2011 BMW 335is - Are the Changes Enough?

BMW recently announced the 2011 model 335is twin turbo will have power, transmission and cooling enhancements vs. the prior year 335i. I question if these enhancements will enough to sway the enthusiast to purchase the standard 335i with the single turbo. Not giving the car a limited slip differential remains a huge disservice.

The 335is will have 320 horsepower with its revised twin-turbo 6-cylinder engine, up from 300hp. Also 7 seconds of overboost will be available raising the torque figure from 332ft lbs to 370ft lbs. This isn't really an improvement over existing aftermarket tuners such as Dinan (which offers a warranty) and Burger Motorsports Juice Box series.

Potentially bigger news is the Non-S model now has a single turbo instead of the "twins". Likely significantly larger in size than the twins in the "S" and last year's model, this will mean greater potential for adding power in the aftermarket.

The 6-speed automatic is replaced by the 7-speed dual clutch transmission which probably won't mean turbo boost levels will fall off since the Nissan GT-R and Porsche 911 Twin Turbo manage. But if the gear ratios are the same from the M3, the 6-speed manual has been shown to be the quicker car once the speeds are above 120mph. Will the DCT transmission withstand higher-than-stock power levels?

An upgraded radiator and motor mounts are included as well for track duty. What is really questionable is the decision to leave out a limited slip differential. Making a car more track ready with more power, a fast shifting automated transmission and cooling enhancements without adding an LSD is like making it a better burnout competition entry. Check out this article on the new McLaren MP4-12C supercar not having an LSD and the problems this poses.

While improving the breed, BMW potentially makes the base 335i the enthusiast's choice with a single turbo system and the "S" model still doesn't have a key performance element. Still world class, will the 335is meet sales expectations vs. the non "S"? Will the automatic transmission, now no longer available, be the desired transmission at the 75,000 mile mark? And will the need for an LSD make itself even more apparent?
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Have a question about cars you would like answered? Want to know about performance, racing, modifying, shopping, makes, models, events, etc? Ask me here: AskRobAboutCars@gmail.com and I'll do my best to answer your question and publish it here on Examiner.com!
BMW 335i Coupe

Will the single turbo 335i be the model to choose vs. the 335is? Is the lack of a limited slip becoming a bigger detriment?
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Porsche Panamera - why is it so quick?

Three letters in the March 2010 Car & Driver question the 3.3 second 0-60mph time of the Porsche Panamera Turbo that was tested the December 2009 issue. That makes it potentially quicker than many cars with much more power and less weight including the McLaren F1, Ferrari Enzo and Porsche's own GT-2. Weighing 4409lbs with 500hp, on paper it shouldn't beat any of them. There are three reasons it's so quick.

All-wheel drive, the dual clutch transmission and gearing that is probably more aggressive than any performance car in history make it accelerate quicker than much more powerful and lighter cars. The Panamera Twin Turbo is in 3rd THIRD! gear by the time it hits 60mph. Many extreme cars like the Bugatti Veyron, Chevrolet Corvette ZR-1 and others go over 60mph in 1st gear. Check out the Bugatti Veyron road test with the top 10 quickest cars they have tested.

The all-wheel drive ensures no slippage unlike the others where power delivery has to be managed with available traction. I eluded to this challenge in my 60-130mph article. A 1.2 second 0-30mph time is extraordinary, on par with the AWD Veyron and GT-R. I would guess this translates to a 1.6 second 60ft at the dragstrip given the previously mentioned gearing.

The horsepower deficit is apparent in the trap speed in the 119mph range vs. the 125-130mph or higher times of the other cars. With excellent track preparation, technique and usually drag radial tires, a few have been able to match the launch of the Panamera and therefore run a much quicker quarter mile. Modern-day street car drag racing legends such as "Ranger" and "Furman" are examples of Corvette and Viper drivers who have done this.

Finally the 7-speed dual-clutch transmission means nearly uninterrupted power delivery. As one clutch disengages, the next engages with a speed and consistency that can't be humanly repeated. With 5 non-overdrive gears, it's fierce.

There is no other-worldly driving skill excuse or strongly suspect fudging of power levels in any gear with the Porsche Panamera Twin Turbo, unlike the Nissan GT-R. The car doesn't defy physics but it's transmission sure tries to make it seem so. Just wait when the new 911 Twin Turbo is tested.

The 2010 Porsche 911 Twin Turbo assuming the gearing is the same as the Panamera is that it will accelerate even quicker since it's about 800lbs lighter than the Panamera. So besides still not matching the GT-R's "factory" 'Ring time, it still won't accelerate to 130mph 1.6 seconds quicker than production models nor accelerate from 120 to 130mph in .9 seconds either in production form.

A great link for various automotive calculators courtesy of Wallace Racing. There are several for 60ft translations and various speed indicators.
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Have a question about cars you would like answered? Want to know about performance, racing, modifying, shopping, makes, models, events, etc? Ask me here: AskRobAboutCars@gmail.com and I'll do my best to answer your question and publish it here on Examiner.com!

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Automotive magazines need help

A letter sent to Car & Driver magazine in response to the 1/09 issue.

Regarding the "Dirty Speed" comparison test, page 41 for the Cobalt SS.

The no-lift shift feature is a factory feature that should be included when conducting your performance tests. If it's engineered into the car, then it should be included. Not using a factory performance feature is a disservice to your readers, the manufacturer and a potential buyer reviewing the test results. You don't lift off the throttle when testing a DCT (dual-clutch transmission) equipped car, correct? This is absolutely along the same line of reasoning.

If you really want to provide an additional data point for your readers (and please, not online), you would reveal the difference in the test results between a lift-off of the throttle and the no-lift feature.

Additional Data Required:

C&D should make it a policy to publish the Road Test Review 6 times a year, perhaps on even-numbered months. Also, an online summary of all test results should be made available. There is a fast amount of information archived in hardcopy form, but it really should be made available online. C&D has always had great test procedures, it's time to make efforts from decades to present available.

Also, and I've requested this before, regarding the skidpad tests, please publish a table of the lateral acceleration measurement and how it translates to mph traveled. Also, what speed differential do you see when you sample the 1/4 mile speed of a car vs. the measured trap speed at a dragstrip (terminal velocity vs. a timed calculation of the last 60ft or so). These would be a great ways for readers to relate to the speed differential of various cars. These tables can be included in your Road Test Review listings.

Update 5/16/09: I thought of something else recently. Aerodynamics and the effect on mileage and performance. A value called a .cd or coefficient of drag is commonly given when describing the aerodynamic design of a car. A second and often ignored value is the frontal area. In other words, and I'm simplifying fluid dynamics hear, how much and how tall is the mass of the car going into the wind? What am I asking for? Supply a reference table showing the .cd x frontal area and how much of an effect it has on performance at various speeds. One idea is to show a table that displays how much horsepower is needed to match superior aerodynamics. And conversely, the mileage benefit.

If a 436hp Corvette and a 426hp Camaro SS is traveling at 150mph, how much do the aerodynamics effect each one? If a Prius could obtain 100mph (can it?) as well as the Tesla (it can), how much hp is needed for the Prius to maintain that speed vs. the Tesla in terms of the aerodynamic design of the car? It's the age of information, time to show it all.

Appealing to a wider audience:

More information is needed, perhaps a monthly guide, regarding dragstrip performance. For instance, you measure the 0-30mph time, but what about translating that to the 60ft time? How does tire inflation play a part in street tires? What does a Cold Air Induction (CAI) kit do for performance from both a standing launch and from a roll? Keep in mind this is a very common item offered by both OEMs AND the aftermarket. How about lowering kits in relation to skidpad and slalom performance? Handheld tuners vs. stock and various octanes used.

Although Car & Driver has been very good about reporting on racing for amateurs, mentioning the SCCA and NASA, the amount of participants in a 1 week time period in any given region at the dragstrip(s) far exceeds that of the SCCA and NASA in that given region. And these are mostly street-going, licensed cars. For example, Infineon Raceway (Sears Point), closes off the entrants at 300 cars for Wednesday night drags. Of the 14 or so staging lanes, at least 10 are for street cars. And many times for owners with the strip-only cars - they have street cars they take to the track for grins once in a while as well. There are 3 dragstrips within 100 miles of the Chicago area, I would be curious how many entrants they have over 7 days vs. the regional track events. Finally, most of the debates on the internet are regarding a cars straight-line performance as well.

I suggest polling the dragstrips to find out how many participants there are during the 7 day week. Additionally, polling the tire companies about their drag radial sales would be very interesting as well. This would lead to an interesting test comparing the 60fts, ETs and trap speeds