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Exhaust temp question?

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Old 09-16-2003, 06:45 PM
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Exhaust temp question?

I mounted my EGT gauge after the turbo. What should the normal readings be? What should the max temp be? I understand that if you mount after the turbo the readings will be off by about 300' if you had mounted the gauge in the exhaust manifold.....
Old 09-17-2003, 07:45 AM
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Re:Exhaust temp question?

The post-turbo myth is that you have a 300 degree drop from the actual combustion temperatures because of the location of the probe. That is sort of correct, but keep in mind that the turbo acts as a heat sink and not only lowers the temperature, but causes a significant lag in the reading. So, you can get excessive EGT and not be aware of it until too late. However, as the turbo housing heats up on a long and hard pull, the 300 degree difference goes out the window.

If your 03 is stock, you should seldom see over 900 degrees pre-turbo because the OEM fuel system exhaust gas sensor will shut down the fueling after 950 degrees. But, because of the exhaust manifold design, you will see 750-800 degrees post-turbo on a really hard pull. So much for the 300 degree myth! If you are not stock, and have a box that defeats the factory fuel cutouts, you should be able to see 900-925 degrees post-turbo before you need to start to worry.
Old 09-17-2003, 10:58 AM
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Re:Exhaust temp question?

Thanks, I have a 4 inch exhaust, AFE filter and Edge EZ...I heard that you don't want to go over 1000'. I just wanted to make sure....
Old 09-17-2003, 12:23 PM
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Re:Exhaust temp question?

I've got a pre/post EGT setup on my 01 and I've seen as big a difference as 500* between the two at WOT. Normal driving varies from 150*-300*. I've got a BHAF, 4" straight pipe, and a Comp in EZ mode. Personally, I'd scrap the post turbo and go pre turbo. It's amazing how much quicker reacting the pre turbo is and how much hotter it is.
Old 09-17-2003, 01:30 PM
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Re:Exhaust temp question?

RCW - can you clarify your statements of seldom seeing over 900* pre turbo because of fuel shutting off.

I have a STOCK 04 HO and the Thermocoupler is mounted on the exhaust manifold between 3 and 4. This position keeps true to the EGT install parameters of keeping it at least 2 inches from the port exit. I towed for the first time yesterday. I pull a Toy Box that weighs about 6 - 8k. I easily saw 1100* and was able to reach 1275. I might have even been able to get a scratch higher if I tried. I'll be towing this weekend (even heavier) for about 300miles. It is very important to get the factory temps right out of the box... it lets you know what you can safely reach with mods. With a fueling box, your temps WILL go up. With exhaust and intake mods, that number will come down. I've heard as much as 250* between both intake and exhaust. Let's hope, cause the stock temps are already up there pretty good.

Chrismez, if you want to take the guess work out of it, plug that hole (weld or tap), and put the probe in the exhause manifold. Quite frankly, it was the easiest part of the entire guage install.

HP
Old 09-17-2003, 11:55 PM
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Re:Exhaust temp question?

I'm not really towing anything, occationally my friends 19ft boat. I have the Edge set on 70 HP. I don't think I should be too concerned about the EGT during normal driving. I only hot rod it once in a while I just want to make sure....Thaks for the info
Old 09-18-2003, 12:57 AM
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Re:Exhaust temp question?

[quote author=BigDaddyMC link=board=20;threadid=19751;start=0#msg185995 date=1063823436]
With a fueling box, your temps WILL go up.
HP
[/quote]

I don't know bout that. I'm seeing LOWER EGT's with the comp plugged in in EZ mode than with it unplugged. Highest I got stock with a 4" straight pipe and BHAF was 1350* pre turbo. Highest I can get now with comp in EZ mode, 1000* pre turbo. Even with the Comp plugged in and just turned off, I'm seeing lower EGT's.
Old 09-18-2003, 05:12 AM
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Re:Exhaust temp question?

I would like to put one on my truck. Any recommendations for a simple, effective unit?
Old 09-18-2003, 07:04 AM
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Re:Exhaust temp question?

[quote author=chrismez link=board=20;threadid=19751;start=0#msg185923 date=1063814300]
Thanks, I have a 4 inch exhaust, AFE filter and Edge EZ...I heard that you don't want to go over 1000'.[/quote]I don't think you want to exceed 1350F (nor maintain that temp for any period of time); any more than that and you have to be worried about aluminum parts starting to melt.
Old 09-18-2003, 12:35 PM
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Re:Exhaust temp question?

Big Blue - you are right. Your temps probably dropped. They did not drop because you added fuel. They dropped because the timing of the injection changed. This makes for a more efficient cycle. What I should of said is that if you add fuel your temps will go up. This is a fact of life. That being said, many will see a drop in temps when adding these particular fueling boxes due to the timing change. If you use the box in the high setting and tow hard, your temps WILL GO UP. The reason why we suggest guages is for that exact reason. If your not towing heavy, maybe a 20ft Bayliner or a flatbed with a couple of quads, your not likely going to hurt anything and you may not see that significant EGT increase. But take my word for it.... tow 10 - 12k and you'll see that heat rise.

Many owners will never see those kind of temps for the simple reason that they are not big tow/haulers. They get the best of both worlds. A super powerful truck and not much comprimise on the longevity of the motor.

Cheers!
Old 09-21-2003, 01:19 PM
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Re:Exhaust temp question?

I am keeping my Standard Output stock so my question is...when I am pulling my 6K trailer up a long grade on a warm summer day can my EGT's get high enough to damage the motor or turbo with a bone stock truck?

DC say no?
Cummins NW says no?
are they being straight?
I really have not found a gauge or location I would like it so hence no egt monitoring on my truck as of yet.
Old 09-22-2003, 03:56 PM
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Re:Exhaust temp question?

Would someone post a pic of the the thermocoupler installed on an HO 03 or similar truck? I will be installing an X monitor very soon and wanted to check on the best location. Thanks in advance. Bryan
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