It would be interesting to see how the new gas engines fair to the new diesels doing the same type calculations.
The calculations are only an attempt to help those who have no idea what horsepower is see that the Tundra wins because it has more horsepower. Power can simply be expressed as torque x rpm but there is no need to calculate anything - the higher HP engine wins. (unless the engineers have no idea what they are doing and put irrelevant gearing behind the engine in which case the engine is not able to run at the necessary rpm to produce the specified power)
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JustLabs wrote: I'm arguing with some guys on a different forum about tow vehicles. One guy wants to sell his F250 with the 7.3 Powerstroke and buy a Toyota Tundra with the 5.7 gas engine.
Right off the bat everyone is claiming the Ford will pull better because its a diesel. They don't care about HP,gear ratios,transmissions,etc. Their entire argument for the Ford pulling better is because its a diesel.
The trailer is 5500lbs. Lets say its a 6% grade for 5 miles, slightly above sea level.
The 7.3 specs
250HP @ 2800
500 lb-ft @ 1600
3.73 axle ratio
I towed with a gasser before my 7.3. The gasser had more horse power than my current diesel but could not even come close to the pulling performance of the 7.3. I will admit that the gear ratio's were a little different but I don't think that it could make that much difference. I have never even rode in a Tundra but they are nice trucks.
biggrigg wrote: I towed with a gasser before my 7.3. The gasser had more horse power than my current diesel but could not even come close to the pulling performance of the 7.3. I will admit that the gear ratio's were a little different but I don't think that it could make that much difference. I have never even rode in a Tundra but they are nice trucks.
I had a '02 7.3 before my current gasser. My butt dyno says my gasser would beat my old 7.3
JustLabs wrote: I'm arguing with some guys on a different forum about tow vehicles. One guy wants to sell his F250 with the 7.3 Powerstroke and buy a Toyota Tundra with the 5.7 gas engine.
Right off the bat everyone is claiming the Ford will pull better because its a diesel. They don't care about HP,gear ratios,transmissions,etc. Their entire argument for the Ford pulling better is because its a diesel.
The trailer is 5500lbs. Lets say its a 6% grade for 5 miles, slightly above sea level.
The 7.3 specs
250HP @ 2800
500 lb-ft @ 1600
3.73 axle ratio
Lets not worry about fuel mileage,life span,or anything other than which rig gets the 5500lb trailer to the top fastest.
In your opinion who wins?
Horsepower is a measurement of work in a measured time. The greater the horsepower the greater amount of work performed in a measured time.
381hp is greater then 250hp by over 150% so 381hp wins. Now some folks think it is a crime to spin a gasser much over 3000rpm so even if the Tundra is only run to max torque at 3600rpm.. 401ft lbs x 3600rpm /5252 = 274.866hp. The Tundra still wins.
Some folks wrongly think torque is everything but time is important too. All the torque in the world with no movement is still 0hp thus no movement while an ant walking at 1/10mph would be producing and achieving more work. Taking the figures the OP posted I find it interesting at max torque...
The 7.3 specs
250HP @ 2800
500 lb-ft @ 1600
3.73 axle ratio
1st gear 2.71:1 = 1355ftlbs on drive shaft 5054ftlbs total at wheels @ 158rpm
2nd gear 1.54:1 = 770ftlbs on drive shaft 2872ftlbs total at wheels @ 278rpm
3rd gear 1:1 =500ftlbs on drive shaft 1865ftlbs total at wheels @ 428rpm
O/D .72:1
The Tundra specs
381HP @ 5600
401 lb-ft @ 3600
4.30 axle ratio
1st gear 3.33:1 = 1335ftlbs on drive shaft 5742ftlbs total at wheels @ 251rpm
2nd gear 1.96:1 = 785ftlbs on drive shaft 3379ftlbs total at wheels @ 427rpm
3rd gear 1.35:1 = 541ftlbs on drive shaft 2328ftlbs total at wheels @ 620rpm
4th gear 1:1 = 401ftlbs on drive shaft 1724ftlbs total at wheels @ 837rpm
1st O/D .72:1
2nd O/D .58:1
The Ford going down the road at 1600rpm has just over half the torque as the Tundra in second gear and only 1rpm difference.
More torque at the wheels at higher wheel rpm. Add the fact that the Tundra most likely weighs less then the Ford, the Ford doesn't have a prayer of getting close to winning.
More interesting if both trucks where run at max horsepower at max rpm we see:
The 7.3 specs
250HP @ 2800 = 472ftlbs of torque
500 lb-ft @ 1600
3.73 axle ratio
At 472ftlbs torque the figures are:
1st gear 2.71:1 = 1279ftlbs on drive shaft 4771ftlbs total to wheels @ 277rpm
2nd gear 1.54:1 = 726ftlbs on drive shaft 2711ftlbs total to wheels @ 487rpm
3rd gear 1:1 = 474ftlbs on drive shaft 1760ftlbs total to wheels @ 750rpm
O/D .72:1
The Tundra specs
381HP @ 5600 = 357ftlbs
401 lb-ft @ 3600
4.30 axle ratio
At 357ftlbs torque the figures are:
1st gear 3.33:1 = 1188ftlbs on drive shaft 5111ftlbs total to wheels @ 391rpm
2nd gear 1.96:1 = 699ftlbs on drive shaft 3008ftlbs total to wheels @ 664rpm
3rd gear 1.35:1 = 481ftlbs on drive shaft 2072ftlbs total to wheels @ 964rpm
4th gear 1:1 = 357ftlbs on drive shaft 1535ftlbs total to wheels @ 1302rpm
1st O/D .72:1
2nd O/D .58:1
At rated rpm 3rd gear the Ford has 1760ftlbs of torque to the wheels @ 750 wheel rpm while the Tundra in third gear has 2072ftlbs of torque to the wheels at 964 wheel rpm.
The poor Ford would be whoopped bad!!!
That is an awful lot of numbers, tell me where the ford gets beat. This is not a drag race, this is pulling a 6% grade with load, where in that 5 mile pull does the Tundra out pull the diesel, if from a dead stop, then I get beat to the top, if we are side by side doing the speed limit when we hit the hill we are going to be side by side doing the speed limit over the top, if in fact the Tundra will do it with 5500 lbs, the ford will, I have done it. Please help me understand how the Ford gets whooped bad. If we want to see how fast one can go over the top then sure I get beat, but lets get into the real world here, normal towing hitting the grade I will maintain the speed limit over the top , if that Tundra wants to beat me to the top, so be it, I will stop ,and wait for him when he stops to fuel up.
Big Katuna wrote: That's what I said; the Tundra wins hands down.
I wasn't disagreeing with you. I noticed many opinions were based on biased ideas or just "seat of the pants" experiences. I decided to throw out some factually calculated figures to prove the Tundra voters correct. Kinda throws all the Diesel Only theories some folks have out the window, aye??
It would be interesting to see how the new gas engines fair to the new diesels doing the same type calculations.
The diesel will downshift less while cruising over the small hills, but as I "voted" earlier, the higher HP wins in contests such as these - as has been proven in the tests at Pickuptrucks.com, which, incidentally, is where DSteiner51 can see a test just like he wants. The HD SHootout did just that - compare gas to diesel pulling similar sized loads. New diesel vs new gas - diesel wins up the hill.
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biggrigg wrote: I towed with a gasser before my 7.3. The gasser had more horse power than my current diesel but could not even come close to the pulling performance of the 7.3. I will admit that the gear ratio's were a little different but I don't think that it could make that much difference. I have never even rode in a Tundra but they are nice trucks.
I had a '02 7.3 before my current gasser. My butt dyno says my gasser would beat my old 7.3
My gasser was faster also. Just didn't have the pulling power.
IMHO...academic discussion till two members go out and actually run that 'race' up an
incline with the same trailer and same trucks the OP spec'd out.
Folks, careful on taking components out of context. As it is a whole system working
in concert
As mentioned, HP is a number derived from torque, RPM, factored by
the constant 5252, and that time frame is the 'M', for minute. Or how
much 'work' is done in a time frame, that minute.
Sure if there is 1,000 ft/lbs with no rotation, there is no HP, but
there is still 1,000 ft/lbs of force on that shaft. Once there is
rotation, then there is HP, but that 1,000 ft/lbs is still there now
doing work. As the RPMs raise, the 1K ft/lbs constant...the HP will
raise accordingly to the RPMs. A small block will have less torque
and will need to spin up higher to gain the HP desired or needed to
that amount of work asked of it.
As someone said, they'd run out of RPMs with that big lever arm, but
then that is what a transmission is for...to keep that torque in it's
sweet spot while the output keeps increasing in RPMs
Then the fuel type, but that then is really how an ICE uses that fuel and the
architecture of that ICE for that fuel
The new close ratio transmissions now remove much, but not all of the time needed
to shift gears. The other benefit is that with the close ratios, it can tailor
the gear ratio to keep the ICE torque curve in it's highest or most efficient
range.
Anyone know what a power shift is and the why of it? Mainly for the
racing crowd, as why expose your stuff that kind of abuse for regular
driving... All about reducing the time it takes to shift and to
keep the ICE from having to spin up in the next gear. That clutch
slippage is also what an automatic's fluid (hydraulic) coupling
does...torque multiplication.
BUT...even with today's marvelous trannies...shifting still does take time and
just below the sweet spot of the torque curve, the ICE still has to spin up "TO"
that sweet spot of the torque curve.
Bottom line for this academic discussion of a 'race' is that time is everything
in a 'race'. That the new stuff is wonderful, but given that the diesel can also
have some of these marvelous technologies...it will still have an advantage of
not having to shift as often as the gasser
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Kinda throws all the Diesel Only theories some folks have out the window, aye??
