MSefi.com read only forum (Jan.15,2018)

last showing in search was over a year ago with no resolution.

Has anyone used a thermocouple ring under the spark plug?

Any input welcome....

I use the VDO one and wired up the circuit for EGT to measure the head temperture on my type 4 engine.

A type 4 has a mounting location for a CHT doesn't it? and a Bosch sensor available?

I am messing with a boosted aircooled motorcycle that has no OEM provisions.

Over here is a discussion about using thermocouples for CHT.

Are you talking about a VDO sensor or a sensor and dash readout.

I am looking for a stable interface to run the MS for engine temp indicator.

Oil temp is too slow to react so that leaves the head and I am trying to discover the most effective method to sense CHT.

The available options would seem to be using some type of OEM sensor or a sparkplug thermocouple.

It seems a sensor would be the easiest to configure but I am not familiar with what is available.

Are the VW sensors a small package?

The Harley temp sensor is fairly large and a little knobby for a I-4 Yamaha cylinder head.

Something with a 6mm thread and minimal protrusion would be easiest to mount.

The Bosch CHT sensor for a type 4 is a 10mm x 1mm thread about 13mm long.

Maybe extending this thread will be OK?

Anyway I have two thermocouples on a blown/intercooled engine with MS-II and I need to input the manifold air temperature to the controller. I have one thermocouple at the blower outlet above the intercooler core and one below it at the discharge into the intake runners. These are K type, have the yellow connectors. For available leads into the MS-II case I have JS5 on SPR3, pin 5 of the main connector DB-37 which was originally intended for a thermocouple input for monitoring the IC on the other engine but never actually used, and the original MAT SIG lead on pin 20 of the DB-37.

I would like to use the MAT SIG input for the lower thermocouple, and input the upper thermocouple on SPR3, then hopefully display or at least log a temperature differential across the IC core.

The question is, what sort of conditioning circuitry do I need to use the thermocouples on these inputs? I suppose some sort of thermocouple amp is needed? Perhaps something right at the junction between the plug and the lead-in wire? What sort of a small and hopefully not too expensive amp has been used successfully? (and are there better alternatives?)

Jim

You would need to put together an amplifier that converts the signal to a 0-5 volt reading, and a custom INC file with the ADC readings to temperature.

Thanks Matt, any suggestions for a suitable amp? I could locate it at the connectors between the thermocouple plug and the MAT connector if I add power. For now, until I am ready to do the MS3 upgrade that would probably be the easiest. If the amp is small enough I may even be able to mold a housing between the two connector bodies to contain the amp in a neat little package and bring in power from one of the other sensor leads like the TPS for instance. That seems like the cleanest solution. A single channel TC amp ought to do it. I'm pretty sure I saw where somebody on here was using one quite a while back but I haven't been able to find it.

Jim

Here you go.
http://www.analog.com/en/mems-sensors/d ... oduct.html

$15 each for 3*C accuracy or $24 for 1*C from digikey. Is that as good as it gets?

Jim

Maybe. Maybe not. I see some TC amps on digikey for as little as two bucks each but not in stock. Cheapest one in stock is about nine. Maybe allied or hosfelt has something though, and there's another one I can't seem to recall... tyco? something short like that. Have to keep looking. Plenty of SMDs not so many 8 pin ICs. I guess either one could be made to work. Been awhile since I etched a board but a small one could come in handy I guess. But I'm thinking if I pot the two connectors together it may not matter anyway.

Jim