 Installed an EGT Gauge today..., Only took 10 minutes |
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| McMark |
 Nov 3 2007, 07:29 PM
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#1
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914 Freak!  Group: Retired Admin Posts: 20,179 Joined: 13-March 03 From: Grand Rapids, MI Member No.: 419 Region Association: None  |
I've had this Exhaust Gas Temp gauge sitting around for a couple months and while I had the car up on ramps getting a new fuel filter (and it needed it!) I decided to pop this guy in place.
I got the parts from Aircraft Spruce, this guage, this clamp-on probe, and this 15' extension cable. All told, I spend around $100. This gauge has the benefit of being semi-original looking, ambient temperature compensated, and matches my Micro1000 CHT gauge. All I did to install it was drill a small hole in the exhaust tube, and insert the probe, tightened everything down, attached the cables and ran them to the cabin. I drove the car around the block, which was very interesting. My car has been running very poorly ever since returning from the RRC, and I thought it was just the fuel filter. But it's not. It was very interesting to watch the needle moving as I opened and closed the throttle and it also helped me visualize the problem that I'm having. My car has been intermittently losing power, and I would be driving along at a nice EGT, and the car would lurch, and I would look over and the EGT was extremely low. And since it is my understanding that EGT is more affected by timing than AFR, I can be pretty confident that for some reason my timing is wonky. This may be the KitCarlson EFI dying or a bad wiring harness connection. It might be time to *GASP* install a spare set of carbs and a Mallory. (IMG:style_emoticons/default/ohmy.gif) This was an affordable and easy upgrade. I expect that it will be a useful tool for tuning the motor and if anyone has an extra gauge slot to fill, I would recommend an EGT after you have a CHT. |
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| TimT |
Nov 3 2007, 07:43 PM
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#2
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retired Group: Members Posts: 4,033 Joined: 18-February 03 From: Wantagh, NY Member No.: 313 |
Timing does affect EGT but not as drastically as you might think. It sounds like when " the car would lurch" you are experiencing a miss, or intermitent ignitoin failure.
The relationship between timing and AFR does show in your EGTs, in the end though tune with AFR. |
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| Rand |
Nov 3 2007, 07:53 PM
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#3
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Cross Member Group: Members Posts: 7,409 Joined: 8-February 05 From: OR Member No.: 3,573 Region Association: None |
This stuff is interesting to me. If for nothing else than the educational factor, I want to put both an EGT and AFR gauge in and learn how to optimally tune an engine - carbs and FI.
Thanks for sharing this Mark. Good to know about some parts options with ballpark pricing. For those who have had experience with AFR gauges, what do you recommend? Clearly it should be wideband, but what kits exactly and what are good prices? Any thoughts on this NGK unit? -> http://www.powerdex.com/ |
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| McMark |
Nov 3 2007, 08:42 PM
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#4
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914 Freak! Group: Retired Admin Posts: 20,179 Joined: 13-March 03 From: Grand Rapids, MI Member No.: 419 Region Association: None |
I have an Innovate Motorsports LM-1 that will get installed sometime soon as well. That will round out my gauges and give me lots to look at while I'm driving. (IMG:style_emoticons/default/wink.gif) (IMG:style_emoticons/default/laugh.gif)
Thanks for the tips Tim. I always appreciate your perspective. You have way more experience than I do. (IMG:style_emoticons/default/smiley_notworthy.gif) |
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| ConeDodger |
Nov 3 2007, 09:49 PM
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#5
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Apex killer! Group: Members Posts: 23,579 Joined: 31-December 04 From: Tahoe Area Member No.: 3,380 Region Association: Northern California 
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QUOTE(McMark @ Nov 3 2007, 07:42 PM)  I have an Innovate Motorsports LM-1 that will get installed sometime soon as well. That will round out my gauges and give me lots to look at while I'm driving. Great! Then you will never see that deer you are about to hit!!! (IMG:style_emoticons/default/biggrin.gif) |
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| McMark |
Nov 3 2007, 11:28 PM
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#6
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914 Freak! Group: Retired Admin Posts: 20,179 Joined: 13-March 03 From: Grand Rapids, MI Member No.: 419 Region Association: None |
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| restore2seater |
Nov 4 2007, 12:19 AM
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#7
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Future 914 copilot. Group: Members Posts: 311 Joined: 30-October 04 From: Dunlap,IL Member No.: 3,037 Region Association: None |
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| McMark |
Nov 4 2007, 12:49 AM
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#8
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914 Freak! Group: Retired Admin Posts: 20,179 Joined: 13-March 03 From: Grand Rapids, MI Member No.: 419 Region Association: None |
I have absolutely no complaints about it. Installation was easy and straight forward and so far it has worked great. The numbers are a little hard to read, but realistically, you don't read the numbers after the first few drives, after that you are just used to it and just look at where the needle is.
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| toon1 |
Nov 4 2007, 01:12 AM
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#9
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Senior Member Group: Members Posts: 1,849 Joined: 29-October 05 From: tracy,ca Member No.: 5,022 |
What are your EGT temps.? What is good temps for EGT on these motors?
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| McMark |
Nov 4 2007, 01:16 AM
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#10
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914 Freak! Group: Retired Admin Posts: 20,179 Joined: 13-March 03 From: Grand Rapids, MI Member No.: 419 Region Association: None |
According to my reading on the RAT Forums, 1275 is a good temp for WOT, and at 1375 you should start looking for your motor to explode. (IMG:style_emoticons/default/cool.gif) But I have no real world experience at this point, my reading ranged from 900 to 1400 at various points and was changing rather quickly. I only took a quick trip around the block to test out the EGT and to see if my new fuel filter fixed my problem.
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| ConeDodger |
Nov 4 2007, 01:25 AM
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#11
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Apex killer! Group: Members Posts: 23,579 Joined: 31-December 04 From: Tahoe Area Member No.: 3,380 Region Association: Northern California
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QUOTE(McMark @ Nov 4 2007, 12:16 AM) According to my reading on the RAT Forums, 1275 is a good temp for WOT, and at 1375 you should start looking for your motor to explode. (IMG:style_emoticons/default/cool.gif) But I have no real world experience at this point, my reading ranged from 900 to 1400 at various points and was changing rather quickly. I only took a quick trip around the block to test out the EGT and to see if my new fuel filter fixed my problem. Hi Mark! Glad to hear you got out of the new house for a bit. Did the EGT guage have a screw in sensor offered? I have the O2 sensor bung welded on my header and with the Dells it would be a waste to use an O2 sensor... |
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| McMark |
Nov 4 2007, 01:35 AM
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#12
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914 Freak! Group: Retired Admin Posts: 20,179 Joined: 13-March 03 From: Grand Rapids, MI Member No.: 419 Region Association: None |
The EGT probe is very small. You would have to custom fab something to adapt and O2 bung to an EGT bung. Actually, it wouldn't be too bad, just drill a hole in an O2 bung plug, and weld the EGT bung onto the O2 plug... (IMG:style_emoticons/default/idea.gif)
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| blitZ |
Nov 4 2007, 10:03 AM
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#13
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Beer please... Group: Members Posts: 2,223 Joined: 31-August 05 From: Lawrenceville, GA Member No.: 4,719 Region Association: South East States |
Interesting info. How close to the head must the sensor be mounted to get an accurate read? Do you need to monitor all four cylinders or is one enough?
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| gregrobbins |
Nov 4 2007, 10:45 AM
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#14
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Member: Team NARP Group: Members Posts: 1,515 Joined: 23-March 04 From: Arizona Member No.: 1,844 Region Association: Southwest Region |
QUOTE(ConeDodger @ Nov 4 2007, 12:25 AM) I have the O2 sensor bung welded on my header and with the Dells it would be a waste to use an O2 sensor... Not so quick, the Formula Vee and Formula First crowd use the Innovate LM-1 for tuning their motors. They only run a single carb. SR Racing sells them. Here is what they said: A high quality Wide Band 02 Sensor with Data Logging (44 minutes) and expandability. We use one here at the shop on our engine dyno. The LM-1 can be expanded with the addition of the RPM Adapter and you have Wide Band 02 Sensing AND 4 additional inputs for anything else you want to data log (Temps, Pressures, RPM, Throttle position etc.) Fully programmable for mapping to any type of sensor you can think of. So that bung might be useful after all. Mark, thanks for the post and link to the site. The CHT dual gauges are affordable and two would allow you to moniter all four cylinders. |
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| McMark |
Nov 4 2007, 02:06 PM
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#15
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914 Freak! Group: Retired Admin Posts: 20,179 Joined: 13-March 03 From: Grand Rapids, MI Member No.: 419 Region Association: None |
With all the talk of 'cold-junctions' and wire extensions compromising CHT readings, I never understood why putting a selector switch for the gauge was never a problem. Isn't extending the wires a big no-no?
Somebody talk thermocouples to me... (IMG:style_emoticons/default/cool.gif) |
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| blitZ |
Nov 4 2007, 03:29 PM
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#16
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Beer please... Group: Members Posts: 2,223 Joined: 31-August 05 From: Lawrenceville, GA Member No.: 4,719 Region Association: South East States |
IIRC, the thermocoupler measures the difference in temperature between the end where the reading is taking place and opposite end. It assumes the ambient temperature for the end closest to the gauge to be some static temperature like 78 degrees. As long as you don't cut the thermocoupler then it is fairly accurate. You can add wire as long as it is under a certain gauge to reach the gauge if needed.
This is is based on the instructions received with my CHT. |
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| ConeDodger |
Nov 4 2007, 03:40 PM
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#17
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Apex killer! Group: Members Posts: 23,579 Joined: 31-December 04 From: Tahoe Area Member No.: 3,380 Region Association: Northern California
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QUOTE(McMark @ Nov 4 2007, 12:35 AM) The EGT probe is very small. You would have to custom fab something to adapt and O2 bung to an EGT bung. Actually, it wouldn't be too bad, just drill a hole in an O2 bung plug, and weld the EGT bung onto the O2 plug... (IMG:style_emoticons/default/idea.gif) I know *someone* who would just JB Weld it!!! (IMG:style_emoticons/default/biggrin.gif) |
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| McMark |
Nov 4 2007, 05:14 PM
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#18
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914 Freak! Group: Retired Admin Posts: 20,179 Joined: 13-March 03 From: Grand Rapids, MI Member No.: 419 Region Association: None |
(IMG:style_emoticons/default/av-943.gif)
Don't poke a sleeping.... um.... well, regardless don't (IMG:style_emoticons/default/poke.gif) . |
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| ConeDodger |
Nov 4 2007, 09:03 PM
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#19
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Apex killer! Group: Members Posts: 23,579 Joined: 31-December 04 From: Tahoe Area Member No.: 3,380 Region Association: Northern California
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QUOTE(McMark @ Nov 4 2007, 04:14 PM) (IMG:style_emoticons/default/av-943.gif) Don't poke a sleeping.... um.... well, regardless don't (IMG:style_emoticons/default/poke.gif) . What??? What did I say??? (IMG:style_emoticons/default/biggrin.gif) |
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| Aaron Cox |
Nov 4 2007, 09:15 PM
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#20
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Professional Lawn Dart Group: Retired Admin Posts: 24,541 Joined: 1-February 03 From: OC Member No.: 219 Region Association: Southern California |
a switch has resistance......
so your true CHT reading would be skewed going through a switch. You would have to find a switch with ZERO resistance.... extending wires is a no-no! (adds resistance!) BUT!!! you can shorten a CHT harness, if you know EXACTLY how much resistance it had in the full length harness, cut it to desired length, and add a resistor to let it reach its original resistance.... i think... cuz yall know i dont know shiiiit |
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