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24v pyro gage

T

Trango

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Any standard mechanical pyrometer will work for you. As has been stated, the light is going to be 12v, but it's not that hard to figure out a small resistor to wire in series to drop the voltage to let it run on 24v.

I have one on my M35 - it was very very easy to wire up and figure out.
 
M543A2

M543A2

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I agree with the comments of the others in this thread. If the gauge is lighted, many time we find we can find a 24 volt bulb that will fit in the same socket. I bought my gauges from Aricraft Spruce. Enter their name in Google and they will come up. Look for EGT gauges. They have quite a selection. You can get a nice gauge for about $150. No need to pay $300 or more.
For our boost gauges we use an off the shelf air pressure gauge and run a line to it from the intake manifold. Again, no reason to waste your bankroll on high priced specialty gauges that do the same thing. Leaves you money to spend elsewhere on your truck!

Regards Marti
 
B

Blood_of_Tyrants

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I pyrometer works with a thermocouple. The thermocouple is just two wires of dissimilar metals that generate a very small voltage depending on the temperature. The meter is a gauge that is sensitive to the change in voltage. As said, the only thing you need to worry about is the voltage of the illuminating light.
 
jatonka

jatonka

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Get ahold of Scrapman here on Steel Soldiers, he sent me a beautiful Stewart Warner Pyro with thermocouple last summer. If he has more, his price was excellent and the gauges are top notch. I changed the 12 volt bulb out to an 1893 dash bulb 24 volt. It is a great setup. I mounted the thermocouple in the elbow just after the Turbo and add 100 degrees to the reading to be safe. JT out
 
ccequipment

ccequipment

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Here is a 3" stewart warner, its a nice quality gauge. I like it because of the colors on the gauge, just a quick look and you know were your egt's are. That way you can spend more time looking at the road. I installed the thermocouple in the front port of the exhaust manifold in the 1/4" NPT hole, it was just a bolt on install, no holes to drill. I just used a 24 volt gauge for lighting. Simple easy setup.
 

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m-35tom

m-35tom

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all well and good, but the newer more accurate and more sensitive gauges use a dc to dc amp to drive the meter, puttng no load on the coupling. with these it is just a matter of hooking them up to 12 vdc, checking the current draw and calculating a 12 volt drop accross a resistor for 24 volt use.
 
wdbtchr

wdbtchr

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ccequipment said:
Here is a 3" stewart warner, its a nice quality gauge. I like it because of the colors on the gauge, just a quick look and you know were your egt's are. That way you can spend more time looking at the road. I installed the thermocouple in the front port of the exhaust manifold in the 1/4" NPT hole, it was just a bolt on install, no holes to drill. I just used a 24 volt gauge for lighting. Simple easy setup.
Click to expand...
How does mounting it before the turbo effect the reading? Is it hotter or colder than after?
 
m16ty

m16ty

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I've been debating where to put my probe. I was first set to pull the turbo and drill the manifold but after reading alot on this subject I may go post-turbo.

Any of the major gauge manufacturers and diesel engine sites say it's ok to go post-turbo as long as you add 200-300deg. Most trucks that have a pyro from the factory has the probe post-turbo also.

I figure if I go post-turbo I'll just keep it around 1,000deg and be ok.

I'm still kind of on the fence on this so feel free to convince me otherwise. :wink:
 
mudguppy

mudguppy

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steelandcanvas said:
Not really, just add 100 degrees. At the time, it was much easier to install the probe post-turbo.
Click to expand...
if you think that's how it works, you are quite mistaken. :rolleyes:

the pressure differential [drop] post turbo will greatly alter temperature indication. gasses pre-turbo are high because of turbine drive pressure; high pressure equals higher temperature. as pressurized gas expands, temperature drops.

your motor is seeing heat from the high pressure side - no one cares what the heat is on the low pressure side. this temperature difference could be 500° or larger in high boost scenarios.

'just add 100°'? come on guys, this is high school physics...
 
mudguppy

mudguppy

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m16ty said:
I've been debating where to put my probe. I was first set to pull the turbo and drill the manifold but after reading alot on this subject I may go post-turbo. ...
Click to expand...
look, drilling / tapping for the probe is easily done with the turbo still on the truck. it should take less than 20 minutes. or, as someone else posted, it looks like there's a fitting already tapped for use - it doesn't get any easier, and it's the right way to do it.


m16ty said:
... Any of the major gauge manufacturers and diesel engine sites say it's ok to go post-turbo as long as you add 200-300deg. Most trucks that have a pyro from the factory has the probe post-turbo also.

I figure if I go post-turbo I'll just keep it around 1,000deg and be ok. ...
Click to expand...
yeah, that's not how that works. you think a guage vendor is going to give a flip when you tell them you melted some pistons and ruined your engine?

let me over-simplify this for you [and others]. remember that (P1/T1)=(P2/T2) thingy? alrighty then, lets say you're aiming for 1200° (T2). now, you're turbo may only make 12-ish psi of boost, but it may take better than 20 psi of drive pressure to do that (P1). so lets just use those numbers. also, we'll say P2 is basically atmospheric pressure. therefore,

P1/T1 = P2/T2, or T2 = (P2 x T1) / P1 = (15psi x 1200°) / 35psi = 514°.

so, sure, just add 200°-300° and you'll be fine... right? well, just as long as you're not using any drive pressure to create boost, you'll be fine. the only time your readings will be "completely worthless" is when you're dumping in fuel to increase drive pressure to raise boost to go. so just don't go. [obviously, there's also volume to consider, but it's still against the post-turbo theory.]


i hate to be so sarcastic, but i don't like seeing blatantly erroneous advice thrown around. so, do some reading and do it right. just do a search for 'pyro' or something and there will be plenty of discussion on how to tap your manifold with the turbo on the truck.

and if you have any questions, shoot me a pm and we can discuss. don't be scared, just get educated. you've got anough working against you with keeping the multifuel reliable, you don't need bad advice on top of that.
 
jatonka

jatonka

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Well, travis, you spent a lot of energy on trying to educate some of us, so I will spend some and install a thermocouple ahead of the turbo on my Hot Rod Deuce. Tell me exactly where you want it installed and I will compare the difference between pre turbo and post turbo probes. I will be using Sterwart Warner aviation Pyro gauges and he K couples that come with them to do this comparison test. I have 2 of each so they can run at the same time. Just waiting for you install instructions JT out
 
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