V-10 problems

jmacpolo wrote:
Thanks again for all of the replies. When I tow at 3000 and higher RPM we get in the 4-5 mpg range. At 4000 rpm the truck is very loud. I am not normally in a huge hurry when I an towing and never go more than 68mph but when you are on a two lane highway in the Mts and you have to slow down below too much, then you wind up in the truck lanes and stuck behind them going 35-40 mph and losing all momentum.

Of course staying at 3,000 RPM with *ANY* diff ratio will still have
the same HP as it shows on the torque/HP chart Turtle posted...but...
the point am trying to make for the OP to 'solve' his complaint is
to change to an even lower (higher numeric) diff ratio so that the
V10 will gain more HP at a higher RPM...but gotta find a way to get
tha point across...

One of the OP's comments is quoted above and in re-reading it, think
the OP wants it all and does NOT understand that in order to have
one aspect...gotta give up something else....

The OP should get a diesel and move up to a higher GVWR/RGAWR TV...that
does get most of what he wants, but still gotta give up something

How come moving to a higher numeric diff ratio and then moving up
about 10% higher RPMs...to get more HP via that is so hard to understand ????

Folks seem to think going to a higher numeric diff will also mean
sticking with the original RPM the OP stated...not my point at all...

Another of course is diesel folks generally like lower numeric and
gasser guys like higher numeric diff ratios...and is another not
an absolute...and another is why the OEMs are coming out with even
more close ratio gears for the trannies

Here is the chart posted earlier and note the higher HP moving higher
in the RPM axis...but as said...up to a point, as the ICE curve
does have a limit as to how high and still gain HP...at some point
both torque & HP will drop off...

Desert Captain wrote:

Turtle n Peeps wrote:

Max HP will not necessarily get you the best performance vs Max Torque particularly when climbing steep grades.

Really? So less HP will get you up the hill faster? :h Why won't max HP get me the best performance because I guess I have been doing it all wrong in the race game all of these years. :R And don't start with the it's two different things because it don't matter if you accelerate a car down the track or accelerate a truck and trailer up a hill it's all the same.

Look at the chart. Max HP is max HP.

Performance:

The accomplishment of a given task measured against preset known standards of accuracy, completeness, cost, and speed.

If all you know is foot to the floor fastest is always best I can understand how the definition of "performance" eludes you. When I climb a long steep grade at 3,250 utilizing max torque cruising at 50 getting about 8 mpg how does flooring it to 4,250 which gains me maybe 5 mph at a cost of twice the fuel consumption improve my overall performance?

I'll stand with my statement "Max HP will not necessarily get you the best performance vs Max Torque particularly when climbing steep grades".

The OP is looking for performance/speed. So Turtle is correct. The best performance is at max HP. But as you pointed out burning more fuel. But the OP was inquiring about performance not relative fuel economy.

Thanks Bryan.
I'm not a big deep gear fan, but I agree with everything you said about them.

This gear thing all started with 2, 3, and 4 speed transmissions. With low power, and not very many gears you needed to jack up the gears in the back to have and chance of making it up a mountain or have any duty cycle at all. With modern 6, 8 and even 10 speeds and big "POWER" there really is no need to have crazy gears in the rear end anymore.

I remember when Ford came out with their "high power" oil burner the whining really started. :B Man, the old timers really didn't like the 340's that Ford put out back. I took one look at the power they were putting out and said to myself; they will be fine. And they were.

The biggest problems I see on this forum and a lot of other forums is reluctance to put an engine into its power band. They have some weird phobia about RPM. If you "need" maximum power, you need to put the engines RPM where maximum power is made. In the old days you had to look at charts and grafts and all of that garbage. Now days the vehicles computer does all the work for us. No need to look anything up. Just put your right foot to the floor and you will make all of the HP the engine can make. The computer "will not" let the engine over rev. Not going to happen; EVER!

K9, if you or anybody else wants to learn about gears and power here is a physics forum that answers that question.

Making less power with gears.
Ben here is a good article about what I was talking about. No need to do your own dyno run. They do it for you!

BTW, Merry Christmas to all of you RV'ers out there!

Great discussion guys. I always learn something here.

Turtle is right... However it's not always intuitive, and some things specific to keep in mind re: the V10 and the TorqeShift 5-speed:

1) Yes, keep those RPMs up. Even exceeding peak HP can be desirable, when the alternative is to either slow down, or go up to the next gear, which will then be making less HP, since it will be way below peak RPM.

2) Low gearing matters. With 3.73 gear, the V10 won't make peak HP in 3rd gear until you reach a speed that is probably un-safe in most mountain conditions. Also higher-speeds increase HP needs anyways..... Which in the real world means you might be dropping into 2nd gear. Too slow.... 4.30 gears lets you hold 3rd gear and pull the grade with the rest of traffic.

3) 4.30 gears puts peak HP in 3rd gear right about 55 MPH, and you can climb to about 62 MPH without losing out on much steam, but much faster than that and you hit the stock rev limiter. With a tuner and better breathing, you can bump that up to 68 MPH. It won't hurt it. The shift points on the V10 were programmed low because stock breathing makes the HP fall off fast above 4700 RPM. The internals aren't any different from 5.4L applications which spin way faster.

Since the ICE is spinning about 10% more rev's...it moves up the HP curve
and take a look at the one provided on this thread (don't know if correct
for the OP's ICE, but for discussion...assume it is correct for the OP's
ICE)...for the same axle speed (AKA rev's...which translates
to tire rev's...which translates to MPH)

Ben, the higher (numerical) gears you have the slower the wheel speed will be.

EX: Lets say with a 3 to 1 gear with a max red line of 5000 RPM the vehicle goes 100 MPH in high gear.

Now put a 6 to 1 gear in it. Know how fast you can now go at 5000 RPM in high gear? Yep, 50 MPH.

Did you make more HP? Nope. Did the vehicle go faster? Nope. Did you make more torque to the ground? Yep! Twice the torque in fact. It didn't do anything to the HP. Nothing at all.

Think I'm incorrect? Take any vehicle to a chassis dyno and have them dyno it in 1st gear. Then have them dyno it in the gear closest to 1 to 1. Did the vehicle make more HP in 1st gear or 1 to 1?

The fact will be the vehicle will make about the same HP in any gear you chose. If anybody wants to split hairs the vehicle will put more HP to the ground in 1 to 1 by a bit.

Anybody know why?

Going higher numeric diff and everything else equal...'can' provide more HP

Here is why or how...

Most diff ratios are about 10% apart going up or down in ratio from
whatever starting ratio you have

Take a 3.73 diff ratio and go to a 4.1 diff ratio...is about 10% more rev's
per axle rotation

That then means the ICE will spin about 10% more rev's per axle rev...again
all other things being equal (meaning the same tranny gear, TC locked, etc, etc)

Since the ICE is spinning about 10% more rev's...it moves up the HP curve
and take a look at the one provided on this thread (don't know if correct
for the OP's ICE, but for discussion...assume it is correct for the OP's
ICE)...for the same axle speed (AKA rev's...which translates
to tire rev's...which translates to MPH)

That is how gearing multiplies torque and therefore HP via the lower/higher
rev's from the gear box input to output shafts

What meant by it depends on the ICE...as if the cam/etc does NOT support
higher rev's (limited...AKA red line), then mut point...but...it still has more
rev's allowed by the computer...more torque multiplication up or down depending
on the ratio moved from

Getting it moving and/or changing speed is about HP doing work to move it
from a stand still to some speed...or from some cruising speed to a higher
speed...why I say for speed performance...I drive to HP

And when towing I drive to torque...but that is just me...everyone decide
for themselves either just because or after they learn the true difference
between the interrelated torque/HP curve of 'their' ICE...

Turtle n Peeps wrote:

Max HP will not necessarily get you the best performance vs Max Torque particularly when climbing steep grades.

Really? So less HP will get you up the hill faster? :h Why won't max HP get me the best performance because I guess I have been doing it all wrong in the race game all of these years. :R And don't start with the it's two different things because it don't matter if you accelerate a car down the track or accelerate a truck and trailer up a hill it's all the same.

Look at the chart. Max HP is max HP.

Performance:

The accomplishment of a given task measured against preset known standards of accuracy, completeness, cost, and speed.

If all you know is foot to the floor fastest is always best I can understand how the definition of "performance" eludes you. When I climb a long steep grade at 3,250 utilizing max torque cruising at 50 getting about 8 mpg how does flooring it to 4,250 which gains me maybe 5 mph at a cost of twice the fuel consumption improve my overall performance?

I'll stand with my statement "Max HP will not necessarily get you the best performance vs Max Torque particularly when climbing steep grades".

Max HP will not necessarily get you the best performance vs Max Torque particularly when climbing steep grades.

Really? So less HP will get you up the hill faster? :h Why won't max HP get me the best performance because I guess I have been doing it all wrong in the race game all of these years. :R And don't start with the it's two different things because it don't matter if you accelerate a car down the track or accelerate a truck and trailer up a hill it's all the same.

Look at the chart. Max HP is max HP.

Thanks again for all of the replies. When I tow at 3000 and higher RPM we get in the 4-5 mpg range. At 4000 rpm the truck is very loud. I am not normally in a huge hurry when I an towing and never go more than 68mph but when you are on a two lane highway in the Mts and you have to slow down below too much, then you wind up in the truck lanes and stuck behind them going 35-40 mph and losing all momentum.