4.30 or 4.88 re-gear

[TomEf]

Part of the difference to your previous experience is that the 5.7L is a brute and makes more torque and power off idle than every other Toyota model/drivetrain. An SC is only going to add to that. The 5.7L doesn't need the type of gearing that lower end models do, including the GX, to be setup for significant overland weight.

I've already shared - I do a lot of towing and overland trips. 15,620lbs combined weight when towing with 35s. 4.3 is perfect. 4.88 would be excess RPM, on the freeway in 6th gear when unladen.

To put things in perspective as these are not minor adjustments we're talking about
- 4.3 is a 10% correction to stock 3.9s
- 4.88 is a 25% correction to stock 3.9s
- 4.88 is 15% more gearing than 4.3! Let that sink in, 15% more is almost like a whole ratio in the 6-speed transmission. It would be like permanently rolling in 5th without the ability to grab 6th on the highway.

4.3s will give you your cake. It's not just gearing, as shift logic and torque lockup will behave like stock and not feel like a 10 yr old tuned the transmission.

It’s worth pointing out what kind of highway speeds you tend to do, what type of terrain, etc. Pulling 55mph along the CA coast is a bit different from pulling 80mph through the mountain west.

 

[NYC570]

Same tire model? I think tire compounds and tread patterns have a lot to do with mileage, so if they are different tire models or brands that would easily explain the mpg difference

Different tire model. I went from passenger Toyo AT3s to Kenda Klever RTs. Even though the Toyos are a lot less aggressive (even more so compared to the LT versions) the kenda klevers seem to have less rolling resistance and feel smoother. I was surprised by how smooth they ride given how aggressive their thread is.

 

[TeCKis300]

It’s worth pointing out what kind of highway speeds you tend to do, what type of terrain, etc. Pulling 55mph along the CA coast is a bit different from pulling 80mph through the mountain west.

Sorta. Higher cruise speeds actually makes a case against too short of gears. The 200-series measures max speed at the output shaft of the transmission. Meaning too much gearing can artificially limit max speed. An extreme example would be 8-speeds models running 4.88s with 35s, could see top speeds limited artificially to 100MPH.

And so you know, I've been all over the midwest through some of the most extreme grades over the Sierras and Rocky Mtns. I'm a firm believer of building a well rounded rig that's capable of hauling and cruising. Maybe a better way to say it is not to ruin the stock goodness delivered from the factory by overly biasing one way or another. With 4.3s, she's happy to tow at 85MPH all day, and will do so in 5th. MPGs are closer to 7MPG at that pace, but that's what happens when punching big holes through air at those speeds.

 

[cubaniche]

Sorta. Higher cruise speeds actually makes a case against too short of gears. The 200-series measures max speed at the output shaft of the transmission. Meaning too much gearing can artificially limit max speed. An extreme example would be 8-speeds models running 35s, could see top speeds limited artificially to 100MPH.

And so you know, I've been all over the midwest through some of the most extreme grades over the Sierras and Rocky Mtns. I'm a firm believer of building a well rounded rig that's capable of hauling and cruising. Maybe a better way to say it is not to ruin the stock goodness delivered from the factory by overly biasing one way or another. With 4.3s, she's happy to cruise at 85MPH all day long, and will do so in 5th. MPGs are closer to 7MPG at that pace, but that's what happens when punching big holes through air at those speeds.

This is my mindset exactly. Towing cross country won't be anything I do but it's nice to know it'll behave with 4.30s if I do. Towing my boat happens way more often but it's through flat south Texas terrain no more than 30 minutes or so. Off road trips only happen 3 or 4 times a year. So, I'd rather plan for the 80% (4.30s) of driving the rig will see, rather than the 20% (where 4.88s might be more useful).

I've got it in thengarage now on stands about to do the front spacers. After that I'll be installing the rear spacers. Prinsu rack arrives this week and CBI sliders sometime at the end of the month.

 

[nor_cal_cyclist]

After several years of ownership and moving full-time to Tahoe, I LOVE my 4.3's with the 305/65-18's I have on my 2019. I live @6330' elev in the Sierra's and drive back to the far northern Sac Valley occasionally. If I'm watching my acceleration, I tend to get around 10mpg cruising @70mph (other than going over Mt Rose).

Now to figure out which custom wheel looks best and is strong enough for my 200 - ditching the SpiderTrax spacers....

 

[Fisher23]

Unless I'm mistaken, your 2016 had 3.307 gears factory so you're looking at a 27% difference.

I have a question:

My tires went from OEM 31.6" to 33.98" = 7.6% increase
My gears went from 3.307 to 4.88 = 68% reduction

When driving my speedometer says 75 mph and the gps says 77 mph. That is an increase of 2.66% from OEM.

Why is it an 2.66% increase? Tread wear?

I would think .. (Tire change 33.98 / 31.6) x (gear change 3.307 / 4.88) = 0.066 which is a 6.6% increase.

My mileage now averaged (not towing) 13.037mpg.

That is city, Interstate, state roads, and county dirt roads. Range approximately 782.
This range and mpg would be much less on an Interstate trip towing and loaded down.

BTW THANKS for the diffs !

 

[kcjaz]

I have a question:

My tires went from OEM 31.6" to 33.98" = 7.6% increase
My gears went from 3.307 to 4.88 = 68% reduction

When driving my speedometer says 75 mph and the gps says 77 mph. That is an increase of 2.66% from OEM.

Why is it an 2.66% increase? Tread wear?

I would think .. (Tire change 33.98 / 31.6) x (gear change 3.307 / 4.88) = 0.066 which is a 6.6% increase.

My mileage now averaged (not towing) 13.037mpg.

That is city, Interstate, state roads, and county dirt roads. Range approximately 782.
This range and mpg would be much less on an Interstate trip towing and loaded down.

BTW THANKS for the diffs !

Because your stock speed-o is ~5% off and reads low from the factory. I think there is a thread or two here on this topic. I believe all JDM produced Toyotas are this way due to a law of some kind in Japan. I noticed this when I went up in tire size doing the same math.

 

[TeCKis300]

I have a question:

My tires went from OEM 31.6" to 33.98" = 7.6% increase
My gears went from 3.307 to 4.88 = 68% reduction

When driving my speedometer says 75 mph and the gps says 77 mph. That is an increase of 2.66% from OEM.

Why is it an 2.66% increase? Tread wear?

I would think .. (Tire change 33.98 / 31.6) x (gear change 3.307 / 4.88) = 0.066 which is a 6.6% increase.

My mileage now averaged (not towing) 13.037mpg.

That is city, Interstate, state roads, and county dirt roads. Range approximately 782.
This range and mpg would be much less on an Interstate trip towing and loaded down.

BTW THANKS for the diffs !

Yes, what @kcjaz said. Also the speedo reports speed from the wheel ABS sensors (only tire diameter change). Rather than the transmission output shaft (tire and gearing change). Weirdly enough, top speed is governd by both.

If you haven't, you'll want to compensate for reported MPG as it's no longer accurate due to tire size. Easiest way is multiply reported MPG by 1.076.

 

[cubaniche]

To add to this speedometer convo. I've been thinking about what was posited in another speedometer correction thread about intercepting the 'simple' wheel sensors signal before the signal is parsed into the canbus where it becomes much harder to intercept and correct so that all controllers that use the speed sensor data can actually benefit. Rather than just the speedometer (via one of the canbus speedo fixers). One option was the yellow box and the other was maybe the lutzauto device. I'd be.willing to buy four of either to test that theory out but I'm not sure which device will actually work with the 2-wire abs sensor. The lutzauto one says its meant to work with three wire sensors like the ones on the transmission. The yellow box, I haven't been able to figure out but it lists a whole host of signals it can modify (hall effect, pwm, etc).

 

[kcjaz]

Yes, what @kcjaz said. Also the speedo reports speed from the wheel ABS sensors (only tire diameter change). Rather than the transmission output shaft (tire and gearing change). Weirdly enough, top speed is governd by both.

If you haven't, you'll want to compensate for reported MPG as it's no longer accurate due to tire size. Easiest way is multiply reported MPG by 1.076.

I recall being puzzled when I first tested the speedo and OD versus gps and mile markers on a highway and seeing my speed was off but my OD was dead on. The ABS speed signal (wheel rpm) must be factored in one of the computers and then sent to the speedo. The “correct” speed signal I assume goes everywhere else that needs wheel rpm. When I went to 4.88s I initially worried that my my OD would now be like 25% off thinking OD was based off trans output. Thankfully (or maybe not ) that’s not the case.

It would really be cool to be able to hack into the software and make these adjustments though I get why auto OEMs make this hard to impossible.

 

[bloc]

To add to this speedometer convo. I've been thinking about what was posited in another speedometer correction thread about intercepting the 'simple' wheel sensors signal before the signal is parsed into the canbus where it becomes much harder to intercept and correct so that all controllers that use the speed sensor data can actually benefit. Rather than just the speedometer (via one of the canbus speedo fixers). One option was the yellow box and the other was maybe the lutzauto device. I'd be.willing to buy four of either to test that theory out but I'm not sure which device will actually work with the 2-wire abs sensor. The lutzauto one says its meant to work with three wire sensors like the ones on the transmission. The yellow box, I haven't been able to figure out but it lists a whole host of signals it can modify (hall effect, pwm, etc).

Others may have a different option, but I’d be very cautious about doing anything to alter the signal that the ABS/VSC systems use for wheel speed input.

 

[Fisher23]

On my other vehicles it not hacking the the signal, there is options in the vehicle program to change the tire size and gear ratio. The program is fairly straight forward provided you have a programmer.

On my lift components for my Jeep from AEV it comes with a module you plug in under the steering column and has dip switches to adjust the gear ratio and tire size.
It also has programming adjustments built in for adjusting the vehicle handling.

It is programming.

 

[bloc]

On my other vehicles it not hacking the the signal, there is options in the vehicle program to change the tire size and gear ratio. The program is fairly straight forward provided you have a programmer.

On my lift components for my Jeep from AEV it comes with a module you plug in under the steering column and has dip switches to adjust the gear ratio and tire size.
It also has programming adjustments built in for adjusting the vehicle handling.

It is programming.

That would be great if it were available on our platform but what I seemed to be understanding is someone would install a general-purpose module on each of the wheel speed sensor circuits.

I'm just pointing out these are safety-critical circuits and anything we install should be appropriate to that need.