EGT owners, HELP - wire length problem
 

I bought an EGT Gauge from Auto Meter (Sport-Comp). The Gauge comes with an 8 foot wire/cable to connect the gauge to the probe. The instructions state that the length of the cable may not be increased or decreased because the reading will be compromised. I guess the wire has a specific resistance for the calibration of the gauge.

What are the options here?
Are there longer cables that will not compromise the reading?

I haven't called Auto meter since I bought the gauge from a friend and decided to ask here first.

I assume that the sensor is a Type K or Type J thermocouple. The leads can be extended if you use the proper type of matching thermocouple wire ... just don't try to use ordinary copper wire! Try a local HVAC supplier ... they should be able to sell you however many feet of additional Type K, or Type J thermocouple wire you need ...

How can I tell if it is a type-K or type-J thermocoupe? I just spent some time on the web and I could always find that the Autometer EGT gauge that comes with an external module uses the type-K, but I could not find the type for the gauge that I have which does not use an external module.

I'm not too up on all the compatibility issues of type K thermocouples. If they have the same connector design, Fluke (manufacturer of digital meters) sells type K thermocouples. They also have a type K harness kit to extend the reach of their thermocouple sensor. Not too expensive but not sure what you and they have are compatible. Check the Fluke website for pics and info.

Sherwood Lee
http://members.rennlist.org/911pcars

there may be a specific type of solder involved.............Ron

Silver solder.

Sherwood

not sure if that was the issue w/EGT wire.. had something to do w/ the high nickel of the wire.. maybe it was the use of zinc chloride flux............Ron

The shop that repaired my type K thermocouple said they used silver solder. Not sure about the EGT wires in your setup.

Sherwood

According to the Autometer installation manual solder should not be used because it affects the calibration. Maybe they assume the general public will not be using Silver solder?

Until the real brains weigh in on this, this is my take on it:
I don't think it is the resistance of they are worried about. A thermocouple wire is just two different metals ("dissimilar metals") sandwiched together or even just wrapped around each other. When you heat them, they produce a small current. If you connect these wires to some other kind of wire you have produced another a junction between two dissimilar metals i.e. another thermocouple. This would be sort of like using a battery for one of your sensor wires; it's going to throw your measurements off.
-Chris

So far I still have the problem that I don't know wether I have a K-type or J-type thermocouple. Once I figure this out, my guess is it should be fine as long as I buy thermocouple extension wire for the correct type of thermocouple as Warren Said.

I have a JPI unit on order.. the JPI tech said I could entend the connectiing wire a LIMITED length by DIY soldering.. so I had them do the 15ft harness extension.. I kinda picked up that it was a sensitive solder job.. and he stressed that I use the engine ground for the instrument computer.. probably to maintain the same grounds as the K probes.. the K probes are grounded in this type of system/maybe all probes are grounded, don't know.........Ron