Egt’s

[Mopar1973Man]

Regardless... I came to the table with what facts that I can provide. No theories here, all post information was taken from the trip to Nampa and back to Ontario. The MPG numbers is posted from my previous trip to Nampa and back to Ontario. 

 

Again EGT's are lower, engine load is lower than most and making 19.58 MPG at 80 MPH.

 

The part most I don't think are calculating is frontal area increase in lifts and larger tires. Then the rotational mass of the larger tires takes even more energy to keep twisting. Wind drag where a vehicle standing taller in the wind is going to have more drag. Like the OP installed a 4 inch lift, and oversized tires. For every 1 pound of rotational mass you can drop is like 8 pounds off the frame in rule of thumb. Again adds up to more drag. 

 

More about rotational mass...

http://hpwizard.com/rotational-inertia.html

 

Still got 3.55 gears, 245/75 R16 stock sized tires, 150 HP injectors (7 x 0.010 @ 320 bar), HX35/40 Hybrid Turbo (60/60/12), factory steel wheels (16 x 7), and my economy tune with some steep timing. No other magic here. Wheels and tires are what Dodge and Cummins designed the truck to run with. 

 

Like the drag coefficient on my truck in factory trim is 0.41. A one ton dually Dodge has a drag coefficient of 0.49. I can see a lift kit and oversized tires going up in the 0.5 to 0.6 realm adding huge amount of drag.

 

 

Edited May 31, 2019 by Mopar1973Man

[kzimmer]

I'm not debating the fact that being higher up adds wind drag. Just strictly gear ratio and RPM, I've always understood the 5.9 to be in it's most efficient "sweet spot" between 1800 and 2000 RPM.

[Mopar1973Man]

Nothing special here just the 3.55 gears, 5 speed transmission, stock 245/75 R16 tires on 16x7 stock steel wheels. This is what Dodge and Cummins designed the truck to run with. 

 

 

10 minutes ago, kzimmer said:

I've always understood the 5.9 to be in it's most efficient "sweet spot" between 1800 and 2000 RPM.

 

As for the quoted sweet spot we can't run that exact sweet spot for all speeds. The only thing that actually changed is I'm 5 MPH slow vs RPM. So I'm about 200 RPM higher for 80 MPH vs 235's / 265's tires. Which all all stock sized tires. My 66 MPH is a exact 2,000 RPM where before it was like 1,8xx roughly. Still running what Dodge and Cummins designed. I do like the rise in RPM it has been netting better MPG overall on average. Being I need less torque to keep rolling which can be seen in engine load. 

 

 

Edited May 31, 2019 by Mopar1973Man

[Dieselfuture]

For what it's worth this truck I used to have did about 12-14 mpg when I got it (pretty much stock with 350sbc) and then I jacked it up and was getting 10-12 mpg with built bbc, comfortable crusing speed was around 60-65 mph. It had michilens 1600 r 20 rims and tires weigh close to 400lb and 6.72 ratio in axles. 

Edited June 1, 2019 by JAG1

[Mopar1973Man]

Awesome Chevy @Dieselfuture. Still that is a lot of rolling resistance and drag. Takes a lot power to keep slinging those huge tires around even with good gearing.

Edited June 1, 2019 by Mopar1973Man

[dripley]

I only 12  or 13 out of 96 with the V10. 3:55 gears with 245s on it.

[Mopar1973Man]

Just now, dripley said:

I only 12  or 13 out of 96 with the V10. 3:55 gears with 245s on it.

 

Funny you bring that one up. I've got my buddy in New Meadows that owns a V10 Dodge and parked it because it cost too much to drive. Loves the power but its a fuel hog. His is a 1 ton truck and more tires and does about the same for MPG's. Told him he should trade that for a Cummins or at least swap a Cummins into the frame. 

[dripley]

I cant imagine owning that truck when gas was 4+ bucks a gallon. Towing i got 4 to 5 mpg.  Had to fill it up evety 150 miles or so when relocating the 5th wheel. It did have good power but it could not pass a gas station.

[Dieselfuture]

2 hours ago, Mopar1973Man said:

Takes a lot power to keep slinging those huge tires around even with good gearing.

True, when I was in mud letting it have it probably did like 10 gallons to a mile, but cruising around I could still squeeze 10-12 mpg out of it.

[JAG1]

2 hours ago, Mopar1973Man said:

Awesome Chevy @Dieselfuture. Still that is a lot of rolling resistance and drag. Takes a lot power to keep slinging those huge tires around even with good gearing.

Yeah, but think how smart it is to use on a date...... if they were willing to climb in you knew they were willing 

Edited June 1, 2019 by JAG1

[dripley]

13 hours ago, Dieselfuture said:

For what it's worth this truck I used to have did about 12-14 mpg when I got it (pretty much stock with 350sbc) and then I jacked it up and was getting 10-12 mpg with built bbc, comfortable crusing speed was around 60-65 mph. It had michilens 1600 r 20 rims and tires weigh close to 400lb and 6.72 ratio in axles. 

I do like this thing. The diesel bros would be proud of that, but they would have squeezed a 12v in it. It is nicely done.

 

I had custom deluxe a good while. The body is the only thing mine had in common with yours.

Edited June 1, 2019 by dripley

[Dieselfuture]

4 hours ago, dripley said:

The diesel bros would be proud of that, but they would have squeezed a 12v in it. It is nicely done

That was my next step is put a cummins in it, life changed and that's how I got my 02 now.

[Mopar1973Man]

4 hours ago, Dieselfuture said:

life changed and that's how I got...

 

My MPG up being its expensive to travel 1,000 miles a week. 

 

I did like you Chevy DieseFuture just not a good daily driver that is for sure. It would kill me to drive that back and forth to Ontario. Out in the back country I bet that thing is a blast.

Edited June 2, 2019 by Mopar1973Man

[Gregturley]

On 5/30/2019 at 10:25 AM, hdpwipmonkey said:

Speaking of brakes, mine dives to the right with braking and has done it since I got it a year ago.  I replaced everything under the front end except ball joints **shudders at the thought** and it still does it (I replaced the steering parts to fix steering wander more than the brake issue).  Going to get new brakes, rotors, and hub assembly today.  Hopefully that fixes it.  BTW, that's a good idea about the IR gun.  

 

Have you replaced the bushings in the front trailing arms? I have fixed braking pulls on many 2nd gen 4wd's with new bushings. I used Energy Suspension many times and really liked them. When the time comes to do the 01 I'll be using them again.

[Dieselfuture]

2 hours ago, Mopar1973Man said:

 

My MPG up being its expensive to travel 1,000 miles a week. 

 

I did like you Chevy DieseFuture just not a good daily driver that is for sure. It would kill me to drive that back and forth to Ontario. Out in the back country I bet that thing is a blast.

I dd it around town and on short trips like half hour to an hour max, it was fun getting gas and just going places, always had someone crawling under it when I came out of store or something lol, then 20 minutes later I'd be on the way. Cops didn't even bother me for the most part, only few times when they seen me crossing the river by roler damb lol, should of seen fishermen eyes it was priceless. I had a lot of fun, wouldn't change anything about that passed. Miss it sometimes, but life goes on.

[hdpwipmonkey]

1 hour ago, Gregturley said:

Have you replaced the bushings in the front trailing arms? I have fixed braking pulls on many 2nd gen 4wd's with new bushings. I used Energy Suspension many times and really liked them. When the time comes to do the 01 I'll be using them again.

The new brakes fixed it.  

[Tymatthew]

So I dropped in my super b special....egt’s are now around 900 @ 75mph....they still get into the 1100s here and there..I’ve checked everything twice and have no boost leaks...I was curious about the accuracy of the quad egt’s....when I was getting around 700 to 800 egt’s that was on my auto meter gauge but I didn’t care for the pillar so I got rid of them and went with just the quad sensors and I didn’t drive it for a month or so couse it’s my boys truck....that’s when he told me about it getting high egt’s so I posted here for sum help....I kinda forgot about doing that and never really thought about the gauges being off....so I hooked the auto meter Pyro back up just to test it and it reads about 650@75mph....the quad was reading  900@75mph....have two ports in the manifold so this was done at the same time...not sure which one to believe....

 

[AH64ID]

How do they read in the morning before you start it?

[Tymatthew]

Before starting this morning,,,70 degrees outside....the iquad was @130 and the autometer was at 50ish....started up the iquad went to 300 at idle in five minutes the auto meter was around 200....took it on a 5 mile loop and left idle in the driveway for 5 minutes the iquad was at 350 and the auto meter was at 250ish....swapped the sensors around and did the same thing just now with about the same result....

 

[AH64ID]

My initial thoughts are that the quad is reading high. The autometer temps sound much more realistic.