Question about black smoke at higher elevations in an HDJ81 (1 Viewer)

[Greg_B]

We kinda use 1300 as a limit I think based on what the domestic diesel crowd uses and internet facts and lore.

Yes, and while this site is for the North American market it has some useful info: Banks Power | Why EGT is Important

Think of all those 3B's running around stock and naturally aspirated and probably hitting 1600 plus getting hot and no one knew better and they still make 400,000 kms or more without ever looking at an EGT gauge.

Locally I think of all the BJ42's and BJ70's on trips up the Coq or the hill on the Crowsnest Hwy before the Hope slide over the years, black belching out the tailpipes...

I think most blindly follow the crowd and run conservative EGTs without full understanding of what's happening.

Tune so EGTs are limited to a max peak that you think is safe. Then driving to the EGT gauge is unnecessary, particularly if you understand that laboring the engine in too a gear is not good

I consciously run conservative EGT's on the 1HD-T. It's a heavy rig. Driveability has increased substantially with the upgrades done so far. The goal is to have it tuned just as you have mentioned. And I'm almost there. This includes the transmission. As it can just keep pulling, I now have had to take it off cruise control on long hills as I'm too fast for the curves. In TC lockup my atf temps are great but if stuck behind slow traffic, no passing lane and unable to maintain TC lockup my ATF temps start heading up. Tuning of the fuel pin and more ATF cooling and/or the Wholesale Automatic GENII TC lockup module should get me to the "set it and forget it" stage. Those are the parameters I am comfortable with on this truck.

There is some suggestion that higher boost levels, the stock aircan with the Safari Snorkel on the 80 is not conservative for longevity of the turbo. That is something I will be looking at as well but is another discussion best left to this thread.

Great discussion. Love this site and appreciate we can all come here with our thoughts, real world experience and opinions. Folks can make their own choices for their risk profiles. An open discussion helps.

To the origional poster...spend some time on the Banks tech site. There is much useful information, specifically things about air density, air flow, diesel fuel, etc:

Mud salute to you all:

gb

 

[Dougal]

Thermal expansion of pistons and having rings binding would be a concern to me before melting pistons

Indeed and I've seen that on a tractor engine before. Ring ends meet under thermal expansion and there's nothing left to do but eat the cylinder wall!

IDI engines pretty much never melt pistons. Instead it's the heads that crack from the thermal cycling.
DI engines get a lot more heat into the pistons because the combustion bowl is recessed down in. More surface area and shorter distance for heat to travel.

What happens is the piston bowl heats, piston crown grows, softens, grows more and starts to rub the cylinder walls.

If you really want to melt pistons, then crank up the fuel and over-advance the timing. Over advancing the timing makes the combustion run a lot hotter than the measured EGT.
With stock timing it's a lot safer. With retarded injection timing you can run truely ridiculous EGT without hurting the pistons at all.

 

[4rings5cyls]

... Which translates to about 65-70mph on the flats (not that we have much of that) but 40mph going up a steep grade, especially Vail pass or Eisenhower tunnel. It's the slow lane with the big diesels for me. Sure, I could pass everyone, but who wants a melted turbo?...

Damn. I was looking real hard at a HDJ to scoot up the passes quicker. The 1FZ still pulls 2nd gear ~50-55mph, but that's at 4-4200 rpm. Would have thought the torque and turbo on the 1HDT would have fared better.

 

[RhinoRig]

Damn. I was looking real hard at a HDJ to scoot up the passes quicker. The 1FZ still pulls 2nd gear ~50-55mph, but that's at 4-4200 rpm. Would have thought the torque and turbo on the 1HDT would have fared better.

Have you ever known any LCs to "scoot" anywhere? It does get much better milage than the 1FZ! And like I said, I think mine needs some fuel system lovin, but I haven't found a local mech up to the task.

 

[4rings5cyls]

I was told the 100s and 200s did...have never ridden in either (no desire), but valid point.

I recall there being a couple european HZJ7x's rolling through CO this past year that had altitude issues - someone in this state fixed them up, but can't remember who.

 

[Lumpskie]

Damn. I was looking real hard at a HDJ to scoot up the passes quicker. The 1FZ still pulls 2nd gear ~50-55mph, but that's at 4-4200 rpm. Would have thought the torque and turbo on the 1HDT would have fared better.

There are a couple Colorado diesel 80s now. I can't remember but one guy (who is also on Expo Portal) runs 70mph up to the Eisenhower tunnel without issue. He's intercooled though.

 

[mudgudgeon]

Have you ever known any LCs to "scoot"

With the right power mods, they can be surprisingly scoot-ish

 

[4rings5cyls]

Well that's the beauty of a factory turbo isn't it? Add an intercooler and maybe a 3" exhaust and you're in business. I see by your signature that you're no stranger to tuning (Lumpskie). I know they aren't OBDII...but is there anything to plug into the ECU and see what it's doing for fuel/boost/timing? Or is that all going to be done with extra gauges?

 

[IanB]

Well that's the beauty of a factory turbo isn't it? Add an intercooler and maybe a 3" exhaust and you're in business. I see by your signature that you're no stranger to tuning (Lumpskie). I know they aren't OBDII...but is there anything to plug into the ECU and see what it's doing for fuel/boost/timing? Or is that all going to be done with extra gauges?

No electronics on the 1HD-T, all mechanical, need gauges for boost and EGT to tune.

 

[Lumpskie]

Well that's the beauty of a factory turbo isn't it? Add an intercooler and maybe a 3" exhaust and you're in business. I see by your signature that you're no stranger to tuning (Lumpskie). I know they aren't OBDII...but is there anything to plug into the ECU and see what it's doing for fuel/boost/timing? Or is that all going to be done with extra gauges?

Yeah, like @IanB said, In tunes to EGT right now. But my long term an is to intercool next summer and use a wideband on a dyno. Knowing afr at every rpm will be interesting.