So this thursday i took off through the hills (hwy50 east from sac) towing roughly 6klbs. temp outside was 96. Hitting the grades i was mostly at 1000* if i stomped it the truck woulld move out and accelerate more but temps went to roughly 1300. Main issue is the water temp. me thinks a new radatior is in the future just to be safe. so my question is, Is it ok to run at 1000 all day long? every uphill was right at 1000-1100 ish temp wise.

PULLED AWESOME for a 13 year old girl.

jiMMy

 

From what i understand thats about right. Maybe 100* high if you were in 3rd gear, but I'm willing to bet you were in 4th. Thats just the load against it making mad boost just cruising.

BTW, sorry to ask but what is BHAF?

 

I could hit the same temps in either Drive or OD. But most of the hills on 50 i was in OD doing 50-65mph

Big Honkin Air Filter

jiMMy

 

everything i've read says 1250* all day long jimmy. i don't think i'd do that, but i know people who do. but i also know people that hold 1600* for 20 seconds. .

dave

how was your tranny temp doing?

 

I'd keep the pyro down to 1200 degrees. The trans will be happier in direct drive on the long grades. Higher RPM means less slip in the converter, which means less heat.

Where was the water temp? The FSM says that halfway between the last two marks (not the last mark and the end of the "bracket") is normal for a heavy load and warm weather. Remember that your trans cooler is dumping a lot of heat into the coolant, so keeping the trans cooler will keep the whole system cooler. Run 'er in direct up the long hills, that's what the 3200 RPM spring is for.

 

Yep Cummins says 1250*f all day long preturbo. I'd be more concerned about the trans temp if anything. But if folks can peg 1800*f pryo's for 10-15secs many many passes, I wouldn't shy away from 1300* or so as long as the top of the hill is coming up within 30secs or so. Just watch that trans temp gauge while up that high.

 

Trans never topped 200(180 on teh gauge but its in teh pan so i assume its atleast 20* warmer if not more) but that was also by teh top of hills then came right back down.

jiMMy

 

tranny temp as wanna said will boot your water temp up quite a bit, a great idea is to get a under bed aux tranny cooler,it keep the tranny and the water temp down a lot. also egt will raise water temp a bit as well, if you havent done so try advancing your timing a tad, it helps in keeping your egt down. but your temps arent out of line, 1300 is a bit high I try keep mine under 1200 as well.

 

yup, underbed cooler has been ont he list for a while now. 200 bucks and some time really.... i think ill do that a flush of the system before next tow to see if anything changes. it sure was nice being able to jump out in teh passing lane when needed and romp on it though to get by someone. he he, jiMMy

 

I'm in Carson City at the moment. Been fighting my way up I-15/US395 from San Diego, and it's been warm. I've hit and held 1000*+ on Deadman Pass and every other upgrade coming up here, towing a 7500# 5er. In fact, with 80* and a hard north wind against me, I had 1000* all the way from Victorville to Lone Pine. Locked OD out and kept going 65. The under-the-bed cooler with fan kept the trans temp around 190-200* in the pan, higher than I like.

I didn't have anything left on the throttle; towing a 5er is like towing a wall and the faster you go, the worse it is. I need the 3200 rpm governor spring.

I've been thinking new radiator also, but you & I aren't all that far apart. Or maybe we both need one.

DBF

 

Cummins tests these engines by loading them to maxed out levels and still hold 1200*F - 1250*F. They run them continuously for hundreds of hours at this level, then tear them down to inspect.
The guys are correct though, you need to watch our water temps closely...after a time, the head/block/exhaust manifold/turbo etc all become heat saturated and that can cause a big jump in coolant temps.... stay in the safe zone for water temps and you'll be ok.
Allow for pyro error though.... I'd recommend no more than 1200*F as a bit of safety measure.
OH....if your tranny pan temps are 180*F or 200*F you can bet the farm that the outlet temps from the TC are alot more than 20*F higher....try 50*F - 60*F more or better....
You'll know when you hit roughly 270*F because the thermo switch in line will kick you out of OD or prevent the upshift into OD....by then it's all pretty much over when it comes to your ATF fluid and in all likelyhood, your internals are going to need serious work....lord only know's why DC set 270*F as an upper thermal limit for that switch....

Keep in mind, that as the ATF leaves the TC and moves up to the primary heat exchanger it is "cooled" by the rad coolant circulating inside it...that temp can be over 212*F when you're running hard and hot so there is a lesson in that one....


pb.....