Exhaust Temperatures

[chowdy6606]

I've been pulling my 3625RT with my F250 SD 6.0L which is 13,640 loaded minus water. First I know I'm alittle over on GCVW but the question is, while pulling in towhaul my exhaust temp remains around 950 and 1000 degrees sustained and about 1100 while pulling hills is this normal. Second question is on the strait aways I usally pull in overdrive and the rpms hold around 1900 to 2000 and when I have it in towhaul on the same strait away the trucks rpm's run about 2300, my question is which is better. I'm not overly shifting the transmission in OD and the rpm's are much lower.

[dfredendall]

Your exhaust temp seems to be in the factory recommended ranges. I went to 4 Ford dealers and asked what is max temp. None knew or would commit. I had to seek answers from after market providers. I have similar temps. Temp readings vary, depending on where the temp probe is installed. If it is post turbo, as are most, figure 300 degrees less on the gauge than actual temp, so mentally compensate. If it is pre- turbo you are right on the money. Sustained 1300 degrees is melt down time, so watch out for anything over 1200, or better yet, don't get there. In fact you have to be pushing it real hard to get there. I try not to push mine past 1000 on long grades, If I get there, I let up on throttle some. Towing in OD is OK as long as you can stay in power range without lugging. I had a '99 V-10 gasser with the 4 spd OD trans. I could not tow in OD because it lugged. I towed with OD locked out, and got the same mileage, while remaining in my power curve for the gas engine. My diesel with 5 spd OD autotrans likes to pull in OD with Tow/Haul on. (Fact is I cannot lock out the OD on my '08.)

[Traveler II]

I don’t have a exhaust temperature gauge, but the truck came with a transmission temperature gauge. What is the advantage of one over the other?

[Merv]

I don’t have a exhaust temperature gauge, but the truck came with a transmission temperature gauge. What is the advantage of one over the other?

Actually, they are measuring two different aspects of your TV's operation.

The temp of the automatic trans. fluid (ATF) has a specific range to be within, especially on the upper end, for proper function and longevity of your transmission. ATF that hits temps above 195deg F starts to degrade through oxidation more rapidly than at the desired temp of 175deg, and the rate of degradation increases non-linearly with higher temps, duration and frequency. The trany temp gauge is a good thing for automatics in a tow vehicle and I rely upon, especially out west here in the mountains going up or down grade.

An exhaust temperature gauge measures that specific engine parameter. As Dana mentioned above, cylinder temps above ~1350deg, sustained, are right at the max valves and pistons can tolerate before meltdown. If the engine is not breathing correctly, a dirty air filter, an obstructed intercooler, a failing turbo or anything that decreases the engines aspiration will raise the exhaust temp. This really becomes noticeable under heavy load on grades or at altitude or both.

For myself, the first mod I made on my Dodge after we ordered our Cardinal was to get the stock air filter assy changed to an ATE filter and the lower intake torque tube so the engine would breath a bit better. The second mod was a BD X-Monitor to measure the exhaust temp, the trany temp and the turbo boost. Those are the three most important parameters to monitor IMHO. Hope this helps.

[Luizianna]

Not to change the subject...or hijack this thread, but had to say something....

"1943 Navigator, great condition, w/ BS detector, warm heart, winning smile"

Merv, that is cute...

[dennis1949]

I had an exhaust temp. gauge and trans. guage installed on my truck. I was told that the exhaust temp. gauge would be the first indication of something going wrong in the motor.

[Traveler II]

Merv,

I’m not mechanical, but at the same time I want to head off problems before they happen. We normally pull at 60 mph unless we are on two lane, than we travel the speed of the traffic. For the trany temp the highest I’ve seen it was 170 traveling out west in the mountains. But it looks like having something to measure the exhaust temp, and turbo boost are something we should also add.

Also the first thing I should do is change the air filter. I should ask for a ATE filter and new lower intake torque tube? Any idea how much something like that cost for a Chevy?

Thanks

[Traveler II]

When I was reading Linda comments my wife wanted to know why I was smiling, so I showed her the post. She said didn’t I know that the BS detector comes as standard equipment with a marriage license.

[Don Wilson]

TravlerII,
Martha agrees with Jane but I pointed out It must only start when they get the licenses because I see a lot of navigators falling for a lot of BS before they find the right pilot!

Don

[Don Wilson]

Traveler II
I have been looking at the AFE and Air Raid intake systems and I have found they run about $400 installed in our area! You have to take the current air filter system off and install the new air intake system in its place.

The question I have about this system is If you are putting more air into the combustion system and not changing anything else doesn't that cause a rise in the (EGT) Exhaust Gas Temp?

Don

[Merv]

But it looks like having something to measure the exhaust temp, and turbo boost are something we should also add.... I should ask for a ATE filter and new lower intake torque tube? Any idea how much something like that cost for a Chevy?

I added the X-Monitor because we do so much mountain driving over the Cascades and Rockies. That, and I'm a belt and suspender type having been bitten by Mr. Murphy too many times in my callow youth. We too keep it down to 60 towing on the hiway, and my egt in OD on the level is around 650 deg east of the Cascades and the trany temp ~135-145deg depending on the ambient temp. My highest trany temps uphill so far was 172 and downhill 178; Homestake pass eastbound on I-90 has a 25MPH limit over 12,000 lbs in first gear all the way down so had no torque converter lockup. One of these days an exhaust brake is going on if for nothing else other than piece of mind.

You can go to AFEfilters.com and get the prices and/or the stock numbers. Then look around the web for the best price. AFE's prices range from ~$480 to $600 for the various options for your rig, a lot higher than the $369 I paid 3 yrs ago. At dieselchips.com, they have the Magnum for the Duramax priced at $325 so it pays to shop around on line. Or you can go to a local diesel performance or RV shop for a quote with installation parts in hand or without. Good luck to ya!

[Merv]

The question I have about this system is If you are putting more air into the combustion system and not changing anything else doesn't that cause a rise in the (EGT) Exhaust Gas Temp?

In the diesel cycle engine, the greater the volume of air that can be coaxed through the engine from intake out the exhaust the lower the egt's for a given amount of fuel. Today's inducted intakes do just that every time the turbo spools up. The higher the air/fuel ratio in the cylinder at ignition the greater the burn rate vs. time. If combustion of the fuel takes longer due to lowered levels of oxygen or is incomplete when the exhaust valve opens, cylinder and exhaust temps increase and fuel may exit the tailpipe in a black cloud. The turbo will induct air actively, and by passive improvements in the ducted flow, the impediments which restrict that flow are eliminated. So the egt's are reduced as a function of the engines volumetric efficiency, which also improves fuel economy.

Ya know Don, it took me a while to get my head around that too. Being the geeky sort I am, I had to go and reinvent the wheel to prove it to myself that the claims the after market folks were making had a valid basis.