Engine/Transmission (1998.5 - 2002) Pre-turbo EGT = cracked exhaust ??

[WEggart]

I am in the process of installing a pyro and have read many threads on this. It seems that you get a more accurate reading if you mount the EGT pre-turbo yet some have reported cracked exhaust manifolds. So how many of you pre-turbo guys have had a cracked exhaust manifold since you did that? Did you have a concern of less or turbulent flow to turbo due to EGT probe?





If I do mount it pre-turbo, what temperature do I wait to until I turn the engine off?

 

[Joe Mc]

I noticed my manifold crack about 2 years after the probe install. I doubt drilling and tapping a hole in cast manifold will relate to a cracked manifold - I've heard of many that crack and do not have a probe. I've read the crack is related to the heat up cool down of such a large/long cast manifold and is usually between #4 & 5 cyl.



The benifit of having the probe pre-turbo is you see what temps are as they leave the combustion chamber not after they've dissipated in the turbo, quicker report of a high temp situation and more accurate cool down report. And I've always shut down @ 300* or less - pre turbo - also read here that's a good "pre-turbo" shut down temp. Good luck to Ya.

 

[WestTN]

I have had my pre-turbo EGT sensor in for about 80,000 miles and have no cracks in manifold. The sensor is 1/8" diameter and does not pose a significant restriction.



As for pre- versus post-turbo shutdown tyemperature, the difference in temps comes from the extraction of exhaust gas energy to drive the turbo. At idle there is no boost so no measurable difference. 300 seems to be the consensus regardless of where the temp is measured. That is low enough to avoid oil coking in the bearings.

 

[aarlucas]

I have my probe pre-turbo and I have no cracks. I also have the 1/8" probe.

 

[DManey]

Mine cracked with no probe in it. Just spent an extra $70 and got the three piece manifold from ATS... Works great.

 

[Trizae]

I had pre-turbo on my 97 and i wasnt cracked when i sold it

 

[WEggart]

Well I installed it and it works fine, pre-turbo. It wasn't as bad as I thought it would be, the drilling and tapping was real slow because I wanted to make sure I got all of the metal particles out of the exhaust. Thanks for the input!

 

[Supermod56]

No cracks on mine, and it does have a nice hole w/pipe plug where some Idiot(me) drilled the probe hole in the wrong place! All that is moot thanks to the ATS Manifold which will be installed shortly. 300F shut down temp is good



Tom

 

[GeneA]

Well, I am one of those that got the cracked manifold right through the hole that was drilled pre turbo. I do agree that the best and most accurate egt reading is pre turbo but have my doubts about drilling an oem manifold. I will say this that I had leaking innercooler boots during a hard RV pull to AK resulting in excessive egt's. The gauge helped me tremendously to keep from cooking the pistons until finally I got the cracked manifold. As I was on the road I hadnochoice but to put on another oem manifold. The Dodge tech told me if I had continued with crack Icouldhave cooked the valves. I have not reinstalled the probe, however.

 

[Joe Mc]

Mine cracked with no probe in it. Just spent an extra $70 and got the three piece manifold from ATS... Works great.

So . . . the extra $70 is $70 more than the cost of the stock manifold?