V6 vs V8 Gear Ratios

[TheBeginning]

I was doing some research into the gear ratios on my 5.0 and noticed some weird differences with the 3.8. When considering the final drive, the V6 has shorter gears than the V8. This makes sense, the V6 has less power and torque, so shorter gears will keep you in the power band.

The weird thing is the V8 has shorter gears in the transmission, but a taller final drive ratio (3.54 vs 3.91).

My question is; why would Hyundai change both of these parts (transmission and differential) rather than just one?

 

[carguy75]

My best guess to why Hyundai went with a 3.54 final gear ratio in the 5.0 V8 over using 3.91 is probably for better fuel economy to meet CAFE standards and a good selling point for having a powerful sedan that does not seem like a gas guzzler. The 5.0 V8 with the taller gear 3.54 ratio is still not very fuel efficient by today's standards; so it would be worst with a 3.91 ratio.

However, I wished that it was an performance option for the 5.0 V8 model to be equipped with a 3.91 rear end since trying to get gas mileage is not the reason why most owners choose the V8 over the V6.

 

[G-883648]

My best guess to why Hyundai went with a 3.54 final gear ratio in the 5.0 V8 over using 3.91 is probably for better fuel economy to meet CAFE standards and a good selling point for having a powerful sedan that does not seem like a gas guzzler. The 5.0 V8 with the taller gear 3.54 ratio is still not very fuel efficient by today's standards; so it would be worst with a 3.91

That’s what I assumed. I’m curious why the 5.0 transmission has shorter gears than the 3.8 transmission. Confused why they didn’t keep the same gears or final drive. I listed the ratios below.

First Gear Ratio (1)
3.67 (3.8) 3.79 (5.0)
Second Gear Ratio (1)
2.40 (3.8) 2.47 (5.0)
Third Gear Ratio (1)
1.61 (3.8) 1.61 (5.0)
Fourth Gear Ratio (1)
1.19 (3.8) 1.18 (5.0)
Fifth Gear Ratio (1)
1.00 (3.8) 1.00 (5.0)
Sixth Gear Ratio (1)
0.83 (3.8) 0.83 (5.0)
Seventh Gear Ratio (1)
0.64 (3.8) 0.65 (5.0)
Eighth Gear Ratio (1)
0.56 (3.8) 0.57 (5.0)

 

[Mcc]

However, I wished that it was an performance option for the 5.0 V8 model to be equipped with a 3.91 rear end since trying to get gas mileage is not the reason why most owners choose the V8 over the V6.

What most owners wishes are not what car makers are trying to satisfy.
The current model year 2026 federal target is set at 49 mpg for light-duty cars and trucks. Including a performance option would make meeting this mandate even more difficult.

 

[EdP]

I was doing some research into the gear ratios on my 5.0 and noticed some weird differences with the 3.8. When considering the final drive, the V6 has shorter gears than the V8. This makes sense, the V6 has less power and torque, so shorter gears will keep you in the power band.

The weird thing is the V8 has shorter gears in the transmission, but a taller final drive ratio (3.54 vs 3.91).

My question is; why would Hyundai change both of these parts (transmission and differential) rather than just one?

For a proper answer you have to look at the power curve on both engines. You want to gear for how it is being driven too. This is a luxury sedan so you want a smooth pull up to highway speed. If it was a sportier model you'd probably want best acceleration for a quick get away from a light.

Just as some of the old Chevy 4 speeds had a wider ratio spread compared to the Corvette with a 4.56 rear. Back then, no EPA regs to meet too.

 

[carguy75]

What most owners wishes are not what car makers are trying to satisfy.
The current model year 2026 federal target is set at 49 mpg for light-duty cars and trucks. Including a performance option would make meeting this mandate even more difficult.

That I do understand; hence my statement about meeting CAFE requirements, however fuel economy is a big selling point to consumers regardless of the model sold. Therefore, automakers do try to satisfiy customer demand for fuel economy and performance. Just look at any car brochure and you will see boasts about fuel efficiency even with performance models.

The performance option for a 3.91 final drive would be nice for the 5.0 engine, but not going to happen obviously since Hyundai ended production of the 5.0 engine I believe already for the G80 and/or just put the 5.0 V8 in the ultra luxury models like a G90; which is not a performance oriented model.

I love the 5.0 engine overall performance, but it will not make the 40mpg 2026 requirement regardless of final drive ratio Hyundai uses.

 

[Suburbazine]

While a 3.91 ratio rear would be sweet, you'd have to also convince Hyundai to not torque limit the hell out of 1st gear on the transmission. 2nd is torque limited too but not nearly as badly, Hyundai has some sort of vendetta against spinning the tires and a 3.91 would make that much easier to do. Sportiness was never supposed to be in the Genesis wheelhouse.

As it is, you will experience a LOT of torque reduction to keep the existing 3.54 from spinning the tires at launch and disabling traction control will just aggressively limit throttle input.

I still haven't found a way to get around the retarded torque management system- it's so aggressive that the car is a tiny bit faster 0-60 launched in 2nd instead of 1st. I have some drag slips somewhere showing the 60-200ft time is faster in 1st, but the 300ft and beyond is faster launching 2nd.

 

[carguy75]

While a 3.91 ratio rear would be sweet, you'd have to also convince Hyundai to not torque limit the hell out of 1st gear on the transmission. 2nd is torque limited too but not nearly as badly, Hyundai has some sort of vendetta against spinning the tires and a 3.91 would make that much easier to do. Sportiness was never supposed to be in the Genesis wheelhouse.

As it is, you will experience a LOT of torque reduction to keep the existing 3.54 from spinning the tires at launch and disabling traction control will just aggressively limit throttle input.

I still haven't found a way to get around the retarded torque management system- it's so aggressive that the car is a tiny bit faster 0-60 launched in 2nd instead of 1st. I have some drag slips somewhere showing the 60-200ft time is faster in 1st, but the 300ft and beyond is faster launching 2nd.

I agree with you on the torque management and throttle modulation used on the 5.0 to reduce its acceleration from a stand still. The only way I found to get around(or reduce the impact of) those two safety features for better off line acceleration is to use good performance tires with plenty of traction while using a Sprint Booster to make the throttle more touchy in ECO drive mode.

However, the 5.0 will spin the tires in Sport drive mode(traction control on or off) with the Sprint Booster. You can long press the traction control button to turn it off, but all that do is allow the rear tires to lose traction. The 5.0 needs a LSD rear end paired with a 3.91 final drive to really perform at it best, but I would be happy just with a LSD rear end in my 5.0.

I understand why Hyundai moderates the throttle input and use torque management in the 5.0 Genesis. Without modulating the throttle input; the 5.0 Genesis/G80 would be too aggressive(rough and jerky) in everyday driving for most of its target audience. The torque management protects the transmission internals(clutches and gears) so it will last a long time if properly maintained.

Trust me; driving the 5.0 Genesis with a Sprint Booster set to Race mode is a very scary experience in traffic if you have a heavy foot.