Aron9000

I've heard that before and will take your word on it, as I haven't had any significant seat time in a V12 car, either Italian exotic or German luxury. Its just when you say V12 I think Ferrari or Lamborghini, not Mercedes-Benz. I also kind of wonder if that the V12 Benz is so refined due to it being stuffed with 500lbs of sound insulation and highly sophisticated(ie $$$) motor mounts. Those V12 Benz cars, with their twin turbos make similar power to naturally aspirated V12 engines from Italy.

Still for the more "average" man with less deep pocket books, I swear up and down that an inline six is smoother than a V8, at least in all the cars I've driven(2JZ Toyota/Lexus products, Jaguar XJ sedans with the inline six), cars with those two engines felt smoother than any V8 I've driven. Maybe not as much personality as some other luxury V8's(love the sound/feel of Audi's old 4.2 V8), but definitely the kings of smooth.

mmarshall

In-line sixes can vary quite a bit in smoothness. The old Chrysler Slant Six, for instance, that I learned to drive on, decades ago, was a durable as a tank (it was commonly used in taxis), but was somewhat lacking in the NVH category.....competitors from Ford, GM, and AMC generally ran a little smoother. The Toyota/Lexus 3.0L straight-six you speak of (I has one in my IS300), yes, was smooth as butter....but it guzzled gas like a V8, with (in the non-turbo version) only a little over 200 HP to show for it. At the time it was produced in the IS300, its EPA ratings, if my memory is correct, were only 23 highway, 17 city.

Fizzboy7

I remember the IS300's inline six. It indeed was a very impressive motor. However, my friend's 1990's ES300 had what I assume was a regular 3.0 V6 in it, and it was far smoother. Maybe it was the added sound-deadening and lack of any exhaust note that gave the impression. You really could not hear or feel anything at all if wound up to redline. Both good motors. I'm a sucker for stealthy power, where a vehicle builds up rapid speed while surprising passengers due to lack of noise or vibration.

Aron9000

I have the same engine in my SC300, completely agree with your assessment. Love that engine, extremely smooth, very quiet, very reliable, cheap to maintain, great torque curve and very broad power band, but it has a serious drinking problem and only likes top shelf liquor. Premium gas is also a lot more pricey than it used to be.

Of course the JZ family of inline six engines were a product of Japan's "bubble economy" of the late 1980's. Fuel economy was not a priority and they were designed to have two turbos strapped on to them that made about 100 more hp than the non-turbo motors. For "reasons" the US Lexus division got the shaft on turbocharged JZ engines that were found in identical Japanese market cars.

RNM GS3

Fizzboy7

I have driven the Lexus inline six, in my friend's IS300. I did not feel it to be any smoother than most other Lexus V6's. It was my other friend's ES's V6 that felt far smoother. Could be his was brand new and the inline six friend's was an over 100k mile car.

bitkahuna

iTrader: (20)

so your example of how in line sixes 'vary in smoothness' is a 50+ yr old chrysler engine? name ANY inline six in the past 2 decades that was anything but silky smooth.

peteharvey

I have driven brand new IS and GS 3.0 in-line sixes, and onwed many V6's.
The IS and GS in-line sixes has straighter inlet ports for superior low RPM breathing, and hence bags of bottom end torque, and a more linear torque curve as some have mentioned.
My Mercedes used the old 90 degree V6 that shared casting dies with 90 degree V8 blocks, and the breathing ability was poor - hence a total lack of bottom end torque!
Benz's 90 degree V6 was rough too.

However, I thought the IS and GS in-line sixes were absolutely no match for the smoothness of Mazda 929, 626, and numerous Toyota/Lexus and Honda 60 degree V6's.

The BMW in-line six is actually smoother than the IS/GS in-line six, probably because TMC did not bother to develop their in-line sixes any further, but the BMW in-line sixes were still no match for Japanese 60 degree V6's for smoothness and quietness...

mmarshall

Outside of Lexus and BMW, there have actually been very few of them in modern American-market vehicles, period....maybe one or two of them from Mercedes. With the push for downsizing in the late 1970s, underhood packaging became an issue, particularly with FWD.

One very interesting exception to the packaging issue, however (though it was a rather mediocre car) was the Suzuki Verona sedan, which was actually a rebadged version of the Korean-designed Daewoo Magnus. It was the only transverse-mounted/FWD application of an in-line six I can ever remember seeing in the American market. Somehow, with small cylinders and only 2.5L of displacement, they managed to make it fit into the mid-sized Verona transversely and hook to up to the transmission and final-drive unit. To be honest, I don't really remember how smoothly or roughly it ran, though I do remember that, like the 1Gen Kia Amanti, The Verona's road manners left a little to be desired....it was a Ho-Hum driving experience at best.

Aron9000

Late 90's/early 2000's Jeep 4.0 inline six comes to mind. Not terribly refined, kind of noisy, thrashy, but they made great torque, very reliable and long lasting. Reason for its greatness is that the Jeep inline six is actually an AMC design, not a Chrysler design IMO, the engine dates back to when AMC owned Jeep, Chrysler bought them, this motor was a carryover for many many years.

SLegacy99

My brother had one. I couldn't separate the feeling of it from the ES350 loaners that my mom used to get. I do remember that the fuel economy was terrible and that the oil filter was impossible to get out. ...loved the design of the first gen IS of course.




As for MB, this makes sense. Especially as they too are pushing more and more 4 cylinder motors.

UDel

Volvo mounted their inline sixes transversely in their fwd based vehicles, though awd was a option or standard.
https://en.wikipedia.org/wiki/Volvo_SI6_engine

Infra

iTrader: (1)

I had a 3.2L I6 in my 2008 Land Rover LR2, from the Volvo parts bin when Ford owned both of them. No complaints about it.