"n54 & s38" (straight6)
10/17/2014 at 16:42 • Filed to: E34, M5, E34 M5, S38 BMW M
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"n54 & s38" (straight6)
10/17/2014 at 16:42 • Filed to: E34, M5, E34 M5, S38 BMW M | 8
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Just been driving the M5 around today. It's hard to imagine BMW ever putting a motor like this in one of their M cars now. Modern M turbo engines have tons of torque at the bottom of the rev range and are smooth and refined. Tons of usable power across the RPM range.
The S38 is none of those things. This obvious from just starting it. If its cold, you won't start it just by turning the key. It'll just click and die. You need to give it some throttle as you crank it, almost like an old carbureted engine. The six cylinders pretty much explode to life with a ton of mechanical noise. The damn thing idles at 1000 RPMs which is apparently normal for these engines. Sounds like a Camaro bracket racer with a lumpy cam, not a luxury four door sedan.
Once you set off you'll notice that while there's reasonable power at lower speeds, it lacks the grunt of modern turbo engines like the N54 in my 335. It's kind of tame up to about 3500 when it suddenly seems to gain a little urgency. I don't really like to rev past 3500 until the oil has warmed up.
At about 4000 the motor takes a deep breath and finally seems to be awakening. At about 5500, a metallic buzzing noise fills the cabin. The car is picking up serious speed now, emphasized by the wide rev band and the tall gearing (3rd is good for up to about 140 kms/hr).
My car has the Turner Motorsports chip which raises the rev limiter. I'm not sure what redline is but it's definitely higher than what's on the tach (7200). Even at 6800 RPMs, the car seems to gain another burst of speed and pull even harder to the limiter.
And then it's time to slow and stop for the red light ahead. As it turns green, you notice that the minivan beside you is dusting you off the line. Until the revs start picking up again.
It's hard to imagine BMW, Audi or any other manufacturer dropping something like this into a modern, pricey luxury car. The torque of modern turbo engines is addictive and arguably way better for daily driving. Plus the S38 swills back fuel like a sailor on shore leave drinks rum.
Still, it makes the car feel pretty damn racy. The way the revs rise and fall, the rush to redline, the throttle response from those six individual throttle bodies.
I need to put up some audio clips of this thing at high RPMs. Sounds crazy. It's kind of the inverse of the N54 or the new Turbo M cars. It really makes you stir the gearbox and work for your speed. In my 335, I can pretty much pick any gear at low speeds and the torque does the rest. Gear selection is far less critical.
Just some random musings while I wait to renew my insurance.
HammerheadFistpunch
> n54 & s38
10/17/2014 at 16:48 |
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Reasons why M cars have lost their way #345
Seriously though, it has to be about more than the numbers. It just has to. cmon bmw, you should know this.
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n54 & s38
> HammerheadFistpunch
10/17/2014 at 16:51 |
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the massive torque is pretty awesome as well. I drove a new M3 a month ago and it was pretty fantastic. It's just VERY different from what BMW M cars used to be like. The turbo engines definitely have some benefits, chief of which is fuel economy. This thing is probably worse on gas than most new full sized pickup trucks.
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HammerheadFistpunch
> n54 & s38
10/17/2014 at 16:56 |
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no I hear you. its better...but worse. If bmw doesn't have at least one car in their range that is rough and raw enough to turn off people who buy M because its the top of the line range...then what is BMW for?
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n54 & s38
> HammerheadFistpunch
10/17/2014 at 17:08 |
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yeah agreed. And I think that's the perception is that the M car engines aren't as special as they used to be: they're not hand built, high revving motors. People tend to think of them as the 335i engine with the boost turned up, not that that's an accurate assessment
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HammerheadFistpunch
> n54 & s38
10/17/2014 at 17:10 |
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its not accurate you are right, but only a German engineer would care if its accurate or not. Its how it makes you feel, and the new M engines....meh. its a large amount of Meh, but its still meh.
RallyWrench
> n54 & s38
10/17/2014 at 18:33 |
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Yes. The sound & building power as the engine really comes on the cams is what I miss most about my old E28. The E34's revised airbox makes an even better howl. A customer has an M635csi that we did the engine for, and with his custom exhaust it's just amazing. I've got to get a clip of that one to share.
BTW, I may be picking up an E34 M5 for cheap. A little beat up, and the head needs to come off, but it runs. We shall see.
Jonathan Harper
> n54 & s38
10/17/2014 at 18:55 |
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Maybe tame sounding, but the performance is anything but tame. More low-end torque = more tire shredding.
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n54 & s38
> RallyWrench
10/17/2014 at 19:24 |
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I hear you. I have a Racing Dynamics carbon fiber intake on mine and a straight X-pipe (with no cats). It howls as the revs build.
That's awesome about the E34. Be sure to share some details on it if you end up picking it up.
I love this car. Had two guys stop me to remark about it in the last two days.
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n54 & s38
> Jonathan Harper
10/17/2014 at 19:28 |
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agreed. I mean in the sense that its not a barely refined, cammy race engine like the S38.
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n54 & s38
> Jonathan Harper
10/17/2014 at 19:29 |
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I do love the torque and creamy smoothness of my N54