
Hey Rich
Your post is very timely with me putting the engine back in my car. A couple of questions: The A/C Spruce website shows a spark plug probe and a 14mm probe. Does the 14mm probe go where the existng probe is in the head or do you buy the spark plug one. The third one looks like an egt probe.
(Edit) I think, after doing a little more research, I answered my own question. The 14mm dimension is the size of the spark plug, right. Also, do you think it would be worth it to buy the dual guage to read both head temperatures? 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
Posted by: r_towle Mar 14 2012, 11:07 AM
QUOTE(rwilner @ Mar 14 2012, 09:34 AM)
QUOTE(r_towle @ Mar 13 2012, 03:04 PM)
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
Posted by: rwilner Mar 14 2012, 12:31 PM
QUOTE(ww914 @ Mar 14 2012, 11:34 AM)
Hey Rich
Your post is very timely with me putting the engine back in my car. A couple of questions: The A/C Spruce website shows a spark plug probe and a 14mm probe. Does the 14mm probe go where the existng probe is in the head or do you buy the spark plug one. The third one looks like an egt probe.
(Edit) I think, after doing a little more research, I answered my own question. The 14mm dimension is the size of the spark plug, right. Also, do you think it would be worth it to buy the dual guage to read both head temperatures? 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
Warren,
Read Jhttp://www.914world.com/specs/JakeRabyHeadTemps.php on this site. My summary and opinions below:
"Cyl Head Temp" is a bit of a misnomer because the temperature of the head varies greatly with location. The best place to measure head temperature is under the spark plug, which, as you point out, is why the 14mm ring terminal (0r 12mm if you've had them welded and tapped) is the probe of choice. So, to properly measure the cylinder heads, you'd need 4 channels of measurement (assuming you're running a 4 cyl)...although #2 is hotter than #4, so if you went for 2 channels, those would be the 2 I'd chose.
The hottest location across both cylinder heads is under the #3 spark plug, so if you're only going to run one channel (like me), this is the place to put the probe. The location of the #3 cylinder combined with the stock cooling arrangement dictates this (Foley's and Raby's horizontal cooling systems are designed to correct this deficiency and deliver much more even cooling across all cylinders).
Measuring individual "spark plug" CHTs and measuring EGT at all is probably only necessary if you're racing your car -- running it up by the redline for extended periods. A race engine may have the ability to more easily adjust the tune of each individual cylinder.
Again, the above is just my opinion based on my limited experience on the street and what I've read. Chris, Jake and others may chime in with professional opinions.
Posted by: Racer Chris Mar 14 2012, 12:31 PM
QUOTE(ww914 @ Mar 14 2012, 10:34 AM)
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.
Posted by: rwilner Mar 14 2012, 12:33 PM
QUOTE(r_towle @ Mar 14 2012, 01:07 PM)
QUOTE(rwilner @ Mar 14 2012, 09:34 AM)
QUOTE(r_towle @ Mar 13 2012, 03:04 PM)
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!
Posted by: ww914 Mar 14 2012, 01:45 PM
[/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
Posted by: 76-914 Mar 14 2012, 02:15 PM
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.
Posted by: ww914 Mar 14 2012, 03:16 PM
QUOTE(76-914 @ Mar 14 2012, 01:15 PM)
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.
Posted by: Racer Chris Mar 14 2012, 03:19 PM
QUOTE(ww914 @ Mar 14 2012, 02:45 PM)
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.
Posted by: Elliot Cannon Mar 14 2012, 03:48 PM
QUOTE(ww914 @ Mar 14 2012, 02:16 PM)
QUOTE(76-914 @ Mar 14 2012, 01:15 PM)
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.
Posted by: Elliot Cannon Mar 14 2012, 03:50 PM
QUOTE(Racer Chris @ Mar 14 2012, 02:19 PM)
QUOTE(ww914 @ Mar 14 2012, 02:45 PM)
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.
A CHT for each cylinder is the ideal setup.
Posted by: jsayre914 Mar 14 2012, 04:11 PM
QUOTE(Racer Chris @ Mar 14 2012, 05:19 PM)
With a 4 channel CHT its easy to identify and resolve problems before they become serious.
What guage do you reccomend Chris (4 channel) ??
Posted by: falconfp2001 Mar 15 2012, 12:04 AM
If you can source a CHT Gauge that will take 4 channels then here is the sensor.
http://thesensorconnection.com/category/cht-sensors/all-cht-sensors
Posted by: Racer Chris Mar 15 2012, 02:50 AM
QUOTE(jsayre914 @ Mar 14 2012, 05:11 PM)
QUOTE(Racer Chris @ Mar 14 2012, 05:19 PM)
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 http://www.tangerineracing.com/engine.htm#EGTandCHTInstruments
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.
Posted by: McMark Mar 15 2012, 09:23 AM
I like http://www.aircraftspruce.com/catalog/inpages/1105578.php. It's got 4 CHT + oil pressure + oil temp + other features.
Posted by: ww914 Mar 15 2012, 09:57 AM
......or this one.
Simple and cheap.
http://www.aircraftspruce.com/catalog/inpages/westcombos1.php
Posted by: Racer Chris Mar 15 2012, 10:02 AM
QUOTE(ww914 @ Mar 15 2012, 10:57 AM)
......or this one.
Simple and cheap.
http://www.aircraftspruce.com/catalog/inpages/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.
Posted by: Racer Chris Mar 15 2012, 10:24 AM
QUOTE(McMark @ Mar 15 2012, 10:23 AM)
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.
Posted by: rwilner Mar 15 2012, 10:30 AM
QUOTE(Racer Chris @ Mar 15 2012, 12:24 PM)
The criteria which make a gauge useful in an aircraft are different from an automobile.
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.
Posted by: rwilner Mar 15 2012, 10:37 AM
QUOTE(Racer Chris @ Mar 15 2012, 12:02 PM)
QUOTE(ww914 @ Mar 15 2012, 10:57 AM)
......or this one.
Simple and cheap.
http://www.aircraftspruce.com/catalog/inpages/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.
Posted by: jsayre914 Mar 15 2012, 10:42 AM
QUOTE(falconfp2001 @ Mar 15 2012, 02:04 AM)
If you can source a CHT Gauge that will take 4 channels then here is the sensor.
http://thesensorconnection.com/category/cht-sensors/all-cht-sensors
So type J 14mm is the correct one ??
Type K seems to do more range wich is NA
![popcorn[1].gif](style_emoticons/default/popcorn[1].gif)
Posted by: Elliot Cannon Mar 15 2012, 10:43 AM
QUOTE(rwilner @ Mar 15 2012, 09:30 AM)
QUOTE(Racer Chris @ Mar 15 2012, 12:24 PM)
The criteria which make a gauge useful in an aircraft are different from an automobile.
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"??
Posted by: Racer Chris Mar 15 2012, 11:49 AM
QUOTE(Elliot Cannon @ Mar 15 2012, 11:43 AM)
QUOTE(rwilner @ Mar 15 2012, 09:30 AM)
QUOTE(Racer Chris @ Mar 15 2012, 12:24 PM)
The criteria which make a gauge useful in an aircraft are different from an automobile.
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.
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.
Posted by: rwilner Mar 15 2012, 11:51 AM
QUOTE(Elliot Cannon @ Mar 15 2012, 12:43 PM)
QUOTE(rwilner @ Mar 15 2012, 09:30 AM)
QUOTE(Racer Chris @ Mar 15 2012, 12:24 PM)
The criteria which make a gauge useful in an aircraft are different from an automobile.
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 you're IFR, anyway.
Posted by: McMark Mar 15 2012, 12:10 PM
QUOTE(Racer Chris @ Mar 15 2012, 09:24 AM)
QUOTE(McMark @ Mar 15 2012, 10:23 AM)
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.
Posted by: falconfp2001 Mar 15 2012, 12:27 PM
QUOTE(McMark @ Mar 15 2012, 11:10 AM)
QUOTE(Racer Chris @ Mar 15 2012, 09:24 AM)
QUOTE(McMark @ Mar 15 2012, 10:23 AM)
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.
Posted by: ww914 Mar 15 2012, 01:31 PM
Rich
The Westach CHT KIT that I saw was a total of $218 for guage, switch and four probes. I called A/S to make sure.
Everyone makes good points about the different needs in an auto as opposed to an airplane. I guess it's just about what convenience you are willing to pay for. In my case, I have gone from thinking about no guage, to one gauge and one probe, to four probes, a switch and one guage, to possibly one guage with all readings nearly simultaneous. All this on a street car. Where do you stop? Back to the drawing board, I guess.
One other point, if someone knows anything about the Westach units, please speak up. I would hate to buy crap and then have to start all over again.
Posted by: jsayre914 Mar 15 2012, 01:57 PM
I am learning sooo much from this thread. I have decided one more guage cant hurt 
While looking at all the 4 channel guages, i found that I really like the idea of seeing all four at the same time and the
http://www.aircraftspruce.com/catalog/inpages/1105698.php
seems to be the perfect one, you dont have to view it as a bar graph, if I am understanding the manual, you can read all four as a digital display at the exact same time in real time. look at the last pic of the guage. That is just cool 
Attached image(s)
Posted by: falconfp2001 Mar 15 2012, 02:04 PM
QUOTE(jsayre914 @ Mar 15 2012, 12:57 PM)
I am learning sooo much from this thread. I have decided one more guage cant hurt
While looking at all the 4 channel guages, i found that I really like the idea of seeing all four at the same time and the
http://www.aircraftspruce.com/catalog/inpages/1105698.php
seems to be the perfect one, you dont have to view it as a bar graph, if I am understanding the manual, you can read all four as a digital display at the exact same time in real time. look at the last pic of the guage. That is just cool
Very Nice. Besides being able to monitor CHT on all for cylinders, does MS have the ability to tune to four CHT inputs?Maybe MS 3?
Posted by: Rand Mar 15 2012, 03:31 PM
Any chance this view will automatically switch the channel reading across the top to show just the hottest cylinder? I would love that, best of both: One number reading for hottest temp, and bar graph for quick visual comparison of differences.
Attached image(s)
Posted by: biosurfer1 Mar 15 2012, 03:42 PM
QUOTE(Rand @ Mar 15 2012, 01:31 PM)
Any chance this view will automatically switch the channel reading across the top to show just the hottest cylinder? I would love that, best of both: One number reading for hottest temp, and bar graph for quick visual comparison of differences.
According to the manual, yes you can. The value across the top can either be the highest current value, or a scanning value. It can also store the highest readings for each cylinder in built in flash drive for retrieval later, not to mention you can set alarm levels for each cylinder.
Posted by: Rand Mar 15 2012, 03:47 PM
Very cool! Thanks Brett. I would definitely set the alarm too.
Posted by: jsayre914 Mar 15 2012, 04:27 PM
I called Dave @ Aircraftspruce, and told him we may need a few of these I also told him about 914world and that we would like special pricing because it makes us feel special. He is going to get me a price on 10 of them, if its worth it I will report back to you guys tommorow.
Posted by: jsayre914 Mar 15 2012, 04:46 PM
I forgot we need sensors too, so I called Harold @ The Sensor Connection and told him we need a quote on at least 40 CHT sensors 14mm and he also said no problem, he will get back with me tommorow, he also said he was just about to pick up the MGL guages himself, and he will beat whatever price aircraftspruce will quote me on 10pcs....
this is getting interesting....
i think i smell a group buy starting tommorow
Posted by: ww914 Mar 15 2012, 07:10 PM
Funny how these things work. Good job Joseph.
Posted by: falconfp2001 Mar 15 2012, 08:50 PM
QUOTE(jsayre914 @ Mar 15 2012, 03:46 PM)
I forgot we need sensors too, so I called Harold @ The Sensor Connection and told him we need a quote on at least 40 CHT sensors 14mm and he also said no problem, he will get back with me tommorow, he also said he was just about to pick up the MGL guages himself, and he will beat whatever price aircraftspruce will quote me on 10pcs....
this is getting interesting....
i think i smell a group buy starting tommorow
OK, if you can get this down to about 370 or lower then I think it is a go for a group buy. All vendors welcome to make other offers as I think this has a lot of interest and potential.
Posted by: falconfp2001 Mar 15 2012, 08:51 PM
QUOTE(falconfp2001 @ Mar 15 2012, 07:50 PM)
QUOTE(jsayre914 @ Mar 15 2012, 03:46 PM)
I forgot we need sensors too, so I called Harold @ The Sensor Connection and told him we need a quote on at least 40 CHT sensors 14mm and he also said no problem, he will get back with me tommorow, he also said he was just about to pick up the MGL guages himself, and he will beat whatever price aircraftspruce will quote me on 10pcs....
this is getting interesting....
i think i smell a group buy starting tommorow
OK, if you can get this down to about 370 or lower then I think it is a go for a group buy. All vendors welcome to make other offers as I think this has a lot of interest and potential.BTW, awesome work on the phone.
Posted by: Racer Chris Mar 16 2012, 05:04 AM
Apart from finding a good location for the large format of the TC-2 instrument it appears to be an excellent choice.
The user selectable multiple configuration display is a huge step forward from previously available cockpit gauges.
Heck, I'll buy one if the price is under $400 delivered.
I don't have enough margin on the units I've been selling to offer any discount.
Posted by: rwilner Mar 16 2012, 07:04 AM
QUOTE(falconfp2001 @ Mar 15 2012, 04:04 PM)
Very Nice. Besides being able to monitor CHT on all for cylinders, does MS have the ability to tune to four CHT inputs?Maybe MS 3?
Out of the box, Micro/Megasquirt, like most EFI systems, performs the fuel injection calculation based on a single engine temperature input. For water cooled engines, it's coolant temp; for air cooled engines, it's cyl head temp. There may be other temp sensors, like an air temp sensor, that go into the injection calculation as well...but there is only one *engine* temp input.
It doesn't matter where (within reason) you're measuring engine temp for this calculation as long as you tune the fuel map to the location at which you're measuring. However, for *monitoring the health* of the engine, you need to measure at the hottest spots...under the spark plug.
I suppose if you were running sequential (not wasted) spark, sequential (not batch) injection, and had individual CHT and/or AFR and/or EGT sensors for each cylinder, you could somehow adjust the mixture for each cylinder. No EMS system that I know of supports this out of the box; however, I guarantee you that you could make a system that would do it. Some combination of MS3 and MSExtra components may get you there.
Unless you are planning to run the engine at 99% of its performance envelope for an extended period of time (a purpose-built motor to set a land speed record or something), this level of cost, control, and complication seems excessive. But, it would be wicked fun to try and build it!!
As far as the group buy...I'm in given my recent experience...although the thought of ripping my interior apart AGAIN to run MORE wires makes me sad.
Posted by: rwilner Mar 16 2012, 07:06 AM
QUOTE(ww914 @ Mar 15 2012, 03:31 PM)
Rich
The Westach CHT KIT that I saw was a total of $218 for guage, switch and four probes. I called A/S to make sure.
Warren
You're right. Because they list the prices for each component separately, I thought you had to purchase everything separately. My mistake!
Posted by: rwilner Mar 16 2012, 07:20 AM
QUOTE(falconfp2001 @ Mar 15 2012, 10:50 PM)
QUOTE(jsayre914 @ Mar 15 2012, 03:46 PM)
I forgot we need sensors too, so I called Harold @ The Sensor Connection and told him we need a quote on at least 40 CHT sensors 14mm and he also said no problem, he will get back with me tommorow, he also said he was just about to pick up the MGL guages himself, and he will beat whatever price aircraftspruce will quote me on 10pcs....
this is getting interesting....
i think i smell a group buy starting tommorow
OK, if you can get this down to about 370 or lower then I think it is a go for a group buy. All vendors welcome to make other offers as I think this has a lot of interest and potential.Don't forget we're going to need about 40' of K-type TC wire as well (purple jacket). A complete kit would include the wire, gauge, sensors, and enough terminals / splices to get the job done.
And oh yeah, probably 3 beers.
Posted by: Racer Chris Mar 16 2012, 07:30 AM
QUOTE(rwilner @ Mar 16 2012, 08:20 AM)
Don't forget we're going to need about 40' of K-type TC wire as well (purple jacket). A complete kit would include the wire, gauge, sensors, and enough terminals / splices to get the job done.
And oh yeah, probably 3 beers.
Any connections added to the thermocouple wires may mean the cold junction compensation feature of the instrument won't work. FYI
My 4 channel instrument comes with extended wires on the gauge, so no need for extra wire, but it has no built-in cold junction compensation. If you understand what that compensation does its a minor feature anyway. I put the connectors inside the cockpit where the temp is most stable and closest to the ideal 75F to minimize any inaccuracies.
Posted by: rwilner Mar 16 2012, 07:50 AM
QUOTE(Racer Chris @ Mar 16 2012, 09:30 AM)
QUOTE(rwilner @ Mar 16 2012, 08:20 AM)
Don't forget we're going to need about 40' of K-type TC wire as well (purple jacket). A complete kit would include the wire, gauge, sensors, and enough terminals / splices to get the job done.
And oh yeah, probably 3 beers.
Any connections added to the thermocouple wires may mean the cold junction compensation feature of the instrument won't work. FYI
Chris
My understanding is that the compensation feature will work correctly if the splices for all 4 TC channels are at the same temperature (i.e. in the same location).
Posted by: rwilner Mar 16 2012, 08:25 AM
QUOTE(rwilner @ Mar 16 2012, 09:50 AM)
QUOTE(Racer Chris @ Mar 16 2012, 09:30 AM)
QUOTE(rwilner @ Mar 16 2012, 08:20 AM)
Don't forget we're going to need about 40' of K-type TC wire as well (purple jacket). A complete kit would include the wire, gauge, sensors, and enough terminals / splices to get the job done.
And oh yeah, probably 3 beers.
Any connections added to the thermocouple wires may mean the cold junction compensation feature of the instrument won't work. FYI
Chris
My understanding is that the compensation feature will work correctly if the splices for all 4 TC channels are at the same temperature (i.e. in the same location).
From the TC-2 manual:
9.4 Extending leads of thermocouple probes
Thermocouple leads as used with the EGT and CHT probes can be extended either with ordinary copper cable or with
special K-Type extension cable. The choice of either depends on your desired accuracy. If it is possible in your installation
to ensure that both ends of a copper extension cable will be at the same temperature (or very close), then it is quite
possible to use the copper cable. In most open-air installations this will be the case. Should this not be possible or you
require best possible accuracy at all times, you can obtain a special K-type extension cable. This cable is made from the
same metals as your probes cable and uses ordinary plastic sleeving as insulation. In either case, ensure that the cable is
not routed close to sources of electromagnetic interference of any kind. The voltages present in this cable are very small
and are subject to changes applied by external fields. This can lead to false temperature indications. You can check your
installation by using a hand-held transmitter, such as an air band radio. If you transmit a signal, no change in temperature
reading should occur.
Posted by: ww914 Mar 16 2012, 09:36 AM
This all sounds really exciting, but aside from having to make the clock hole larger (no big deal), I like the idea of a larger display for these old eyes. The other side of the coin is that Chris' set up has been tried and trued, let alone customized for the 914. That might be worth the extra bucks. From reading posts on this thread, some guys have spent a lot of money trying to get it right. Just my thoughts. 
Posted by: jsayre914 Mar 16 2012, 10:11 AM
QUOTE(rwilner @ Mar 16 2012, 09:20 AM)
Don't forget we're going to need about 40' of K-type TC wire as well (purple jacket). A complete kit would include the wire, gauge, sensors, and enough terminals / splices to get the job done.
And oh yeah, probably 3 beers.
I forgot to mention, the quote was for the guage and four J style 10 foot wires with the 14mm rings. No splicing or cutting neccessary. I should have somthing in writing this afternoon.
as far as the beer.... your on your own
Posted by: jsayre914 Mar 16 2012, 10:13 AM
I was told the J style was 1/2 percent more accurate 
and the cost would be about the same.
Does this sound the right way to go??
Posted by: rwilner Mar 16 2012, 10:50 AM
QUOTE(jsayre914 @ Mar 16 2012, 12:13 PM)
I was told the J style was 1/2 percent more accurate
and the cost would be about the same.Does this sound the right way to go??
Joe
The J type will give slightly better *precision* because it is more sensitive (1mV per 25 deg C for J and 1mv per 18 deg C for K), but I believe the *accuracy* of the J and K will be the same.
HOWEVER:
The J type TC uses iron (iron-constantan) as one of the metals. Iron = rust. The K type uses aluminum (cromel-alumel).
I'd recommend going with the K.
http://www.omega.com/thermocouples.html
Posted by: jsayre914 Mar 16 2012, 12:55 PM
so, so far no go.
I have heard from both vendors and they both cried me a river, no margin, no room, etc. I just left a message for Matt, the owner of MGL located in Torrence. I am not trying to make money here, I just want to give his company some good publicity. Heck, he might even own a Porsche
I see no reason to move foreward on the sensors until I can get the best price possible on the guages.
...to be continued.... hopefully within the hour
btw: sensor connection said 10 @ 242 ea
aircraft spruce said 10 @ 246 ea
i think we can do better 
Posted by: Racer Chris Mar 16 2012, 01:30 PM
QUOTE(ww914 @ Mar 16 2012, 10:36 AM)
This all sounds really exciting, but aside from having to make the clock hole larger (no big deal), I like the idea of a larger display for these old eyes. The other side of the coin is that Chris' set up has been tried and trued, let alone customized for the 914. That might be worth the extra bucks. From reading posts on this thread, some guys have spent a lot of money trying to get it right. Just my thoughts.
I just looked at my supplier's website and their listed price for the units I've sold (but without the custom mods I have them make for me) at the same price for at least 5 years appears to have gone up.
I don't have any in stock (can't afford the inventory in this economy) so I may have to increase my price by $50 to keep offering them on my website.
Such a dilemma.
Posted by: falconfp2001 Mar 16 2012, 01:36 PM
QUOTE(jsayre914 @ Mar 16 2012, 11:55 AM)
so, so far no go.
I have heard from both vendors and they both cried me a river, no margin, no room, etc. I just left a message for Matt, the owner of MGL located in Torrence. I am not trying to make money here, I just want to give his company some good publicity. Heck, he might even own a Porsche
I see no reason to move foreward on the sensors until I can get the best price possible on the guages.
...to be continued.... hopefully within the hour
btw: sensor connection said 10 @ 242 ea
aircraft spruce said 10 @ 246 ea
i think we can do better
For what ever discount they give on the gauge, they should make up on the sensors. Just like popcorn at the movies.
Posted by: jsayre914 Mar 16 2012, 03:52 PM
I am satisfied now. I cant get the price any lower. We are getting custom 10 foot sensor's K style (they ended up being the better buy, and they are more common) and the gauge is top of the line.
http://www.914world.com/bbs2/index.php?showtopic=174745&hl= is open.
375.00 plus shipping
Posted by: grogthegreat Mar 18 2012, 08:40 PM
Does anyone know if this kit could be used with Megasquirt to provide the MS ECU with temp info for things like cold start enrichment?
Posted by: shuie Mar 18 2012, 09:03 PM
Those of you who have spent time on the Pelican tech forums over the years probably know who Grady Clay is. If you don't know him, he is a really sharp retired ex-racer & Ace mechanic who raced a 917, owned a 904, Abarth Carrera, currently owns a 2.8L MFI RSR powered -6, etc., and then ran a shop in the Denver area for many years. Anyway, he has posted there many times about his 'rubbermaid solution' for keeping -6 cylinder head temps down during tracks days in Denver at high altitude with crappy fuel. Grady's rubbermaid solution is basically just a cool water reservoir/bladder, a stock VDO windshield washer pump, and a stock washer nozzle that is fixed in front of the cooling fan. The water gets pumped and sprayed into the fan when a switch is flipped from the passenger compartment.
It all sounds pretty hokey when you read about it for the first time on the interweb, but it really works. Grady knows his stuff and has posted the math about how much heat the cool water vapor that is sprayed through the fan sucks out of the -6 heads and the hp figures to back it up over on Pelican for years.
I have seriously thought of implementing something this on my 914 just because of the ambient temps here in the summer months and crappy fuel. I sent Grady a PM about it on Pelican a couple of months back and didn't get a response. I don't know if this kind of thing is necessary for a big IV, but it seems like it might be worth a shot.
Here is an old thread from Pelican where Grady posted the details.
http://forums.pelicanparts.com/porsche-911-technical-forum/150982-water-vapor-cooled-911-rubbermaid-solution.html
Posted by: rwilner Mar 19 2012, 06:21 AM
QUOTE(grogthegreat @ Mar 18 2012, 10:40 PM)
Does anyone know if this kit could be used with Megasquirt to provide the MS ECU with temp info for things like cold start enrichment?
You can use the stock 914 CHT sensor for this, if you're willing to tie the sensor ground to the engine ground.
Posted by: grogthegreat Mar 19 2012, 07:45 PM
Unfortunately me heads no longer have the stock CHT sensor.
Posted by: rwilner Mar 20 2012, 07:12 AM
QUOTE(grogthegreat @ Mar 19 2012, 09:45 PM)
Unfortunately me heads no longer have the stock CHT sensor.
hm...
MS is looking for a NTC (negative temperature coefficient) resistance for head (or coolant) temperature. This is a signal whose resistance is inversely proportional to temperature, i.e., higher temps = lower resistance. The device that accomplishes this is called a thermistor.
The CHT gauges use thermocouples. These devices output a voltage in response to a temperature change -- not a resistance.
Off the top of my head I can think of 3 options for you:
- Do a blind drill and tap in your head to receive a stock CHT...this is really the best option IMO. The location isn't very important.
- Locate or fabricate an NTC thermistor (parts are at digikey, mouser or similar) with a 14mm ring terminal end and put it under #3...this is the least complicated if this device exists or can be easily fabricated
- Purchase a CHT gauge with a resistive output to feed MS...that might be a tall order to locate. I don't think the gauge in this thread has any outputs to feed downstream devices.
Good luck
Rich
Posted by: brant Mar 20 2012, 08:04 AM
QUOTE(shuie @ Mar 18 2012, 08:03 PM)
Those of you who have spent time on the Pelican tech forums over the years probably know who Grady Clay is. If you don't know him, he is a really sharp retired ex-racer & Ace mechanic who raced a 917, owned a 904, Abarth Carrera, currently owns a 2.8L MFI RSR powered -6, etc., and then ran a shop in the Denver area for many years. Anyway, he has posted there many times about his 'rubbermaid solution' for keeping -6 cylinder head temps down during tracks days in Denver at high altitude with crappy fuel. Grady's rubbermaid solution is basically just a cool water reservoir/bladder, a stock VDO windshield washer pump, and a stock washer nozzle that is fixed in front of the cooling fan. The water gets pumped and sprayed into the fan when a switch is flipped from the passenger compartment.
It all sounds pretty hokey when you read about it for the first time on the interweb, but it really works. Grady knows his stuff and has posted the math about how much heat the cool water vapor that is sprayed through the fan sucks out of the -6 heads and the hp figures to back it up over on Pelican for years.
I have seriously thought of implementing something this on my 914 just because of the ambient temps here in the summer months and crappy fuel. I sent Grady a PM about it on Pelican a couple of months back and didn't get a response. I don't know if this kind of thing is necessary for a big IV, but it seems like it might be worth a shot.
Here is an old thread from Pelican where Grady posted the details.
http://forums.pelicanparts.com/porsche-911-technical-forum/150982-water-vapor-cooled-911-rubbermaid-solution.html
We used to do that back in the 80's on a track 914/4
This was before I knew Grady... but it was really a common practice at the time.
it is not ideal for a number of reasons but yes it will work with trade offs.
brant
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