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 > Your search for posts made by 'RoyJ' found 52 matches.

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RE: F450 vs Ram 3500 DRW tow vehicle

Well I'll be darned, that is indeed a very steep, in fact, negative slope on the ideal BSFC land! With these curves, you could have a situation where a downshift @ light load gives better economy. Especially with the 2019 spec and a hypothetical 10 spd. If you were WOT @ 1500, a downshift to 9th / 8th could land in the sweet spot, at say 60% loading and 1900 rpm. These graphs reveal another interesting point, modern diesel pickups are tuned so aggressive it's difficult to achieve good economy at 65 mph empty cruise. You'll be at roughly 200 Nm output, 1500 rpm. No matter what gear we choose, it'll end up in a poor region. Unless it's geared so tall that it cruises at 1000 pm, bringing torque up to the 350 Nm region.
RoyJ 08/29/20 12:25am Tow Vehicles
RE: F450 vs Ram 3500 DRW tow vehicle

The engine output torque curve of a Cummins 6.7 is MUCH steeper than that at the lower rpm range. On the left is the curve of a 350hp/800lb-ft Cummins 6.7L from similar to what my truck was stock but with 20 less hp. Max rpm is 3,000. 6th gear at 65 mph in my truck is a 1,370 rpm. 5th gear at 65 mph is 1,790 rpm. I know the torque curve of a turbo-diesel is much steeper, I was referring to the steepness of the BSFC ringlands (320, 365, 410, etc.) on my graph. If the curve of the 410 and 365 bends up vertical, so that 6th gear (1370rpm) high load lands above 410, and when you shift to 5th (1790rpm) low load, it falls to the 365 ringland, then you could get better fuel economy. On my graph, this only happens once, where the 200kW constant power curve intersects the 275 BSFC curve @ ~3250 rpm. So running that engine at 3200 rpm WOT lands you in the 320 BSFC zone, with a downshift to say 4200 rpm, and 70% load, you land just within the 275 zone. But we'll need to see an ISB map like that.
RoyJ 08/28/20 11:28am Tow Vehicles
RE: F450 vs Ram 3500 DRW tow vehicle

This is very useful info but it needs to be interpreted properly. So the 5.9 was capable of achieving its best fuel economy at 2000 rpm BUT that is under heavy load. Under heavy load it was able to make 175 hp at 2000 rpm. If its fuel consumption was measured at 2000 rpm and it was only loaded to 50% of its capability it certainly would have been using more fuel than .334 lbs per hphr. I'm talking about slowing an engine down under light load conditions to improve fuel economy. If that old Cummins had a demand on it of 80 hp, I would call that a light load, It could easily produce 80 hp at 1500 rpm and I would be willing to bet it would achieve better fuel economy producing 80 hp while running at 1500 rpm than it would running 2000 rpm with a 80 hp demand on it. What I'd really like to see is the following BSFC map (key work being map, not curve) for an ISB or any other modern diesel: This shows for a given power, a heavily load 5th gear, vs lighter loaded 4th gear, at constant road speed, constant power output (110 kW), you always land on a better BSFC map. That absolute best for this NA engine is between 4000 - 4500 rpm, and between ~80% - 95% of max torque output at that given rpm range. Unless a Cummins' curve is MUCH steeper at the lower rpm range, so that 6th gear lands on a lower BSFC "ring" than 5th at a higher rpm, Shiner's case of better fuel economy (in 5th @ lower load) is unlikely. But then again I haven't seen a Cummins BSFC map.
RoyJ 08/28/20 03:17am Tow Vehicles
RE: Cybertruck has 400 horses

Oh I'm sure it won't go that high. I was making a point about extrapolating the instantaneous mpg readout on an IC engine pulling 18,000 lbs uphill @ 60 mph, and comparing to the unloaded cruising EV range. If a 100 kWh pack was asked to put out constant 350 hp (261kW), it'll be drained flat in 23 minutes. Provided the pack can take a continuous 3C discharge without overheat.
RoyJ 08/05/20 03:22pm Tow Vehicles
RE: Payload Rating vs Tongue Weight

Thank you. Being a unibody passenger vehicle, my guess is rear GAWR and the hitch attachment points on the chassis. Both of those are a non-issue @ 500 lbs tongue on a light truck. Based on 975 lbs remaining capacity: at 500 lbs tongue, geometry would place around 600 on the rear axle, leaving 2 passengers in the rear seat, or 1 pass and some rear cargo before capacity is reached. The factory attachment points are essentially strengthened sheet metal. The actual bolt holes may experience 2 - 3 times the tongue weight depending on hitch geometry. 500 lbs may be all the OEM engineers want to validate, given shock loading (say a speed bump). Now, if you ensure no weight behind the front seats, remove the spare tire, and strength all attachment points with steel plate, I'm sure you can safely go above 500 lbs. As long as you remain within rear GAWR. As long as you're okay with any risk.
RoyJ 08/05/20 03:16pm Tow Vehicles
RE: Cybertruck has 400 horses

TFL Truck testing the 7.3 Ford gasohol V8 / 10 spd / 4.30 ratio in Loveland Pass with 18,000lbs trailer. aka THE IKE GAUNTLET OMG! Anyways the grade pulling fuel economy should give a person range anxiety - dividing what they got into what a 40gal tank... 7.3 Ford gasohol V8 - 18,000 trailer If you thought that was bad, wait till you see the instantaneous range readout on a Cybertruck pulling 18k lbs up that grade. I'll place my bet at 30 miles, 10% of its empty cruising range.
RoyJ 08/05/20 02:50pm Tow Vehicles
RE: Payload Rating vs Tongue Weight

OP - what's the vehicle in question? Relatively rare for OEMs to specify tongue limits for hitches they didn't supply. With an aftermarket hitch, tongue weight is just (badly placed) payload. As long as you don't go over rear GAWR, then I don't see why you're limited.
RoyJ 08/05/20 02:38pm Tow Vehicles
RE: How much weight is too much?

Does anyone have links to even *1* lawsuit against an overweight RV combination? A very common scare tactic here - go over 1 lb of a powertrain warranty driven "tow rating", you'll be sued till your wife and kids are living in the park... 4x4ord brings up a good point - if I overload my Corvette (easy with 440 lbs payload), and stopped in 110' from 60mph, instead of 97', I can be sued?
RoyJ 08/02/20 01:13pm Tow Vehicles
RE: Tesla Model X Towing 5,000-lb Camper: 600-Mile Road Trip

Correct. C/5 would be drained over 5 hours That is one very fast Semi to drain the 600 mile range battery in one hour... OK climbing a hill or even accelerating could well be at the 1C rate for a short time. Although I believe this is all within design specification as long as the battery is kept within proper temperature range. Where did I mention a semi drained the batt in 1 hour? I specifically said high duty cycle applications are designed for C/5 to C/10 drain rates.
RoyJ 07/31/20 02:35am Tow Vehicles
RE: Tesla Model X Towing 5,000-lb Camper: 600-Mile Road Trip

Correct. C/5 would be drained over 5 hours
RoyJ 07/30/20 12:30pm Tow Vehicles
RE: New Hummer has crazy good specs. 1000 HP and 1150 torque.

Torque is always HP / RPM x 5252, it's law of physics that applies to any angular "force". In metric terms, torque (n-m) = power (watts) / rad/sec. While meaningful to portray the shape of power curve on IC engines, torque becomes useless on electric motors. Motors by nature are nearly constant hp, with an inverse torque curve, i.e. immense torque rise. Close to 0 rpm, a theoretical motor would have infinity torque. In real life, you're limited by current capacity of the motor windings. The EV torque rating at the wheels is only meaningful to measure tractive effort, not motor performance. 11,500 lb-ft, with say 35" tires, roughly translates to 7886 lbs of tractive effort (assuming the truck weighs enough). How long it maintains that depends on the duty cycle of the motors at max torque (winding current). However, 1000 hp, if true, is nothing to sneeze at...
RoyJ 07/30/20 12:27pm Tow Vehicles
RE: Tesla Model X Towing 5,000-lb Camper: 600-Mile Road Trip

My concern is the speed at which the pack is drained - nearly 1C. This is very hard on a big battery pack. Batteries from lead acid to lithium are used in plenty of heavy duty applications, but they're sized for closer to C/4 to C/12 rates. That's why I mentioned 1000 kWh - at that size, we could tow a regular commercial travel trailer and maintain say, a C/5 rate of discharge. Ideally you'd arrive at a campsite and charge overnight at C/10 rate. Not being blasted by a supercharger at 1C+
RoyJ 07/30/20 12:14pm Tow Vehicles
RE: Buy a 2020 Ram diesel?

Two questions for the Ram fans: 1. If the worst happens, can I put an older junk yard, say 2010 and up, Cummins in the new trucks? No emissions testing where I live, and my first Cummins was in a 1971 Ford dump, I know that one would not fit. 2. What is the best forum for the Ram diesels? Thanks for the help. Highly unlikely you'll integrate a '10 engine with a '20 chassis. Even if you get the engine itself to run, mating it to the newer transmission control modules, and chassis control modules (say, for traction and stability control systems), may be next to impossible. You may have better luck finding an ISB / transmission package made for RVs. They're made to integrate with independent chassis builders. Of course, you'll likely have to run custom gauge clusters. Conclusion, just not worth it to think / plan that far ahead...
RoyJ 07/30/20 12:25am Tow Vehicles
RE: Tesla Model X Towing 5,000-lb Camper: 600-Mile Road Trip

This hasn't been mentioned yet - but wonder if constant heavy discharge, followed by fast charging, will take a toll on battery life. Much more so than an IC engine running high duty cycle. I'm far from anti-EV, in fact, I believe 99% (not an exaggeration) of commuting should be done with EVs. But the fact is battery technology is not quite there yet to support heavy duty-cycle. The motors are, and have been ever since GM introduced the first diesel-electric locomotive. 99.9% of rail freight use electric motors for motive, the <.1% being heritage steamers. As soon as we have reliable 1,000 kwh battery packs, with negligible Peukert factor, then bye-bye ICs.
RoyJ 07/30/20 12:17am Tow Vehicles
RE: dodge 3500 frame

Broke clean in half or bent? Unless there's corrosion damage, the relatively low ksi steel is unlikely to just snap. What's the total weight? And off road or big speed bumps at speed? Being rear heavy, a Lance 1181 should place the weight close to the rear axle. Meaning there's relatively low bending moment around the rear seat area (middle of wheelbase). For illustration:
RoyJ 07/21/20 10:46am Tow Vehicles
RE: Toyota fake 3/4 ton spotted, overheated

You'd be surprised how many people neglect their cooling system. With a simple coolant flush, new thermostat, and clean rad fins, very few 1/2 tons would over-heat pulling their rated capacity. Nothing wrong with the Tundra, reliable. However, SERIOUSLY out of date, and the sales number shows. I remember jumping up and down when the specs were first released in 2006, the 381hp engine and 6 spd crushed every import and domestic competition. That was 14 long years ago, the Tundra barely changed. Ford when from outdated and underpowered 4.6s and 5.4s with ancient 4 spd autos, to state of the art twin turbo engines making up to 450hp and 10 spd autos. And 3 chassis generations.
RoyJ 07/18/20 01:46am Tow Vehicles
RE: 2021 Ford Bronco

Nice rugged vehicle, but the unanswerable question at this point is- just how many of the new Broncos will EVER be driven off-road? Much like any other SUV, regardless of their actual capabilities, very very few ever see anything other than pavement under their tires. Just an observation. The beauty about that, is without gleaming mall crawlers, there won't be abundant used vehicles in good condition for enthusiasts to built on. Remember, at one point, TJ/JKs, 80/100 Series, 3rd gen 4runners, LR3/4s, etc., were all street queens. Just like the modern JL / 200 Series and upcoming Bronco.
RoyJ 07/17/20 01:35am Tow Vehicles
RE: GM HD Trucks Many with AWD instead of 4WD

One big advantage to 4wd, is kits allow for 2-Lo. You have massive torque multiplication for back up heavy trailers, especially up grades. My old truck spends quite a bit of time in 2Lo. Easier on the engine and transmission. Less of a factor with modern 8 - 10 spd transmissions, but still nice to have.
RoyJ 07/12/20 02:02am Tow Vehicles
RE: Ford running out of diesel engines

You are right about one thing here. Many don't "feel" that is cost effective but they don't actually know. I did the numbers myself calculating initial cost, finance charges, tax, registration, fuel cost, DEF, maintenance, trade in value at 100k and so on of my 2014 CTD versus a 6.4L Hemi of my year. I came out ahead with the diesel by about $700. This was just calculating unloaded mileage for each truck. This won't be the same for most because fuel cost and resale values differ from one region to the next. However, I would wager that if everyone actually did the math, the total cost on the diesel for most (not all) would be within $2,000 +/- of the gas version at the end of the 5 year 100k mile warranty that currently comes with all of the diesels. Most gassers values start to tank after this. That is really not a lot of money over the 5 year period. I spent more upgrading my F150 to a 4wd with an Ecoboost engine over the base 2wd 3.7L back in 2012 and both of those things cost me more overtime because it got worse fuel mileage than the base 2wd 3.7L unlike my diesel that gets around 3 mpg better than the gas version(when it was stock). Remember not everyone buys new - that huge depreciation of a gasser now works FOR you, not against you, when buying used. I can find many pristine low mileage 6.4 / 5.7 trucks, 10 years old, for less than 1/2 of a Cummins truck. I have 5 vehicles, meaning my 1 ton gets 1000 - 2000 kms a year. I've owned everything from old Detroit Diesels to 8.3 ISCs, and for my use, diesels always cost more, not to mention wasteful to let such a heavy duty engine sit. If you're buying a brand new top of the line pickup, putting on 10k+ miles on each year, then it'll be foolish to get a gas.
RoyJ 07/12/20 01:57am Tow Vehicles

seems to me that DRW trucks sort of stick out wider than SRW ones?????? bumpyYes I am still wanting a SRW with some type of super singles tucked under the rear of a SRW body with dually payload capacity. Going to say the exact same thing - anyone know what's the maximum load on a single tire on current 1 tons? Sprinter vans have gone to super singles, 285/65/16 tire with 4300 lbs or 131 load rating, pretty impressive: That's only a 30" tire. If we scale it up to 33", it should easily do 5,000 lbs @ 90 psi, giving a near 10k axle rating.
RoyJ 07/11/20 02:20pm Tow Vehicles
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