Ask Rob About Cars 12-20-09

Question: What is the cost estimate on changing a ’72 Impala Custom Coupe(Hard top) into a convertible top?
-T.D. Wise

Answer: Thank you for your question! A convertible top conversion is a huge undertaking but companies have been doing it successfully for years. Figure about $15,000 to $20,000 for a professional job.

Additional structural bracing must be added as well so weight will be added. For vehicles designed with a convertible model in mind, the weight difference is negligible. A good example is the Chevrolet Corvette. For others such as the BMW 135i, the convertible is over 300lbs heavier. An aftermarket conversion means you'll feel the chassis flex over bumps and handling will be compromised. This isn't uncommon from factory convertibles as well. Other drawbacks are the value will probably be negatively affected and safety is compromised.

The process is time consuming but there are a couple of companies that have been doing it quite successfully for years with impressive results. Newport Convertible Engineering is one of them. Another is a regular SEMA participant called Drop Top Customs by Convertible Builders LLC.

Good luck and thank you for your question.
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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!

Drag racing tips for your street car

Many amateur drag racers already know the tricks, tips and techniques to help their car go faster and more quickly at the dragstrip. However, there could be a few you're not aware of. Additionally, there is one potential major misconception and a technique for automatic and perhaps manual transmission cars that could be key as well. Listed are some obvious old-school and some not so obvious tips due to rampant electronics in modern cars.

Weight reduction - easily established by racing with a low tank of fuel. Modern fuel injected cars won't run lean with less fuel - don't worry. Remove the spare tire, etc. Removing rear seats (if equipped) is not uncommon. However, a totally stripped interior, if a daily driver or even weekend car, just really looks cheap and junky unless the interior is purpose built and finished for racing. Edit: Extra weight in the rear may allow for a lower 60-foot time and hence lower ET while making only a minor difference in trap speed. Experimentation is the key. 

Run cooler - icing the intake manifold. Cold air is denser air which translates to more horsepower. A hot engine will heat incoming air. There isn't much that can be done with the ambient air temperature, but running extra hot doesn't help. Without going deeply into modifications, a lower temperature thermostat is used for this reason. Push your car if feasible instead of the stop-n-go in the staging lanes. There are handheld tuning tools and even fusebox modifications that allow the cooling fans to start and run at lower than factory-set temperatures. Being the only guy pushing your nearly 2-ton car gets old real fast.

Something you may not know regarding running cooler. Some cars actually make more horsepower due to fuel programming when coolant temperatures are below 180 degrees vs. the normal operating temperatures of 200 degrees or higher. The balance of engine temperature, fuel economy and emissions is altered when seeking maximum power at wide open throttle.

Tires - lower tire pressure may very well be worse for two reasons. Losing traction from lack of grip means sitting and spinning while your opponent is accelerating. Also, if there is an increase in the rolling resistance of the tires, that is a parasitic drag. Every little bit counts when counting in tenths of a second or miles per hour.

When equipped with high performance low-profile tires which have stiff sidewalls, a common misconception is that if you lower the tire pressure significantly, you'll have more traction. This is because racing slicks use lower tire pressure to soften the sidewalls and increase the size of the contact patch. If the modern low-profile tires have structurally stiff sidewalls, less air will mean less contact patch in the center of the tire while the sidewalls maintain their stiffness. What is very important here is knowing how your tires respond to air pressure. Unless there is an established technique that is getting 60ft times below 2.0 seconds, try starting with pressure in the high 30s and work your way down. You may find a range that your car performs the best is far higher than those that are running 22psi in their low-profile 35 or 45 series high performance tires.

One last point regarding tires. The smoky burnouts look and sound fun, but do it for too long and a street tire can become slippery rather than sticky. A general rule used for non-drag radial street tires is do it just long enough to see smoke, then stop.

Fold your mirrors inward. Minor I know, it sounds silly, but trapping at 109.9mph vs. 110 can be frustrating. The competitors at the Bonneville Salt Flats who use duct tape to seal body gaps wouldn't laugh. Do you think that's allowed at the Texas Mile?

If equipped with adaptive shock absorbers, the "comfort" mode may allow for more weight transfer to the rear, facilitating better traction and a better launch. Conversely, "comfort" mode may also trigger a slower shift from the transmission with more slippage and even at a lower rpm. Who the heck drag races a car with a "comfort mode" anyway? Well, Mercedes Benz E55 owners with smaller-than-stock supercharger pulleys have been known to run 10-second quarter mile times. Crazy but it really pays to know how the various electronics influence the behavior of the vehicle.

Use a toilet brush to scrape debris off the tires. Buy a new one at the grocery store (please) and before you get in the staging lanes, a quick scrub will remove some of the larger debris. Does it work? Well I'd say it doesn't hurt. Pebbles in the tread can cause voids in the contact patch.

Related to the toilet brush, VHT track bite traction compound helps immensely for traction off the line. Spray after taking off the debris and preferably by crew member after doing a brief burnout on your street tires. Granted, if track prep is fresh, this probably isn't necessary. At some tracks, it's essential for street tire cars. I wouldn't be surprised if some of the street tire equipped cars that run fantastic times do this during track rental days.

Adaptive transmissions and electronics can be the most confusing and impactful of the various necessary steps to run the best times. It's important understand your car and how it reacts. Read up on the forums from other owners for their techniques. Others may do certain routines not even realizing why they seem to work. I'll list examples of how some cars respond to various inputs.

A slow diagnostic transmission shift may occur after start-up. Not noticed during daily driving, but at full-throttle, it could be painfully apparent, hurting trap speeds. One resolution I'm aware of is to drive over 20mph before lining up at the lights so the initial 2nd to 3rd gear shift is done. Even a single or dual clutch automated manual might do this. At some dragstrips like Infineon Raceway at Sears Point, the staging lanes are so close to the "christmas tree" this occurs.

Manually shifting the automatic transmission, while not as consistent, may make for firmer shifts. On the other hand, another car may shift better if simply left in "Drive". Further complicating things nowadays some mechanical tachometers actually can't keep up with the engine speed which means easily "banging" off the rev limiter when manually shifting while trying to judge the optimum shift rpm. Hitting the rev limiter means blowing your run and maybe losing. Lexus actually has a digitally simulated tachometer for this very reason in the new LF-A. Remember, this can apply to automatics, dual clutch and single clutch automated manual transmissions.

Lastly, when you sometimes pull the fuse to the transmission, it resets the "adaptives". What this means is some types transmissions will "learn" how you were driving previously and mimic that. For example, if you're idling at the stoplight waiting to enter the track, slowly driving to tech inspection and finally in the pits, your transmission could possibly store this and repeat this in the form of sluggish yet smooth shifts. Pulling the fuse will reset it to the default setting and the wide-open throttle will signal faster and firmer shifts. This can really make for a literal checklist.

Modern cars with all the electronics that make our lives easier and safer also are a pain in the butt to extract the maximum performance they are capable of. Keep in mind the basics - keep it cool, learn how your tires react to air pressure changes and finally learn how the electronic nannies hurt or help your car.
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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!

Tesla updates and changes for 2010: T1 vs. T2

Test driving the 2010 Roadster Sport was an eye opening experience. Keeping in mind the 2009 model year was skipped without a one-year break, the improvements are significant. Here are some changes from the 2008 (T1) to the 2010 (T2).

The interior has been upgraded and features a push button "drive" selector vs. a lever. The video display screen was moved to the central dash area. It gives various information such as estimated range, power regenerated, number of barrels of oil saved, etc.

Enhanced battery cooling is also part of more powerful and quicker cabin cooling (air conditioning) as well as heating and overall ventilation.

Toggling between performance and "max range" is done by turning the key, even with driving. Needless to say, during my test drive I kept in the Performance mode notated by a tiny "P" in the upper right corner of the display screen.

A variety of sound-deadening techniques were utilized to reduce noise, vibration and harshness (NVH). One of the interesting methods was the use of pellets in a chassis side rail that expand by 5,000 percent during the adhesive heat cycling to eliminate rattles. Adhesives are used throughout virtually all automobiles. If you strip the interior and sound deadening material, any car is going to have some interesting squeaks and rattles. Tesla is obviously striving for improvements for mainstream appeal rather than kit-car refinement.

The Roadster Sport 215 kilowatt motor produces 288hp and 295 ft lbs of torque and is most noticeable up to 5,100rpm. As you can see from this graph from Motorcyclist magazine , power will fall off at higher speeds. I predict one of the next major improvements will be a multi-speed transmission that not only will make for great acceleration, but potentially a longer range during highway usage. You may remember the first generation T1 had a two speed transmission put problems meant abandoning it for a single-speed fixed gear. You can see Tesla's technical specs here.

The options available seem to be areas of profit as opposed to some seeming to be package deals. Quite clever - the vast majority of buyers can afford it and I would guess they contribute significantly to the margin of revenue. Remember, low volume doesn't make for discount prices. The Executive Leather Interior is $,6000. Alternately the Premium Carbon Fiber and Leather Interior is $9,000. Keep in mind this is a two-seater. A body color hardtop is $3,200 or $5,000 for carbon fiber. Exterior carbon fiber treatment is $9,000. The most common question - how much is a replacement battery? It's $12,000. A replacement engine for a high-end car can be far more costly.

While it doesn't appeal to everyone, Tesla has established credibility, viability and continue to evolve their daily driver. Their initial product, a high performance car that never needs gasoline, a high price-point (including the options) for profitability is a proven platform for further development before going mainstream. Will the T3 feature a multi-speed transmission? Perhaps it will have artificial intelligence...

Check out my test drive of the 2010 Roadster Sport here.
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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!

Tesla Roadster Sport driving impression

If you like your head getting snapped back with turbine-like smoothness while removing your dependency on fossil fuels, the new Tesla Roadster Sport is your sports car. This higher horsepower Sport version of the Tesla Roadster, new for 2010, is even quicker. Skipping the '09 model year, the 2010 Roadster model has multiple improvements vs. the first generation including the Sport model. I'll refer to the '08 and '10 as T1 and T2, pun intended.

The Roadster Sport is a $19,500 option over the standard $109,000 Roadster. Adding 40hp to a total of 288hp, the 2,690lb car is very quick. Tesla reports a 0-60mph time of 3.7 seconds which is entirely believable. Considering the power delivery from a dead stop and rear-biased weight distribution, owners can expect this with regularity as traction is excellent.

The "Very Orange" model I drove also had the $9,000 Clear Carbon Fiber Accent Group which made for a very sporty appearance. This paint would be perfectly at home on a Lamborghini. The carbon fiber on the rear spoiler, hood vent and roof cross piece were nice accents complimenting the black finished forged alloy wheels.

The drive selection lever from the T1 is has been replaced with lighted buttons; park, reverse, neutral, and drive. At low speed the first thing noticed is the silent and smooth drive-off, much like a golf-cart. Turning the steering wheel at low speed and you immediately notice the unassisted effort. A larger steering wheel would probably work if the extra leverage could be felt.

Eerily quiet at first, punch the accelerator (no longer the gas pedal!) the response is immediate. This is truly a point-and-shoot type of car. There is no build-up of acceleration, no downshifting, no lag, no hesitation, nothing. It's like always being in 1st gear. The 3.7 second 0-60mph is so easy and even turning off the traction control, I couldn't get the aggressive Yokohama A048s to break loose on dry pavement. Believe me, I tried. A brake torque doesn't do anything either.

Like the Lotus, the steering wheel wiggles over bumps but smooths out at speed unlike my impression of the Lotus. However, around triple digits it loosens up again. But this car isn't about high speed cruising. The motor whine is noticeable and a little loud but what I found more disturbing was the excessive wind noise around the A-pillars and removable soft-top. I'm told the hardtop reduces the noise noticeably.

Having seen a Tesla T1 crack off a 12.9 1/4 mile run, and multiple tests put the car in the high 12second range at 103-105mph, the T2 Sport is quicker but probably won't pick up any mph. I say this because acceleration noticeably falls off after 75mph due to the nature of the engine and powerband. An owner has ran a 12.643 ET, but at only 102.89mph. 

To put it in perspective, a Ford "Terminator" Cobra with bolt-on modifications and stock pulley caught up from a 2 car length deficit at low speed and streamrolled past me once it hit 3rd gear. This car rocks up to legal speeds though. To be honest, that is all anyone really needs on public roads.

The ride is very compliant and quite comfortable. The body roll is minimal and despite the weight distribution, this one was tuned to predictable understeer. The Sport model includes 10 level shock adjustments, 3 position anti-roll bars and a remote shock fluid reservoir. It has very high cornering limits, the non-Sport model recording .90 and .92 on the skidpad so despite nice seats, better side bolstering is needed.

Braking is quite good and I would be curious how the Sport model compares in an instrumented test with it's softer, more aggressive tires. The brake lights activate automatically because the car will decelerate at a rate to activate energy regeneration when off the throttle. Apply the brake pedal for a quicker stop or modulate the accelerator. Again, like driving a car that is permanently in a lower gear.

Getting in, despite a .5" narrower sill, cover, now carbon fiber, is still quite difficult for a 6-footer. Literally climbing out is hardly easier. A side-by-side comparison would be needed with the Lotus Elise, but I seem to remember it being a little easier. Remember, the Tesla has major structural revisions to cope with the battery weight. You can read my review of the Lotus Elise here, but keep in mind, it's based on a very small car. My left calf rested against a support structure on the left side and the lower center console on the right.

When my Pretty Navigator, who is used to large sedans, first saw the car she asked, "Where is the rest of it?" And then during the walk-around, "Oh Honey, it's so cute!". But that isn't so bad because when you really like your passenger, sitting shoulder and hands on thighs is kinda nice.

The view for the ventilation controls were partially obstructed by the dashboard ledge under the radio. One advantage though is the immediate response of the heater - you don't have to wait for engine coolant to warm up since an electric heater starts producing heat immediately.

Having driven about 60 miles with a lot of full-throttle bursts and 75mph cruising, despite the limitations of a very small car design with weight concessions such as soundproofing and wind noise, Tesla has done an admirable job modifying an existing platform and developing a powertrain that is undoubtedly functional, fun and reliable for everyday transportation. As of the writing of this article, Tesla Co-founder Elon Musk's '08 Roadster has over 13,000 miles on it.

Keeping mind no gas station fill-ups, no oil changes, no engine warm-up, minimal maintenance (no spark plugs, belts, air filter, pcv valve, etc. etc), electric vehicles are here to stay. This one is groundbreaking and may be the most fun EV for a long time.

Stay tuned for a future article on Tesla and the improvements made for the 2010 model year.

Instrumented tests with spec sheets: Car & Driver and Road & Track

Sound Off! Lexus LF-A vs. Mustang GT

The super high-tech, incredibly fast and expensive ($375,000) Lexus LF-A actually has something in common with the $30,000 '10 Ford Mustang GT. Believe me, they don't share any common components and they are not even remotely related in any way. But they do share one common trait that is rather unique. They both have methods of directly transmitting the sound of the engine into the passenger compartment.

The new 560hp Lexus LF-A, with it's 9000rpm V-10 engine has sound tubes that transmit the engine sounds into two locations in the passenger compartment. As reported in the December '09 Road & Track, the sound comes in above and below the dashboard. The 2010 Mustang GT also has a "sound induction tube" as reported in Car & Driver, February 2009.

To be perfectly honest, it's an ugly addition to the engine compartment on the Mustang. Looking at the photo here, it unfortunately looks like an afterthought and creates clutter. This engine compartment looks better.

Is this a sign of performance cars being so refined that sound effects are needed to engage the driver? As if the car is so quiet that the enthusiast driver receives so little audio feedback the factory deems it necessary to "pipe it in". What happens when the owner installs a less restrictive "cold air intake"? That is a common upgrade that not only can increase horsepower, but also the audible sound level of the engine as well. Will these "CAI's" still allow for the "sound injection" as well?

Is it another foreshadowing of upcoming sound regulation? Electric cars are naturally very silent and so are hybrids when under full electric power. Is there anticipation of internal combustion engines having even stricter sound requirements? That doesn't bode well for diesels, does it?

A question I always ask is how much R&D and resulting cost did it take? And for these cars, was it really necessary? Is there an after-thought to discourage modifications to the cars?

If that much R&D goes into the sound tube design, shouldn't it be driver selectable? Many want the speed, but what about their music? Gotta have the tunes! Others may want to impress those outside of the car. with the sound. If there are passengers, they are already impressed, right? Hopefully by both you and your car.

Unless exterior sound regulations get so outrageous, I predict the sound tube fad may become an adjustable "feature" in high-end cars and simply fade away in the rest. Just like the digital dashboard. Which, by the way, the Lexus LF-A also has but luckily in the shape of a traditional speedometer and tachometer. The reason? Lexus states the engine revs too fast for an analog gauge to keep up.

So do you want two volume control dials plus the one under your right foot?
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Got 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!

How fast? And is it stock? Bone Stock defined

How quick and is it bone stock? That is the question among fans and owners of various cars with lots of debate about who is faster. Top speed is easily measured by magazines and meaningless in terms of acceleration. Zero to 60mph sounds good but doesn't tell the whole story. The 60-130mph timing is growing in popularity but many don't have the means to measure it. My article about that here. It all comes back the the 1/4 mile drag race.

The trap speed is the real indicator of which car is quicker once rolling and takes out the factor of a bad start (launch). In this age of the internet, claims and scanned timeslips can be seen across the country causing instant rivalries and debates. But the question remains, is it stock or modified? Is it just as it was off the showroom floor or has it been secretly enhanced?

The following examples are trap speeds that push the envelope of believability and all of them have the these factors in common: Great driving, proper vehicle preparation and cold, crisp air for maximum horsepower output. Examples such as: Corvette ZR1: 132mph, Dodge Viper ACR: 130mph, Corvette Z-06: 129mph, Dodge Viper 4th gen: 129mph, 03/04 Ford "Terminator" Cobra: 115mph, SRT-8 Charger/300C: 111mph, 05/06 Pontiac GTO: 110mph, 98-02 Camaro/Trans-Am: 110mph, Dodge Challenger R/T: 108mph and many more. Funny thing in the realm of "who is faster debates" is that in most cases, subtract 1mph from many of those and there are suddenly multiple examples.

A "bone stock" vehicle must be as if it rolled off the showroom floor. There are many ways to "cheat" but no performance modifications are allowed. In another article I'll list some drag racing tips for those looking to maximize the performance from their street car.

The rules of "bone stock" are as follows: The original or similar paper air intake filter must be in place. The stock shifting mechanism cannot be substituted for a short-throw shifter, the tires must not be designed for drag racing (drag radials). The vehicle cannot have weight reduction by removing parts. The spare tire is debatable but that weight difference is easily made up with differences in driver weights so I say it's okay. The exhaust as it came from the showroom floor must remain as well.

When magazines test cars, they may be criticized for not representing the "real world". If you take into consideration they don't do any type of weight reduction, a full tank of gas usuallyy, no powershifting, no "drag prep" techniques, they start to look pretty realistic. Another factor is automated clutch cars (single and dual) and fully automatics (torque converter) will have minimal variance. Finally, taking into account the magazines sometimes have fairly fast times because they do not use a dragstrip where the last 60 feet is used as an average for the trap speed, the results are spot-on for probably 90% of the bell curve. Variance due to condtions alone can be huge. A 50 degree swing in outdoor temperatures can translate to about 5mph.

Really the meaning of "bone stock" is pretty basic and the trap speeds listed are in the extreme minority and a couple are no doubt questionable. Others are verified and it's really a simple rule: The same equipment as when the car rolled off the showroom floor, from the factory, no more, no less.

Design flaw in the new McLaren MP4-12C?

There is a disturbing trend in the automotive world of eliminating the limited slip differential (LSD). Manufacturers are promoting alternatives with fancy names, but none of them do what an LSD can do and this can be an issue. If you're spinning, you're not accelerating. This can be a big, big problem on the street and on the track for reasons I'll explain.

According to Road & Track Magazine, Nov. 2009 issue, the upcoming McLaren MP4-12C doesn't have one! This car has every ingredient to make it one of the greatest sports cars on the road except for the potential penalty of lacking an LSD. This is could be a major compromise from a company that is renowned worldwide for it's engineering expertise and racing pedigree. Multiple championships in Formula 1 and at the worlds fastest production car for 7 years are their best known accomplishments to the public.

The MP4-12C is their first entirely designed in-house street car that will compete head-to-head against the upcoming Ferrari 458 Italia and F430, Porsche GT2, the Lexus LFA and the Lamborghini LP560. Pinnacles in modern sports car design with lightweight materials and horsepower levels in the mid-500 range for extreme performance and race bred technology for the street and for the track. Ferrari in particular emphasizes their E-diff for 32% better longitudinal acceleration vs. the F430 and 1.25 second improvement in lap times at their Fiorano track. Read more about it here. The Porsche is a rear-engine design and the Lamborghini is all-wheel drive, both of which aid traction.

Other greats like various BMWs and Porsches also have this "deficiency" as well, but not their flagship or higher performance models. The BMW 335i series vs. the M3 is an example of the more sport orient ed model having a limited slip differential. Due to owner feedback (complaints), the Dodge and Chrysler SRT-8 models finally received LSDs in their 4th model year. One could surmise several specific makes and models always have LSDs. Corvettes come to mind. How about Ferraris? It's a safe assumption, one would think.

With an "open" differential, both wheels apply engine power to the ground and even can lay down twin black strips of rubber when there is a loss of adhesion or overpowering the tires. However, when one becomes "unloaded" due to less traction and starts to spin, the power isn't transferred to the other wheel which means the rate of acceleration doesn't increase. This causes headaches on the street, the racetrack and the dragstrip.

Most annoyingly daily driving can be compromised. Uneven surfaces encountered pulling out of a parking lot or driveway onto a road when the rear tire (or front tires for front wheel drive vehicles) slips and the manufacturer promoted traction control kicks in. Begin accelerating and if aggressively programmed, the engine power could be reduced besides just the rear brake being applied. A real pain in the ass. A little extra brake wear over time and now you're maintaining your speed or slowing down when you should be accelerating. Try it when a vehicle is headed your way and you "thought" you had enough time... That is why many drive with Traction Control partially off. I'll control my throttle, thank you very much.

How about in rain and snow? Drive over or start on a slippery patch and you just sit and spin, the wheel with traction never getting the available power transferred. Apply more gas and you spin faster. Great. At the dragstrip it's the same thing. Get "out of the groove" with one tire and the other doesn't pick up the slack. For those that run higher traction tires such as drag radials at the dragstrip, the uneven distribution of the power from one side vs. the other can break a rear differential or half-shaft at some point.

Where all these exotic cars are meant to be is on the race track and the potential oversight of the McLaren means in tighter turns, the inside wheel can spin and power isn't then applied to the outside wheel of the turn, meaning a slower corner exit. Spinning is neither winning nor accelerating.

There has to be a good reason why the McLaren doesn't have an LSD so I contacted them with that question. The MP4-12C has multiple systems that they call the Proactive Chassis Control system that McLaren feels eliminates the need for the LSD.

The system consists of adjustable roll control for precise body lean control during high lateral acceleration cornering and it decouples for a better ride when in a straight line. The shocks are interconnected via hydraulics and adjust depending upon conditions and driver preferences. Finally it has a system called Brake Steer which brakes the inside rear wheel when braking into a corner and if spinning when accelerating out of a turn. Obviously brake steer is controlled via electronics and McLaren feels this eliminates the need for the more mechanically complex and heavier LSD. In other words, optimize chassis control and steering and the power delivery takes care of itself.

Granted there are some innovative weight savings with the MP4-12C such as the 175lb carbon MonoCell tub. Interestingly, aluminum brake hubs are used but not carbon ceramic rotors. Also the body panels are not carbon fiber either. Couldn't the weight of the LSD be offset in more traditional areas? I wonder if an LSD would actually be larger, compromising the design with the mid-engine and transmission placement. Perhaps it would have meant additional width, length or even height to the components, raising the center of gravity?

The drawback of a limited slip differential, besides extra cost, complexity or weight (as I roll my eyes) is potential snap oversteer which means when then the wheel with traction "hooks up" suddenly from excess power, it could cause the car to fishtail. That is something you could catch on Youtube. The "open" differential is quite predictable since the power isn't being transferred to the other side. The other disadvantage, and it's quite minor, according to the SRT Engineers the constant transfer of power can cause a ever-so-slightly decrease in acceleration. The benefits far outweigh the costs.

Adding an LSD is a common upgrade among owners of many performance-oriented cars via aftermarket parts. Can it be done with a rear transaxle, dual clutch transmission in a mid-engine car? Doubtful. There are reports of a planned hardtop convertible version of the MP4-12C that would be a first for a mid-engine car. Could this be a business decision to keep the components lower in the chassis, forgo the LSD and accommodate the folding top design? Also a higher performance is supposedly planned and perhaps this model will be "properly" equipped.

The reason many manufacturers leave out a limited slip differential is because of cost savings, pure and simple. Less mechanical parts means less cost. If it was a size and packaging issue that meant raising the center of gravity, extending the wheelbase, or something else radical, will it mean the McLaren, while wildly fast and capable will still be left behind by the competition?

2/8/2017 Edit:  Car and Driver published an article comparing an electronic torque vectoring differential vs. a standard limited slip differential in the Lexus RC-F in October 2015. They didn't bother with the obviously slower brake torque vectoring open differential. The e-diff car was quicker around the track and higher skidpad results. www.caranddriver.com/features/whats-the-diff-we-put-torque-vectoring-to-the-test-feature

6/1/2019 Edit: Being that the cars are fair weather driven, with rear weight bias, the open differential seems to work for McLaren with the selective brake bias (braking one rear wheel) used for quicker turn-in. This may cause excessive wear on the brake pads, but that isn't the concern. Meanwhile the E-diff continues to be the preferred equipment among other manufacturers.

Having driven over 150,000 miles in a '06 Charger SRT-8 6.1 and a BMW 335d, both with 425lb ft. torque (when stock), I can attest that open differentials suck. That's why owners screamed for an LSD and Dodge later added it as standard equipment.
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Got 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!

Toyota 4Runner Driving Impression

Recently I had the opportunity to drive a 2008 Toyota 4Runner for a few days while my daily driver was being repaired due to running over debris. While familiar in some respects from previous ownership of three Toyotas ('95 Camry XLE V-6, '94 Supra Twin Turbo, '99 Solara SLE V-6), I also found some aspects objectionable even compared to a 14 year-old model. First the circumstances of the accident which is another lesson I learned that I can add to previous articles, "Accidents - what I've learned" and "What Traffic School should teach - lessons for all of us".

While in heavy traffic I was changing lanes from right to left to avoid the slower traffic from merging lanes. I ran over some debris left in the road by a landscaping company pick-up truck. I chose to swerve back into my lane rather than have my momentum carry me too far, possibly into the other lane. Regardless it probably wouldn't have mattered. Obscured by the cars in front of me, I caught a brief glimpse of green leaves and the handle of a wooden tool and yelled an expletive as I ran over some items.

I called CHP and saw that the suspect truck and another vehicle were on the side of the road. Lessons for recourse: Pull over too and inspect the damage before it's too late. Don't believe CHP will make it to the scene on time prior to the offending vehicle leaving. Don't count on fellow motorists to report items falling off of vehicles.

Anyway, the initial impression was one of familiarity with the interior. If it ain't broke, don't fix it. But the seats were the big objection. Being cloth covered was okay, but they were very shallow and when the seat bottom tilt was adjusted all the way, it still didn't seem to enough. The material and design seemed as if they came from a Corolla from the early eighties. Totally unacceptable in any vehicle that costs over ten grand. The problem with the support only in the small of your back is the bumpy ride. The swaying motions meant your upper moves around while your lower back stays supported. Not very comfortable if you have back pain or even if it's tender or sore. The floor is also very close to the bottom of the seat so your feet are out in front of you, instead of down. However, this seemed to be a result of the high floor height for increased ground clearance. Truly truck-like.

Speaking of truck-like, the ride definitely gave the impression of off-road capability. More "jiggly" than harsh, the driver is acutely aware of what each each corner is doing. Impacts are absorbed well, you just know they are there. It wants to go off-road.

The interior has similar designs from Toyotas of the past. Another example of sticking with what works. The climate controls were unique 5-spoke buttons which worked fine and were intuitive. But what I did notice is the text on the buttons was too dark and combined with a dark interior, didn't stand out enough. Sunglasses just made it worse. Despite the good feel of the controls, the dashboard is too far from the driver. Keep in mind, with you legs out in front of you, it creates a greater distance than if they go down a bit. So reaching for the dash controls requires leaning forward if have long legs. Even if you have long monkey-arms like me.

Acceleration however is effortless. Seemingly aggressively geared and with a lightly sprung pedal, speeding seemed easily, even in inappropriate places like parking lots. It was fairly fast with WOT (wide open throttle) to 60mph being quite satisfactory. In fact, it was downright quick and effortless. Gas mileage suffers as a result, however. Alright, did I open the hood? No I didn't. I acted like my non car- DNA brother and didn't even bother. I'll take an educated guess that it was the V-8 because it scooted!

The 5-speed automatic responded well but I am not sure I'm sold on the multiple detent shifter gate. I did get used to it after a while but the first few times shifting to and from reverse I would look down to see why it seemed jammed only to find it was a matter of moving it side to side.
The rear hatch offered spacious cargo capacity which doesn't hide anything from prying eyes. However the door was excessively hard to close, basically requiring both hands. I doubt "they are all like that" - as in all SUVs. When you've got your laptop and lunch bag in one hand, your keys and whatever else in another, even a tall male who spends time in the gym will frown, or get frustrated, with the effort.

Consider the daily usage when buying any used car. Every car has it's quirks, and for my use, sitting high up isn't all it's cracked up to be sometimes.
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Got 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!

170mph at dusk: American LeMans racing at Mazda Raceway Laguna Seca

The second weekend in October saw the American LeMans series racing at Mazda Raceway Laguna Seca near Monterey, California. The weekend was packed with racing action highlighted by the title event on Saturday afternoon. When four hours of top-level racing at speeds reaching approximately 170mph with driver changes and multiple pit stops has a .662 second margin of victory, you know you've seen something special.

This race also marked the retirement of the great racing champion Gil de Ferran who also appropriately won in the Acura ARX 02a race car after being dogged for quite a while by the Fernandez racing Acura from the P2 class, even regaining the lead after a pass into the slowest turn.

The other big story was the fierce battle between the Porsche and Corvette in the GT2 class at the end of the race. The Corvette all over the back of the Porsche lap after lap. An illegal pass by the Corvette by crossing the white line of the pit lane exit going into turn 2 was called back. Then the Corvette tried unsuccessfully to pass again on the next lap, bumping the Porsche before turn 3 and getting a little loose in dust. Finally in the last turn on the last lap, the Corvette bumped the Porsche from behind which ended up with the two side-by-side in a drag race towards the checkered flag with the Porsche forcing the Corvette towards the wall. The resulting contact, either between the two or the 'Vette and the wall caused the Corvette to spin in front of the Porsche, crossing the track and crashing hard into the opposite wall, wrecked and in second place. Check out the video here.

The drivers, Jorg Bergmeister in the Porsche and Jan Magnussen in the Corvette have been placed on a two race probation leading into the 2010 season. More details here. Jorg has been in the position of being squeezed out before, notably at Sebring losing to Ferrari. However considering Magnussen may have had a faster car, he couldn't get a clean pass and Jorg obviously wasn't going to lose the last race of the season due to being bumped in the last turn. If you can't do it cleanly, then don't try it.

There were some unfortunate signs of the economy affecting the event besides a lower entry count. There was no big screen for the main grandstands which actually has the most limited view of the circuit, nor for the stands between turns 4 and 5. Quite unfortunate considering how much occurs on the other parts of the track. The car count was lower as well but isn't as bad as it sounds and I'll get into that later.

The vendor area was also smaller than usual but still offered a great selection of clothing for men, women and children. All racing/automotive themes, of course. Piloti shoes was also there along multiple paraphernalia and excellent model car vendors. A special mention of Sin City clothing and Need For Speed Design with their automotive-themed jewelry and items such as bracelets, wallets, pens, rings, etc. One of the major sponsors, Patron Tequila had an all-day party in the vendor area with a lot of cute tequila girls. After all, for women spectators, the paddock area is full of studly drivers and team members, right? Even though the number of car manufacturer tents was down to one this year, Chevrolet had a nice display with a helpful staff and free Corvette Racing t-shirts for filling out a marketing survey.

Even a first-time race attendee commented on how organized the event was. From parking assistance to the layout, children's play center, go-kart track and even clean bathrooms, it was well done.

Some observations regarding the food and drink. The mixed drinks were a bit weak but the quesadillas were spectacular and right across from a tent with a variety of nice, cold English Ales. Across the Cooper Tires pedestrian bridge in the vendor area, their were other food and drink areas also. How much better could it get?

The sounds of the cars were simply extraordinary. The Corvettes and Panoz were thunderous going around the racetrack. The pushrod V-8 motors were a stark contrast to the screaming fury of every other high revving overhead camshaft motors of every other car on the track. The difference between the pushrod Ford powered Panoz and the overhead cam, 4-valve per cylinder Ford GT was especially interesting. Oddly, the Rahal Letterman Racing (yes that David Letterman) V8 BMW M3s seem to sound not unlike a street-legal M3 with aftermarket intake and exhaust modifications. Perhaps the closest resemblance of the race cars from a sound standpoint.

Driver access: As usual with the ALMS, the driver and team access is excellent. Autograph sessions with lots of posters and/or "hero cards" were common sights with many fans. Unheard of in the past, fans were allowed on the starting grid before the race, standing next to the cars and drivers with great photo opportunities.

Race cars: The major manufacturers represented in the ALMS were Acura, Lola, Porsche, Chevrolet, Panoz, BMW, Ferrari, Ford and Jaguar. The lone Ferrari dropped out due to a mechanical problem and the Dodge Viper was missing from this event. The Jaguar was basically testing for next season and it looked great. Also missing were Audi and Peugeot who only ran a few races this season in the US. Thirty-two cars on the starting grid was actually a somewhat low number but since there were 4 classes of cars running, the passing and dicing was frequent. Also, since this is the last race of the season and on the West Coast which is far for many teams to travel, not everyone was there. Next year the race will be in May which should mean more participation due to being earlier in the season and hopefully a better economy. More teams, more car counts.

Car corrals, while a little smaller than previous years, are always good display for fans of Corvette, Porsche, Audi and BMW. Even the Acura NSX club had a huge turnout in the past and I spotted some cars this year too. On the forums, it's common to read complaints that high-end car owners rarely drive their cars hard. Besides track days during the work week, owners of such are supporting the racing efforts of "their" cars. Not only were there two Ford powered cars in the ALMS race but 3 Mustangs in the Speed GT race, including one driven by Boris Said. Are you a "Said Head"? So I'm calling out Mustang and Ford GT owners to come check out the racing action too. And since Viper is heavily represented in Speed GT, where were you guys too?

Speed GT is one of the best racing series in world. High horsepower street-related sports cars compete in a 50 minute sprint which was a great conclusion to the weekend and racing season. The best bet next year is to attend the race (obviously) and record it on the DVR. Then you can watch what you missed to really get the big picture. Don't miss it, in person or on TV.

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Got a question about cars you would like answered? 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!

High Mileage Tires - Test Results on the Toyota Prius

The Tire Rack recently tested six environmentally friendly tires designed for low rolling resistance for higher miles per gallon vs. the original tire equipped on the Toyota Prius. The results were surprising and quite promising. See the report here, "When Round and Black Becomes Lean and Green"

It was always an interesting dilemma regarding tires and how they perform. Get more tread life from your tires and sacrifice performance or emergency maneuver capability (braking distance) due to hard compounds. Achieve better performance and suffer from faster tire wear and higher cost of ownership.

I never understood why low rolling resistance tires would wear out quickly. The assumption was always a hard tire would have less rolling resistance and therefore would last longer. Instead, as explained by Matt Edmonds, Vice President of Marketing at The Tire Rack, the low rolling resistance tires in the past would "give themselves up" to the road, hence wearing faster. But due to advances in tire compound technology and tread design, this is no longer the case. These modern tires now show advantages over the same model that comes on the car, in this case a Toyota Prius, from the factory. Check out the Test Result Charts here.

An interesting observation is that the original Goodyear Integrity tires perform the best in the dry, but not by a large margin. However, they were rather poor in the wet. Especially in wet braking distance, inexcusably worse than the rest. Of course, when the tire was first introduced, it may have been the ideal choice for cost and performance.

Tread wear would be the final aspect that a 550 mile test loop cannot show. However, looking in the "warranty" link for each tire, most have very good tread life warranties. Contrast that with more expensive (albeit larger/wider) high performance tires that last 20,000 miles if you're lucky. and the appeal of lower operating costs and less waste looks very attractive. One thing about all-season tires, they don't react negatively to cold temperatures like high performance tires. Here is my idea for a tread temperature measurement feature.

Take a look at the test results and you'll see not all tires are created equal. The variance is not just the tread pattern. The Tire Rack is an excellent resource for information including tires and equipment. Even if you don't buy from them, when shopping for new tires many retail outlets will have a price matching policy to within a certain amount so you always know you're getting a good deal.

Now when shopping for tires for your daily-driver, a low rolling resistant tire is no longer a compromise in safety or tread life. As technology advances with a continued emphasis on safety and miles per gallon, tires continue to be another avenue of improvement as well.

Got a question about cars you would like answered? 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!