Question about EGT's

[Evotrucker]

06 Volo, cm870 with a 13 spd tranny

So last night i was coming back from chicago, i was paying attention to my EGT's " in dash guage". I was driving around 60-67 mph in 13th gear at around 1.3k-1.5k rpm and my the egt would stay steady around 400 or close to 600 degrees BUT! when i dropped it in 8th gear and drove around 55 mph - 64 mph my EGT readings would be around 300-400 degrees at 1.3k-1.5k rpm's.... what could be the cause for that?.

[Rawze]

when engine is doing less work and burning less fuel, it makes for lower egt.

[Evotrucker]

(11-22-2019 )Rawze Wrote:  when engine is doing less work and burning less fuel, it makes for lower egt.

Thanks rawze!

so ill continue to drive slower!

[SquareOne]

Rawze, I remember you mentioning here that you installed a switch and ran a probe on the outside the manifold as well as the one in the exhaust stream behind the turbo. I believe you said the person who had that setup preferred the reading outside of the manifold and rarely switched to the EGT sensor within the exhaust stream.

- My question is...have you ever compared your temp outside the manifold to what the temp was within the exhaust? Just curious. Mine is located on the outside of the manifold and mainly hovers around 3-350 degrees @ 62-63mph. (Little higher when loaded and will occasionally break the 550ish mark depending on the ambient temp, eng load, etc.). Would be curious to know what the actual exhaust temp is - no real reason - just curiosity.

[ynot]

I've had both, and personally i like the temps from in the manifold before the turbo. I always found myself looking at the internal temps more then the external on the manifold temps.

My reasoning behind that is on the outside your only measuring the heat soak so if your running hot its gonna take a bit too reach an get into the DANGER ZONE(Archer.. kenny loggins anyone lol) VS the internal before the turbo temps are instantaneous so when you breal the danger zone you know it an arnt holdong your foot in it blasting away at the turbo while you wait on the external temps too let you know you've got a bad tune or something else is wrong with your truck. There's alot going on in the motor in the 3+ minutes of lag waiting on the external temps too rise an alert you.

Now that being said the internal temps are more for the guys that like to tweek an try different things higher HP ect., if you've got a low HP conservative tune an are driving for mpg the external temps are a more useful average to let you know how much fuel your putting through the motor.

Really to each his own an boils down too what your doing with your motor, an either or of course is better then none

[Magard]

(11-22-2019 )Evotrucker Wrote:  06 Volo, cm870 with a 13 spd tranny

So last night i was coming back from chicago, i was paying attention to my EGT's " in dash guage". I was driving around 60-67 mph in 13th gear at around 1.3k-1.5k rpm and my the egt would stay steady around 400 or close to 600 degrees BUT! when i dropped it in 8th gear and drove around 55 mph - 64 mph my EGT readings would be around 300-400 degrees at 1.3k-1.5k rpm's.... what could be the cause for that?.

remember that the dash reading in a Volvo isn’t a actual reading it is interpolated by the computer. I wouldn’t trust it 100% maybe watch your real time fuel economy also.

[smorgan87]

I like internal temp myself so that i know im not roasting my turbo but rawze's reasoning behind watching heat soak is to keep an eye on fuel burn. Heat goes up its time to down shift and slow down. Kind of a matter of ur goals. Get there faster or burn less fuel getting there and making the $. My particular line of work usually involves turning, burning and getting there fast so i can squeeze in another load for the day. Most otr work u have plenty time to get there and ur not gonna make any more $ if ur there an hr early. In fact they dont usually give a damn that u exist at all.

[Evotrucker]

(11-22-2019 )Magard Wrote:  

(11-22-2019 )Evotrucker Wrote:  06 Volo, cm870 with a 13 spd tranny

So last night i was coming back from chicago, i was paying attention to my EGT's " in dash guage". I was driving around 60-67 mph in 13th gear at around 1.3k-1.5k rpm and my the egt would stay steady around 400 or close to 600 degrees BUT! when i dropped it in 8th gear and drove around 55 mph - 64 mph my EGT readings would be around 300-400 degrees at 1.3k-1.5k rpm's.... what could be the cause for that?.

remember that the dash reading in a Volvo isn’t a actual reading it is interpolated by the computer. I wouldn’t trust it 100% maybe watch your real time fuel economy also.

whats up magard, how would i go about the real time fuel economy? what kind of guage should i use?

[Evotrucker]

(11-23-2019 )smorgan87 Wrote:  I like internal temp myself so that i know im not roasting my turbo but rawze's reasoning behind watching heat soak is to keep an eye on fuel burn. Heat goes up its time to down shift and slow down. Kind of a matter of ur goals. Get there faster or burn less fuel getting there and making the $. My particular line of work usually involves turning, burning and getting there fast so i can squeeze in another load for the day. Most otr work u have plenty time to get there and ur not gonna make any more $ if ur there an hr early. In fact they dont usually give a damn that u exist at all.

I would like to be able to be flexible vs being ridged in this business, me personally it depends. I wouldn't rush to pick/deliver a load if it paid 1.60 but if it compensated more then enough for the fuel and and extra hastle of worrying will i be able to make it on time or not. it would depend on the situation with me. does it pay enough or worth enough. We need to make money one way or another with out cutting corners because that doesnt help no one especially the o/o or company's.