Seems weird. The I6 has a few packaging issues that made them unpopular in the 1980s when front drive vehicles became the standard.
Australia was awash in I6 motors, from the GM Holden motors, the Ford Falcon engine and the Chrysler slant 6 that got replaced by a locally developed version of a Chrysler 6 that was never finished by the US corp. they were all boring, mostly durable, mostly reliable engines for a family car.
Even BMC/Leyland had one. Uniquely they fitted it across the chassis of a land crab derived vehicle which showed why the I6 was ill suited to being packaged as anything other than in line with a rear drive drivetrain.
The V6 fits better in front drive cars for obvious reasons.
Hybrid cars change the equation somewhat, the skateboard chassis doesn’t seem all that suited to an I6 but here we are.
Chrysler have unfortunately found out that no matter how good you make one, customers still want a V8 and I concur.
Upsides are that they're both first- and second-order naturally balanced, requiring no balance shafts, which reduces weight and makes them very low vibration. I keep waiting for someone to come up with a lightweight, turbonormalized straight six that runs on Jet A to replace old turboprop engines on aircraft, but I digress...
Question about that, wouldn't packaging be an issue unless you really shrunk the engine size? I thought that's what makes LS swaps into planes so interesting because you get a fair amount of power in a small package.
I don't think hybrids use skateboard designs the way EVs do? The battery for a hybrid is so much smaller, they usually steal space under the rear seat and/or in the trunk afaik.
in the wild Inline 6 (I6) engines have proved reliable and just going on regular maintenance
B58 (BMW) is super reliable & high performance
same as the I6 used in certain landcruisers & other Toyota cars etc
though now of course - with super cheap solar etc - if you can go electric go electric but if you've to buy an ICE car - yeah buy an I6 - fuel efficient & performance & reliable
I had an '89 Cherokee to 235k and sold it for ~60% of my purchse price after 6 years after garages only quoted insanity for the smallest things (Dad is a mechanic, but the commute there for repairs isn't feasible on the regular and apartment living is not conducive to the required garage/tools).
Dad has seen AMC I-6s go 400k before the transmission died and ended its run.
From Toyota there are many greats: 1FZ-FE, 1HZ, 1HD-FT, 12H-T, etc
The Cummins 5.9L is excellent, particularly the 12 valve with P7100 pump. Awesome low end torque.
From Mercedes the M104 and OM606 are phenomenal. Powerful, efficient, incredibly reliable. The only drawback is the aging engine management software is not very well supported by aftermarket code readers anymore. In the case of an OM606 you can fix this by deleting the ECU entirely and installing an M pump from an OM603, or replacing the ECU with a DSL-1 standalone unit.
The logical, socially-conscious side of my brain can't wait to see 6 cylinder engines go the way of the v8. Four cylinders and a hybrid system ought to be able to generate enough torque for just about anyone (except maybe heavy-duty hauling?). And the future is of course BEV.
But have to admit there is a part of me that would really love to drive something like the BMW M340i [1]. And the gas mileage (26/33 MPG) isn't even too bad.
That's probably the reason - we only need dressage horses and pure bloods now that the real draft horse is getting put to pasture.
These are no longer workhorses.
Six cylinders are the smoothest engines out there.
Honda used to have a 1L 6 cylinder engine for their bikes - the Gold wing has a 6 cylinder still.
The perimeter of the piston goes down in relation to its area (& multiplied by BMEP) when the radius goes up - looking at you Africa Twin.
The perimeter is where the unburnt fuel lives and gets caught up in the emission rules. So fewer larger cylinders is better according to EPA - 500cc each, maybe.
If we're only going to have hobby vehicles with internal combustion, then a six cylinder or doubling up to a v-12 makes sense.
They're toys for the weekend, not to put a 100k miles on it.
Even 4 cylinders and a turbo (like my GLI) are plenty fun. I’m tire grip limited as it is, but it probably keeps me out of trouble, as tempting as something with more pep is.
Longer stroke provides a greater lever arm on the crankshaft, allowing the same combustion force to generate more torque during the power stroke. What's your counter-argument?
That sounds fantastic but it means nothing in practice. It's like something you'd hear in a "Engineering Explained" video, but with no real-world application. There's so much more that goes into an engine that it doesn't matter.
Again, it's a myth.
Similarly, there was always the debate over rod length (in the same displacement engines). You use the same crankshaft but the piston has the wrist pin located higher. The longer rod was always supposed to make "more torque" because of the angle but that ended up not being the case.
You can verify this buy putting engines together with different bores and strokes that are roughly equal displacements, and with the same heads/cam on them, they will make identical power. Picture something like a 3.50" bore and 4.00" stroke, and vice versa. Look up someone like Richard Holdener on YouTube for actual data. Displacement is displacement, it doesn't really matter how you make it.
Bore is what would make you more power after a certain point, anyway. You get more surface area to fit larger valves, etc. But again, using the same heads (that aren't shrouding the smaller bores), either combination of bore/stroke will make the same power throughout the rev range.
Then you get into things like piston speed and all that but none of that matters unless you're talking about a race engine. And when you are, they'll just rebuild it more often so they don't care how long it lasts.
I love a straight-6 so much that I drive a car that uses two of them joined at the crankshaft! Each I6 has its own ECU and is entirely unaware of the other. Crude, but very smooth nonetheless.
Even in the US, I4 engines are by far the most popular. Most consumer cars are built for fuel economy with the one notable exception being the suburban tacticool pickup truck, which are often modded to burn MORE fuel.
It does not hurt that you can easily get 200+ horsepower from the factory with one, either. My car is a series hybrid with an Atkinson-cycle I4 but it still bursts to 200hp because it's a hybrid.
The inline four has largely converged around a 2.0L displacement with an equal bore and stroke. IIRC, it's fairly optimal from a performance and thermodynamic efficiency standpoint.
Europe has stupid displacement taxes so they'll make some high strung 0.9L turbo 3/4cyl with all the technology that gets .01mpg better MPG than a ~2L engine while taking twice as much $$ in service to make it to any given milage.
IDK why they don't just tax the actual fuel used like the rest of the world (not that they don't do that).
There's potentially an even better option than the I6 layout: opposed piston I3 2 stroke. Same number of power pulses per rev as I6 4 stroke, no valves, no cylinder heads. It seems that these guys solved the oil loss problem and by using 2 injectors and some awesome combustion modeling they've been able to beat emissions standards without after treatment: https://achatespower.com
For buyers today that may actually mean less depreciation as six cylinder engines become harder and harder to find. But yeah I'm sure automakers can see the writing on the wall.
Seems weird. The I6 has a few packaging issues that made them unpopular in the 1980s when front drive vehicles became the standard.
Australia was awash in I6 motors, from the GM Holden motors, the Ford Falcon engine and the Chrysler slant 6 that got replaced by a locally developed version of a Chrysler 6 that was never finished by the US corp. they were all boring, mostly durable, mostly reliable engines for a family car.
Even BMC/Leyland had one. Uniquely they fitted it across the chassis of a land crab derived vehicle which showed why the I6 was ill suited to being packaged as anything other than in line with a rear drive drivetrain.
The V6 fits better in front drive cars for obvious reasons.
Hybrid cars change the equation somewhat, the skateboard chassis doesn’t seem all that suited to an I6 but here we are.
Chrysler have unfortunately found out that no matter how good you make one, customers still want a V8 and I concur.
Upsides are that they're both first- and second-order naturally balanced, requiring no balance shafts, which reduces weight and makes them very low vibration. I keep waiting for someone to come up with a lightweight, turbonormalized straight six that runs on Jet A to replace old turboprop engines on aircraft, but I digress...
Question about that, wouldn't packaging be an issue unless you really shrunk the engine size? I thought that's what makes LS swaps into planes so interesting because you get a fair amount of power in a small package.
Toyota with the G family and JZ family + Nissan with the RB family too. They were prolific in RWD cars.
Daewoo put one in a FWD car in the mid 2000s for some reason too.
I don't think hybrids use skateboard designs the way EVs do? The battery for a hybrid is so much smaller, they usually steal space under the rear seat and/or in the trunk afaik.
in the wild Inline 6 (I6) engines have proved reliable and just going on regular maintenance
B58 (BMW) is super reliable & high performance
same as the I6 used in certain landcruisers & other Toyota cars etc
though now of course - with super cheap solar etc - if you can go electric go electric but if you've to buy an ICE car - yeah buy an I6 - fuel efficient & performance & reliable
I had an '89 Cherokee to 235k and sold it for ~60% of my purchse price after 6 years after garages only quoted insanity for the smallest things (Dad is a mechanic, but the commute there for repairs isn't feasible on the regular and apartment living is not conducive to the required garage/tools).
Dad has seen AMC I-6s go 400k before the transmission died and ended its run.
From Toyota there are many greats: 1FZ-FE, 1HZ, 1HD-FT, 12H-T, etc
The Cummins 5.9L is excellent, particularly the 12 valve with P7100 pump. Awesome low end torque.
From Mercedes the M104 and OM606 are phenomenal. Powerful, efficient, incredibly reliable. The only drawback is the aging engine management software is not very well supported by aftermarket code readers anymore. In the case of an OM606 you can fix this by deleting the ECU entirely and installing an M pump from an OM603, or replacing the ECU with a DSL-1 standalone unit.
The logical, socially-conscious side of my brain can't wait to see 6 cylinder engines go the way of the v8. Four cylinders and a hybrid system ought to be able to generate enough torque for just about anyone (except maybe heavy-duty hauling?). And the future is of course BEV.
But have to admit there is a part of me that would really love to drive something like the BMW M340i [1]. And the gas mileage (26/33 MPG) isn't even too bad.
[1] https://youtu.be/kr-h9T42NAI?si=IZaDC9UqAsUtjQN9
> the future is of course BEV
That's probably the reason - we only need dressage horses and pure bloods now that the real draft horse is getting put to pasture.
These are no longer workhorses.
Six cylinders are the smoothest engines out there.
Honda used to have a 1L 6 cylinder engine for their bikes - the Gold wing has a 6 cylinder still.
The perimeter of the piston goes down in relation to its area (& multiplied by BMEP) when the radius goes up - looking at you Africa Twin.
The perimeter is where the unburnt fuel lives and gets caught up in the emission rules. So fewer larger cylinders is better according to EPA - 500cc each, maybe.
If we're only going to have hobby vehicles with internal combustion, then a six cylinder or doubling up to a v-12 makes sense.
They're toys for the weekend, not to put a 100k miles on it.
> can't wait to see 6 cylinder engines go the way of the v8.
You want to stuff an in-line six in every race car, buggy, and Jeep that you see, with a supercharger slapped on top? Why not just go with an LS?
Even 4 cylinders and a turbo (like my GLI) are plenty fun. I’m tire grip limited as it is, but it probably keeps me out of trouble, as tempting as something with more pep is.
Love me a straight-six.
Why anyone thought "inline" was a better prefix, I have no idea.
Smooth, and sound great.
It's a German thing.
> Inline-sixes also tend to have more low-end torque as their balanced design allows for a longer stroke, which promotes low-rev performance.
Automotive myths that won't die. 'Stroke' doesn't make more low end power than bore, displacement is displacement.
Longer stroke provides a greater lever arm on the crankshaft, allowing the same combustion force to generate more torque during the power stroke. What's your counter-argument?
That sounds fantastic but it means nothing in practice. It's like something you'd hear in a "Engineering Explained" video, but with no real-world application. There's so much more that goes into an engine that it doesn't matter.
Again, it's a myth.
Similarly, there was always the debate over rod length (in the same displacement engines). You use the same crankshaft but the piston has the wrist pin located higher. The longer rod was always supposed to make "more torque" because of the angle but that ended up not being the case.
You can verify this buy putting engines together with different bores and strokes that are roughly equal displacements, and with the same heads/cam on them, they will make identical power. Picture something like a 3.50" bore and 4.00" stroke, and vice versa. Look up someone like Richard Holdener on YouTube for actual data. Displacement is displacement, it doesn't really matter how you make it.
Bore is what would make you more power after a certain point, anyway. You get more surface area to fit larger valves, etc. But again, using the same heads (that aren't shrouding the smaller bores), either combination of bore/stroke will make the same power throughout the rev range.
Then you get into things like piston speed and all that but none of that matters unless you're talking about a race engine. And when you are, they'll just rebuild it more often so they don't care how long it lasts.
Here's another read:
https://rehermorrison.com/tech-talk-53-big-bore-or-long-stro...
This is an extremely popular layout in heavy duty applications.
https://en.wikipedia.org/wiki/Cummins_B_Series_engine
I love a straight-6 so much that I drive a car that uses two of them joined at the crankshaft! Each I6 has its own ECU and is entirely unaware of the other. Crude, but very smooth nonetheless.
Need more details of this beast!
Older BMW 7 series?
this thread is worthless without pics ;)
Well for Stellantis their fans rather want the Hemi V8 back, but they are offering a turbo charged inline 6 (Hurricane).
Badging a Mercedes as an AMG and asking the price for it and you just fit turbos on a 4 cylinder.
fwiw, the M139 engine they're putting on those AMGs is completely insane.
It's a production 2.0L 4-cylinder engine making (in the most powerful config) 350kw. From the factory. Insane.
Ford F150 buyers quickly came around to the turbo V6 instead of the V8. I wonder if the Ram buyers will as well.
In europe inline-fours are more popular. Cheaper and less fuel.
Even in the US, I4 engines are by far the most popular. Most consumer cars are built for fuel economy with the one notable exception being the suburban tacticool pickup truck, which are often modded to burn MORE fuel.
It does not hurt that you can easily get 200+ horsepower from the factory with one, either. My car is a series hybrid with an Atkinson-cycle I4 but it still bursts to 200hp because it's a hybrid.
The inline four has largely converged around a 2.0L displacement with an equal bore and stroke. IIRC, it's fairly optimal from a performance and thermodynamic efficiency standpoint.
Europe has stupid displacement taxes so they'll make some high strung 0.9L turbo 3/4cyl with all the technology that gets .01mpg better MPG than a ~2L engine while taking twice as much $$ in service to make it to any given milage.
IDK why they don't just tax the actual fuel used like the rest of the world (not that they don't do that).
In my country its based on emissions, 1.6l 4 cyl 140g/km co2 is ~150e, 3 litre V6 300g/km ~500e.
Americans like their cars enormous and heavy.
Buggy makers building fancier sounding whips.
There's potentially an even better option than the I6 layout: opposed piston I3 2 stroke. Same number of power pulses per rev as I6 4 stroke, no valves, no cylinder heads. It seems that these guys solved the oil loss problem and by using 2 injectors and some awesome combustion modeling they've been able to beat emissions standards without after treatment: https://achatespower.com
My TR6 is happy to see this.
Great news!
Yet Another Bad Idea. The only engine that makes sense is a small generator married to an EREV. Everything else will be dead in 10 years.
For buyers today that may actually mean less depreciation as six cylinder engines become harder and harder to find. But yeah I'm sure automakers can see the writing on the wall.