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August 11, 2009

V6 Engines VS. Inline-6 Engines: Which is Better?

By Alex Vickers


I’ve actually seen people argue about whether a V6 is better than an inline-6. Personally I feel an inline-6 is better, but that’s not really the point.

V-shaped engines all have a slight loss of power on the down-stroke. Regardless of the piston angle, this cannot be remedied. V6 engines in particular run rather roughly. This is due to primary dynamic imbalance which is caused by an uneven number of pistons in each cylinder bank causing a rocking motion from one end of the engine to the other. Straight engines, such as the optional inline-5 in the Chevy Colorado have this problem also because of the uneven cylinder number. V8s don’t have this problem because they have an even number in each cylinder bank which cancels out any rocking motions or vibrations. This should explain why in cars such as the Caprice or a lot of trucks that have an optional V8 without a lot of power, because they tend to run smoother than most engines, thus being a luxury option. Volkswagen’s VR6 engines come in 10.6 degree angles and 15 degree angles. The angle is so narrow that they use just one cylinder head. While this is extremely compact (and they sound orgasmic), they can run more rough than fat kid on gravel if they aren’t designed well. Certain angles can mitigate the vibrations, but it’s impossible to design it out completely, regardless of its piston angle  A V6 isn’t without its merits, though: They’re less complex, they’re more compact thus allowing car manufacturers to produce smaller cars and they can produce just as much power as any type of engine, naturally aspirated or not, and advancements in the engine type’s design have relatively reduced the preference for the inline-6.

File:Lancia V6 engine v TCE.jpg

An inline-6, on the other hand, would run very smooth compared to a V6 because it has only one bank of cylinders with an even number. The firing order of an inline-6 is rather easy to articulate because there is really only two ways to fire the pistons: from the piston at the front of the block towards the back of the block, and vice versa. The Toyota Supra used an inline-6 throughout its entire lifespan because it has proven to be durable, with some owners modifying theirs to have well over five-hundred horsepower with stock internals. The inline-6 isn’t without its faults: It’s rather susceptible to torsional vibration, they don’t fit in most modern car’s engine bays, and they’re expensive to produce. Alas, they have fallen out of disfavor over the V6, because it’s seen to some as an outdated engine. BMW is one of the few car manufacturers to mass produce an inline-6 in passenger cars, while Dodge uses them as diesels in their Ram 2500 and 3500 trucks.

File:BillR's 1969 FB 250 I6.JPG

They both have their merits and their faults, but everyone has a preference for either application. Which is better?


Aug 14, 2009 at 1:38 pm

RiceOnMyShirt: The reason car makers are switching to V6s instead of I6s is because of shape and size. Cars that have an infinitly long hood aren’t as attractive to your daily commuter or even sports car fanatic (unless you’re obsessed with the Viper). Also the weight balance is easier to manifest in cars with a shorter engine.

Aug 14, 2009 at 1:34 pm

I only have 3 things to say on this topic…2JZ, RB26/28, Cummins…Need I say more?

Aug 12, 2009 at 8:27 pm

I will say this the V6 in my fathers 94 Ford Ranger was a beast for a truck in hauled and was way easier to work on with the space it saves but i would still take an i6 any day they are just to awsome reliable and yes they vibrate less and for the dude who mentioned the amazing 3800 series from gm hell ya my sisters olds intrigue has the 3800 seriesII and that is one V6 i have completely fallen in love with but in front wheel drive cars just too little space to work on the damn thing but if gm got one engine right other than the V8s it was the 3.8litre v6 thankyou gm.

Aug 12, 2009 at 6:49 pm

There’s a lot more to an engine than just the sound (which can be made to sound a dozen different ways depending on the exhaust anyway).
I’m not into hiring midgets to turn my wrenches and when an engine is in intended working order but still runs hot, I’d call that a design defect. If the fin fan coolers weren’t enough to cool down the LMS100 turbine generation unit my company designed in a previous project, the customer wouldn’t just stand around saying “yeah its hot but just listen to it!”… there would be lawsuits, lol… big ones.

Aug 12, 2009 at 8:22 am

VR6 FTW!!!! Rough running, hot as hell, and you need midgets to help you work on it, but the sound justifies everything.

Aug 12, 2009 at 5:30 am

RiceOnMyShirt, BMW would never stoop that low!

troutster52, The only domestic I can think of are the HD Rams with the 6.7L Cummins. And the Traverse(Lambda platform) is the replacement for the TrailBlazer(GMT 360). Yes that means GM is replacing a mid-size “SUV” with a full-size crossover! Welcome to the future my friend, isn’t it GRAND!

Aug 11, 2009 at 11:41 pm

I was wrong looks like a 69′ mustang fastback with a 250cid. Which is even more impressive.

Aug 11, 2009 at 8:16 pm

I like them both, but I run older cars that dont use fuel injection so the V 6 gets not not because of better fuel mixture with the use of a single carb. They also tend to be cheaper to hop up because many of them are closely related to a V8 so parts like pistons are easy to find. Other advantages are typically weight, although some of that could be due to V engines tending to be newer designs and on a rear wheel drive car it is easier to move more of the engine weight toward the rear wheels. Since the engine is shorter you can move it back and get better weight distribution for acceleration and handling. I wouldnt get in a heated arguement over it though, because inlines usually have a stout bottom end and are cool in their own right. As far as looks go its hard to beat a I6, the only engines I think can are early Hemis and Flathead Fords. Honestly though most of the advantages you listed for inlines are minute, the early V6 engines ran rough but modern ones run rather smooth and if you have an auto it is likely you wont notice the difference.

Aug 11, 2009 at 7:55 pm

I’m a fan of the straight 6 but with advances in technology a tuned V6 can match up nowaday.

Trouster52 In answer to your question I believe that is the engine bay of a 66 Mustang with the 200 cid. Been under allot of mustang hoods it just kind of jumped out at me.

Aug 11, 2009 at 7:49 pm

you mentioned supra’s jz, and with the skyline’s rb engine, those are two of the top engines out there, so it says something about straight 6s, however lately everyone’s been switching to v6 from i6s in their cars (lexus, nissan, bmw too right?), so that says another thing.

but good post, im in college for mechanical engineering and the technical points you bring are very enjoyable.

Aug 11, 2009 at 6:12 pm

Slant/straight 6, V6… man its like trying to choose between my kids! I can’t do it! Nope… I refuse.
The 4.0 Litre straight 6 in my Cherokees, all three of ‘em well that engine was a goddam beast. Nothing could kill ‘em but when the ceramic injectors started to crack, get out your wallet and replace ‘em all. Despite this one real weakness, these engines were awesome.
On the other hand there’s the GM 3800 V6 Series engines, old-school design but comes back for more and more like it’s an all you can eat buffet.

Aug 11, 2009 at 6:08 pm



Alex Vickers
Aug 11, 2009 at 5:31 pm

You know how powerful the inline-6 in a Trailblazer is? They put out nearly what a 2JZ-GTE Supra does with a couple turbos. They sprint to sixty in the mid seven second range, and a quarter mile in the mid fifteen second range.

Aug 11, 2009 at 5:24 pm

in my 2004 Chevy Trailblazer i have the inline 6 and love it…honestly with the sub i have in the back and no engine mods i beat an 2004 Audi A4 quatro off the line 2 out of 3 times. Its all about preferance though. I love the I6 its a great engine

Alex Vickers
Aug 11, 2009 at 1:09 pm

Traverse is more like a Crossover Utility Vehicle. I highly doubt a 2JZ-GTE (am I right or wrong) can handle that kind of muscle with stock internals, and the inline six I used as an example is a 250 cubic inch Ford inline-6. It’s exclusive to Australia. I don’t recall the particular mode Ford, though.

Aug 11, 2009 at 11:26 am

What car and what inline is that pictured at the bottom?

Aug 11, 2009 at 11:10 am

Toyota Supras can have over 1000HP.
You said 500.

Aug 11, 2009 at 10:51 am

Didn’t know that. I thought they were still making them. Whats the GM ute in its place then? Traverse is more like a van, right?

Alex Vickers
Aug 11, 2009 at 10:21 am

Troutster52, I didn’t count the Chevy Trailblazer because it ended production already. The last one built rolled off the line last December.

Aug 11, 2009 at 9:33 am

Straight six is more efficient al around it’s just too long
V6 les efficient but more compact, and much more widely used

Aug 11, 2009 at 8:45 am

inline 6′s, i dont know of any that wont stand the test of time.

Aug 11, 2009 at 8:19 am

Straight 6.

Aug 11, 2009 at 8:02 am

I was like two days from writing my blog about the overlooked glory of six-in-a-row. I guess I won’t write the article now but I will still speak my mind.
Six-in-a-Row is 1000 times better. They are torquey, simple and extremely reliable. Greats in the inline 6 category include the Ford 300, the Chevy 235, Plymouth slant six, the Jeep 4.0, the Supra 3.2, the BMW 3.0, and many many others. The diesel applications of this configuration are also endless. Add to that that many inline sixes have 7 bolt mains instead of a comparable V8s that only have 4. That means you can rev the piss out of them as long as the valvetrain can keep up. Performance parts are almost as plentiful as their V8 siblings but they are typically easier to install and cheaper. One bank of pistons vs two means one valve cover, one head, one row of spark plugs, etc. I often dream of building a 300 inline with an Offenhauser intake, four barrel, a mild cam and Mallory Ignition. I would love to bounce around in an old truck or rat rod in something like that. The only current domestic vehicle that I know of that makes an inline six now is a Trailblazer. Are there others?

Aug 11, 2009 at 4:58 am

I absolutely loath V6′s. And as IH-international brought up the flat six has even better merits. Still prefer V8′s though.

Aug 11, 2009 at 4:47 am

Straight 6…. Datsun/Nissan L-series anyone? Or maybe the RB series? Or how about Toyota’s JZ series?

Aug 11, 2009 at 4:31 am

if you get yourself a flat six like a corvair or porsche then you you don’t have to worry about it at all!!! because both sides contradict eachothers vibrations thus having virtually none!

Aug 11, 2009 at 4:30 am

It’s not really because of an odd number of cylinders on a bank that causes vibrations–a V8 still has free moments of the first order. (See the SAE Automotive Handbook’s section on balancing.)
The smoothest running engines are actually V12s and V16s, which aren’t used in automobiles very often.
You also must realize that many modern V6s, such as Nissan’s VQ and Honda’s V6, use active computer-controlled engine balancing.

Aug 11, 2009 at 3:48 am

I only have one thing to say. Nissan VQ.

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