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4x4ord

Alberta

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Joined: 12/23/2010

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Posted: 12/16/20 11:15am Link  |  Quote  |  Print  |  Notify Moderator

ShinerBock wrote:

4x4ord wrote:



That is a cool pic. I am not certain how the ECM determines when to defuel to keep your engine from melting down but my suspicion is that your not making 385 hp on a 100 degree day pulling a long steep grade. Shiner can probably set me straight here.

I think safe temperatures are controlled based on things like charge air temp, boost pressure, rpm and the amount of fuel being injected. (Basically EGT can be calculated without being directly measured). So it is likely that defueling occurs based on indirectly measured EGTs. Because the engine defuels on long hard pulls in hot weather the radiator is not being taxed the way it would if the engine was able to put out its full power all the way up the hill. I would be very interested in knowing what it takes to get these trucks to defuel on a long hard pull in 100 degree heat. I think when our pickups defuel it might not be that apparent ...we don’t feel a sudden power loss ... rather the power tapers off. (Im not aware of a time that my pickup defueled but then I’ve never pulled a long steep hill in 100 degree temps)

I’ve never witnessed my Peterbilt defuel on account of EGTs ... The 15 litre engine will put out 550 hp and pull like a freight train until the coolant gets hot. At 220 degrees a red light comes on but there is no reduction in power. I believe it’s 230 degrees where the engine light comes on and the power is suddenly and severely backed off till the coolant drops back down to 220. (It very seldom happens that 230 degrees is reached but 220 is fairly common)


1) There are many variables that cause an engine to defuel, not just EGT's. On a 100F day, he might be closer to 360 hp depending.

2) Not all engine are designed the same and may have different cooling needs especially V engines that generally run hotter and need more cooling capacity than inline designs. Even with two I6 engines, you may have slightly different cooling needs depending on whether it is a closed/semi/open deck design. Diesels generally have a closed deck.

3) When was the last time you replaced or checked the pressure on your radiator cap? If it has been on there for a while and lost it's holding pressure, then it will cause the engine to run hotter under heavy load like that. It is probably a 16 lb cap. Adding 16 lbs of pressure to the system raises the boiling point of water from 212F to 260F. For every 1 lb in pressure that is lost, due to the cap wearing out over time, that boiling point drops by 3F. I would also recommended a boost leak test if you haven't done one in a while. Boost leaks cause higher EGT's which will cause the engine to run hotter under load.


As far as the Pete goes, it never boils. The truck has been in for service and the entire cooling system has been checked out. I actually replaced the thermostats, radiator and even went to the expense of having the water pump removed checked just to be sure. I think the coolant thermostat is 195 degrees, the fan thermostat 210 and warning light 220. They tell me it is working as it should.


Your claim that v engines require more cooling capacity than inline engines is confusing me. I might believe that heat management in a V engine is more involved. I can see why a v engine might tend to run a little hotter (which could mean less demand on the cooling system). What exactly do you mean saying a V engine require more cooling. Are you simply meaning that the greater surface area of an inline engine can radiate a little more heat directly into the engine compartment vs a more compact v engine?


2021 F350 SRW Platinum short box 4x4.
B&W Companion
2008 Citation Platinum XL 34.5

ShinerBock

LVTX

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Posted: 12/16/20 12:54pm Link  |  Quote  |  Print  |  Notify Moderator

4x4ord wrote:

Your claim that v engines require more cooling capacity than inline engines is confusing me. I might believe that heat management in a V engine is more involved. I can see why a v engine might tend to run a little hotter (which could mean less demand on the cooling system). What exactly do you mean saying a V engine require more cooling. Are you simply meaning that the greater surface area of an inline engine can radiate a little more heat directly into the engine compartment vs a more compact v engine?


It's actually not a claim. It is the truth according the PB/KW/PACCAR engineers and is one of the reasons why engines CAT 3408 or Detroit 8V92 is no longer around in the class 7-8 trucks anymore. The cooling system requirements were greater than the comparable inline 6 engines and added more weight which is a hot commodity on a commercial truck. The other main reason was that it was a fuel hog. As far as the exact or scientific reasons why V engines tend to run hotter, I have am not 100% sure.


I would still check that cap and the system for boost leaks.


2014 Ram 2500 CTD
Highland Ridge Silverstar 378RBS

4x4ord

Alberta

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Posted: 12/16/20 02:12pm Link  |  Quote  |  Print  |  Notify Moderator

ShinerBock wrote:

4x4ord wrote:

Your claim that v engines require more cooling capacity than inline engines is confusing me. I might believe that heat management in a V engine is more involved. I can see why a v engine might tend to run a little hotter (which could mean less demand on the cooling system). What exactly do you mean saying a V engine require more cooling. Are you simply meaning that the greater surface area of an inline engine can radiate a little more heat directly into the engine compartment vs a more compact v engine?


It's actually not a claim. It is the truth according the PB/KW/PACCAR engineers and is one of the reasons why engines CAT 3408 or Detroit 8V92 is no longer around in the class 7-8 trucks anymore. The cooling system requirements were greater than the comparable inline 6 engines and added more weight which is a hot commodity on a commercial truck. The other main reason was that it was a fuel hog. As far as the exact or scientific reasons why V engines tend to run hotter, I have am not 100% sure.


I would still check that cap and the system for boost leaks.



The inline has many advantages over the V configurations especially with regard to servicing and especially in something like a class 8 truck where an inframe engine rebuild is common. I think the way the inline breaths can sometimes encourage better cylinder scavenging which can contribute to a more efficient engine. The reverse flow cylinder heads of the 6.7 Powerstroke is, in part, an attempt to gain better scavenging.

"it was a fuel hog" Might have been in part due to the challenges arising from the V block configuration. A fuel hog needing more cooling makes perfect sense. If one engine vs another burns more fuel to do the same amount of work, the less efficient engine is converting less of the fuel's energy to power output and therefore a higher percentage of energy is being lost. A small amount can be lost through the exhaust as unburnt fuel (smoke) or in the form of noise and vibration but the majority of loss is in the form of heat energy lost through the exhaust (higher EGTs), or into the cooling system. I am not certain but I think the idea of a V running hotter has to do with the heat from the engine accumulating in the V which can lead to all sorts of challenges from warming the intake air and fuel to heat stressing wiring harnesses and electronics. In my way of thinking about this an engine running hotter (assuming the same efficiency) is putting less heat into the cooling system.

I think the cap on my Pete was checked but I'll have it rechecked. I can check for boost leaks as well. Thanks.

ShinerBock

LVTX

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Posted: 12/16/20 02:29pm Link  |  Quote  |  Print  |  Notify Moderator

4x4ord wrote:

Your claim that v engines require more cooling capacity than inline engines is confusing me. I might believe that heat management in a V engine is more involved. I can see why a v engine might tend to run a little hotter (which could mean less demand on the cooling system). What exactly do you mean saying a V engine require more cooling. Are you simply meaning that the greater surface area of an inline engine can radiate a little more heat directly into the engine compartment vs a more compact v engine?


I think you might be on to something regarding the difference in the engine compartment. My father in law just came by to pick up a trailer and I looked at the engine bay of his F350 versus mine.

I took that plastic upper piece off of mine a few years ago. Without it, you can get a better look at both sides of the engine. The driver side has a ton of room between the block and wheel well. I can literally stick a soccer ball or maybe even a basketball between there. The passenger side has the turbo so there is less room, but still has a lot of daylight. My father in laws truck was the complete opposite. I was hard to see daylight from either the top or bottom. So maybe it does have to do with more air circulation under the hood being able to removing heat off the longer and thinner block. How much of a difference that makes? Not sure.


EDIT: I was easily able to fit a regulation sized football between the block and fender well long ways (11 inches).

[image]

* This post was edited 12/16/20 02:42pm by ShinerBock *

blofgren

Surrey, B.C.

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Posted: 12/16/20 06:56pm Link  |  Quote  |  Print  |  Notify Moderator

Yes, there is considerably more available real estate under the hood of the Ram/Cummins compared to the Ford/Powerstroke. This was another one of my reasons for going with the Cummins; more room=easier repairs=less overall operating and repair costs over the long haul. There is a reason why most hotshotters use the Ram/Cummins! [emoticon]


2013 Ram 3500 Megacab DRW Laramie 4x4, 6.7L Cummins, G56, 3.73, Maximum Steel, black lthr, RAM 20k sliding hitch, Retrax, Linex, and a bunch of options incl. cargo camera
2008 Corsair Excella Platinum 34.5 CKTS fifth wheel with winter package & disc brakes

4x4ord

Alberta

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Posted: 12/16/20 08:35pm Link  |  Quote  |  Print  |  Notify Moderator

blofgren wrote:

Yes, there is considerably more available real estate under the hood of the Ram/Cummins compared to the Ford/Powerstroke. This was another one of my reasons for going with the Cummins; more room=easier repairs=less overall operating and repair costs over the long haul. There is a reason why most hotshotters use the Ram/Cummins! [emoticon]


I think the Powerstroke is pretty easy to get at once you get the cab lifted off.[emoticon]

Flashman

Tucson, Aizona, USA

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Joined: 01/02/2005

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Posted: 12/17/20 06:21am Link  |  Quote  |  Print  |  Notify Moderator

4x4ord wrote:

blofgren wrote:

Yes, there is considerably more available real estate under the hood of the Ram/Cummins compared to the Ford/Powerstroke. This was another one of my reasons for going with the Cummins; more room=easier repairs=less overall operating and repair costs over the long haul. There is a reason why most hotshotters use the Ram/Cummins! [emoticon]


I think the Powerstroke is pretty easy to get at once you get the cab lifted off.[emoticon]


Easy Peasy - do it on the side of the road all the time.

ShinerBock

LVTX

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Posted: 12/17/20 06:59am Link  |  Quote  |  Print  |  Notify Moderator

blofgren wrote:

Yes, there is considerably more available real estate under the hood of the Ram/Cummins compared to the Ford/Powerstroke. This was another one of my reasons for going with the Cummins; more room=easier repairs=less overall operating and repair costs over the long haul. There is a reason why most hotshotters use the Ram/Cummins! [emoticon]


Yeah, I have done my own work on my engine except for the water pump that was replaced under recall by the dealership. So for I have removed some engine exhaust parts, replaced the turbo for a larger fixed geometry turbo, replaced the exhaust manifold for a higher flow pulse manifold, and installed head studs. I also replaced the after engine exhaust system myself which was kind of a pain in the arse holding the downpipe on the turbo with one hand while trying to the clamp around it and the turbo flange with the other. Never had an issue with space or needing to remove a ton of plastic parts to get to stuff.

Cummins12V98

on the road

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Posted: 12/17/20 09:54am Link  |  Quote  |  Print  |  Notify Moderator

When asked for my opinion on the big three I just say go open the three hoods and then tell me.


2015 RAM LongHorn 3500 Dually CrewCab 4X4 CUMMINS/AISIN RearAir 385HP/865TQ 4:10's
37,800# GCVWR "Towing Beast"

"HeavyWeight" B&W RVK3600

2016 MobileSuites 39TKSB3 highly "Elited" In the stable

2007.5 Mobile Suites 36 SB3 29,000# Combined SOLD

ShinerBock

LVTX

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Posted: 12/17/20 10:20am Link  |  Quote  |  Print  |  Notify Moderator

Cummins12V98 wrote:

When asked for my opinion on the big three I just say go open the three hoods and then tell me.


Well that kind of depends. If you are like 4x4ford where you will leave it stock and trade it in every 3-4 years without going past the warranty, then accessibility under the hood is not an issue. For people like us who will either modify, go well past the warrant period/mileage, and/or planning on doing our own repairs then it is a huge factor.

I know with my brother's old truck, I would not want to do many of the things I have done with my truck because of all the stuff I would have to remove and what is involved. I would have likely paid someone thousands of dollars to do what I have done on my own to mine. This would also take all the fun out of it because most of the enjoyment of moding is being there with my son showing him how to do it and seeing his face light up when we get to test the results of what we did. Since this truck hasn't needed many repairs, moding is my only way to teach him.

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