3.21. vs 3.92 gear

[SnowBlaZR2]

I wish I could find a test, but I haven't yet.

Which is the point. Garbage in, garbage out.

That MT test doesn't really tell us much of anything.

 

[Scram1500]

I just bought a 2022 Big Horn with the 3.92. I test drove a Laramie with the etorque 5.7l with 3.21 then got in the Big Horn 5.7l (non etorque) with 3.92. It didn't even seem like the same truck to me. The Big Horn was so much quicker. Plus, towing 11,400 compared to the Laramie at 8,300. I'll eat the extra couple miles per gallon to have such a drastic increase in performance.

The Bighorn is about 400 lbs lighter than a Laramie. Basically, less weight=more horsepower, couple that with a 3.92 and you're off to the races

 

[HSKR R/T]

All the 3.92 does, is take the same 8 gears and move them down 1 rung. You gain an extra first, and lose the 8th. So that means there is no difference in shifting patterns, unless the 3.21 is in 8th and can't hold that gear at which point it will downshift to 7th.

Since the entire point of the 3.21/8th gear is fuel economy, I'll take that extra shift. With the super smooth 8 speed and the difference being 400 rpms, its not noticable at all, and if you happen to hit that rare road and wind condition and speed where you find yourself downshifting more than normal, just use the gear limiter. I haven't ever done that yet in my almost 3 years of ownership.

Obviously you misunderstood what I meant when I said it would be shifting more. Even where I live with rolling hills, occasionally my 3.92 has to downshift to 7th. As proven by the other "ultimate guide" thread, for the 3.21 truck to march, or be better than 3.92 it has to be a gear lower. So while my 3.92 truck only has to downshift 1 gear, the 3.21 truck might have to downshift twice. And going just off the final drive ratios, a 3.92 in 7th gear should get better fuel economy than a 3.21 truck in 6th.

 

[silver billet]

Which is the point. Garbage in, garbage out.

That MT test doesn't really tell us much of anything.

The test is comparing 2 trucks that are very close. The 3.92 takes a slight hit because of the taller tire, but gains a slight advantage due to being 120 pounds lighter.

All in all, pretty fair comparison.

The towing numbers are what really stands out to me, over the course of 20 seconds (which is much less prone to timing/precision errors than a 6 second test), there was no difference in towing despite all the 3.92 claims that it can tow 3000 pounds more. I'm not seeing that paper certification being supported by the data.

 

[silver billet]

Obviously you misunderstood what I meant when I said it would be shifting more. Even where I live with rolling hills, occasionally my 3.92 has to downshift to 7th. As proven by the other "ultimate guide" thread, for the 3.21 truck to march, or be better than 3.92 it has to be a gear lower. So while my 3.92 truck only has to downshift 1 gear, the 3.21 truck might have to downshift twice. And going just off the final drive ratios, a 3.92 in 7th gear should get better fuel economy than a 3.21 truck in 6th.

Exactly what I said; there is only 1 difference in shifting patterns, the 3.21 might have to downshift one extra time to come out of it's super tall gear that the 3.92 doesn't have; once it's done that, there are no further differences in shifting patterns, so if my truck needs another downshift, your truck will downshift as well.

When the 3.21 is in 6th, it's gear ratio is 3.21 (direct drive).
When the 3.92 is in 7th, it's gear ratio is 3.2144

So actually the 3.21 will get better MPG if you want to split hairs.

 

[HSKR R/T]

Exactly what I said; there is only 1 difference in shifting patterns, the 3.21 might have to downshift one extra time to come out of it's super tall gear that the 3.92 doesn't have; once it's done that, there are no further differences in shifting patterns, so if my truck needs another downshift, your truck will downshift as well.

When the 3.21 is in 6th, it's gear ratio is 3.21 (direct drive).
When the 3.92 is in 7th, it's gear ratio is 3.2144

So actually the 3.21 will get better MPG if you want to split hairs.

So, like I said, would have to shift more. Cause for every time it down shifts, it will shift back up, unless you are using gear limiter, which most people won't use. And while my truck can hold 8th gear up a hill, yours may have to downshift. And shifting hurts fuel mileage as the torque converter will unlock for each shift reducing efficiency. There's a lot more to it than just the gear ratios themselves.

 

[HSKR R/T]

The test is comparing 2 trucks that are very close. The 3.92 takes a slight hit because of the taller tire, but gains a slight advantage due to being 120 pounds lighter.

All in all, pretty fair comparison.

The towing numbers are what really stands out to me, over the course of 20 seconds (which is much less prone to timing/precision errors than a 6 second test), there was no difference in towing despite all the 3.92 claims that it can tow 3000 pounds more. I'm not seeing that paper certification being supported by the data.

A 0-60, or 1/4 mile acceleration test doesn't prove one way or another how much a vehicle can safely tow. Just because the numbers are close between the two trucks in 1/4 mile acceleration towing the same weight doesn't tell you anything about how much less or more one truck can tow.

 

[silver billet]

So, like I said, would have to shift more. Cause for every time it down shifts, it will shift back up, unless you are using gear limiter, which most people won't use. And while my truck can hold 8th gear up a hill, yours may have to downshift. And shifting hurts fuel mileage as the torque converter will unlock for each shift reducing efficiency. There's a lot more to it than just the gear ratios themselves.

This is getting very silly my friend. Nobody is losing fuel efficiency due to torque converter unlock in a shift. The weight of your shoelaces have more effect.

 

[silver billet]

A 0-60, or 1/4 mile acceleration test doesn't prove one way or another how much a vehicle can safely tow. Just because the numbers are close between the two trucks in 1/4 mile acceleration towing the same weight doesn't tell you anything about how much less or more one truck can tow.

The paper tow ratings come from J2807 standard which most definitely uses both 0 to 30 and 0 to 60 as part of it. That's the only thing that can give the 3.92 the 3000 pound increase, as the other tests deal with things like understeer/oversteer, braking, weights etc. None of those other tests can be affected by gear ratio, just acceleration.

 

[HSKR R/T]

The paper tow ratings come from J2807 standard which most definitely uses both 0 to 30 and 0 to 60 as part of it. That's the only thing that can give the 3.92 the 3000 pound increase, as the other tests deal with things like understeer/oversteer, braking, weights etc. None of those other tests can be affected by gear ratio, just acceleration.

But even you said acceleration was only part of it. And trying to use numbers from an non-scientific test isn't worth even mentioning

 

[silver billet]

But even you said acceleration was only part of it. And trying to use numbers from an non-scientific test isn't worth even mentioning

My position is that I don't worry about 0 to 60 numbers, and definitely not while towing. The 3.92 gives you a "granny first gear", which is cool but I never need more power in first gear; my truck is super responsive in first and I'm never at a lack of power there. I need more power on on-ramps, and while passing a trucker up a hill on the freeway.

So the 3.92 gives you more towing power off the line, but again that's not where I need it. It doesn't give you more power in the city, or on the freeway, or while passing, and that's where I do need it.

When you write a test (like the J2807) to measure 0 to 60, then the 3.92 is going to come out on top by 3000 pounds and sound impressive. But that 3000 pound difference is only "off the line", once you're moving and needing power in the city/highway, there is no longer a 3000 pound difference between the trucks; there is a 0 pound difference because the same gear ratios are available in both trucks at that point.

If you're sitting in the 3.21 on the highway thinking "my truck can't pull this very well", then you'll be thinking the same thing in the 3.92.

As for "non scientific test", agreed, there is lots of room for error. Unfortunately that's all we have, even from outlets like TFL Truck etc they're all unscientific and I've found flaws in their test more than once.

 

[SnowBlaZR2]

The test is comparing 2 trucks that are very close. The 3.92 takes a slight hit because of the taller tire, but gains a slight advantage due to being 120 pounds lighter.

All in all, pretty fair comparison.

The towing numbers are what really stands out to me, over the course of 20 seconds (which is much less prone to timing/precision errors than a 6 second test), there was no difference in towing despite all the 3.92 claims that it can tow 3000 pounds more. I'm not seeing that paper certification being supported by the data.

I don't think the two trucks they used were that close, so I'd disagree that it was a fair or even useful comparison.

 

[HSKR R/T]

My position is that I don't worry about 0 to 60 numbers, and definitely not while towing. The 3.92 gives you a "granny first gear", which is cool but I never need more power in first gear; my truck is super responsive in first and I'm never at a lack of power there. I need more power on on-ramps, and while passing a trucker up a hill on the freeway.

So the 3.92 gives you more towing power off the line, but again that's not where I need it. It doesn't give you more power in the city, or on the freeway, or while passing, and that's where I do need it.

When you write a test (like the J2807) to measure 0 to 60, then the 3.92 is going to come out on top by 3000 pounds and sound impressive. But that 3000 pound difference is only "off the line", once you're moving and needing power in the city/highway, there is no longer a 3000 pound difference between the trucks; there is a 0 pound difference because the same gear ratios are available in both trucks at that point.

If you're sitting in the 3.21 on the highway thinking "my truck can't pull this very well", then you'll be thinking the same thing in the 3.92.

As for "non scientific test", agreed, there is lots of room for error. Unfortunately that's all we have, even from outlets like TFL Truck etc they're all unscientific and I've found flaws in their test more than once.

At least TFL does more real world testing when doing the towing comparisons on the Ike.

 

[SnowBlaZR2]

As for "non scientific test", agreed, there is lots of room for error. Unfortunately that's all we have, even from outlets like TFL Truck etc they're all unscientific and I've found flaws in their test more than once.

Which is why it's odd to find this one test and run with it as an indicator of anything.

 

[ferraiolo1]

Probably because the difference stock to stock between the two ratios is so close it doesnt make that big of a difference, and not worth taking the time to do actual comparison tests.

 

[silver billet]

I don't think the two trucks they used were that close, so I'd disagree that it was a fair or even useful comparison.

Which is why it's odd to find this one test and run with it as an indicator of anything.

They're the same truck in all areas that matter, except for gear ratio and tire size and 120 pounds of weight. The tire size (negative against the 3.92) and 120 pounds (positive for the 3.92) probably cancel each other out for the most part, leaving just gear ratio. If you can find a closer match up I'd love to see it.

The 0 to 60 difference/loss in the 3.92 could maybe be explained by an extra gear shift.

 

[SnowBlaZR2]

Probably because the difference stock to stock between the two ratios is so close it doesnt make that big of a difference, and not worth taking the time to do actual comparison tests.

We have 17 pages in this one thread on this one forum dedicated to just that...for something that's "not worth the time."

 

[SnowBlaZR2]

They're the same truck in all areas that matter, except for gear ratio and tire size and 120 pounds of weight. The tire size (negative against the 3.92) and 120 pounds (positive for the 3.92) probably cancel each other out for the most part, leaving just gear ratio. If you can find a closer match up I'd love to see it.

The 0 to 60 difference/loss in the 3.92 could maybe be explained by an extra gear shift.

No, they aren't. They're not even the same trim. They have different aerodynamics, different tires (not just different sizes), and different software.

I haven't seen anything closer, but I'm not the one making pronouncements from this fairly useless "test."

 

[silver billet]

At least TFL does more real world testing when doing the towing comparisons on the Ike.

The one test they really did that left me scratching my head is when they tested the new 6.6 gas engine in the Chevy 2500. They put the pedal down and drive up the hill, but the transmission needs to be better tuned (so take off points for that); so instead of downshifting and running at 4000 rpms, it's sitting there lugging at 2000 rpms for a few minutes. Then they say "this truck is 3 minutes slower than the Ford 7.3". No it's not, not really, it needs better shifting strategy but most guys using that truck would have just forced the downshift. It's definitely slower than the 7.3, but since the HP and torque numbers are quite similar, it won't be 3 minutes differnce despite the 10 speed advantage from the ford.

 

[HSKR R/T]

They're the same truck in all areas that matter, except for gear ratio and tire size and 120 pounds of weight. The tire size (negative against the 3.92) and 120 pounds (positive for the 3.92) probably cancel each other out for the most part, leaving just gear ratio. If you can find a closer match up I'd love to see it.

The 0 to 60 difference/loss in the 3.92 could maybe be explained by an extra gear shift.

The taller tires on the 3.92 have more rotational weight, which is a lot different that static weight. But also effectively changes the gear ratio when compared to another truck with different tire size. It would effectively make make it a lower(numerical) gear since transmission ratios aren't changed with tire sizes.