EGT temps

changingtime · **Posted:** Tue Aug 16, 2011 9:55 am

For those who have installed a gauge...how long is it taking to get around 400 degrees egt after running on the highway (with nothing and when towing)? also stop and go traffic?

Does your real world results equal what the manual says for turbo cool down?

Joe Romas · **Posted:** Tue Aug 16, 2011 11:46 am

Timley question :BANANA:

I installed a pyrometer just before a 2500 mile vacation trip towing our camper last month :SOMBRERO:

First normal city driving in the summer. 200 is reached by the end of my short driveway and 400 is reached by the end of the block where it mostly stays. Turning on the AC raises it another 100 to 500. Getting on the freeway raises it to 600 then it slowly dropps (ac on) to 500. Once in the parking lot of wally world 8 miles down the interstate it takes about a minute to drop to 400.

Towing a 3000-3500# trailer on interstates in 90 and 100 degree heat :ALONE:

600 is normal with light peddal used to maintain interstate speeds per my tom-tom, not the speedometer. Going up a grade will cause it to raise to 800 and in extreme cases when fuel pressure was cut (outside temperature was over 100 at that point) and full throttle is needed it jumps to 900 and that's when I ease up.

My sending unit is located 150mm per the location GDE calls for. That's about 5.9" and is in about the middle of the 90 degree turn.

On our trip after say an hour or two of interstate driving towing the trailer when I stopped at rest stops it would take at least 5 minutes to get back down to 400 WITH THE HOOD OPEN :dizzy:

I hope this answers some of your questions.
Joe

changingtime · **Posted:** Tue Aug 16, 2011 12:01 pm

perfect. sounds inline with the manual.

DocB · **Posted:** Tue Aug 16, 2011 10:11 pm

On mine, on a hot day, it will not drop below 400* at idle with the A/C on.

The A/C must be turned off for the EGTs to fall below 375* for shut down, which takes about 15 seconds to 2 minutes, depending on how hard you just ran her.

Probe is in the exhaust manifold collector just before the turbo.

Hope this helps.

P.S. Then again, on any vehicle, the A/C should be turned off before shut down, and not started with the A/C already turned on.

geordi · **Posted:** Tue Aug 16, 2011 10:45 pm

DocB, Your probe is in almost the same location as mine is. I have mine in the inlet of the turbo, just b/c it was easier to weld a nut onto the turbo when it wasn't in the engine.

You have to remember: 400 degrees PRE-turbo does NOT EQUAL 400 degrees POST turbo. More like 150-200 degrees. In normal driving, not towing, I will see 700-800 degrees on the highway at 75mph. That is all day long rock steady at that temperature. What does that equal in real numbers, post turbo? Probably about 500-600. Not bad AT ALL for these turbos, and normal drop across the turbo is anywhere from 200-300 degrees, less drop (of that range) when the engine is not loaded heavily.

Its all about pressure drop. Just like the high pressure side of the AC system is hot b/c it is a compressed liquid, the act of releasing that pressure across the orifice tube releases ALL that heat and the pipe is frosty cold and full of vapor. Obviously the turbo doesn't cool THAT much, but the principle is the same. I have seen 1400 degrees for extremely brief periods on my EGT gauge (less than 30 seconds at a time) but even when towing, the normal running temp on the highway is only up to 1000. And even on my pre-turbo gauge, the temp is down to 500 almost immediately after I let off. Certainly an off-ramp and the inevitable light at the end is more than enough time that I don't even think about it unless I am towing a lot.

For the people who see higher temps on a post-turbo gauge, and in normal not-towing driving... What is your exhaust system set up as? Stock? Cat, but no muffler? No cat, muffler? Nothing but an open pipe?

Mine is a Flowmaster all-metal muffler (2.5 inch) and nothing else but 2.5 inch pipe. I kept the stock tail behind the muffler b/c I don't think that matters much. Maybe y'all are having too much backpressure?

EGT temps

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