Not to say you numbers are wrong, but assuming you have an auto, would the TC effect any of you numbers? most rigs have a 1.73 in the case of GM, last I saw ford uses a 2.05, then less 20% for heat and slippage of your (3.55x3.97) so about 23.17 overall low ratio assuming a 2.05 TC. If not, that would at least be the OA low of the uphill part assuming you have used fords numbers. about 16-1 for a GM. The 23-1 with 600-700 lb of torque would give someone 30-35% gradabilaty in 1st gear.
Looking up some charts I have with 650, that would be just over 30 and under 25%. The chart is at 25K and with 20K, just over 30 and 35%. As a comparison the GM 6.0 gas has a 27.56 with 4.10s, 300 lb ft would net you just under 30 at 20K and about 20% at 25K. The GM gas is not that far behind what a dmax would in 1st gear. The dmax would be about 15% at idle with 300 lb ft at 20K 9-10% at 25K, ford about 18 and 23% at idle.
Assuming the reverse from som holding power, one can see the steepest grade one would hold a given gear.
Marty
on edit,
I am remembering the chart I am getting numbers off of, uses a 10.00x24.5 tire as its base diam, IIRC 36" maybe 40, so the above % grade numbers would be increase by the smaller tire diam of Ford 34", GM 31". Multiply the grade by 40/31 and 40/34. or 36/31 and 36/34. Puts GM's numbers a bit better in realation to the Ford figures.
I am not sure what kind of numbers might be used on your charts for the lost torque in the drive line but assuming a 30% slope, 34" tiress, 3.55 rear axle and 3.97 first gear ratio the torque on tje crank would be 722 ft lbs taking no loss into account. The T/C would likely not make much diffetence to the numbers because by the time the engine reaches max torque the TC would likely be locked up. The max torque multiplication of the TC is achieved at stall speed prior to the vehicle moving. As soon as it starts to move the multiplication factor starts dropping off.
I was looking at some specs on the 6R140 that say the stall speed is 1900 rpm. So I guess for pulling up a a grade maybe the TC multiplication is taken into account. Obviously for holding back the torque converter would have to be taken out of the equation. What are these gradability charts used for?
* This post was
edited 04/03/12 12:05pm by 4x4ord *
2011 F350 SRW short box 4x4 CC 6.7 PS King Ranch
B&W TurnoverBall and Companion
2003 Citation Supreme 34 RLTS
The charts I have are from a "How to spec an MDT/HDT" from navistar. Helps one decide on the drivetrain needs for the task the end user has in mind.
One issue I potentially see, is is relates to clutch vs auto. So the numbers may not be totally correct from that standpoint. The do see to work for my old K3500 and my navistar since they are manuals.
The TC part is something I was told about in the past re specing a rig from a "go power" standpoint, From a freeway "go power" once in an upper gear and the TC is locked out, then that ratio is defunct. Then again, being since I was told those specs, TC's etc have what I am going to say "changed", but not "changed" per say. With some of the electronic controls in a trans, things can be modified from how they function a decade ago etc.
As such, my numbers/figures may be correct, then again, they could be off some too. I also have charts that show HP figures high/low etc for frontal area, HP to pull ea additional 1% grade from a level. Ways to figure HP based on a clean dry surface like concret, vs asphalt vs crushed rock vs spongy ground....tire types, be then traction vs low profile low resistance radial vs bias, vs std radial........
As much as folks like to say the GCWR figures especially are cut and dry, I can pull a few things out of a hat and say it is not so cut and dry, if anything a scientific SWAG on the part of the auto makers!
Then navistar has different specs depending upon the what the end user is using the rig for from a how they will allow something to be built. Ask Bruce about that!LOL An off road dump truck will have a different set of HP/torque. trans axle gear specs than an OTR tractor using the same chassis. Chassis's them selves have chassis GCWR/gvwr specs, so ea end user gets the appropriate frame etc for that users end use.......Then again, with so few of these rigs built, ea one can be special built per say vs pickups, where to make 300K per year per manufacture vs 30-50K is not possible to have that many options. Hence why our light duty trucks have a one size fits all set of ratings, when reality is, what works for you, may not work for me and vise versa.
Marty
05 Chev CC D/A LS Dooley
92 Navistar dump truck, 7.3L 7 sp, 4.33 gears with a Detroit no spin
00 Chev C2500, V5700, 4L80E, 4.10, base truck, no options!
92 Red-e-haul 12K equipment trailer
3 Single axle utility trailers
4x4ord wrote: On I another thread i was accused of being arrogant for claiming I need a bigger trailer to find my truck's towing limit. I know allot of people on here think the gvwr numbers are some kind of magical numbers that actually mean something - I used my cell phone to make a little video that I hope gives some indication of how comfortably my F350 SRW handles a 30,000 lb trailer. This new truck is easily towing twice what it is rated for. (towing this trailer is as relaxing as taking the car for a Sunday drive) My 03 diesel didn't handle half this weight as confidently yet both are rated for roughly 15000 lb 5th wheels. My point is that the new series of diesels are much more capable than the old even though the weight ratings haven't really changed all that much. http://i1117.photobucket.com/albums/k585/4x4ord/2012-03-28155731.jpg
where i'm from this is a norm lots of farms doesn't change is hard on the truck is legal with farm plate far as know...not really rv topic i know people that had pick-ups plated for #48,000 in a matter of years the repair bills added up to the cost of a used class 8 truck
How dare you state the obvious. After all this knowledge?
MM49
Good post Marty. Caught your comment about International's engineering restriction and my experience. Whew! That was a walk over hot coals for sure.
Commercial truck build sheets are based on their mission requirements and projected loads so when someone sits opposite a salesguy and plugs into their database to spec a truck to perform relatively light service duty pulling an RV with no loads over the frame to speak of, well, let's just say it gives the computer on the salesguy's desk a severe case of "heartburn".
Those gradability charts figured prominantly in the allowed options selection of gearbox, rear axle ratio, selected engine hp, torque, etc., Lotsa fun.
Today is just the tomorrow you worried about yesterday!
E&J push'n wind wrote: Following this thread is truly informative and entertaining! Many of the points have been made time and again and it seems to be turning into an arguement (civil mind you) to see who is gonna have the last word.
You can really see when name calling starts that nothing constructive can be offered.
4X4ord, and Marty seem to be offering reasoned arguments IMO. BenK, while I see your point. 4X4ord's point makes sence in that inexperience really wouldn't matter if the inexperienced driver/tower had to much combination vehicle (for them) even if the TV was fully up to the task. If in a class A motor coach, you lack training/experience but have a license that says you can, legally you can. That's when they say, you know just enough to be dangerous.
An example of this, in America most states will allow you to test to get a motor cycle liscense with a say 200 cc MC. You then have a license that says you know how to ride/operate a MC. You now can go out and buy a 1100 cc MC and ride it legally. You at that point know just enough to be dangerous. For those that know what I'm talking about, it is a VAST difference between a 200 cc MC and an 1100 cc MC. You see it all the time, solo accidents W/MC's and inexperienced riders that thought they knew what they were doing.
So.., with all of that said. I fully see the points Marty and 4X4ord are making. If I can sum it up (what I'm saying), just because your TV has the ability and you fall within the spec's doesn't make you safe. Only time and experience can do that and if I may, my signature kind'a speaks to this.
For the person that has to ask, can my vehicle do this? It's assumed that the person asking the question has a 35' Jayco and a WD hitch and they want to know if their 1.6L Smart Car can do the job. I've seen people with fully capable vehicles ask this question. That takes away from the "logic" of if they have to ask.., and the advise that follows.
Just for the record, a smart car diesel is 799 CC, 40 HP.
The gasser is 999 CC with 70 HP
and the electric is...well...electric.
* This post was
edited 04/03/12 07:09pm by John & Angela *
2003 Revolution 40C Class A. 2002 Vanguard 22 foot Class C. Diesel smart car Toad or pulling a 2009 Timeout Tent Trailer.
Life is not measured by the number of breaths we take but rather by the moments that take our breath away.
John & Angela wrote: Just for the record, a smart car diesel is 799 CC, 40 HP.
The gasser is 999 CC with 70 HP
and the electric is...well...electric.
Thank you, that's good to know. It was a shot in the dark, I obviously had no idea. That's smaller than some motorcycle engines, WOW!
Wisdom is the right use of knowledge. To know is not to be wise. Many men know much, and are all the greater fools for it. There is no fool so great a fool as a knowing fool. But to know how to use knowledge is to have wisdom.
John & Angela wrote: Just for the record, a smart car diesel is 799 CC, 40 HP.
The gasser is 999 CC with 70 HP
and the electric is...well...electric.
Thank you, that's good to know. It was a shot in the dark, I obviously had no idea. That's smaller than some motorcycle engines, WOW!
Yah I'm still waiting to hear from someone who takes the motor from a diesel smart car and bolts it onto a motorcyle. It would be kinda cool. A diesel motorcycle. Who knows what the mileage would be. if the car gets 75 mpg I'll betcha a motorcyle would get north of 100.
John & Angela wrote: Yah I'm still waiting to hear from someone who takes the motor from a diesel smart car and bolts it onto a motorcyle. It would be kinda cool. A diesel motorcycle. Who knows what the mileage would be. if the car gets 75 mpg I'll betcha a motorcyle would get north of 100.
Is that diesel a turbo or natural? That would be interesting if it'd fit on one. MC's engine & tranny are typically one unit with exception of Harley which has a seperate (bolt on) tranny.
That V10 Dodge.., someone had the idea to bolt that to what they called a MC. There was only one made and it had 4 wheels real close to each other. I suppose you could call it a MC.
EDIT; Corection, one prototype and nine replicas
I hope this isn't jacking the thread but it seems to be pretty quiet now.
* This post was
edited 04/06/12 09:32am by E&J push'n wind *
John & Angela wrote: Just for the record, a smart car diesel is 799 CC, 40 HP.
The gasser is 999 CC with 70 HP
and the electric is...well...electric.
Thank you, that's good to know. It was a shot in the dark, I obviously had no idea. That's smaller than some motorcycle engines, WOW!
Yah I'm still waiting to hear from someone who takes the motor from a diesel smart car and bolts it onto a motorcyle. It would be kinda cool. A diesel motorcycle. Who knows what the mileage would be. if the car gets 75 mpg I'll betcha a motorcyle would get north of 100.
they have diesel motorcycles
http://www.youtube.com/watch?v=CRzP_NMIYrU
John & Angela wrote: Just for the record, a smart car diesel is 799 CC, 40 HP.
The gasser is 999 CC with 70 HP
and the electric is...well...electric.
Thank you, that's good to know. It was a shot in the dark, I obviously had no idea. That's smaller than some motorcycle engines, WOW!
Yah I'm still waiting to hear from someone who takes the motor from a diesel smart car and bolts it onto a motorcyle. It would be kinda cool. A diesel motorcycle. Who knows what the mileage would be. if the car gets 75 mpg I'll betcha a motorcyle would get north of 100.
they have diesel motorcycles
http://www.youtube.com/watch?v=CRzP_NMIYrU
Well.., there it is! The clip said it gets 96 mpg. Wonder why one hasn't made it to the market yet? Probably because it gets close to 100 mpg. What would the oil company's think of that? They've probably lobbied to keep them off of the streets.
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