egt's

[Kurt Henzler]

what makes higher egts'



1. trying to get up a hill towing in six gear lugging to stay about 50 mph



or



2. dropping to fifth with higher rpm and staying about same speed.

 

[MikeKelley]

Same question here. Anybody with the answer?

MK

 

[JRMora]

I'll take a stab at it:



Lugging up the hill in a high gear with low RPM.



In order to keep your speed up you'll be pressing on the throttle pumping more fuel in than the engine can burn efficiently causing a higher EGT.



Well, do I win a prize?



Juan

 

[Parshal]

I usually drop down to a lower gear when EGT's get higher but I don't necessarily see a difference in temperature. If I slow down in the lower gear I do, though.

 

[Radshooter]

Hi Kurt... . I can't give you a scientific answer, but can relate what I have observed on my truck. I have to agree with Parshal. When we pulled our 16k fiver down to Yuma from Idaho, I had several ocassions to drop out of fifth gear down to fourth. I like to keep my RPMs around 2100 when towing. When I dropped to 4th, I didn't notice much change in EGTs just due to the gear change. What I did notice was I could run the EGTs right up to the red mark or drop them down to around 1100 just by how much throttle I applied. I learned to "feather" the throttle as I went up the hills to keep EGTs in a safe range, but still on the hot side. I could push them right up to 1250 and keep them there for a while, then back off just enough to cool down to 1150 or 1200 for a while. By then, I would be catching up to the Ferds and Chebbys pulling smaller trailers than mine and still be able to pass them while keeping the EGTs below 1300! In a nutshell, my personal experience says amount of throttle has more input than what gear you are running.

Hope this helps.

Steve

 

[DLeno]

I was doing some light towing, perhaps 5,000 lbs, over the mountains a while back. I had the Volumizer hooked up on its 50 HP setting (moderate pressure fueling, plus a small amount of timing)



what I noticed is that I could run WOT mashed to the floor at 60 mph steady in sixth gear and EGTs stayed at 1100. As soon as I shifted down, rpms go up above 2500 and EGT rose. hmmm.



At high rpms, the ECM turns off pilot injection I think. can someone correct? anyway, from my observation I'd say high RPMs are an EGT problem.

 

[RankRam]

At high rpms, the ECM turns off pilot injection I think. can someone correct? anyway, from my observation I'd say high RPMs are an EGT problem.



Yes, that is my understanding as well. I remember 2250 rpm's being the cutoff for the pilot injection.

 

[BRayls]

one thing we can agree on the pilot injection does shut off,but I thought it was closer to 2600 rpm.

 

[Bertram65]

I do not have a stick but I have noticed when towing below 2000 RPM in OD the EGTs are 150 to 200 higher than with it off at 2500 RPM. What also happens with OD off is the oil temp went up 15 degrees to 230. Put OD back on EGTs up, oil temp down to 215. I do not know which is worse.

On edit, I am talking about engine oil not transmission.

 

[DaveMorris]

I think that down shifting on the new ones does not help ETG's because of the tiny turbo they have on them now. The turbo doesn't seem up to feeding the higher CFM's without getting itself hot, so (just my opinion) it is kind of a wash...



the only difference I see in mine is by lifting the pedal a little...

 

[JRG]

With a 130 hp Volumizer, 80 hp injectors, and 12,350 gvw I could hit 1425-1450* WOT. I noticed that when the transmission shifted EGTs would drop if I didn't already lift. OTOH, by the time it got up to those temps I was going fast enough. (65-70+) This is mostly flat as any up hills were too curvy to stay in it for very long due to speed.



Also, this box has a weird way of "boost fooling" as it will throw a pair of codes every once an a while, seemsc to be only when the EB is engaged, but I still not sure. PDQ said it does't boot fool but reads boost to know how much fuel to apply. ??



JRG

 

[SRadke]

Here's how I look at it...

It takes a certain amount of fuel to move a give load up a given hill at a given speed. If you increase RPM you increased the air volume being consumed by the motor and therefor leaned out the air/fuel mix while burning the same amount of fuel. This will not only cause lower egt's but also may provide for better economy due to the more efficient burn caused by added air. Now if you get your rpm up and floor it rather than just maintaining your speed you will see much higher egt's with more rpm. My $. 02



-Scott

 

[Shooter]

Originally posted by Kurt Henzler

what makes higher egts'



1. trying to get up a hill towing in six gear lugging to stay about 50 mph



or



2. dropping to fifth with higher rpm and staying about same speed.

Same question here. Anybody with the answer?

MK[/B]

Where are your gauges ? on the pillar or column mount??

 

[MikeKelley]

Re: Re: egt's

Originally posted by Shooter

Where are your gauges ? on the pillar or column mount??

Both Cummins and Dodge say you don't need gauges on a stock truck. However, we are still be interested in what causes the increase in EGT's and would try to avoid driving habits that increase them beyond acceptable limits. Not everyone wants to bomb or modifiy their trucks.

MK

 

[Parshal]

Re: Re: Re: egt's

Originally posted by Mikelley

Both Cummins and Dodge say you don't need gauges on a stock truck. However, we ... would try to avoid driving habits that increase them beyond acceptable limits.

I have gauges but am back at a stock truck. Based on my observations, I would say you're not going to have EGT problems if your truck is stock no matter how hard you drive it.

 

[David Oxland]

I kind of thought of it this way. The main injection period advanced until it became one with the tail end of the pilot injection or continous. I know even at lower rpm if you poke it a bit it, it knocks as if there's not been time for a bit of a preinjection heatup.

 

[Matt400]

Originally posted by Kurt Henzler

what makes higher egts'



1. trying to get up a hill towing in six gear lugging to stay about 50 mph



or



2. dropping to fifth with higher rpm and staying about same speed.

#1. IMO and based on what I have seen in my truck. The key being what you said last- staying about same speed



I have a digital pyro and its very responsive and easy to see that lugging the truck with more throttle produces higher EGT's than a lower gear and less throttle.

 

[Dean Upson]

Originally posted by Radshooter

Hi Kurt... . I can't give you a scientific answer, but can relate what I have observed on my truck. I have to agree with Parshal. When we pulled our 16k fiver down to Yuma from Idaho, I had several ocassions to drop out of fifth gear down to fourth. I like to keep my RPMs around 2100 when towing. When I dropped to 4th, I didn't notice much change in EGTs just due to the gear change. What I did notice was I could run the EGTs right up to the red mark or drop them down to around 1100 just by how much throttle I applied. I learned to "feather" the throttle as I went up the hills to keep EGTs in a safe range, but still on the hot side. I could push them right up to 1250 and keep them there for a while, then back off just enough to cool down to 1150 or 1200 for a while. By then, I would be catching up to the Ferds and Chebbys pulling smaller trailers than mine and still be able to pass them while keeping the EGTs below 1300! In a nutshell, my personal experience says amount of throttle has more input than what gear you are running.

Hope this helps.

Steve

This is the same method I use. When the rpms drop down, I grab a lower gear. The egt's will go up because I am burning more fuel, I just back off a bit in the lower gear and my egt's will drop.



Dean