sorry i have searched everywhere and not been able to find this. i would like to know what egts i should watch for over short and extended periods of time. thanks
nate

 

i do not exceed 1250 degrees while towing, and i didn't even look at the gauge while sled pulling or drag racing. the pyro goes to 1500 on my truck. it has been pegged many, many times for short bursts. the hx 35 held up till 259k miles and the head gasket has never been touched. it has 260k and the hx55 pushes about 50 lbs of boost and runs much cooler than it used too with the hx 35.

 

Gunracer, would your numbers be pre-turbo? I think the post turbo numbers are lower but there is too much guess work so pre turbo is definitely the way to go, in my opinion anyway.

 

Rule of thumb is Post Turbo temps are 300-500 degrees cooler.

1500 pre turbo for extended periods is really bad mojo, so there ya go.


phox

 

Auto meter told me add 200-300 for 6 inches post turbo. They also said that they have had that capillary tube (sensor) come apart pre-turbo so they don't reccomend it. For what a turbo costs I can add 250.

 

People I've talked with who have both a pre and post gauge say the difference can be up to 500°.

 

I have mine mounted post turbo, per 3 cummins certified techs. I mounted the probe as close to the turbo (post) as possible. Had one Cummins tech look at my install afterwards and was told to add 200*.

 

I would never consider mounting the probe post turbo......there are too many variables that will effect the egt when measured there. To have a variance of 200 - 500* degrees is simply unacceptable to me. Engine load has a smaller effect on post turbo temps and ambient air temperature has a larger effect on post turbo temps as compared to pre turbo.....because it is mainly the operating conditions that are the main variables, you see 200 - 500* variance. With this much variation in egt, you could be running dangerously hot and literally not even know......at best, you are guessing what the egt is pre turbo when it is mounted post turbo. Why guess? Why assume your egt is ok? Wouldn't you want to be certain? We are talking about the most important gauge in our CTD's here......isn't this the gauge you want to rely on being the most accurate? Please take the extra time to mount the probe pre turbo.....I think it is fair to say it is worth the extra effort.

I have personally never seen or confirmed an actual case where a probe has broken off in a CTD.....has anyone else?....or is this just another internet rumour? I have heard of them melting and breaking but not in a CTD......if it is getting hot enough to melt the probe so that it breaks off, I think the last thing you will care about is your pyro probe or turbo since there probably won't be much of a motor left to care about......the pistons don't belong in the bottom of the oil pan!!!

 

My feelings exactly CTD. From what I have researched, if that tip did burn off it would just go through turbo and out. It's pretty small.

 

Agreed! All diesel pyro probes of which I am aware are "K" type...good to 2000 degrees!

Also have never heard of CTD probe breaking off.... Have heard the 500* differential figure, under load, from members with two probes.

RJ

 

okay so it should be absolutely safe to never exceed 900? if it is true that it can vary between 200-500* difference, that is saying it would be 1400* at 900* on my gauge.
while towing last weekend it only went over 900* for a few seconds as i crested a hill. it was always under 900* otherwise.
i hate the idea of the probe breaking (pre-turbo), as fast as the turbo spins... i imagine it could really do some damage to the turbine wheel!
if i get an ats manifold i will put it in pre-turbo.
anybody here have the ats manifold and like it?

 

Umm... HELLO?!?!?! Ever think of what a new engine costs? I would gladly pay the $750 or even $1500 for an aftermarket turbo instead of the $10K+ it's costing me to replace my engine... which by the way includes a replacement turbo ($1200) because pieces of my melted piston killed my turbo.

If you insist on putting the probe post-turbo, you'd better add 500 instead of 250 as suggested by xj... Do you really think Autometer would do anything for you if the variance is greater than 250 and you burn up a piston?

But seriously, for the love of God man... and your truck... put it pre-turbo!

 

There was a fellow on TDR a few years back who had an engine melt down after following the 300° pre/post difference rule. Things went fine for him towing his fiver all over the country for over two years till one hot summer day in New Mexico climbing over the Continental Divide in a strong headwind...