A Prado you can easily tip over but a BMW? I don’t see how

Hello Sir,
I need some clarification on two issues. A friend of mine says that Toyota Prado is one of the easiest cars to flip over.

I have seen a couple of overturned Toyota Landcruisers, although they were older models. How stable is the Toyota Prado V6 4000cc?

I have driven a not-so-recent model BMW 523i series in which I skidded, but miraculously didn’t flip. I guess it would have been a different story with a Prado.
Please advise.

Your friend is right. A Landcruiser Prado is notoriously easy to roll over. This is because the vehicle is tall and narrow.

The great height and small base area give it a high centre of gravity, so when that centre of gravity starts swinging about, the amount of effort required to overcome the stability offered by the base area is very small.

Small effort = easily done. Therefore, the Prado is easy to tip over. All you need to do is take a corner at high speed. The 4000cc V6 Prado is a Prado, is it not?

Not flipping a BMW is the rule, not the exception. Flipping a 5 Series is the miracle here.

Obviously, it has a very low centre of gravity, so it won’t be easy getting the centre of gravity to start swinging about, and if you get it to, it will still take considerable effort before getting the car to topple.

The actual explanation of this phenomenon can be found in classical mechanics, under the topic covering moments, inertia and centres of mass and gravity. Mechanics in this case has nothing to do with cars.

Calculating the likelihood of this event requires a series of equations that will send you running for the hills. However, I will simplify it using an analogy.

Let’s start with the Prado. Compare its overall shape to that of a book. Its height-to-width ratio is more like a book balancing on its spine, is it not? Getting that book to fall over is not hard; all it takes is a simple tap on the side.

Now consider the BMW. Its height-to-width ratio is more like a book lying flat on the table. Try getting that book on its spine using the same single-finger tap that you used above.

Nothing happens, right? The book is infinitely stable, it will not turn over. If anything, it will start sliding along the table the more you push it, but it will not flip, unless other forces are introduced. This explains why you were skidding but not rolling or flipping over.

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First, thank you for not imitating other car reviewers (i.e. Autocar, Top Gear, Fifth…, etc) with your style of journalism.

I really appreciate that and if you can, please intervene in Autovault by bringing in a “natural” character for a presenter (they do a good job but they appear to try too hard)…that would be swell.

On to your critic, the Mike Mouth: If anyone has to explain Top Gear to him, then he really needs to stop drinking.

As for the Demios, I believe you are talking about small practical cars that don’t need super charging or turbo charging to spike the driver’s adrenaline. I totally get your point. But do this: try the Swift Sport 1600cc… You will trade in the Demio. I can guarantee you that.

Now, on to a personal query, could you compare the Lexus IS250 with the GS 300 and how can one get a brand new one, given that there are no specialised dealerships. I have gathered that second-hand luxury cars are time bombs and I am trying to avoid that.Kim

Hello,
Thank you for the compliment. And you are most welcome: I prefer to be original. I discovered that one tends to achieve more that way.

Unfortunately, I cannot intervene on Autovault. To start with, my contributions are in the editorial department, while Autovault is on TV.

Secondly, I cannot intervene without invitation. That is someone else’s project; Car Clinic is mine. And you say they do a good job, so where exactly is the problem?

I have not watched the show, and I am not exactly clear on what a “natural” character is, so I might get on board and appear even less natural than the current presenters do.

I have seen and heard about the Swift Sport, but I haven’t driven it. What I have driven is the standard Swift, and first impressions were excellent, to be honest. I might believe you: the Swift Sport could just knock my socks off.

Where do I get one and how much will it cost me? I will also consider how it stacks up against a MazdaSpeed, which is what I have been thinking of lately when the time comes for me to graduate from the Demio “Sport”.

Now, the Lexuses… Lexi… Lexus cars. The GS is bigger than the IS, but the IS handles better and in my view, looks sharper. It should be more responsive on the road, making it more fun to drive.

If you are into creature comforts rather than outright driving experience, then the GS is more up your alley. Getting a brand new one will not be easy or cheap.

Off the cuff, I’d say these are your options: contact Toyota Kenya and see if they can bring one in for you. The whole idea is they import the car and you buy it from them, though in effect you mported the car. You have to promise to pay them once the car gets here.

If you change your mind when the vehicle is already on the ship, they won’t be very happy with you. Also, I cannot guarantee that they would agree to such a proposal.

The second option is to buy it yourself. You will buy it expensively brand new to start with, then get it to the port (Mombasa) — or Nairobi if by air — and discover that the taxman assumes a DIY import of a brand new car means the importer has more money than he knows what to do with, and will thus be glad to assist him reduce that money to manageable levels, and no sir, don’t worry, it is all very legal, they are not stealing from you, it is right here on paper.

Look, it is called Customs Duty and what in the name of… isn’t that a little high, yes it is, but rules are rules. If you want lower taxes, then buy older cars that have already been used and the whole process is frustrating and confusing.

In the end you will discover that maybe, just maybe, importing brand new cars is a bit of a no-no for those who do not enjoy tax exemptions or government subsidies.

There is a third option, which focuses on exploiting loopholes and operating in legal grey areas. It also involves dishonesty, and that is what might land you in trouble.

Take this path at your own risk. The overall picture is this: buy the car from wherever you are buying it. While still there, drive around in it a little. Put a few miles on the odometer. Then import it as a used car.

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Hi,
I followed club the TT Murang’a circuit very keenly from route practice in June until the actual race on August 3.

However, I noted the following issues and would like you to clarify:

1. Some Evolutions and Subarus produced a unique “Shhhh” sound like gas coming from a jet, (like a perfume spray can) when slowing down. What is the cause and purpose of that sound?

2 There is that Toyota 110 GT. How is it different from a normal 110? Apart from being fast and, of course, having orange rims and a big exhaust pipe. Any other difference?

3. I noted that most drivers had their front windows open; why? Yet we are told that open windows increase drag/wind resistance, thereby reducing speed.

4 Are you sure you were there? I never saw a clean shaven face with a goatee. I actually looked around for you.

Murage

1. The source of that sound is the BOV (blow-off valve), also called the dump valve, in the turbocharger. The purpose of the dump valve is to “dump” or “blow off” air from the turbo once the throttle is closed to prevent something called compressor surge.

This is what happens: when a turbocharged petrol engine is running, the turbo is forcing more air than usual into the engine by compressing the air first then sending it into the inlet manifold. When you take your foot off the accelerator, the throttle valve closes.

This means that the compressed air that was coming in from the turbo now has nowhere to go; the way into the engine is closed. The only way is to decompress backwards, and given that the turbo spools in one direction, when the air moves in reverse, there is a sort of “clash”.

It is called compressor surge, and is the one that causes the turbo to slow down suddenly, and in a potentially fatal manner; given that it was spinning at speeds that can go up to 60,000rpm, spooling down to or near 0rpm in an instant does stretch its physical abilities to the limit. You could very easily kill your turbo like that.

To prevent compressor surge, the BOV gives the compressed air a way out. When the throttle is closed, the dump valve opens, dumping all the compressed air, usually into the atmosphere, though some dump valves send the air around and back into the turbo. This dumping of compressed air is what makes the “pfff!” noise on lifting off the accelerator.

2. The difference between a Corolla 110 GT and a regular Corolla 110 is that it’s code is E111, not E110. The E110 is the “regular” Corolla. The GT uses the high-performance 1600cc DOHC 165hp 4A-GE engine with 5 valves per cylinder, while the rest use lower output engines (perkiest being the 100hp 4A-FE 16 valve DOHC).

It also came with a 6-speed gearbox versus 5-speed. Optional extras include a subtle body kit, red and black interior, silver or white dash dials, 15” alloy rims and fog lights.

However, orange rims and fat exhausts were not part of the manufacturer’s offerings, so this particular Corolla GT you refer to may be a lot different from regular Corollas… and regular Corolla GTs for that matter. The owner might have done any number of modifications to it.

3. That is purely a matter of choice for them. I, however, recall telling them explicitly to wind their windows up at the starting line just before being flagged off, because, as you say, the buffeting that comes with a lowered window is an aerodynamic fiend.

4. I am sure I was there, otherwise point 3 above would not make any logical sense, would it? (not the part about aerodynamics, but the part about me telling them to put up their windows).

I was at the starting line, wearing a high-visibility jacket and doing my scrutineer’s duties of ensuring everything was tip-top and stamping inspection forms (at which point the drivers then wound up their windows) before sending them on their way.

There is an issue here, though: if you came to look for me at the TT, then that was not very wise use of your entry fee. Watch the cars. That is where the fun is.

I am not much to look at, and I certainly wouldn’t charge anyone to look at, or look for me. See you in Kiambu on October 19. Just watch the cars. I will be the one stamping inspection forms and asking drivers to roll up their windows…

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