Newbie With Exhaust Questions

[MCecil]

Hello All,

I'm new to this board, with this my first post and questions. Some background first.

We just picked up our new trailer last month in Elkhart, IN and towed it home to Washington State. Coming over the Montana Rockies and the Washington Cascades I had pyro alarms (X-Monitor) at the recommended preset alarm level of 900 degrees so backed off accordingly.

I've done a search on this forum, checked Cummins.com (but didn't want to pay $50 to ask a question if I read the info correctly) and got an idunnaknow shrug form my Dodge dealer mech. in looking for the maximum SAFE post-turbo EGT.

So my first question is: What is the safe maximum post-turbo EGT for a prolonged period, such as pulling a long grade, which will ensure no damage to the turbo or engine, and is this spec published anywhere?

My second question is: What is/are the best exhaust mods to maximize the CTD's breathing with all else, save the intake, remaining stock, and what are the trade-offs if any?

Thanks in advance for your inputs.

Merv

 

[ASchwartz]

Not sure of the safe post turbo EGT, as I am running mine pre turbo. I do not think there is a published number from Dodge since they believe that the vehicle as provided by Dodge (stock) does not need gauges. I do know that the third gen's can take more heat then the second gens.



As for aftermarket ways to lower EGT's, ATS exhaust manifold, larger intercooler, afe stage II (noticed you had the mega cannon), and Piers turbo to name a few. You could also install an aftermarket intake manifold, but I saw that you did not want to go that route.



Hope this helps.



Avi

 

[SRadke]

It's difficult to make an accurate measure of how hot the engine is if you measure EGT's post turbo. Too much heat is lost in the turbocharger.



-Scott

 

[ASchwartz]

Not sure of the safe post turbo EGT, as I am running mine pre turbo. I do not think there is a published number from Dodge since they believe that the vehicle as provided by Dodge (stock) does not need gauges. I do know that the third gen's can take more heat then the second gens.



As for aftermarket ways to lower EGT's, ATS exhaust manifold, larger intercooler, afe stage II (noticed you had the mega cannon), and Piers turbo to name a few. You could also install an aftermarket intake manifold, but I saw that you did not want to go that route.



Hope this helps.



Avi

I fogot to mention, a free flowing muffler or straight pipe kit.

 

[DPKetchum]

I've asked the same question several times about post turbo egt from the folkes that INSISTS its where to install it. NEVER have gotton a answer. Until the 3gs I never read a post of it being installed post turbo. About 5 years of reading Diesel forums!

 

[MCecil]

Avi,

Thanks for the info. I've researched the ATS exhaust manifold and have a call into a dealer for an estimate. Gonna get the aFe torque tube to upgrade the aFe to intake stock setup also. Now all I have left to do is convince my wife how absolutely necessary it is to have a good T-304 stainless 4" exhaust... lol.

Thanks Again,
Merv

 

[MCecil]

It's difficult to make an accurate measure of how hot the engine is if you measure EGT's post turbo. Too much heat is lost in the turbocharger.

-Scott

Scott, of course you are correct. I never stopped to think about the variable pressure differentials pre vs post turbo; definately not a linear function for either pressure or temp, one to the other. The laws of thermodynamics rule.

All I need do now is install an ATS exhaust manifold with the pre-turbo port and see the Dr. about the added slope to my forehead from smacking myself after reading your post.

BTW, do you know the maximum safe pre-turbo EGT?

Thanks Scott,
Merv

 

[ASchwartz]

Avi,

Thanks for the info. I've researched the ATS exhaust manifold and have a call into a dealer for an estimate. Gonna get the aFe torque tube to upgrade the aFe to intake stock setup also. Now all I have left to do is convince my wife how absolutely necessary it is to have a good T-304 stainless 4" exhaust... lol.

Thanks Again,
Merv

Merv,



I purchased the ceramic coated exhuast manifold directly from ATS and had them tap it for me. It also came preassembled. I am running 450 degrees and 4. 5 lbs of boost at 70 mph level, unloaded, and with the volumizer set on level 1 (stock). Also if you run a prefilter on the afe, keep it clean.

 

[crobertson1]

Merv,



Here's another thread that may interest you and welcome to TDR.



https://www.turbodieselregister.com/forums/showthread.php?t=140648&highlight=Cummins+EGT

 

[cerberusiam]

The tests I have seen indicate about a 300 degree drop from pre to post turbo prode locations. Max suggested for sustained temps is 1300 degrees so about 1000 on a post turbo setup is a good place to start looking for a lower gear.



A generally accepted rule of thumb is you can do up to 1300 constantly and be pretty safe. Temps 1300 to 1500 should be kept to 2 or 3 minutes out of 5. At 1800 degrees you have about 60 seconds to a melt down. Keep in mind these are guidlines only and it will vary. Type of oil, maintenance frequency, exhaust, etc all play into the equation.



The debate on the probe location rages on. The pre-turbo is the most exact and fastest reacting to changes but always the specter of the probe going into the turbo is mentioned even though it so rare the turbo will probablty succumb to other things first. The post turbo location varies widely with turbo and housing and does not climb as fast so the accuracy is a big question. Either way the temps you are seeing are still well under actual cylinder temps so the best thing you can do is use good oil and change it based on use. If you are running hard and seeing lots of high temps change the oil more frequently. It doesn't take much to plug the cooling ports for the pistons and then you won't need high temps to melt a piston.