I For One Will Welcome Our Inline Six Overlord.
The V8 is in decline. It’s rare already in some countries but here in the U.S you can still find one relatively easily on a showroom floor.
The V8 is in decline. It’s rare already in some countries but here in the U.S you can still find one relatively easily on a showroom floor. However the reality is the twin pronged attack of government meddling by way of fuel economy regulations along with demand for economy and ecologically friendly cars from consumers means the end is coming for the V8.
The reality is a turbocharged V6 uses less fuel than an equally powerful naturally aspirated V8.
Except of course a turbocharged V8 will be able to make even more power, so the rise of forced induction hasn’t made “there’s no replacement for displacement” a dated truism, and don’t anyone tell you otherwise because math.
However, a six cylinder car will always be more economical and take the place of V8’s when they are legislated out of existence and forced induction will be how we make real power.
“So why not a V6 instead of a straight 6?” I hear you ask.
It’s a good question. After all, a V6 can be made from an existing V8 relatively simply by removing two cylinders from the existing design which cuts out a lot of R&D time and money.
Well, sort of yes. There are issues and it mostly boils down to the angle between the cylinder banks. The angle between cylinder banks on a V8 is inevitably 90 degrees. A V6 generally ideally needs to be at a 120 degree angle to allow it to run somewhat smoothly. The problem there is that you have now made the V6 wider with that more splayed out V. Not such a problem with a four banger boxter engine where the cylinders are laid flat and horizontally opposed, because there are two less cylinders to take up room.
If you see a 90-degree V6 it will have had a lot of work done to balance everything out so it doesn’t just shake and vibrate itself apart (looking at you Mercedes). That’s added complication in an attempt to solve an issue that can be avoided by spending the money developing an inherently smooth inline six in the first place. BMW for the longest time built their cars on that predication, and as far as I can tell are still the only car company on the world stage doing so.
More will start to develop them now though. Three cylinder engines are becoming more common place so car companies developing a series of three, four and six cylinder engines off of the same basic blueprint makes a lot of sense. A four cylinder engine can be developed, then a cylinder removed or two added without the issues that grow from trying to make a V8 into a V6. A modular engine system for a car company will certainly make the accountants happy for the cost savings, and the marketing departments happy because it makes very easy model distinctions to cover multiple demographics - all the way from the eco warrior to the people that want to be able to put their foot to the floor and something exciting happen.
Personally, I’m not that bothered about the V8 going away as we have reached a stage in engine development where six cylinders are capable of making plenty of power. BMW were knocking out the naturally aspirated M3 fifteen years ago with 340bhp.
Now, bear that in mind while I mix a metaphor so hard that if an English teacher read it they would surely try and hunt me down to inflict physical pain…
Once the arms race for BHP starts with inline sixes then all the car companies will be racing to build a better mousetrap.
That means we will have an all new horsepower war with the net result being a broad choice of smooth and fast as hell inline sixes.
Just as god intended.
(A very good comprehensive explanation given here on angles and balancing V engines here)
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Comments
Chadkake Szymek S Schlawyaya Matt Robinson
This is something we’re seeing already, actually - Merc has a new range of inline-sixes inbound, and Jaguar is rumoured to be replacing its ancient, Ford-derived V6s (related to the 5.0 V8) with straight-sixes, and sourcing its V8 from elsewhere.
Like you said - the modular thing has a big part to play due to lower costs and better manufacturing efficiency.
Well I’m going to be buying an E34 with an I6 so that’s a thing :)
You’ll love it. I didn’t really realise just how smooth an I6 was until I drove one. It’s a large part of the reason I went for a BMW.
Why do 6 cylinders mostly come in V layout not inline layout?
Pretty much because an inline six is a whole new engine to research and design. A V6 can be made from a pre-existing V8 design and then modified - that’s why Mercedes do them and they suck. It’s a cost cutting exercise..,
I think I read recently Mercedes are starting to develop an inline six again (they used to before they were bought out by the parent company) so that will probably be the start of the revolution.
V6 are easier to package.
Because the v6 is a hell of a lot shorter, and cheaper, and the final reason is why i don’t see the inline 6 take over again anytime soon, the v6 fits a FWD package. yes there have been straight 6 fwd cars, (Volvo T6’s,) but they are large cars and still does not have room for decent steering angle (they actually have rubber stoppers on the spindles to stop them from rubbing on full lock).
Simply because of packaging. Inline 6’s end up being quite long, as anyone with a 6cyl E36 can attest to. Took forever and a damn day to replace the starter on my 325is because of how long the engine is.
Hell even a standard v6 can be a bit of a pain to squeeze into some cars as well hence why VW used the VR6 design.
Great blog post, and I agree. While it’ll be sad to see the V8 go, especially for a serious gas-powered-only-Tesla-hating purist like me, we still have MANY many older V8 options. I would really like to see car companies develop more inline 6 cylinder engines. They are fantastic. BMW has the right mindset with that. They are very smooth.
The biggest problem with the inline 6 is not its fuel economy or its ability to produce power, it’s packaging. Most inline sixes are still going to be longer than even some large v8s. Couple that with engine accessories, and ahead of that a radiator and with turbocharging inevitable nowadays an intercooler as well. And ahead of the mechanical components, we still have to have all the government mandated safety features present in the front bumper assembly. I would love to see new inline sixes as much as any other carguy but I don’t think it’ll happen. Last I heard the new supra will likely only be available with a 4 cylinder base and a turbo v6 as the performance engine.
That’s specifically why they brought up beamers as they still make inline 6 today as does the Australian market with an upgraded version of fords old 300 ci inline 6.
Whenever I hear “90° V6/V10”
I’m pretty sure the v10 in the gallardo/r8/huracan are 90 degrees
488 gtb has a 90 degree mounted V8…and thats a beauty
Right?
Mercedes seems to make theirs as quiet as possible with the resonator and muffler but when you give one beans… Eeeugh.
hello brother
“A V6 generally ideally needs to be at a 60 degree angle to allow it to run somewhat smoothly. The problem there is that you have now made the V6 wider with that more splayed out V.”
Hold up.
A 60 degree V6 is actually a narrower engine than a 90 degree V6. That means it’s actually more compact, which allows it to be used in transverse FWD configurations more easily for instance. Back when F1 was still fun most engines had a narrow angle V too to aid packaging. Weight distribution is also better with a V6 because it is much shorter than an inline engine.
I agree with your view on the modular idea though. I think that’ll definitely be something we will see very soon.
I was about to say…..
Also the ideal V-angle for V6 is 120 degrees I think
I believe he was referring to a 90° V6 made from a V8 in the second sentence.
My old Jeep Cherokee was a rough mother but that 4 litre straight-six was the smoothest and quietest engine I’ve owned
I miss my i6 BMWs :(
You could always get a certain i6 Nissan very cheap and hope it doesn’t get stolen…
? BMW is making I 6s they just strapped on a Turbo onto those. I mean I prefer good old responsive I6s, but unless you have an M division car, throttle response on the old cars, certainly with automatic, was not as fast as Turbo I6s
good news then. i was always asking myself, how long will bmw be able to make inline 6. as far i know they are testing v6 all the times,
I’ve heard that too. And also that Mercedes is thinking about switchong back to straight sixes again.