Stellantis replacing hemi with 3.0L I-6 engines?

[Hay Dude]

So my old SD would only benefit from an 8spd in fuel efficiency?

Yup pretty much.
Your old 4 speed (I owned plenty E4OD and 4R100 transmissions and they were awful) only locked up in 4th gear. First couple are slush. The new transmissions have more gears and lock up in more of them. That creates more efficiency and better fuel mileage. You will get better performance in that the ratios between gears are improved. Instead of sitting in one gear through a longer RPM range, the engine moves to another gear, staying at optimal RPM.
The main reason for more gears is fuel efficiency, better performance is a side benefit.

 

[ovrszd]

Yup pretty much.
Your old 4 speed (I owned plenty E4OD and 4R100 transmissions and they were awful) only locked up in 4th gear. First couple are slush. The new transmissions have more gears and lock up in more of them. That creates more efficiency and better fuel mileage. You will get better performance in that the ratios between gears are improved. Instead of sitting in one gear through a longer RPM range, the engine moves to another gear, staying at optimal RPM.
The main reason for more gears is fuel efficiency, better performance is a side benefit.

And you have that exactly backwards.

 

[Hay Dude]

torque is a function of bore x stroke...not cylinder configuration. Inline motors usually have a longer stroke, which gives them an advantage in torque. However a long stoke is bad for RPM's So it's always a trade off.

In line six also lasts longer because their crank has more bearing support than a V-8. Lower RPMs results in less wear & better longevity.

 

[Snobdds]

Yup pretty much.
Your old 4 speed (I owned plenty E4OD and 4R100 transmissions and they were awful) only locked up in 4th gear. First couple are slush. The new transmissions have more gears and lock up in more of them. That creates more efficiency and better fuel mileage. You will get better performance in that the ratios between gears are improved. Instead of sitting in one gear through a longer RPM range, the engine moves to another gear, staying at optimal RPM.
The main reason for more gears is fuel efficiency, better performance is a side benefit.

The more it locks up the more heat it creates and heat robs power.

New trannies have better torque management and allow for closer gear spacing. It makes it more efficient by not having to wrap out an engine to shift gears.

 

[Snobdds]

In line six also lasts longer because their crank has more bearing support than a V-8. Lower RPMs results in less wear & better longevity.

I know plenty of diesel engines in a V that have huge bed plates to support the crank. That is not the reason.

Inline diesels are simple and cheap to manufacture...which has been and always will be the biggest advantage over a V engine.

 

[Hay Dude]

And you have that exactly backwards.

Taken from source below:

“For example, automatic transmissions used to only have three to four speeds. Now, you can get automatic transmission vehicles with up to eight gears. That said, having more gears means there’s no need for the vehicle engine to revolve higher during each shift. That alone, it makes automatic cars more efficient than they already were.”

Source: Do Automatic Cars Use More Fuel Than Manual? | Carketa

 

[Hay Dude]

I know plenty of diesel engines in a V that have huge bed plates to support the crank. That is not the reason.

Inline diesels are simple and cheap to manufacture...which has been and always will be the biggest advantage over a V engine.

Yep, theres gazillions of V-8’s in those expensive high end PACCAR trucks, isn't there?

V-8s are toast. They are inefficient and expensive. They dont run as long and they have more moving parts. Still a good engine for racing though.

Thats why V-8s are disappearing in favor of in-line six configurations.

 

[ovrszd]

Taken from source below:

“For example, automatic transmissions used to only have three to four speeds. Now, you can get automatic transmission vehicles with up to eight gears. That said, having more gears means there’s no need for the vehicle engine to revolve higher during each shift. That alone, it makes automatic cars more efficient than they already were.”

Source: Do Automatic Cars Use More Fuel Than Manual? | Carketa

You just made my case. Thanks.

 

[Snobdds]

Yep, theres gazillions of V-8’s in those expensive high end PACCAR trucks, isn't there?

If the V8 was simpler and cheaper to make, they would be. But as always you argue in absolutes and come back to the stellar example way too much.

 

[Snobdds]

Yep, theres gazillions of V-8’s in those expensive high end PACCAR trucks, isn't there?

V-8s are toast. They are inefficient and expensive. They dont run as long and they have more moving parts. Still a good engine for racing though.

Thats why V-8s are disappearing in favor of in-line six configurations.

The package is more compact, meaning they have broader appeal to a wider range of vehicles.