AH64ID

The torque to the wheels is the same 1600 vs 3200 but as you pointed out the hp is much higher. Higher horsepower with the same torque means the work can get done faster and thus it won't slow the same, load dependent. As I pointed out if it does slow the same it is an indication of the added power simply from the additional power requirement to be going 2x as fast. If HP didn't matter and TQ was the only important thing then rancherman would have slowed down MUCH faster due to an additional 170% power required to maintain speed on the same hill. There is reason I say find the load that can be held at the higher rpm and see how it does at the lower rpm. This is because you cannot use the rpm governor as a good example when the torque curve is flat. They are both the same engine right up until the 2nd on governs, so if one can't accelerate past 1600 then neither can the other. You have to find a way to demonstrate the additional power at the upper rpm, so you need to get there first. Take 2 identical trucks, and put two different electric motors on the wheel.. no diff, no trans, just a direct drive from the motor. Give them the 3280 ft/lbs of torque we are talking about, but give one of them 400hp and one of them 200hp. See what they do for loads, the 400hp motor will do more work over time.. about 2x as much :-) I was thinking about the large power increase required simply to go from 44 mph to 67 mph, my truck in 5th at the "test" rpms. It's too much to help quantify, as I mentioned around 170% from one Cummins article, compared to only a 150% increase in hp. So a better test would be at a slower speed, with a MUCH heavier trailer. A NV5600 truck with 4.10's in 3rd gear only has a 11 mph split from 1800 to 2500, and at that low of a speed the power difference in minimal (maybe 10%, and very little is aero dynamic). Now the problem with this is in order to find a load where the truck is stable at 2500 rpms WOT in 3rd means a LOT, LOT, LOT of drive-train stress... I don't want to test it, even at a stock tune.. or lower. But at least in 3rd gear you can quantify the 150% increase in horsepower and only a 10% increase in power requirement. As you said torque without rpms won't get a lot of work done, no horsepower. Lots of rpms with no hp, or torque, won't get a lot done. But if you have the appropriate tq at the correct rpm you also have the correct hp. I think we talked about it in the other thread, but take 3 different identical trucks. Each one with a different rear end ratio and give them all the same load. Put them on a flat road at 60 mph where they can all maintain speed. All 3 engines are making the same horsepower but different torques. The wheel torque will be identical thou. What does that tell us? That the torque to the wheels tells us how much force is needed to keep them moving at that speed, and the horsepower tells us how fast they can do it which in this case is 60 mph. 3 different rpms, same horsepower. If the torque was the same but the horsepower dropped the speed would drop. It doesn't matter how you look at it. On that same token lets look at a truck that is traveling at 60 mph, and lets assume that the wheel torque required was 800 ft/lbs. Let's look at the different gears, useable-ish ones at 60.. 4-6 (NV5600, 3.73's, 245/70R19.5) Torque Requirement 4th gear 3235 rpms, engine torque required 192.8 ft/lbs 5th gear 2328 rpms, engine torque required 268.1 ft/lbs 6th gear 1699 rpms, engine torque required 367.3 ft/lbs Horsepower Requirement 4th gear 3235 rpms, engine horsepower required 118.8hp 5th gear 2328 rpms, engine horsepower required 118.8hp 6th gear 1699 rpms, engine horsepower required 118.8hp Even gearing doesn't change the horsepower required (I am sure this is nothing new). So this engine needs to be able to make 118.8hp to maintain 60mph with the given load. If the engine can't make 118.8hp it won't be able to do 60 mph in any gear, regardless of the torque capability. An engine rated at 100/400 has the torque to meet all 3 of the gears torque requirements but doesn't have the horespower so the speed could never be reached or held. Why do semi's have advertised horsepower ratings? Because regardless of the gearing the horsepower tells you how fast you can go up a grade, considering they all operate in similar rpm band. Same thing with boats, hp tells the boat builder how fast one can spin a prop... Same as a helicopter. Since you cannot increase horsepower thru gearing the engine must be able to make the appropriate horsepower for the task at hand. I generally think we are all on about the same page, but some of the terms are different. I love hearing the argument that horsepower is useless, it's torque at the proper rpm that counts... Well what do you think horsepower is???? The above numbers show that perfectly.

I am not sure on the ohms, but based on it's size it shouldn't be very high. Generally the issue is that they are loose. Mighty Whitey must not like you killing snow geese.

The fact that the truck slowed the same, assuming that the grades were identical, proves you made more power. The speed you were driving required more power at 2600 rpms. So if your power requirement is higher and your WOT deceleration is the same your power production is higher. On my truck 1700 is 44mph and 2600 is 67mph, that's a 50% increase in speed which will account for a major power requirement increase. Using an example from a Cummins fuel mileage secret bulletin the power requirement increase from 45 to 70 is about 170%... So yes, you were making lots more power at 2600 rpms. 1700 to 2600, given a flat torque curve, provides about 150% more hp. So you have about a 170% increase in power requirement and a 150% increase in horsepower.. in fact you should have slowed just a little faster as speed too more power.

Good catch! The voltage regulator isn't in the alternator, it's part of the ECM. If you have different voltages between batteries the cause is almost always a bad/loose crossover cable. With temps that low the charge voltage will be around 15V, I have seen the desired voltage as high as 15.0xx in the teens and colder so I wouldn't think anything bad about 15V and it means the alternator was working properly when checked. Your alternator was either failing, or it had a loose connection. Hows the hunting???

I would check your rear driveshaft carrier bearing, your description sounds exactly like one of those failing.

How fast is it spinning? How much does your head weigh? :duh:

I have always been told that torque gets you moving, horsepower maintains once your there. If torque held you then horsepower would have no bearing on pulling a grade, and we know it does in application. Don't look at acceleration, it's not a good argument with your goverenor example. Instead take the 1700rpm one and put so much weight on it that it can only hold speed at 1650 rpms at WOT. That way we know that 100% of the power is holding it at the speed. Now take the 3400 rpm governor and put it at 1650 rpms, it will be un-accelearated as well. Now approach the same grade at 3000 rpms, go WOT and watch it accelerate. It doesn't have more torque, but it does have more horesepower. That additional horsepower is enough to not only hold the vehicle with a higher power requirement (since the speed is higher) but it has enough spare power that it can accelerate. Horsepower is doing that. Why is HP such a fleeting value? At 3400 rpms torque is falling off about 1.5x faster than hp :-) Welcome to the world of Common Rails. High rpms negates the need for high torque, if properly geared. Remember my 1427hp and 700 ft/lb of torque helicopter example. If a 600hp 10,000 rpm engine is geared to make peak power in it's 1/4 mile race then it will do better with its 315 ft/lbs of torque than a 315 hp 5,252rpm engine with 315 ft/lbs. If geared to run the same speed the 600hp will get there first, but makes the same torque. That is not a formula, it's a measurement. You are not calculating how long it takes the horse to move the 550lbs, you are measuring it. You are still looking too much at acceleration. Think about a static rpm and torque output. I keep going back to the 1600 vs 2500 rpm real world scenario. Both have 800 ft/lbs being made at the crank, which is 3280 ft/lbs with 4.10's to the ground before the standard Dodge 15% drivetrain loss. So 2788 ft/lbs of twist is where the rubber meets the road. One one them has 243hp to do the work with, and the other has 380. The 380 hp scenario will out pull the 243 hp scenario. The way to test it would be to take the engine and load it up so that at 2500 rpms it barely holds on the selected grade, i.e. another 1000lbs and it would slow down. Then slow down (same gear) to 1600 rpms and watch the truck struggle and slow down. This will happen, the horsepower is needed. No apologies needed, this is fun :-)

I don't view it as apples to oranges at all. It's only apples and orages if you assume the engine will slow from 2500 rpms. If it hold 2500 rpms with 555-610 ft/lbs, but doesn't hold 1600 rpms with 610 ft/lbs (which it won't if the load is maxed out on the 2500 rpm run) then horsepower is what keeps you moving, not the torque. I don't pull grades at 1600 either, just simply using the ratings. The Cummins 600 (04.5-07) has a peak torque of 610 ft/lbs at 1600 rpms. It makes at least 555 from 1400-2900. So torque at 1600 rpms is at least equal to, if not greater than, torque at 2500 rpms. I am talking about a fixed load, gearing, tire size, etc... That's apples to apples, the torque output is basically the same. The variable is rpms, which given a flat torque curve means more horsepower. More horsepower, the faster the work is done. In my truck if I hit that grade at 1600 rpms in 5th I will be in 4th by the top. 41 mph in 5th is 1600, which is 2200 in 4th. But if I hit the same hill in 5th at 2500 rpms, 64 mph, I will make the top in 5th.. even on a 7-8% grade at 20K GCW on a 75° day at 7K feet. There are ways to measure horsepower. Think about the original horsepower calculation. It's the ability to move 550 lbs 1' vertically in 1 second. If it takes 2 seconds you measured at 1/2 horsepower, or if it take 1/2 a second you have 2 horsepower. The torque is the same in both of them, so you are not measuring torque... heck it could take an hour and the torque is the same. That's how a chassis dyno works. To rotate the drum 1 time takes the same torque, whether you are at 1 rpm or 1000 rpms of the drum. The difference is horsepower, that's why they cannot tell you the torque output of your engine only the horsepower output. A water-brake, or other engine dyno's are the opposite. They measure the work being done, not the rate at which they are done.. they needs rpms to calculate hp. A chassis dyno needs rpms to calculate torque.

I am talking about maintaining speed, not accelerating. The reason you settle to 17-1900 rpms is as much about power production, as it is about power requirements. The speed associated with 2500 rpms takes too much power to maintain and you slow down. When you slow down to a 17-1900 rpm your power output is now equal to your power requirement. Torque rise is real, and I am not pushing that off but your beyond that. It also means you have to lug the engine to get there, which is not reccpmmended. My example still stands. A truck with a flat torque curve struggles to maintain speed at peak torque of 1600 rpms, but can pull the same grade in the same gear at 2500 rpms without being WOT. There is more parasitic engine drag, and a higher power requirement from the increased speed.. Yet it's easier to maintain speed. The acceleration difference is from the horsower. Yes the inertia helps, but it still takes an increase in power to accelerate. Good times.

It's more complex than many people realize, but a fun conversation. Which is what I like about this board, things are fun discussions and not arguments, or bashing.

If your talking the 1600 vs 2500 I mentioned earlier then you misread what I typed. It was all in 5th gear, so the ratio's don't matter a lick. The only change is horsepower... which is a single word used to describe torque at speed. In my example the torque to the ground is identical, but the ability to get up the hill is not the same. Some interesting numbers if you run torque to the ground at different gearing options (as you mentioned). Let use 3.42, 3.73, and 4.10. Lets also assume a flat torque curve of 800 ft/lbs. Speed in 60 mph in direct gear. Let's say that the twisting for required to keep the load moving is 1000 ft/bs. The 3.42 truck needs to make the most torque at the engine, 292 ft/lbs followed by the 3.73 at 268 ft/lbs, and finally the 4.10 needs the lowest at 244 ft/lbs. Okay there is your gearing, here is the hp kicker... all 3 engines are making the exact same hp, 118.8119. Why? Horsepower is real, it's the rate that the work is done at and they are all doing it at 60 mph. The work is twisting the tire with a force of 1000 ft/lbs, the speed is 624 rpms (tire size I used).. which is how we get 118hp. I agree you can't argue with physics, but horesepower is real. Given any two of the three, hp/tq/rpms, you can calculate the 3rd. So torque is just as easily calculated. I've been playing with the calculations for a long time, they blow most people away. Torque is useless without horsepower... I know you call it speed, but that's what horsepower is! Horsepower is the rate at which work is done, torque is the amount of work that is done. Inertia dyno's measure horsepower, not torque. The twisting force required is set, so all the varies is the rated of acceleration. That's a horsepower measurement. So a chassis dyno will measure horsepower, but a engine dyno will generally measure torque and use rpms to calculate horsepower. Both are in-fact measurable, it's just a matter of how. Think about the old way horsepower was measured. A vertical lift of 550 lbs 1' in 1 second, that is measuring horsepower not torque. The only variable is speed, just like my 1600 rpm vs 2500 rpm example.. that's a horsepower difference and it will win the hill climb every time. Water-brakes are great ways to measure. The torque measurement on the GE T-700 engine I fly with works on a similar principle of deflection. Torque is easier to measure this way, as there isn't (that I know of) a good way to measure horsepower while the engine is installed and functional.... you can measure hp, just not in this instance. FWIW the engines produce up to a combined 1427hp and 700 ft/lbs of torque to keep the helicopter flying, which can be up to 23K lbs but generally 17-18K. By the time the gearing reduction occurs there can be around 50K ft/lbs to the main rotor :-) My motor makes more than 900 ft/lbs (flywheel) but doesn't have the hp to make it fly, not even close. Turbines are also rated in SHP, not torque. I just happen to know the torque numbers from some GE training. Additionally look at a NV5600 diagram again, it initially appears that 1:1 is on the counter-shaft but it's not. There is a direct link of the input to the ouput in 5th. Here is a good image of a NV5600. There is a 5th gear c/s gear (a), but there in no reciprocal 5th gear. The 5th c/s gear is simply called the 5th gear, but not used for direct drive it's more the c/s input gear. 5th gear is direct and connects at (I) when it's used. The c/s is still spinning but its not transferring any power. I am not sure how the shifting forks of a NV5600 work, but the direction must be reversed on the 5/6 fork. So 5th is fwd on the shifter and fwd on the fork, and 6th is back on the shifter and back on the fork.. otherwise 6th wouldn't engage with a back shifter.

The only reason I ran in 5th for my most recent dyno tuning was my tires. They are only 75 mph rated, so I didn't want to be taking them to 100+mph at full power. As for the question on how dyno's measure, their output is horsepower and if you give it a tach signal you can get engine torque. I know there is the whole hp doesn't matter, it's torque vs hp is better debate... but that's what it is. Horsepower is how fast work can be done, and the dyno computer knows how much work it takes to accelerate the drum, the faster the work is done the more hp is made. Without knowing how fast the vehicle engine is spinning only horsepower can be measured. Just like with our rigs, torque is great but it's nothing without horsepower. If you think the hp doesn't matter then hook up to a load and try to climb a big grade at 1600 rpms in 5th and again at 2500 rpm in 5th. On any of the ~00ish and newer rigs the torque should be the same but there is a decent difference in hp. 2500 rpms will pull the hill much easier, and the power requirement is higher with the increased speed. Using the OEM numbers from my 2005 there is 610 ft/lbs at 1600 which means the motor is making 185hp, and at 2500 there is at least 555 but less than 610 ft/lbs. At 2500 there is at least 264hp being made, and possibly up to 290. That extra 79-105hp is going to make a HUGE difference in towing, even thou the torque is the same. I love torque, but at the end of the day it's useless without hp.

4th will give you similar hp, but less torque than 5th. I saw a 50 ft/lb drop in tq doing my runs in direct instead of OD, as the turbo doesn't have time to light at the lower rpms in direct. How you load the engine prior to the green light is how good your torque will come off. Personally I get to 1400-1500 rpms and start aplying brake and throttle to get the load/boost up and then let her rip. The total and mid range power is very different than just dropping the hammer. Take a few seconds each run while you prep to ensure the motor it up to operating temp as well.

Wow, seems like a really long time. Did Spyntec give you a service interval? I was told 24 months or 25K miles. I need to do some research and see what is was back in the 80's and 90's. I know my trailer axles are annually or 12K miles.

Is that going to be your 1st repack?

Yep, but no where near as limiting as the 17's on 3rd/4th gens. Even then with a set of decent LRE 16's and wheels one can hit/exceed the 11,000 Frame GVWR so unless one is planning to exceed that number there isn't much "need" for 19.5's, or anything but 16's, on a 2nd gen. Now having run 19.5's I can tell you that at a 6K lb load the 19.5's are far far far superior to LRE in every way, unless you drive above 75.

It's no different that applying 3500 DRW GVWR ratings to a 2500 on a 3rd gen, or 4th gen. The frames are the same, steering, brakes, etc... Lets look at 03-09. Take a QC LB Hemi 2500, QC LB CTD 2500, QC LB CTD 3500 SRW, and a QC LB CTD DRW you will find 1 frame part number, 1 front axle, 1 size brakes, etc. All of the 3 diesels even use the same axle. You don't need a 3500 SRW to compare to, just look and see if the frames are the same. Are the brakes the same? It's all personal homework to determine what you are comfortable with. On any 2500 HD I can think of the limit is tires/wheels. So exceeding GVWR but staying within FAWR and rear tires/wheels is fine as long as you stay within the highest GVWR the frame received (regardless of door badging). Looking up a few posts I see Micheal's door sticker. 5200+6084 = 11,284 which is over the GVWR for a DRW. Load that 2500 up to 11,000lbs and you should be within OEM axle limits, with OEM wheels/tires. OEM tires are plenty for the max GVWR the frame received. (Please correct me if the 2500 and 3500 don't share a common frame, but I understand that they do). My truck OEM limits are 5200+6200 = 11,400 but the tires are actually good to 5200+6390 = 11,590. I found myself right on the edge of those tires/wheels so I upgraded and now run at 75-80% of tire/wheel rating instead of 95-100%. No you won't brake the axle, but you will overload many components before the axle. Suspension, frame, brakes, etc. The AAM 11.5 in 3rd gens is rated for 10,912lbs but that's not a number people use for loading like you are implying with your Dana 80. The highest RAWR for the AAM 11.5" axle on a 3rd gen frame is 9,350 and that is the limit people talk about, for SRW or DRW when tires are adequite. That same thing would want you to limit your Dana 80 to 7500lbs , with suspension enhancements.

Weight ratings are a common discussion, especially when legality is concerned. Each state is different, so those outside of Idaho need to do their own research. But here is what I know about legal loads in Idaho. GVWR means nothing, in terms of legality. All that matters is registered weight and tires. The max single axle load limit in Idaho is 20K lbs, so we are all WAY under that. Next is registration, and in Idaho you register for GCWR. I am registered for 26K lbs. The tire limit is the sidewall limit or 600lbs/in of width, whichever is lower. That's it. My door sticker says 9,900 GVWR, with a 6,200lb RAWR. I am 100% legal to load my rear axle to the 9Klbs the 19.5's can hold. Now, that's the black and white.. .lets talk grey. You can get an unsafe vehicle ticket for being overloaded, such as 19.5' on a Ranger could be DOT legal but won't pass many safety inspections. So you need to know your parts, and there isn't a 2500 out there that is actually anywhere near it's design limits at door sticker GVWR or RAWR, FAWR is a different story. 2500 and 3500 Dodge's in 98.5-02 share the same frame, correct? Same brakes? See were I am going... what is the GVWR of a 3500?? That is the number I wouldn't exceed with a 2500, as long as you are within FAWR and rear tires. So on my truck here is what I am comfortable doing, based on knowledge of frame/suspension/axle design limits (not always door sticker). OEM vs Personal FAWR 5200_____5200 RAWR 6200_____9000 GVWR 9,900_____12,200 GCWR 23,000_____23,000+ (never really needed to go above it, but it's based on acceleration and ability to hold speed, I'm good there). On an average camping trip I am 4800 FAW, 7,100 RAW, 11,900 GVW and 20,000 GCW. I am over my door stickers on 2/3 of ratings and 100% legal, and not running the risk of getting a safety ticket either. YMMV, so do the research and determine your personal safety level from there. I am probably safe exceeding 12,200 GVW based on all the 5er and TC folks that do it on my frame without issue but 12,200 is enough for me 99.999% of the time. In the end if you are not sold on exceeding your door sticker limits then don't.

Even under pressure the gelling will occur. It has happened to me once (B20 -8°F, long story)... but the first unheated filter inline is where is will plug. That can be a 2um or a 144um filter.

The only time I worry about gelling is elk season. It's too early for most stations to start winterizing and I am 65 miles of dirt from town and it can get quite cold at 6-9K feet in October. That's also the only time of year I worry about cetane, and actually bump it by 3 points. I spend 7-10 days without going over 20-30% load and the cetane is great for that kind of use. It also helps it start faster, which isn't bad when in the boonies. Not that my truck starts slow, I just like the added insurance. Now a couple years ago I was messing around with Cetane and a 7 point increase on a warm day would knock like a rod with a cold motor.

I am not sure if they are in your neck of the woods, but outdoors RV is a Nash Family brand as well. Everything the Nash Family builds is top notch and overbuilt.

Not all trailers are created equal. You will need one that is 4 seasons. We can camp in ours down to around 0°F without any outside insulation/heating and not freeze anything... but it does burn some propane. I would look at a slide for comfort, but it will increase your heating costs. A 5er would be more comfortable. Plan on using electric and propane for heat. Double pane windows would be a big plus for winter.

I haven't. I am not sure it would make a difference thou. Haha.. many of the miles were towing, that's hot enough.

My CR did not like 2-stroke at all. It made my exhaust brake stickey, so I cannot imagine what other places it left a coating on.

Many places don't blend 1/2 anymore, but that doesn't meant it's not winterized. Most ULSD #2 is winterized with additive. Standard #2 can start to cloud in the 40's.