Texaschevelle

What is the temp ranger different on these??? I just installed an edge juice w/att and it said plumb it pre turbo, I did, at idle it is in the low 300's, high 200's, when I turn it up and put my foot in it a little it quickly climbs to 1150. What temp is safe on my year truck? I have a dual 3 inch exhaust.

pokapotato

You definitely want the thermocouple in the exhaust manifold. My truck when idling runs at about 280 degrees. I rarley let mine get over 1250 and never over 1250 for prolonged periods of time. Your truck sounds normal to me.

HOHN

I relocated my probe from post to pre. It was initially installed post because I was afraid to drill and tap.

I can tell you that under some conditions, the difference between the two readings was almost 500º.

The pre-turbo (manifold) location is unquestionably where you want to be.

ct2500

mine is pre and when i hammer down i can buriey the gauge at 1600 degress but normal highway drivein is 700 never shut truck off until 300 or lower.

Texaschevelle

500 degrees in which direction? Which location is generally hotter?

ratsun

Pre is going to be hotter, try and instal the probe in the section of manifold that has the exhaust from your #6 cyl as this one usually runs the hottest.

Texaschevelle

Well that is good to know because i did install the gauge at the part closest to the firewall on my manifold

motochamp250

i dont understand why everyone says pre-turbo is where you want the EGT probe. In ALL big trucks it is POST-TURBO......when you put the probe pre-turbo its still reading flame coming out of the motor......i juss dont understand how that is a true EGT reading....

Texaschevelle

I honestly just put it where edge recommended it on an 02

Big Blue24

It may not be a true egt reading in your book but everyone knows the safe level based on that flame coming out of the cylinder. 1250 post turbo in high boost situations will equal a melt down.

FYI, most trucks will make peak HP around 1700* on the pyro. How long she will stay together at that temp is negotiable.

HOHN

Okay, here we go.

A big truck has a completely different purpose for a pyro than a Dodge truck does.

First, the big truck isn't hotrodded. It's designed to run quite clean, actually, and EGTs should always be in check. The engine has a proportionally larger turbine housing the spools much slower but pulls like a freight train and while it runs higher AVERAGE EGT, the peaks are lower.

Pyros are on these truck to monitor the TURBO-- not the ENGINE. They're basically just there to force a trucker to cool the engine a little after a hard run, instead of shutting down right away and heat soaking the turbo.

But on OUR trucks, we aren't as much worried about the tough little Holset-- we're far more concerned with the potential of dangerously high EGT because we're overfueled by 20, 30, maybe 50 percent. VERY different.

Finally, there is no flame in the exhaust manifold. That's a hilarious myth. There are hot gases, not flame. The pyro in the manifold more accurately tells us how hot the gases are in the cylinder-- that's what we really care about. We're not worried about melting the exhaust manifold, we care about pistons and rings and valveseats and such. The gases coming out of the turbo don't tell us much about combustion because the work they do on the turbine cools them down. (loss of enthalpy).


Finally, when a big rig is changed from a mildly fueled stock truck to a higher performance engine, the pyrometer is installed PRE-turbo by Diesel Injection of Pittsburgh.

From Bruce Mallison himself on hotrodding bigrig Cummins engines:
Taken from: http://www.dieselinjection.net/BRUCE...beginning.html

Now, Bruce says 1200 degrees for th eolder engines he deals with, Cummins says 1300 for our engines. The newer HPCR can sustain 1400.

Justin