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 > Your search for posts made by 'RoyJ' found 107 matches.

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  Subject Author Date Posted Forum
RE: Lowering TV tire pressures

Load charts are about load, not wear. You can have two different vehicles, weighing the same using the same tires that will need very different pressures to give optimum performance because they are very different in other ways and uses. The tire manufacturer doesn’t know how the tire will be used in every case, only how much weight it can support at a given pressure. For a given class of tire (Class 3 - 5 trucks), how much can the intended use differ? I'd imagine A Ram 3500, vs F450, vs Silverado 3500, all towing a 30k horse trailer, or carrying 5k lbs of cement in bed, would put very similar loads on a tire - mostly vertical. NASCAR is a whole new extreme, where a 3000 lbs car can weigh 10,000 lbs on a steep enough embankment, and generate over 7000 lbs laterally. Therefore the tire loads are significantly different than say, a street going Camry.
RoyJ 10/08/19 12:13pm Tow Vehicles
RE: Ford 6.7L 1050 ft lbs TQ at 1,600 rpm, 475 HP at 2,800 rpm

What was thought behind 12K fronts and 46 rears? It would seem that you would over on the fronts before you got to take advantage of the 46 rears? I am not sure I have seen that combo before. To be honest I'm not sure, our axle limits are no different than down south. But we do have a lot of mountain passes in BC, and crappy weather, and 132k B-trains, so perhaps it's done strictly for durability reasons (in a GCWR sense). Either way, the axle capacity to gross combined ratio is much higher on a semi than these new crop of 37,000 lb towing duallies. I can tell you grossing 100k on a triple axle reefer feels more stable than towing 20k 5th wheel on a dually. You feel the combination is designed for it.
RoyJ 10/07/19 02:50pm Tow Vehicles
RE: Ford 6.7L 1050 ft lbs TQ at 1,600 rpm, 475 HP at 2,800 rpm

A better comparison would be tow truck's total GAWRs vs total towing weight. A tractor typically have 44k rears with 13k fronts. That's 57k for 80k combined weight. A dually has 10k rears and 6k fronts, at best. That's 16k for 40k+ combined. So the semi tractor has a much better running gear toughness to GCW ratio.
RoyJ 10/06/19 02:18pm Tow Vehicles
RE: Toyota Highlander and 26' Trailer

GCWR is just a performance and longevity rating. Not everybody needs to tow their trailer up davis dam grade in the middle of summer, and most folks only tow infrequently. As long as his hitch receiver is good for it, he's probably fine, even though there is certainly better tools for that task. This needs to be emphasized! GCWR is not a legal spec - no DOT / Transport Canada dept that I know of enforces it. What is enforced is GVWR. Personally (as a ME), GAWRs are the "hard limits" that should not be exceeded. It includes your tire, suspension, axle bearing, AND braking load limits. Could the setup work? If he used a Hensley, it could work safely. It gets rid of the short wheelbase concern, and can keep both axle / GVWR under limit. A highlander has 1340 lbs payload - higher than some Ram 1500s that are rated to tow 10,000 lbs. Of course, if he overheats and burns up the engine / transmission, kiss the warranty goodbye - that's where GCWR kicks in.
RoyJ 10/03/19 11:16pm Tow Vehicles
RE: 2020 Chevy 2500HD Gas

I don't beleive you could get a 3.42 in a gasser 3/4 ton. That would make it largely worthless as a heavy duty truck unless strictly for hauling 3-4 or a ton in the truck bed. It wouldn't pull a ..........nevermind, my dads old saying for this isn't family friendly! You have to take trans ratios into account when looking at rear end ratios. A 6L90 with 3.42 is equivalent of a 4L85 with 5.54 diff ratio. 4.02 1st gear vs 2.482. To call a 2008 6.0L gasser (4L85) with 5.54 ratio "worthless" is a bit of an exaggeration...
RoyJ 10/03/19 09:16pm Tow Vehicles
RE: Jeep Rubicon Gladiator vs the Rubicon Trail

Much prefer overlanding, where you go off the beaten path to visit remote places, instead of messing around in a rock garden ruining your truck.
RoyJ 09/30/19 07:54pm Tow Vehicles
RE: Ford 6.7L 1050 ft lbs TQ at 1,600 rpm, 475 HP at 2,800 rpm

I think you're right that a 515 hp engine in a heavy duty truck cn put out peak power all day long. These pick up truck engines may also be capable of running at peak power all day long. It is possible that the reason they don't make advertised hp on the Ike run is due to the extreme elevation. I wonder if the turbos on the pick up truck engines are capable of pumping enough air at 10,000 feet elevation to allow full fuel to be delivered? Maybe fuel is restricted under those conditions to prevent excessive exhaust gas temperatures? Big trucks do lose a bit of power at 10,000' elevation. Even if the turbo has excess boost capacity, it'll be running at a higher pressure ratio to attain the same manifold boost. This means high intake air temperature. The fan (40 - 50hp) would either run more to move air across the intercooler (much harder in thin air), or run the same, but with hotter air (less O2) reaching the cylinders. Both saps power. I also doubt the PS or any other pickup engine can sustain full power up the IKE.
RoyJ 09/30/19 06:25pm Tow Vehicles
RE: Ford 6.7L 1050 ft lbs TQ at 1,600 rpm, 475 HP at 2,800 rpm

The industrial diesels move a little more air per HP but when you actually do the math the numbers might surprise you. A Cat C13 can be speced to produce 520 HP (and we have Cat C13s in some of our equipment where they produce up to 543 HP) The C13s produce peak HP from 1800 rpm to 2100. So it is designed to run all day long delivering 520 HP @ 1800 rpm. The C13 has a displacement of 12.5 liters. So at 1800 rpm it can produce 520/(1800 x 12.5) = .023 HP/rpm liter. If the Powerstroke were tuned to produce .023 HP/rpm liter it would make 431 HP (.023 x 2800 x 6.7). So although the industrial engine at 1800 rpm produces less power per litre displacement it doesn't pump a whole lot more air per HP produced when compared to the Powerstroke at 2800 rpm. You'd also have to factor in boost and volumetric effciency with those calculations. By your math, I'd guess the PS has higher boost as it makes more hp/rpm/L. Plus at high rpm the VE is usually lower, so it needs even more boost to overcome that.
RoyJ 09/30/19 06:19pm Tow Vehicles
RE: Ecoboost vs. V8 - Can you explain?

Very simple answer - because the EB makes more power. At a given speed, power determines how much thrust you have.
RoyJ 08/28/19 12:25pm Tow Vehicles
RE: Has anyone looked at the Jeep Gladiator?

It still rides and drives like a Wrangler. So having a V8 is not a big deal for extra towing. The engine performance seems in line for the intended use. If you like the capabilities of the Wrangler but looking for more cargo space this is a good option. Most medium size trucks are limited by cooling capacity. Jalopnik has an excellent article, where a Jeep engineer explained just how far they went to achieve the tow rating: https://jalopnik.com/the-engineering-behind-the-jeep-gladiators-tow-rating-1833657453 Many people wonder why the diesel Colorado can't tow much, and it's not because of power / torque. With a diesel's heat rejection: intercooler, the engine itself, and EGR load, it can't tow 7000+ lbs which uphill in 100-degree ambient with AC on. OEM have very rigorous cooling requirements. This is why DOT and Transport Canada here do not enforce "tow rating", as it's not primarily safety driven, but power-train/marketing.
RoyJ 08/23/19 03:56pm Tow Vehicles
RE: Ford 7.3L gas power numbers

That's weird, I can both click on link by wnjj, or directly view the photo I posted. Anyway, the L8T makes just over 400 lb-ft @ 2000 rpm, but dips sharply down to 340 lb-ft @ 1000 rpm, in a fairly linear fashion. The 7.3 holds on much stronger at low rev.
RoyJ 08/18/19 12:33pm Tow Vehicles
RE: Ford 7.3L gas power numbers

Please repost as I am unable to open whatever graph, chart, whatever you are talking about. Look at the post again, I've adjusted the image size.
RoyJ 08/18/19 12:40am Tow Vehicles
RE: Ford 7.3L gas power numbers

https://www.gm-trucks.com/forums/uploads/monthly_2019_06/5cffff9056848_L8TvsL96SAEHPTorque.jpg.09ecd46ae6943e11235a5d6986010343.jpg height=667 width=557 Here's the power curve of the L8T and L96. Power softens under 2000 rpm. What's crazy? The 7.3 has nearly double the torque of the 6 liter L96 at 1000 rpm!
RoyJ 08/17/19 02:00pm Tow Vehicles
RE: Ford 7.3L gas power numbers

https://www.gminsidenews.com/forums/f37/fords-7-3l-numbers-lower-than-we-thought-294405/ Has some good discussion on the pros and cons of each engine, strictly from a performance perspective. Looks like the 7.3 has more power down low, at sub-2000 rpm. Hard to beat displacement when it comes to the very low end power output - case in point, the GM/PSI 8.8 big block has nearly 500 lb-ft at 1000 rpm! Which one works better in the long run, in terms of reliability and overall operating cost is yet to be seen. No doubt the L8T is a technologically more advanced engine.
RoyJ 08/17/19 01:54pm Tow Vehicles
RE: Hope you travel alone?!!!!

A lot of this is driven by consumer demand - if buyers of "premium" 1/2 ton trucks didn't expect the ride of a Cadillac Fleetwood, then we wouldn't have such soft springs. Front and rear GAWRs of the Ram can be up to 3900 and 4100 lbs respectively. If sprung properly, with a bare bone 5000 lbs truck we'd have 3000 lbs payload. Same reason a Lexus LX470 can have a payload of 1200 lbs, but the frame / axles in a 3rd world country can have 2800 lbs payload.
RoyJ 08/17/19 12:22am Tow Vehicles
RE: Tesla X Towing Videos

For the electrical engineers that really want to get into the weeds on this, real question for you. IF you had a Tesla truck and TT and ran out of power in the desert southwest. And you had a trailer with 400 watts of solar, and a 430 Amp/hr battery pack. Along with a 1500 watt inverter. How long would it take to generate enough power to get the truck, without the trailer, 20 miles, to a real power source for recharging if you dont run anything else in the trailer? It may be a lot better than I am guessing, but I really do wonder if there is an optimistic answer. That there is a self sufficient method is a positive, just curious if the method would be real world useful. Well, a kw will take you about 6.7 km in our cars. So 30 km is around 20 miles. So let’s say you need 5kw total. I’ll leave it to someone else from there. I'm going to guess it takes from than 1 kwh to drive 6.7 km when TOWING. Let's say you tow at a very conservative 90 km/h, or 56 mph. It takes 0.0744 hrs to drive that distance. Your average power output would be 1kwh/0.0744hr = 13.42 kw, or 18.01 hp. There're very few trailers you can tow with an average of 18 hp. Drag = Cd*A*rho*V^2/2 Assuming a small 7' wide 8' tall trailer, your frontal area is 5.17 m^2. The combined Cd of a truck and trailer would be lucky to hit 1. Rho of air is roughly 1.2. Plugging in the numbers, drag at 56 mph is: Drag = 1973N Power = F*V = 1973N x 25m/s = 49.33 kw, or 66hp In conclusion, the required power is far greater than the 18hp assumed. Re-calculating with 66hp, it takes 49.33 kwh to drive 56 miles, or 1.13 kwh per mile. A 1.5kw generator + 0.4 kw solar makes 19 kwh in 10 hours, assuming PERFECT charging. You can tow 21.47 miles after 10 hours of generator + solar. In real life, with charging inefficiency and less than 10 hrs of perfect sun, you'd be lucky to get 15 miles.
RoyJ 08/16/19 01:27am Tow Vehicles
RE: Is the EV transformation of the market over hyped ?

F... without stinking up the air ... If I did not have 2 coal burning electricity power plants out my back doorwall, and watch the coal be unloaded from 1000 ft ships, and then pushed by diesel dozers, I might believe your statement. For now, it is just a trade off. And, we're not even counting the mining, processing, and manufacturing of the batteries. Some of the most environment devastation is done in the 3rd world which most of us don't see.
RoyJ 08/10/19 01:22pm Tow Vehicles
RE: Tow/Haul off or on(ram)

I use tow mode and OD off every time I tow. Less shifting = cooler transmission. Maybe not. OD OFF keeps it out of direct final drive. The torque converter is in constant use and likely will tend to make it run a bit HOTTER. The act of shifting up and down does not itself generate any more or less heat. I'd like to know what transmission does that. In most, OD off means exactly that - overdrive gears are not used, only up to and including direct drive. Again, *most* transmissions would lock up sooner in direct drive, with OD off. I've never come across one where in OD off it stays in direct but with the converter unlocked.
RoyJ 08/07/19 03:26pm Tow Vehicles
RE: Ford 7.3L gas power numbers

I thought the only gas truck to come with a 4.30 with the new 10 speed was the Tremor due to it's 35" tires. I don't know the specifics, just trying to show speed vs hp potential of the 10 spd. If fuel economy wasn't a concern, I'd gear the gas so the speed in each gear matches a diesel's. If the diesel came with 3.73, then the gas would need 7.32. (5500 rpm vs 2800 rpm hp peak)
RoyJ 08/07/19 11:44am Tow Vehicles
RE: Ford 7.3L gas power numbers

Yes, better gearing will tow better. Glad you now understand! And with enough gearing (10 spds), two engines of the same hp, one with double the torque, will perform IDENTICAL except right off the line. I hope you understand that now. I agree with you in principle but in every dyno test I have seen the diesels produce much more of their rated horsepower than the gas engines in the same vehicle. So, a diesel will frequently outrun a gas engine of the same rating. I haven't found any explanation for this and it is just a personal observation. It may have something to do with diesels being considered commercial engines being tested to a different standard. Oh I agree, in reality any forced induction engine will likely be under-rated. A 430 hp diesel will dyno a lot healthier than a 430 hp gas. I was strictly explaining the theory behind it. We should compare a diesel and gas that dynos the same peak hp. The diesel with an older 6 speed, and the gas with 10 spd. I bet at sea level they'd pull very close.
RoyJ 08/07/19 11:31am Tow Vehicles
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