Category Car Chat

One example of why you need the in-vehicle emergency communication system

Last year, a SoCal man was missing for almost three weeks. Despite his relatives calling for the police to search for him, the man was not found until 15 days later, police notified them the missing man’s body and the wreck of his car was found in the bottom of a steep embankment near the city of Los Banos.

It was a woman on a tour bus that traveling westbound on Highway 152 near the San Luis Reservoir, spotted a vehicle 200 feet down an embankment, then she informed the police who finally found the missing man.

When police finally brought the wrecked car up from the enbankment, the driver had been dead for many days and his body was still tied on the seat.


Had his car h...

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Will BMW make a 720i sedan?

The rumor started earlier this year, when one day BMW official website suddenly posted a page of the 720i model, then withdrawed that webpage shortly after.

Although no one inside BMW ever commented, denied or confirmed the existence of 720i, I still consider this model actually make a business case, not in US or north America, but in Europe and Asia, especially the Chinese market.

Perhaps still not widely known for US customers, BMW did create some very special version of their 3 and 5 series in the Chinese market: they have a long wheel base versions of the 3/5 sedans there.

For example as shown below, a 2014 model year 520Li (“Prestige” trim in the following photos), s...

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Luxury sedan AWD system review – part 2

In part 1, we reviewed some basic knowledge of AWD system, BMW xDrive and Mercedes-Benz 4Matic system. Now we continue our discussion on Lexus and Audi.

Lexus: the IS250/350 AWD and GS350 AWD are using a planetary-gear center differential, plus a wet-type multi-disc clutch control to act as slip control. This is a very advanced and complex design. Because the multi-disc clutch can be 100% locked, it means Lexus’ AWD can handle the case that even front or rear wheels completely lose traction, than the rest side of the two wheels still have full power. The disadvantage of this design is it is complicated and the parts take space...

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Luxury sedan AWD system review – part 1

For US market luxury brands, most of their upscale sedans offer the AWD option nowadays. However, not all AWD systems are created equal. Before our review, let’s look at what goes into a luxury sedan AWD system.

Differential: this is a device to let both sides of output rotate at a different speed, and still obtain torque. For example in your front-wheel-drive car, your front wheels are connected with a differential.

Open differential: when one side of output loses traction, there will be no torque available at another side at all...

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Insight: the Mercedes-Benz 9G-Tronic nine speed transmission

Last year, Mercedes-Benz debuted its 9 speed transmission (called 9G-Tronic) in its European market E class sedan.

Although with the same aluminum made torque converter bell housing, compared to the current 7G-Tronic, this 9G-Tronic transmission changes to use magnesium alloy to construct its main casing, which is lighter and retains the same strength. The transmission oil pan is made with plastic though.

However, there is no dramatic difference of the mechanical shifting parts between the 9G and 7G transmission. Both of them have 4 planetary gear sets and 6 shifting elements (3 multi-disc clutches and 3 multi-disc brakes)...

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