EGT and Boost

[Don]

I have a 2004. 5 with an automatic and 3. 73 gears that is stock except for Edge with Attitude. When pulling my 5th wheel, I often see EGT's above 1350 and boost above 40. My question is how much is to high and how can I get them down if they are to high?

I've tried to search here for the information, but didn't find it.

Thanks,

Don

 

[cerberusiam]

The answer really depends on what level your running the Edge on. Added fuel and timing demands you keep extended EGT's much lower than what the engine will take stock.



The EGT is not out of line with stock numbers, but, it is pushing it with much dialed into the Juice. The 2nd thing if this is just spikes for a couple seconds on shift points or short hills its not a big deal. As long as you keep it under 1200 degrees constant there doesn't seem to be much problem even with some added power.



If your reading over 40 psi either the Attitude is just not spot on or your adding fuel. To get 40 psi out of the stock turbo and fueling your running at redline with a load. Either way, 40 is about the limit on an analog gauge you really want to go to. Its starting to get out of the turbo map at that point but if it is only short burst then again its not a big deal.



The EJ boxes run hot to begin with and you need to watch extended temps more than anything. A good rule with them is keep it under 1200 constant and no more than 1300-1400 for 30 seconds.

 

[JMarketos]

Side note-
cerberusiam already touched on it, I'd like to offer just a bit more- when my truck was stock, towing meant trans in 4th gear and I found the engine would operate at relatively high boost, and EGTs not critical but well "up there", just pulling a shallow grade. That was towing ~ 6K enclosed car hauler. (In that "stock" config, highway RPMs were around 1700-1800) Eventually I installed a GearVendors overdrive unit and run the truck trans in 3rd, with the GV engaged when towing. This results in engine RPMs of around 2100 for same highway speed as before. That 300-400 RPM increase made a big difference. EGTs are significantly lower when towing, and it runs at lower boost. Towing MPG increased also- was originally 10-11MPG, now with GV it's solid 14MPG, sometimes 15. (side note- that is apples-apples comparison. I put the GV unit on before I put the Banks stuff, so I'm talking strictly before and after the GV, that was the only change). Sorry I can't offer much in the way of info for OP original question- how much EGT is too much etc. I'll leave that to the experts !

 

[AH64ID]

The efficiency of the stock turbo starts to fade at about 35 psi, and I wouldn't run mine over 38 psi.

While the E J/A do sometimes have faults and nearly always read higher boost than an analog gauge they are actually giving a more accurate representation of what PR the turbo is pushing. The E J/A gets boost by subtracting absolute manifold pressure from absolute ambient pressure. If you have an airflow restriction pre-turbo this will manifest with higher than measured boost becuase the intake pressure drops from the suction.

Either way I would be slowing down or dropping the power off, 1350° with added timing is too much for me.

My personal numbers are 1250° continuous and 1300° max.

Best way to drop EGT's is a Smarty Jr, it will also increase power and lower boost for the same fuel burn.

 

[Don]

Thanks for the input. Would a different turbo help?
Don

 

[AH64ID]

Yes a different turbo would help.

The stock turbo is good to about 350 rwhp for towing and not worrying about EGT's, the stock cooling system is good to about 400 rwhp for towing and not worrying about coolant temps.

What power level do you want to tow at?

There are other benefits to a new turbo at less than 350-400 rwhp, just depends on what you are looking for.

 

[cerberusiam]

The stock turbo is good to about 350 rwhp for towing and not worrying about EGT's, the stock cooling system is good to about 400 rwhp for towing and not worrying about coolant temps.

While a new turbo will help it is still more than adequate at the levels he is talking about. I disagree on the HP lmits of the cooling system, its better than that.



The cooling system in good shape is adequate for at least 450 HP constant and possibly closer to 500. While the stock turbo is going to start having issues at 400 HP, the bottom line is nobody runs these trucks at that as a constant level.



Aside from starting off and heavy grades constant use rarely exceeds 200-250 HP. A stock turbo is more than adequate at that level and will support short usage at 400-450 HP. In fact, the stock turbo is probbaly as good or better than anything out there at those levels without dropping a lot of cash. You can get better but the ROI is questionable unless one is wanting to crank things up quite a bit.



While a new turbo would be nice, there are other things that should be higher on the OP's list than a turbo. For the most part, these trucks will tow easily at GCVW in all but the most extreme situations stock. If they are tweaked correctly the stock parts will perform beyond the stock power levels quite well.

 

[AH64ID]

While a new turbo will help it is still more than adequate at the levels he is talking about. I disagree on the HP lmits of the cooling system, its better than that.

He hasn't yet said what levels he tow's on.

The cooling system in good shape is adequate for at least 450 HP constant and possibly closer to 500. While the stock turbo is going to start having issues at 400 HP, the bottom line is nobody runs these trucks at that as a constant level.

How do you figure? 400 is what is generally stated as the towing limit. I believe it, max allowed coolant temp, per Cummins, is 225° with the 190° thermostat. Pulling grades at 80-90% load on a 400 rwhp puts the coolant in the 215° range, only 10° to go, no sure I could hold 50-100 more hp and stay below the 225° max on a warm day. Thou on a cool day I rarely even get over 200°, despite how hard I am pulling the grade. So it really depends if you are building a 365 day truck or a 300 day truck.

Also consider that my cam dropped my coolant temps a few degrees, as did the turbo, and coolant filter... Stock setup pulled about 5-7° more for the same load.

Auto trans trucks will also add heat to the system with both of the coolant exchangers.

Aside from starting off and heavy grades constant use rarely exceeds 200-250 HP. A stock turbo is more than adequate at that level and will support short usage at 400-450 HP. In fact, the stock turbo is probably as good or better than anything out there at those levels without dropping a lot of cash. You can get better but the ROI is questionable unless one is wanting to crank things up quite a bit.

I agree for the most part. At 350 rwhp and the stock turbo I was running too hot on EGT's and coolant when pulling 6-8% grades at 6000' plus, on the flats or lower/smaller grades the stocker does amazing (as long as you don't look at drive pressure!)

I didn't go cheap on my turbo choice but its working better than the stock setup from stock tuning to 400 rwhp.

While a new turbo would be nice, there are other things that should be higher on the OP's list than a turbo. For the most part, these trucks will tow easily at GCVW in all but the most extreme situations stock. If they are tweaked correctly the stock parts will perform beyond the stock power levels quite well.

Agree. . really need to know what setting he has the E J/A on to make further recommendations.

 

[cerberusiam]

He hasn't yet said what levels he tow's on.

Extrapolating from the numbers he posted, it look slike the tow setting of the J/A. That is subject to change when he verifies, but, it is comparable to what others have posted.

How do you figure? 400 is what is generally stated as the towing limit. I believe it, max allowed coolant temp, per Cummins, is 225° with the 190° thermostat. Pulling grades at 80-90% load on a 400 rwhp puts the coolant in the 215° range, only 10° to go, no sure I could hold 50-100 more hp and stay below the 225° max on a warm day. Thou on a cool day I rarely even get over 200°, despite how hard I am pulling the grade. So it really depends if you are building a 365 day truck or a 300 day truck.

5000 HP has been the ceiling as far back as I can remember on the 12V's. Then again, 240 to 260 as a max coolant temp is higher than you suggested. The CR's are better at cooling so all things equal they should be able to go farther longer.



What is the max allows 225 figure though? Constant duty at 70% load, partial duty at 90% load? There has to be a context there for valid comparison. An arbitrary number like that would suggest constant duty, not intermittent spikes. If it is a Cummins number it has a LOT of fudge factor built in, kinda like the EGT limit.



Can I assume the 215 you saw was a mechanical gauge? Still, that load percentage and temp is on the outside of the norm. I personally have never seen that load with my 05, the 12V yes and temps over 240 are not unusual with it. Still running the factory HG at over 300k so I have a pretty good idea there is wiggle room in there.



If one was constantly running and towing at 7000 feet its a different story. The truth is 99% of our roads are in good to excellent air conditions and the grades to the higher elevations are not that long or steep. If one wants to hit every scenario then compounds is the only way.



Like you, waiting to see what the OP runs for power and his normal terrain for better ideas.

 

[mwilson]

Extrapolating from the numbers he posted, it look slike the tow setting of the J/A. That is subject to change when he verifies, but, it is comparable to what others have posted

That is what my '06 equipped with the J/A throws for Boost/EGT numbers on Setting 2 / Towing.



Happens fast under the right circumstances.



Mike

 

[AH64ID]

Extrapolating from the numbers he posted, it look slike the tow setting of the J/A. That is subject to change when he verifies, but, it is comparable to what others have posted.

Man that's way out of my comfort level for towing! If the timing is close to stock the EGT's are fine, but the boost is not good for an HE351!

500 HP has been the ceiling as far back as I can remember on the 12V's. Then again, 240 to 260 as a max coolant temp is higher than you suggested. The CR's are better at cooling so all things equal they should be able to go farther longer.

What is the max allows 225 figure though? Constant duty at 70% load, partial duty at 90% load? There has to be a context there for valid comparison. An arbitrary number like that would suggest constant duty, not intermittent spikes. If it is a Cummins number it has a LOT of fudge factor built in, kinda like the EGT limit.

400 is the only number I can recall seeing on HPCR's, don't know about 12V trucks.

The number comes from Cummins, and to me max is max. I am sure spikes are fine, but for the most part I try to stay under the max.

I list ratings that allow you full use of power under 99% of circumstances.

Can I assume the 215 you saw was a mechanical gauge? Still, that load percentage and temp is on the outside of the norm. I personally have never seen that load with my 05, the 12V yes and temps over 240 are not unusual with it. Still running the factory HG at over 300k so I have a pretty good idea there is wiggle room in there.

I read coolant temps thru the OBDII port. The OEM thermostat doesn't even go full open until 207°. On a hot day with a good load 207° isn't hard to hit, takes a bit of power to get above that thou.

The hottest I have seen my 05 go is 223°, long before mods other than the SJR.

 

[Don]

The earlier post was correct in assuming that I have been towing on level 2.
Don

 

[goodguys75]

I have a 2004. 5 with an automatic and 3. 73 gears that is stock except for Edge with Attitude. When pulling my 5th wheel, I often see EGT's above 1350 and boost above 40. My question is how much is to high and how can I get them down if they are to high?

I've tried to search here for the information, but didn't find it.

Thanks,

Don

back off the gas, more fuel hotter temps..... :-laf

 

[JJPage]

If I tow heavy, and anything over SW1 Smarty TNTR (which has me at 447hp on a dynojet), my coolant temps on my dash gauge starts climbing quickly, never out of the black, but over 200* for sure. Higher than SW1 my egt's were fine, but not my coolant temps.



On SW1 my coolant temps stay just above 200*, and egt's never above 1300, usually 1200/1250 pulling hard. I believe the truck is actually creating more power on the road than on the dyno, because the load is greater...



I guess my point is, 450hp is the max I can tow heavy and stay comfortable, this is my real world experience. Probably pushing it, and AH64ID's recommendation of 400hp is most likely a safer level.



I would actually prefer to tow on the stock setting, more than enough power, but my S04 Smarty will not retain my tire calibration when I return to stock. that messes everything up with my 35"s.