Quad Commander...Pre or Post Turbo EGT Probe

[chills]

Hey Guys,

Quick question...I am installing the Quad Commander with the TS 6 pos, and I was reading through the directions, they have Pre Turbo and Post Turbo mount areas for the EGT probe...What is the prefered method for this probe?

I know the Pre-Turbo goes into the Drivers side exhaust mani just before the turnup, but where would the probe go if I decided to put in Post-Turbo? Or is it recommended to do Pre-Turbo?

Thanks in Advance,

Chris

[Patrick]

Pre turbo is the temp you are most concerned about.

[Ramsmoker]

I'm sorry but I totally disagree. The people that build the engines don't put them in the manifold and haven't since the mid 60's. On a powerstroke you not only have the probe outside one cylinder, but you also have only one bank to judge from. I have had both on at the same time and found over all that there just different. the manifold is a little jumpier but not really any more accurate. Once you get used to it, you will know if something's going wrong. With the manifold, unless you do both sides, you could melt a piston and never know it was happening. Not one of my trucks bought since 1969 have had a manifold thermocouple. My CAT and Cummins dealers stand by the aft turbo mounting.

[stump0331]

i smell a debate brewing

[chills]

Ummm,

Im not debating or arguing the point of Pre or Post turbo, I am nowhere near the expert on these, but, after talking with Larry from DPP, and understanding the concept on Probe placement and purpose, I have it close to the coupling, not by the cylinder, and It is there to monitor the EGT so I dont smoke my turbo. If I was to run Post Turbo, how am I to know what temp the turbo is taking in so I can protect it in the event its getting too hot of an exhaust gas?

[CHenry]

you can run both post and pre tubo if your really want to get down to the nitty gritty. I ran mine preturbo and that was just what I was told to do. I'm no expert either.

[99Smokin73Stroker]

Chills the chances of you actually melting a piston are slim to none unless you just got nuts with mods dumping all kinds of fuel in and whatever....From what I see you just want a little extra power. Sometimes the EGT debate can get really stupid.....I mean jeez.....come on.... You don't have a drag truck or pulling truck, it's your daily driver and you just want to see what your egt's are...you don't have to have a probe in both banks. Ever seen an 03+ Cummins exhaust manifold? The manifold is sort of a two bank setup as well, although it's just one actual manifold. The 4 cylinders toward the front of the engine flow into one chamber down to the turbo and the rear two do likewise. So I guess I'm just going to melt one of the two rear pistions since I don't have an EGT probe to pick up their temps!! As for post turbo, my EGT's vary as much as 4-500 degrees between the two! There've been times I've been "testing," you could say, and seen the pre temp over 1200 but the post is reading around 800 or so. Also some people tell you to shut down at a certain temp, but they don't specify whether to go by the pre or post gauge. My pret temp can get below 300 within a minute, but once again during testing i've seen the post take nearly 5 minutes to even get to 300. They say it's to prevent coking in the bearings. Okay, understandable. But the tests i've run have been very similar whether I had everything stock, or I had the PPE loaded and the TST on. If i'm close to 300 pre i'll go ahead and shut it down. I have a manual so I usually just take it out of gear and coast into the driveway and by then it's cool enough. You're not going to hurt anything...........now put your probe in and enjoy your truck!

[chills]

Originally Posted by 99Smokin73Stroker

Chills the chances of you actually melting a piston are slim to none unless you just got nuts with mods dumping all kinds of fuel in and whatever....From what I see you just want a little extra power. Sometimes the EGT debate can get really stupid.....I mean jeez.....come on.... You don't have a drag truck or pulling truck, it's your daily driver and you just want to see what your egt's are...you don't have to have a probe in both banks. Ever seen an 03+ Cummins exhaust manifold? The manifold is sort of a two bank setup as well, although it's just one actual manifold. The 4 cylinders toward the front of the engine flow into one chamber down to the turbo and the rear two do likewise. So I guess I'm just going to melt one of the two rear pistions since I don't have an EGT probe to pick up their temps!! As for post turbo, my EGT's vary as much as 4-500 degrees between the two! There've been times I've been "testing," you could say, and seen the pre temp over 1200 but the post is reading around 800 or so. Also some people tell you to shut down at a certain temp, but they don't specify whether to go by the pre or post gauge. My pret temp can get below 300 within a minute, but once again during testing i've seen the post take nearly 5 minutes to even get to 300. They say it's to prevent coking in the bearings. Okay, understandable. But the tests i've run have been very similar whether I had everything stock, or I had the PPE loaded and the TST on. If i'm close to 300 pre i'll go ahead and shut it down. I have a manual so I usually just take it out of gear and coast into the driveway and by then it's cool enough. You're not going to hurt anything...........now put your probe in and enjoy your truck!

HAHAHA....Nice response Adam...I needed this last week...hehe I ended up calling Larry, getting some more techie info, and just drilled it. I was more concerned about not having enough diameter and the probe hitting on the opposite, inside wall when putting the probe it. After all, being updside down, looking up at the mani, and trying to twist and turn and drill hoping you're doing it right as a newbie was my concern. The directions offered pre and post but didnt stipulate either one is I recall. Either way its done, and yes, you are right, everyday driver wanting some more ponies to smoke a rice burner every now and then and leave in a black cloud, still looking for a candidate, but hope to find one soon!! :-)

[Logan]

The nice thing about the commander is that you can adjust the EGT sensor. So if you go post, you can bump up the sensor readings to get a little closer to what it would be pre turbo. Just a thought. That way if you think you might be getting too hot, you can adjust it to warn you sooner.

[99Smokin73Stroker]

Originally Posted by chills

HAHAHA....Nice response Adam...I needed this last week...hehe I ended up calling Larry, getting some more techie info, and just drilled it. I was more concerned about not having enough diameter and the probe hitting on the opposite, inside wall when putting the probe it. After all, being updside down, looking up at the mani, and trying to twist and turn and drill hoping you're doing it right as a newbie was my concern. The directions offered pre and post but didnt stipulate either one is I recall. Either way its done, and yes, you are right, everyday driver wanting some more ponies to smoke a rice burner every now and then and leave in a black cloud, still looking for a candidate, but hope to find one soon!! :-)

Yeah drilling is also another touchy subject. I used a few large magnets that I stuck to the outside of the manifold when I drilled mine to help hold shavings to the walls instead of dropping down to the turbo since my mounting location was directly above the inlet. That paired with a greased bit took care of most of the shavings. Afterwards I started the truck and let it idle to blow out any remaining shavings. I think that is the best way and not nearly as time consuming and unnecessary as removing the entire manifold. You can also drill with the engine running, but there are many that wet the bed over drilling with a running engine. The turbo is spinning of course, but it's spinning slowly and shavings are not going to do anything to it. Of course the magnet strategy I mentioned above is also if you have room to fit them along with the drill! And as for the probe, I too thought it was huge and would bottom out but they don't. They scare you though, lol! Enjoy your truck!

Originally Posted by brrs3633

The nice thing about the commander is that you can adjust the EGT sensor. So if you go post, you can bump up the sensor readings to get a little closer to what it would be pre turbo. Just a thought. That way if you think you might be getting too hot, you can adjust it to warn you sooner.

I really don't recommend this method. While there isn't necessarily anything wrong with it, it's just that i've observed way too much variation in temps. Sometimes the temps are closer at the same speed and conditions, and other times they're way off. I think that for a more accurate reading of temps the thermocouple should be in the manifold....just too much margin for aft. If you happen to be one of those that always wastes fuel for often unnecessary cool downs then mount it or a second thermocouple post turbo. The heat retention in the turbo/downpipe area is a little more than you might think, but still not enough (for me at least) to warrant long idle times just for a few degrees. Now after a lot of load exertion on the engine, that's a different story.