7/27/2011

07-27-11 - Car News

The continuing series in which I pick up the slack for the fucking pathetically awful car journalists of the world, who cannot even get the basic facts that are in the fucking press release right, much less actually tell you anything subtle or revelatory about cars.

08+ Subaru WRX's have open front & rear diffs and a viscous center diff. They use an "e-diff" (aka fucking horrible computer-controlled braking and throttle cuts) to limit side-to-side wheelspin. So basically the famous Subaru "4wd" is no 4wd at all. A viscious center diff + open front and rear diffs is a real shit system, it's almost useless and definitely not fun to drive, for example it doesn't allow throttle steering ; pre-08 WRX's had proper LSD's for front & rear at least optional. It does seem you can swap out the front & rear diffs to Quaifes reasonably cheaply, though this is not a common mod (most of the modders, as always, are posers who don't actually want a good car). This seems to be part of the general de-rallification and cheapening of the WRX post 08.

So in summary, modern Subarus (a brand whose whole image is having good AWD) have terrible AWD systems. (the STI is still okay).

I like the way the BMW 1M is basically mechanically unstable - without traction control it's probably too oversteer biased to sell in the modern world - but you can still use it safely because of the electronic protection. IMO that's a nice way to build a modern sports car (which have to be sold understeer biased generally), as long as you can turn the electronics all the way off to have fun. I'm not delighted by the reports that it still has the 135 numb steering, the electronic variable power steering, the ECU mapped throttle, all that nonsense.

But I'm also disenchanted of stiff cars like the 1M or Cayman R. My car is already way too stiff, and those are much stiffer. Making a car handle well by making it stiff is just not interesting.

The next Porsche 911 (2012 991) will finally have electric power steering, which is a bit of a bummer. Almost all modern cars do, but it generally feels like ass. The BMW M cars have a hybrid system with an electric pump still running a hydraulic system (BMW non-M's are fully electric). The reason for all this is that apparently the power steering pump is a massive parasitic drain, almost 5% of the engine's power, which is bad for acceleration as well as fuel economy. But hydraulic power steering just feels good! I've never driven a car with direct mechanical rack steering, I bet that's wonderful.

I think the new Z06 vette is probably the greatest performance bargain right now; they've moved a lot of the ZR1 goodies down the line. Still, the real bargain is probably in buying a base vette (or a "grand sport") and upgrading a few parts yourself; change the brakes, change the suspension, install a dry sump, and you're good to go, and it's much cheaper. It's just staggeringly good, there's really nothing even close for the price, or really for any price! Huge power, RWD, good balance, front mid-engine, light weight (just over 3100). The base Vette is an LS3, Z06 (C6 not C5) is an LS7, ZR1 is an LS9. Newer "Grand Sport" LS3's and Z06/ZR1 have a dry sump. The older cars didn't have a dry sump and it was a frequent cause of engine explosion :

Let me ask another way, who's LS3 HASNT blown up on the track - Corvette Forum
Let me ask another way, who's LS3 HASNT blown up on the track - Page 7 - Corvette Forum
2009 Z06 dry sump vs ARE dry sump - LS1TECH

(this is not unusual, most factory sports cars have some kind of problem that will make them blow up under track use (non-GT3 Porsches for example, and Caymans in particular)) (apparently even the new vettes cars with factory dry sump can blow up if driven hard enough with slicks, but if you're going into real racing, you didn't expect the factory oiling system to handle it, did you?)

A lot of the doofy car press who like to just repeat cliches without thinking about it like to complain about shit like the "leaf springs" in the vette. If you really don't like them, you can swap the suspension for a few grand, and the car is still cheap as hell. Most of those fancy European suspensions are just Bilstein or KW or whatever off-the-shelf kits, so you can easily have the same. Other doofs like to complain about the "push rod block" with its supposedly ancient technology, or that it takes "umpteen liters of engine" to make power that Europeans make in many fewer litres. That's silly. Who cares how many litres of displacement an engine has? (it's funny that the same doofies will turn around and brag about the giant 6.3L engine in their Merc ; wait, is displacement good or bad? I forget? Oh, actually it's irrelevant and you're an inconsistent moron). The thing that's important is how much does the engine weigh, and how big is it, and in fact, those big 7 L vette engines are physically quite small and light compared to even 4 L european engines.

(part of the reason most euro engines are small is that they tax by displacement, which is retarded; taxing by emissions makes sense, but attaching rules to things that aren't the final metric just creates artificial incentives and stifles creative solutions)

The reason vette engines can be so small and light is because of the magic of pushrods. A modern DOHC euro engine has 4 cam shafts - two for each cylinder bank in a V - with chains running from the drive shaft to the cams to keep timing. The cams are mounted on the tops of the cylinder banks, and this all makes the engine quite large, heavy, and complex. (timing chain guide or tension problems are a common issue with all modern euro engines). In contrast, a push rod motor only has one cam shaft that is directly mounted right next to the drive shaft, between the V's of the cylinder banks. This makes it very compact, and eliminates the chain timing problems.

DOHC engines are complex and have delicate long chains, and are volumetrically much larger than their displacement :

Vette LS engines are very compact, with a low center of mass :

See also :
Pushrod Engine - YouTube
3D animation of a fuel injected V8 - YouTube
Nice comparison diagrams

The disadvantage of pushrods is that you can't run 4 valves per cylinder and you can't run complicated adaptive valve timing, but who cares? The drawback is that it's hard to make them low emission / high mileage and also big power ; certainly the car nuts who intentionally ruin their emission systems shouldn't care. Fetishization of the number of valves or whatever is retarded; the only thing that matters is power to weight. If the power to weight is good, it's a good engine. And the GM LS engine has excellent power to weight, is very cheap to make and maintain, has a wide power band, and is durable if oiled properly.

If there's a valid complaint about the LS engines (other than environmental), it's that flat power curves just somehow don't feel as good as peaky ones. It's satisfying to have to wring out an engine to the top of its rev range; an engine that just burbles and takes off at any speed is just too easy. This is one of those cases where I feel like only the Japanese really get it right with cars like the S2000, having to make lots of shifts and get the revs screaming is part of the visceral, tacile, involved fun of a sports car.

It's the very compact geometry of the LS engine that makes it possible to swap into old cars that had much smaller displacement engines originally (Porsche 914's, Nissan 240's, Mazda RX7's, etc.). A big DOHC V8 doesn't fit in those cars but the pushrod LS does. (that's not the only reason for its popularity of course - it's very cheap, powerful, easy to work on, etc.).

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old rants