What is a flow meter

[PaulHail]

I don't see a thermocouple probe offered by eagle tree. The problem is that as far as I know the smallest diameter high temp thermocouples are 1/8" diameter. Not a big deal in a 1 1/2" or larger header in regards to disrupting flow, I would be concerned that in a 7/8" header that the flow disruption would be to the point of robbing some engine power. If someone made a 1/16" or 2mm diameter probe, I think you'd be good to go but I don't think such a beast exists.

Paul,

The Eagle Tree logger (black box data logger version) comes with an RTD type of temperature sensor. This is intended to measure cylinder head temp by wrapping it around the head of an engine. The RTD sensor is only good to about 450 deg max. In order to measure Exhaust Gas temperature, Eagle Tree offers a thermocouple expander board. This allows you to connect a type K thermocouple - which goes up to something like 2000 deg. The expander board allows for two thermocouples. The type K thermocouples can be purchased from other companies that specialize in industrial type ones.

I am using a 1/16" diameter thermocouple to measure exhaust gas temp in an 67 and 90 nitro application. The end of the thermocouple extends into the center of the tuned pipe to read the gas temperature. I have the thermocouple located right next to the tank pipe pressure tap. I have not found a smaller diameter than 1/16" that would work for the application. I am sure they exist - just have not found yet. The thermocouples I am using come from a company called Pyromation.

I chose to locate the EGT sensor at the center of the tuned pipe (widest section) vs in the header to minimize flow disruptions - as you mention above.

Hope this helps.

Mike

Mike,

Thanks for the info. I'd think a 1/16" thermocouple wouldn't disrupt the flow too much. It would take some dyno testing to confirm the effect of locating it in the header. IMHO where you locate it isn't nearly as important as knowing what the danger temp is and keeping just under that temp.

Now if someone made an expander for my Hitec Lynx so I could run a thermocouple on my exhaust.

 

[Mike Larson]

You can get the parts from Dwyer to build your own propane style for a little over 100... youll need a regulator off a coleman propane stove or equivalent... and skills to build a box... somebody... has the plans floating around on the forum that lists the guage number you buy.... and how to build the thing... marty and I got ours from here... and they had a range sheet with numbers for the engine displacement sizes for a baseline start too... idk.... somebody tap fingers... now... Even with the boris style meters... I have both.... I rarely use either... except to pre set my third channel needle to a known baseline number... because... I raced at the same elevation in my district and one other.... that in reality... my top end just take the plug out setting will and always has been within my third channel needle swing... so... during mill... I find the engine and its done... up to you... now... rarely... rarely... in spring and fall with just awesome oxygen conditions... have I ever had to change my main on my third needle.... maybe 4 times in 15 yrs... granted... I raced south Carolina twice.. and went from 600 ft... to sea level... and... at a race of that proportion and size open water showed me a massive main needle change to test... found quickly... flowed best run with boris and race er up... idk... use the tools you have... keeping statistics never was in my stature vs the engines wear out quickly and change... nitro..., whatever ... sometimes I never variable my boats to death... good luck... build em up.....