we may be arguing different points, so let me clarify myself. using my 5.4 and 7.3 again. if we stay in 3rd gear and never shift to 4th, both with 4.10 gears, my 5.4 will go faster at top speed no questions asked, because it turns more rpms. my argument is about acceleration. with the same gearing(no matter what rpm my 5.4 is turning) and us in the same tranny gear, my 7.3 is going to have more get up and go as soon as we hit the go pedal even though the 5.4 has more hp. depending on my load size, i can accelerate faster with my 7.3 in 5th gear than my 5.4 will in 3rd.

 

The reason that the 7.3 can still accelerate is because of torque. Most of the people here continue to say and show using math formulas that HP is what makes things move. The truth is without torque, you are not going anywhere. That is why the Diesel can move a heavier load with a higher gear. If the V-10 made the same torque, it would be able to use a taller gear. S

Since everyone seems to say that HP is the deciding factor then gearing should have nothing to do with it. The V-10 makes about the same HP as the diesel at about the same rpm's but the torque is so much less it needs the gears to compensate for the torque.

 

No, the gears are to let it run a higher RPM to get to the HP.
Torque is great for getting a load started but HP is what keeps it moving.

 

The difference is still hp. I don't know what the transmission ratio difference is between your 5.4 and 7.3 in third gear but I doubt they are too different, if at all. That being the case, there is NO WAY that the 5.4 is anywhere near its hp peak whereas the 7.3 is much closer. So even though your 5.4 has a higher peak hp, the amount it is producing at the time you start accelerating, is probably much lower than the 7.3. Also remember that torque is an input in the hp formula so it plays a significant role in how much hp the engine has.

The thing that is important to realize here is that the hp numbers we're talking about is "peak" hp. The physics behind the claims here are accurate. Just keep in mind that they are based on very narrow snapshots of engine output. We can take the hp peak numbers as a snapshot and determine that a V10 can "pull harder" than a psd but we can only be certain of this if the V10 is at its hp peak at sea level. So don't think of it as the higher hp, lower torque motor will pull harder, think of it as that it will eventually pull harder.

The argument I make is that the peak hp of the V10, or 5.4, is severely diminished because in order to outpull a psd, it has to rev significantly higher than highway rpm to get the power. They say the V10 "likes" high rpm. I say no engine "likes" high rpm, the V10 just needs it to get its power.

EDITED TO ADD: In order to explain why your 7.3 will out-accelerate your 5.4, it would take an accurate dyno sheet for both of them. I would guarantee that your 7.3 is producing a whole lot more hp at the rpm where you start the acceleration than the 5.4 is.

 

It really does seem to like it, or at least put up with it very well.
Mine has had the **** revved out of it most of its life, and it does not have any problems.

 

Actually the fairest test is a "black box" test. Two identical trucks, except for no restrictions on drivetrain, and identical weights and loads. No one cares about the drivetrain ratios, it's an ENGINE comparison. Forget all the ratio calculations, let the individual trucks be optimized, and it all comes down to HP. Perfect solution for either vehicle would be a CVT tranny.

 

This is the right approach. If you really want to compare the engines directly, they have to be allowed to run at their optimum RPMs. Comparing them in two identical trucks with identical drivetrains is not a fair test.

 

And the beat goes on...

 

I see nothing wrong with taking both engines and putting them in the identically set up vehicle. Kinda like taking a 500 pound pile of bricks, and timing both a slim and fast guy move them 50 feet, or a slower, stronger guy. My money would be on the slower, but stronger guy to finish first- he can carry more and won't get tired as fast.

 

I said I would show my math on how the V10 is cheaper than a 7.3 PSD and is more profitable as my work truck.
I finely got the time to type it all out, here it is.

This is all based on the miles I have put on mine and my maintenance schedule.

All the prices are from O'reillys.


The 7.3 was $6,000 more than a V10 new.

V10 164,000 miles at 10mpg at $2.40 = $39,360
7.3 164,000 miles at 14mpg at $2.60 = $30,457.

That puts the 7.3 $2903 ahead.



57 oil changes using castrol synthetic blend and wix filters.

V10 6 quarts at $5 = $30 + filter at $6 = $36. 57 x $36 = $ 2,052
7.3 15 quarts at $5 = $75 + filter at $22= $97. 57 X $97 = $ 5,529

That puts the V10 $574 ahead.

9 air filters

V10 $19 x 9 = $171
7.3 $26 x 9 = $234

That puts the V10 $637 ahead.

fuel filters

V10 $13 x 9 = $117
7.3 $41 x 9 = $369

V10 $889 ahead

belts X 2
V10 $29 x 2 = $58
7.3 $36 x 2 = $72

v10 $903

hoses x 2
V10 upper $18
lower $70
heater$39
heater$17 = $144 x 2 = $288

7.3 upper $15
lower $20
heater$36
heater$38 = $109 x 2 = $218


V10 by $833

coolant x 2

v10 5 gal at $11 = $55 x 2 = $110
7.3 8 gal at $11 = $88 x 2 = $176

So, by my math the V10 comes out $899 ahead of the 7.3 power stroke.
More miles and more maintenance should continue to stretch that gap.

 

Bill, your truck and my truck has about the same HP at 2500 RPM. Not peak for either one of us. I will have more torque and therefore out pull you. It doesn't matter what gears you have because 2500 RPM is 2500 RPM. I will also be going faster than you at 2500 RPM due to a taller gear.

When You get to your Peak HP you will begin to catch up but it will take you a while because I am already in my powerband. I am not saying you are not faster, I am saying I am quicker. This again is because of torque.

 

From a start, yes.
from 35 mph up I can run a gear lower than you can, even if we make the same power at the flywheel, I have a better pulling gear, the same hp and will pull better than you because of that.

 

How can you run a gear lower than me? You have a lower rear gear already. We will probably be in the same gear at 2500 rpm. You will only have so much power even after the math because you have less torque. Once you shift to the next gear guess what, you have lost that HP advantage and you are working to get back up to again.

 

That's a lot of figuring there!

Couple of corrections for ya.

I have always changed my oil every 7-8k miles in my 7.3's so that would put it at around 20 changes in that many miles.

A 7.3 was not a $6k option. IIRC it was around 3500.

Edit: mine was actually a $4114.00 option

 

I thought it was a 6k option, that kind of messes up all my math.
Your oil not get filthy by 5K?