Next Lexus IS Might Get Supra’s BMW-Sourced Straight Six

[MX793]

Which is why the Japanese, the best engine designers and builders on Earth, have abandoned it en masse?

And BMW spent much of the last 30 years fucking them up in one way or another?

Still the cylinder arrangement of choice for BIG engines.  Practically every big rig you see on the highway has a big ole, 12-15L Inline-6.

[r0tor]

V6 is a better motor than the I6, and Toyota has almost always built a better motor (reliability, durability, longevity) than BMW (or any other German automaker for that matter).

The devil is the details. The detriments to the inline engine are in length - crankshaft, camshaft and engine block are longer and have to be relatively heavier as a result. Other non-load bearing elements are heavier too as lost is the economies of geometry in parts such as the intake manifold to oil pan. This all usually results in a bit heavier engine per unit of displacement. Length of course is also an issue with packaging in the car. US and Japanese automakers had to dump the I6 as the transition to FWD hit full swing. The V6 does have more parts - double the camshafts and associated drive gear, balance shafts, etc., but on balance, especially in situ, the V6 is the better engine (and the V8 is the best engine of all).

The I6 is a balanced engine design. A V6 is not.
An I6 sounds interesting.  A V6 does not.
Packaging doesn't mean shit in a front engine / rear drive layout.

The best engine Toyota has ever put in a passenger car was an I6.

[12,000 RPM]

The I6 is a balanced engine design. A V6 is not.
An I6 sounds interesting.  A V6 does not.
Packaging doesn't mean shit in a front engine / rear drive layout.

The best engine Toyota has ever put in a passenger car was an I6.

All this internet bench racer Wikipedia search bullshit is irrelevant

(but lol @ packaging being irrelevant in sports sedans)

In real life, where people buy, own and operate cars, Toyota

- Has been making better 6 & 8 cylinder engines than BMW for the last 30 years
- Made one of the greatest I6s of all time
- Just made a new RWD platform and V6

So we come back to the original question... why in the fuck would they run to BMW for this? They are demonstrably more capable in every capacity.

[GoCougs]

Still the cylinder arrangement of choice for BIG engines.  Practically every big rig you see on the highway has a big ole, 12-15L Inline-6.

Actually, big rig engines aren't BIG; they're on the small and low(ish) performance side of industrial engines, aka, don't forget I'm into trains!

BIG IC engines  - say 1000 to 20,000 hp and have am extreme operating envelop; need for both variable and sustained (relatively high) RPM for thousands of hours over many years, such as trains(!) (or generators, pumping stations, marine, etc.), are typically V-engines for the reasons I gave as to why the V6 engine is superior to the I6 engine. Big rig engines are typically I6 these days, but that's because they're relatively low performance in a conservative/stagnated/consolidated industry. Before that happened; i.e., when there were a lot more players in the market; V8 and V12 diesel big rigs were common.

But here's a 95L 4400 hp V16 Cat locomotive diesel:



And here's a 1600L 20,000 hp V16 Cummins marine diesel as large as your house (~350,000 lbs):



Peruse Caterpillar's or Cummins' commercial engine offerings and you'll see that above ~1000 hp it's mostly V-engines:

[GoCougs]

The I6 is a balanced engine design. A V6 is not.
An I6 sounds interesting.  A V6 does not.
Packaging doesn't mean shit in a front engine / rear drive layout.

The best engine Toyota has ever put in a passenger car was an I6.

Those are 4 points that either don't mean anything or are incorrect.

There are some advantages to the I6, but on balance, for retail vehicles, as the industry has shown, V6 > I6.

[Eye of the Tiger]

This is basically just like GMC's 4.3 V6. You can put it in a truck and it will last 31 years, or you can put a turbo on it.

[12,000 RPM]

Still the cylinder arrangement of choice for BIG engines.  Practically every big rig you see on the highway has a big ole, 12-15L Inline-6.

Pretty extreme use case compared to sports sedans, no??

[Laconian]

Which is why the Japanese, the best engine designers and builders on Earth, have abandoned it en masse?

Because many of their cars come with transverse I4s as standard equipment, and the shorter block of the V6 is easier to shoehorn in under the hood?

If I got a six cylinder car again, I would definitely prefer a nice creamy I6 over a V6.

[FoMoJo]

Because many of their cars come with transverse I4s as standard equipment, and the shorter block of the V6 is easier to shoehorn in under the hood?

If I got a six cylinder car again, I would definitely prefer a nice creamy I6 over a V6.

Yes, the predominant reason for a V6 is compactness; fits where an I4 can, for the most part.  There are several variations of V6; angle, firing order, crankshaft design, balance shafts or not, but none run as smoothly an an I6.  The iconic I6 is the Jaguar XK.

[Morris Minor]

A V-6's advantages over an I-6 do not include innate balance and smoothness.

[MX793]

Actually, big rig engines aren't BIG; they're on the small and low(ish) performance side of industrial engines, aka, don't forget I'm into trains!

BIG IC engines  - say 1000 to 20,000 hp and have am extreme operating envelop; need for both variable and sustained (relatively high) RPM for thousands of hours over many years, such as trains(!) (or generators, pumping stations, marine, etc.), are typically V-engines for the reasons I gave as to why the V6 engine is superior to the I6 engine. Big rig engines are typically I6 these days, but that's because they're relatively low performance in a conservative/stagnated/consolidated industry. Before that happened; i.e., when there were a lot more players in the market; V8 and V12 diesel big rigs were common.

But here's a 95L 4400 hp V16 Cat locomotive diesel:



And here's a 1600L 20,000 hp V16 Cummins marine diesel as large as your house (~350,000 lbs):



Peruse Caterpillar's or Cummins' commercial engine offerings and you'll see that above ~1000 hp it's mostly V-engines:

V12 or V16 have the same inherent shortcomings of an I6 (or I8).  Longer crankshafts that can be fragile and sensitive to balance, particularly if your engine runs at higher RPMs.  Putting another bank of cylinders off of that crankshaft doesn't change that.

You don't see V6s used in big rig sized engines (or larger).  You did used to see more V8s and even V12s back in the golden days of trucking (back when 2-strokes were common).  The V8, V12, and I6 were all preferred layouts for engines that size because they have very good primary balance (cross-plane, specifically, when talking V8).  V6s are imbalanced, which is why you tend not to see them in larger displacements.  When you have pistons displacing a liter or more, running at 4-digit RPMs, balance is important.  The I6 persevered in that market because it's the best balance of cost and performance for the application.  Same reason why V6s largely displaced I6s in automobiles.  They work better for that application, all things considered.

[r0tor]

All this internet bench racer Wikipedia search bullshit is irrelevant

(but lol @ packaging being irrelevant in sports sedans)

In real life, where people buy, own and operate cars, Toyota

- Has been making better 6 & 8 cylinder engines than BMW for the last 30 years
- Made one of the greatest I6s of all time
- Just made a new RWD platform and V6

So we come back to the original question... why in the fuck would they run to BMW for this? They are demonstrably more capable in every capacity.

BMW produces the best balanced and smallest front overhang of pretty much all sedans on the maket... So fuck your packaging argument.

I'm not sure when the last time I heard a BMW owner wishing thry had a Toyota V6

[r0tor]

Those are 4 points that either don't mean anything or are incorrect.

There are some advantages to the I6, but on balance, for retail vehicles, as the industry has shown, V6 > I6.

Luxury segment should have smoothness - an I6 excels at this as the I6 is an inheritently balanced design.

A sports luxury sedan should sound good and have great power... also where an I6 beats the pants off of a V6

[MX793]

Luxury segment should have smoothness - an I6 excels at this as the I6 is an inheritently balanced design.

A sports luxury sedan should sound good and have great power... also where an I6 beats the pants off of a V6

Either motor can sound great or bad depending on the exhaust.  Ford SVT Contour, Acura NSX, Jag F-Type, and even the 3.7L S197/S550 Mustangs all sound damn good.  So did the 3.0L Nissan VQs.  Have you listened to a BMW S54 at full song recently?  They sound... thrashy and metallic up top.  Not good, at any rate.  I'd gladly listen to any of the aforementioned V6s over an S54.  The newer, turbo BMW 6s don't sound great either.  There's a reason BMW has fitted all of their turbo I6 cars with fake engine sounds pumped through the speakers.

[r0tor]

They pump artificial sound in not because it sounds bad, but so they can achieve a quiet and refined ride when they want it and a more aggressive sound when they want it.

F30s and 2ers sound great with exhausts - especially the factory option M performance exhausts

[Laconian]

I thought the muffling from F/I was the reason everybody "symposes" their engine sounds nowadays.

[MX793]

They pump artificial sound in not because it sounds bad, but so they can achieve a quiet and refined ride when they want it and a more aggressive sound when they want it.

F30s and 2ers sound great with exhausts - especially the factory option M performance exhausts

They pump artificial sound in because the turbo motors sound bland and characterless.  Though I suppose that's better than sounding outright unpleasant like the S54.  They do sound pretty good with the M Performance exhaust setup.  Any other factory exhaust setup just sounds generic.

[MX793]

I thought the muffling from F/I was the reason everybody "symposes" their engine sounds nowadays.

That's part of it.  You don't get the same induction noises and the turbo(s) muffle a lot of the exhaust sound.  Some do it because their engines just don't sound great (like the Ford 2.3T).

[giant_mtb]

I thought the muffling from F/I was the reason everybody "symposes" their engine sounds nowadays.

I always thought it was more because newer cars are simply that much quieter inside.

Regardless, it's a lame gimmick, but there are levels to it. BMW doing it digitally via audio files and TPS?  Lame as fuck. A resonator tube like a Mustang has (I think?)...less lame, because it's actual engine sound.

[Morris Minor]

Luxury segment should have smoothness - an I6 excels at this as the I6 is an inheritently balanced design.

A sports luxury sedan should sound good and have great power... also where an I6 beats the pants off of a V6

The new M-B GLE 450 has Mercedes' new inline six.
Kinda surprised the E-Class still has the V-6 - but the base E-Class has a four-banger so I'm guessing they've given up in that segment, now owned by the Model S

[Laconian]

I would love a "symposer" feature that would let me load in custom WAV files. I'd turn my Miata into a Cylon Raider.

[MX793]

I always thought it was more because newer cars are simply that much quieter inside.

Regardless, it's a lame gimmick, but there are levels to it. BMW doing it digitally via audio files and TPS?  Lame as fuck. A resonator tube like a Mustang has (I think?)...less lame, because it's actual engine sound.

Sound tubes basically compensate for the better sound insulation that cabins have today compared to old cars.  In the pursuit of minimizing wind and tire noise, engine noise in the cabin got muted as well.  The tube allows just the engine sounds back into the cabin. 

BMW has to resort to electronic symposers because even with a sound tube, the engine note wouldn't really sound like anything special.  The symposer is pretty much a must-have with the 4-banger (4-banger Mustangs have it as well).

[GoCougs]

Luxury segment should have smoothness - an I6 excels at this as the I6 is an inheritently balanced design.

A sports luxury sedan should sound good and have great power... also where an I6 beats the pants off of a V6

When's the last time you were in any of these vehicles? The Honda J-series is smoother than any BMW I6 I've ever been even near. But non-advantage doesn't really matter. Most any car these days has active engine mounts.

But with the displacement limitations of an I6 seemingly capped at ~3.0L, in this day and age an I6 necessitates forced induction (usually turbo) which is sucky on multiple levels.

[12,000 RPM]

I would love a "symposer" feature that would let me load in custom WAV files. I'd turn my Miata into a Cylon Raider.

You joke, but video game engine sounds are really good. I'm surprised in the gap between those and real cars.

Luxury segment should have smoothness - an I6 excels at this as the I6 is an inheritently balanced design.

A sports luxury sedan should sound good and have great power... also where an I6 beats the pants off of a V6

Most luxury cars these days are sold with clattery 2.0T four cylinders, so in real life smoothness isn't that big of a deal. A V6 is much smoother than the standard 4 banger in the majority of luxury cars sold today.

BMW produces the best balanced and smallest front overhang of pretty much all sedans on the maket... So fuck your packaging argument.

I'm not sure when the last time I heard a BMW owner wishing thry had a Toyota V6

They might not have pined for the Toyota V6 specifically, but plenty were pissed at the timing chain failures on the bread and butter turbo 4, the rod bearing and throttle actuator maintenance items on the ///M V8/V10s, the myriad issues with the N62/N63/S63 TT V8 etc

I6 smoothness is one very minor advantage against a big backdrop of disadvantages for BMW as an engine supplier.

[r0tor]

Your only kidding yourself with million mile reliability comverns in a predominately lease segment

[12,000 RPM]

Reliability is a big part of why BMW is the #1 most leased brand (77%!!!!!)

People know to get out while the getting is good

[shp4man]

I'm going to make a recording of the 250 inch I6 in my truck running through the gears. It's a sound you don't hear anymore, but was common back in the day.

[Laconian]

Yes please do.

[r0tor]

Reliability is a big part of why BMW is the #1 most leased brand (77%!!!!!)

People know to get out while the getting is good

Yea, it's not because leasing allows people to get into cars they can't afford to buy and maintain... Or have enough disposable income that they want to have new cars every couple years

[GoCougs]

Absolutely ze German brands are designed to be leased.