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Take note, Shell V-Power won’t turn your Vitz into a Ferrari

Hello Baraza,

Kindly enlighten me on the difference between the ordinary super petrol and the V-Power fuel sold by Shell. I drive a supercharged Vitz — RS 1600cc — and have tried using both fuel types and experienced no difference at all in terms of speed, performance and kilometres per litre. Let me hear from you on this.

Nawaz Omar.

Shell were very careful when pointing this out. Much as the ads starred a Ferrari road car (and an F1 racer too, if I recall), it did not mean that putting V-Power in a Vitz will turn it into a 458 Italia. Nor did it mean that the fuel economy of a small car will be changed from the incredible to the scarcely believable.

Shell V-Power contains extra cleaning agents that will wipe away all the dirty sins, sorry, dirty deposits from your engine and fuel system, just like Christians insist Jesus will if you call out to Him.

Even more importantly (for those of us who love performance engines), it also contains octane levels high enough to allow high compression engines to run on it: engines such as those with forced induction (turbocharged/supercharged) or even… yes, a Ferrari F1 racer.

So Nawaz, take note: V-Power will clean the engine of your Vitz, not transform it.

Hi Baraza,

I enjoy reading your column every week. Good work! I would like to know the relationship between engine size and fuel consumption. Basically, what is the relationship between the fuel injected into the combustion chamber and engine size?
Thank you,
Kiama.

If we were in the year 1930, there would be a clear-cut answer to your question, but it is 2012 and we have with us technologies like Variable Valve Timing and Direct Injection which make things very hard to explain without pictures.

Anyway, I will try to make things as simple as possible, and, before I start, I hope you know the basic physiology of an engine.

For normal running, we have what we call the stoichiometric intake charge ratio, which is simply referred to as air-fuel ratio, and stands at 14.7:1. If it goes lower, it is called a rich mixture (such as 10:1 or 5:1). If it goes higher, it is called a lean mixture.

Now, if it was the year 1930, the calculation would be simple: for every 15 metric units of air sucked into the engine, the fuel levels would drop by just a shade more than 1 metric unit.

So for a 2.0 litre engine operating at a constant 1,500rpm, you have four cylinders, which go through 1500 revolutions in one minute, consuming fuel in one stroke out of every four, and two strokes make one revolution (0.5×1500=750 fuel-intensive strokes). Since the cylinders occupy 2,000cc, 750 strokes of 2,000cc would be 1,500,000cc worth of intake charge.

I talked about metric units, and it is here that you have to pay attention because it ties in with all the economy advise I give people about filling up early in the morning.

While at the dispenser down at the petrol station you will buy fuel by VOLUME, the injection system of a car measures it by MASS for the intake charge ratio.

The density of air at 25 degrees Celcius (RTP — room temperature and pressure) is about 1.2 kg/cubic metre. So 1.5 cubic metres (1,500,000cc) will weigh 3.6 kg, which constitutes 14.7/15.7 (93.6%) of the intake charge, with fuel covering the remaining 1/15.7 (6.4%), which by simple arithmetic translates to about 0.25 kg of fuel.

Fuel has a density of 0.74 kg/L, so 0.25 kg of petrol will translate to roughly 338 ml of the stuff, or about 1/3 of a litre.

This is for the 2.0 litre engine running at a steady 1,500rpm for exactly one minute under the stoichiometric intake charge ratio. In the year 1930.

Nowadays, with electronic engine management, direct injection and variable valve timing, the cars can run lean and the effective volume of the cylinder changed in real time, so it is not that easy to calculate the consumption by hand like I just did.

Hello JM,
I drive the new-model Caldina and whenever I encounter dusty roads or wade through muddy waters, the brakes become a gamble. Recently, I noticed the same on my friend’s Subaru Outback. Is it a manufacturer’s error or just the pads? I almost rammed another car because of this.
Sam.

No, Sam, that is not a manufacturers’ mistake. It is your mistake. What you are telling me is: “Look, I drove over a police spike strip and now all my tyres are flat. The manufacturer must be really useless.”

When wet or dirty, brakes don’t work as well as they should because the foreign material interferes with the friction surfaces that convert your kinetic energy into heat energy; and that is why at the driving school they told you to increase your braking distance by at least half if you are driving on a wet surface.

Just to prove my point, tell me, honestly, really truthfully, with a straight face: When clean and dry, the brakes work fine, don’t they?

Hi Baraza,

I imported a Subaru Imprezza GG2, 2004 model late last year and the mileage on the odometer at the time was around 82,000km. I had a small accident with it along Valley Road, Nairobi a month ago and the insurance company fixed the car, but since then there’s a “wheezing” sound that comes from the back as I drive.

Two mechanics have independently confirmed to me that the rear right bearing is the source of the noise and that, for this particular model, the bearing and the hub are sold together as one component. Could you confirm this? What would be the risk of driving it that way before I get it fixed? Can the rear right wheel come off as I’m driving?

Secondly, having done that mileage, what particular parts or components should I replace? Do I need to change the timing belt or any other particular thing? Kindly advise.

You could go to a shop and ask to buy a bearing. If they tell you that it sold with the hub as a unit, then there’s your answer.

I went through a similar case with a Peugeot 405 I had: the fourth gear synchroniser unit was damaged, and when I went to buy a new one, they handed over the unit, to which was attached a gear, and they quoted an unfriendly price. Told them the gear in my car was fine: lose the cog and drop the price. Can’t do, they said; the synchro is the one that costs that much, the gear is actually free. I wanted to weep.

The rear wheel will not necessarily come off, at first, but the bearing could collapse and this might lead to the studs in the hub breaking when the wheel wobbles. Then the wheel will come off.

You could pre-empt breakages by replacing parts such as the timing belt, but the Kenyan way is to drive a car until it stalls, right at the moment when you are at the front of a queue in a heavy traffic jam and the lights turn green or a traffic policeman waves you off.

A physical check will let you know what to replace before your dashboard lights up like a gaudy neon sign, but look at tyres, brakes, the timing belt and the transmission. The suspension too, the shocks especially.

Hi Baraza,

On a trip abroad I had a taste of the great Lexus LS400 and the Chevrolet Lumina SS, though I fell in love with the Lexus as it had a huge, all-leather interior and that ‘cruise feeling’ to it.

You wouldn’t want to go to work in that car, it makes you feel rich and lazy. The consumption, I was told, is on the higher side, but wouldn’t that depend on how heavy your foot is?

Then came the Lumina. She is a beauty, though fitted with plastic interior. I couldn’t help but feel the car had that ‘I’m gonna fall apart soon’ look. I mean, it looks like it wouldn’t survive a head-on with a Vitz. Fuel consumption was much the same.
Considering I can afford the two cars, which one would you suggest I go for?

Wilson.

Buy the Lexus and feel like you have arrived.

The SS is not meant for driving to the office through heavy traffic (the Lexus will shine here), it is meant to go through corners while facing the wrong way, executing massive powerslides and doing great big drifts in the process. It is a car for having fun in.

Your wife will not take it kindly if you show up one day exclaiming: “Honey, we are broke, but at least we have a 6.0 litre V8 car to show why.” The massive spoiler, fat tyres and unsubtle body kits will not tickle her fancy as it would yours. The SS is a sports car. Buy the Lexus.

Hi Baraza,

The ‘check engine’ light on my Nissan Wingroad 2001 model is permanently on. I did an OBD and the fault detected was the primary ignition coil, which I replaced. The plugs were also checked and found sound and of correct specification, but the engine light has refused to go off. I have tried four other OBDs and the result is the same. My mechanic is advising that I change the computer unit. Are the units repairable? Kindly advise.

Isaac.

You should have flushed the ECU after replacing the coil, especially if that cured the problem. It has to be done to most cars. The recommended method is using the same OBD scanner or a PC with the appropriate software and hardware links. Another method is to disconnect the battery overnight.

Dear Baraza,

I drive a 2002 Toyota Corolla station wagon EE103, 1490cc. It has served me diligently, but I would like to sell it to another financially challenged Kenyan and upgrade myself. I like fancy cars but I’m afraid of the cost implications.

I have made many visits to garages manned by thieving mechanics and would like my next car to guarantee me few mechanical breakdowns.

So help me make the big leap. Of the following, which one should I go for: Toyota Mark X, Mitsubishi Lancer, Mitsubishi Diamante, Nissan Wingroad or Toyota Wish? If I remember, you likened the Wish to a bicycle, but still….

Hassan Mahat

The only fancy cars in that list are the Mark X (lovely machine) and the Diamante (dodgy ancestry — Diamantes of old were unreliable). The rest are common fare, especially among the “financially challenged”.

The Wingroad feels — and is — cheap, and ages fast. The Lancer is pretty but suffers from wonky powertrains, especially as an auto. The Wish is aimed at those who have little interest in cars (and from the seating capacity, little control over their loins too).

Hi Baraza

I am 29 and want to buy my first car. I have sampled what’s on offer and this is the fare that has caught my attention: VW Golf, VW Polo, Toyota RunX, Mazda Demio, Toyota Cami, Toyota Opa, Suzuki Maruti and Suzuki Swift.

I’m looking for a second-hand car priced between Sh500,000 and Sh750,000, a car that can do long-distance drives twice a month (Nairobi-Mombasa), a car that is not a ‘Kenyan uniform’ and would still have a good resale value after four or five years. What should I go for?

Second, where is the best place to buy a car? Is it okay to trawl through the classifieds?

Job. 

Job, maintenance and consumption aside, what you want is the Golf if you are serious about doing the Nairobi-Mombasa run once in a while. The rest of the cars will prove to be a heavy cross to bear. For economy, get a diesel Golf.

On where to get it, cars can be bought from anywhere, but do not commit yourself to anything until you see the car itself. I know of some people who have been sold non-existent vehicles after following newspaper and Internet ads.

Hi Baraza,

I want to buy a car for the first time and I’m so much interested in the Subaru Forester. But after enquiring about it from various people, I’m beginning to get confused. Those who own it swear it’s the best car on Kenyan roads today, while those who don’t feel nothing for it. Kindly tell me more about this car, especially the 2000cc model.

Also, between the turbo-charged and non-turbo, 4WD and 2WD, which one is better in terms of fuel consumption, availability of spare parts, durability and performance.

In addition, what is the difference between these two Foresters: the 2.0XT and the 2.0XS?

Thank you.

I had no idea 2WD Foresters existed, but if they do, then they should have lower consumption but lose out on performance to their 4WD compadres. Turbo cars are faster, thirstier, harder to repair and a touch fragile compared to NA versions of the same vehicle. Generally.

The XS model is naturally aspirated (non-turbo) and has auto levelling rear suspension, 16-inch alloy wheels, fog lamps, climate control and a CD Stacker (six-disc in-dash).

The XT is turbocharged and shares features with the the XS, but additionally, also has 17-inch alloy wheels, high-intensity discharge (HID) headlights, a Momo steering wheel and a seven-speaker stereo.

Hi Baraza,
1. I recently came across and advertisement for a motorcycle that can do 70 kilometres per litre. Is this practical?

2. VW have developing a car called the 1L and claim it can do 100 kilometres per litre, thus 10 litres will take you from Nairobi to Mombasa and back. Kindly shed more light on this.

Chris.

1. Yes, especially if it’s engine is of 50cc or less.

2. The reality remains to be seen, because the self-same Volkswagen had a “three-litre car” (3L/100km) which I have  discussed before, the Lupo/SEAT Arosa/Audi A2. It might have done the 33kpl, but not exactly daily. Our roads, diesel quality and traffic conditions may hamper drivers from easily attaining this kind of mileage.

Practicality will depend on the intensity of engineering genius behind it: how many passengers, how much luggage, whether or not it can sustain highway speeds, how easy it is to live with, and so on.

Posted on

An electric vehicle in Kenya? Not a good idea

Hi Baraza,
1. Do electric vehicles stand a chance in Kenya?
2. Is it possible to convert a car to use electricity? If so, what are the pros and cons of implementing such an idea in Kenya?
Nick

1. At the moment, not a chance in hell.

2. Yes, but the costs and labour involved are prohibitive, especially given that the end product will not be worth the sweat or the money.

Pros: Your running costs will go down tremendously. Electricity is cheaper than petrol per kilometre driven.

Cons: Travel any distance greater than 50 km and you will be very, very late for whatever you were going for.

Also, self-servicing when things go on the fritz, and of course acquiring the vehicle in the first place (whether bought or assembled in your backyard), calls for a massive financial outlay. Not worth it at all.

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Baraza,

I drive a pre-owned FWD automatic transmission Subaru Impreza GC1, 1998 model with an EJ15 engine. The car has 140,000km on the odometer and I service it regularly. It serves me diligently.

I have been driving it for the past one year. I have taken it for OBD diagnosis and no faults were found, apart from a problem with the ABS and the thermosensor, which I sorted out.

I also feel that the thirst that is associated with Subarus does not apply to this one; I am able to do 10 km/litre, except when I floor the accelerator. Here is what I would like to know:

1. In your opinion and knowledge, how much mileage should one clock on a car before declaring that it has served its purpose?

2. Would you recommend to anyone driving such a car to do an engine swap with a bigger engine like an EJ20, tune the car, sell it, or do a trade-in? Is it sensible to change the engine or is it better to just buy another car altogether?

3. For the past one week, my car occasionally sputters in the morning when starting, especially during cold weather. But if I start it with the gas pedal partially depressed, it starts just fine, though I notice that the fuel consumption is not good. What could be the problem? The problem is much worse when I put it in reverse gear. But once the engine warms up, all this disappears. On the highway it does just fine.

4. Is it true that all EJ engines, both the naturally aspirated and turbocharged, including WRX EJ engine variants, can fit in a stock GC1 1998 Impreza? If so, what other modification should I do if I instal such an engine?

5. Can someone fit a used engine from a manual transmission model into an automatic transmission model, or one has to change the tranny completely? And how realistic is it to change from FWD to AWD on such a car?

Robert

1. It depends on the state of the car. Some world record holders have done more than two million kilometres in their cars. The general rule of thumb is roughly 500,000km for passenger cars before an engine swap or grounding of the car.

2. Do an engine swap if repairs on the current unit prove to be too expensive to justify. Tune the car if you want to liven things up (or even resort to settings close to new) without having to buy another car. Sell it if you are sick of it.

Trade it in if the finances for a replacement vehicle lie just outside your reach. Changing the engine or buying another car: that is up to you, to be honest, but here is a guideline. Replacement engines are a lot cheaper than replacement vehicles, but if the swap is done poorly, you will regret it.

3. The issue could be a clogged fuel filter, requiring a wider opening of the throttle plate to create negative pressure high enough to suck fuel through the filter.

Another problem could be the idle air control valve (IAC), which allows air to come into the engine whenever you do not have your foot on the throttle.

It automatically varies idle speed by load, temperature, etc. If it fails, you will not have sufficient air flow into the engine to make it run when the throttle is closed.

That is why the car runs normally when it goes down the road. Some people talk of cleaning the IAC but replacement is usually the best option.

4. Yes. The GC chassis can accommodate any of those engines. Most of those engines are similar anyway, the difference being the presence of turbos/intercoolers and capacity.

However, the peripherals may necessitate some modifying, especially of the front air dams, to accommodate intakes/front-mount intercoolers.

5. Changing from auto to manual tranny is a common practice in the car world, and is quite easily done. However, changing from 2WD to 4WD is a lot more complex and may not be worth it. Changing from 4WD to 2WD is easy: you just disconnect the offending drive shaft.

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Hi JM,

What is your take on 2005 Nissan Tiida Latio in terms of performance, availability of spare parts, and fuel consumption? How does it compare with the 2005 Toyota Corolla (NZE)? In your opinion which is a better buy?

Henry

Performance is poor but economy is good and spares are available at DT Dobie. The NZE may be a better car, especially on the performance front, but the Tiida is prettier.

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Hi Baraza,

I own a BMW E34 (520i), with a 2000cc, six-cylinder M20 engine. Now, can a 6-cylinder engine be 2000cc? If it is true, how is the consumption compared to a four-cylinder 2000cc engine and a 2500cc, 6-cylinder one?

Otieno

Yes, a 2000cc engine can have six cylinders. Yours does, doesn’t it? Alfa Romeo race cars of yore had 12-cylinder engines of only 1500cc. Consumption may be slightly higher than a 4-cylinder of similar capacity, but this is tied to so many factors that the question cannot be answered in black and white. It will be less thirsty than a 2500cc six-cylinder, though.

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JM,

I have a 1997 Nissan B14 that I took for an overhaul. Afterwards, it did only 100km before it heated up badly. It has now stalled. What could be the problem here and what should I do?

The problem is exactly as you have described it: the car over-heated. What to do: Since the heat problem came about after the overhaul, the prime suspect is the cylinder head gasket.

Either the product itself was low quality or the work done was low quality, but in each case, the gasket may be leaking.

Other things to do: Check the obvious. Was there enough water in the radiator? Is the radiator leaking? The overflow pipe/jar? Are the fans working? What about the water pump?

Is the radiator clean (outside)? What of internal blockages?

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Hello JM,

I own a Nissan Hardbody double-cab. Whenever I make a sharp turn, there is a sharp creaking noise from the front right tyre area. I have no idea about what could be causing this problem. Any ideas?
Fide

The fan belt is either old and worn out or is sitting badly within the pulley of the power steering pump. A quick cure of the symptom is to splash some brake fluid on it, but check the two above parameters for a longer lasting solution.

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Hi Baraza,

1. I have a differential problem with my 2004 Nissan Navara 2.5D double-cab, turbocharged, D22 chassis, diesel. In December last year, it started producing a funny noise and my mechanic suggested replacing the bearings.

The whole job ended up being messy due to the inexperience of the mechanic and resulted in differential lock, damaging the crown wheel and the pinion.

I looked for another mechanic who initially suggested repairing the differential, but even after replacing the pinion and the crown wheel, the noise still remained.

Later, he suggested replacement of the entire differential assembly, including the casing and the axle. We did this but since it was not the right fit, the vehicle lost power.

I therefore had to go back to my repaired differential. I now rarely use the vehicle.

(a) Can you advise on a mechanic who can be of assistance?

(b) Where can one obtain such a differential, locally or elsewhere?

(c) Do you think the continued use of the vehicle in its current state could create other complications?

2. I also have an auto 2004 Mitsubishi Lancer Cedia with a 4G15 engine, 1460cc, CS2A model. Sometime back, I noticed that the car had a problem with gaining speed and its fuel consumption had gone up significantly.

My mechanic checked the plugs and the fuel filter but these were okay. I then carried out a computer diagnosis that pointed to a faulty exhaust system. The mechanic recommended replacement of the catalytic converter and the car improved, slightly. What could be the problem?

The advice I have received, so far, including replacement of the gear system, is just scary.
JMM

1. Why did you not go to the franchise holder, DT Dobie? And did you just put any diff or did you buy a Navara diff? You have to be careful about specifying the vehicle make and model (and YOM) when buying spares.

What we know as the Hardbody NP300 double-cab is actually called Navara in other markets, but it is mechanically different from the current Navara car. So, here are your answers:

(a) DT Dobie. They sell Navara vehicles under franchise, so they must be able to service/repair it and provide spares.

(b) DT Dobie. For the same reasons as above.

(c) Yes. The entire 4WD transmission may be ruined, more so given that the Navara is a delicate vehicle and uses electronic 4WD engagement.
2. The diagnosis said the exhaust system is faulty and changing the converter improved things slightly, so that is where the problem is: the exhaust system. After changing the converter, have a look at the lambda sensors also. And check for a leak too.

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Hello Baraza,
I recently bought a 2005 VW Jetta 1.6-litre engine. The check engine light is always coming on and when I raise this with my mechanic, the answer I get is that I over-rev the engine.

Is this true? Also, whenever I park the car on a gentle slope, I get the check oil light even though I changed the oil a couple of weeks ago. Is this a common feature with VWs?
Mshengah

Do a diagnosis. That is the only way you will know what that check engine light is all about. Your mechanic is very dodgy, judging by his response; over-revving will not necessarily cause the light to come on.

Parking the car on a slope means that the oil level in the sump goes up on one side and down on the other. The oil level sensor is on one side, so that change of level causes a false reading:
either too much or too little, depending on which side the sensor is mounted.

Park your car on level ground, wait for the engine to cool, and use the dipstick to establish whether or not, in fact, your oil level is outside the accepted range. I do not think it is a common feature with all VWs.

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Baraza,

I will skip the details about how much of an old school enthusiast I am but and ask: What are the odds of being able to put a new engine into an old car? For instance, I would like to fit a 1977 Toyota Celica with a Subaru WRX or Impreza engine. What should I consider when taking such a step? Will it be as efficient as it should be, and what are the constraints?

Do not be afraid of trying that out; it is actually a common method of tuning cars. Just make sure the engine fits, and if it does not, you can always make modifications to the mounts and firewall (front bulkhead). Also, remember to strengthen the mounts and front cross-member.

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Hi Baraza,
1. Does engine capacity significantly influence the car’s road speed? Case in point: A Toyota Prado with a 3.4-litre V6 petrol engine doing 100 km/h versus a Mercedes Benz E240 with a V6 petrol engine and around 200hp also doing 100 km/h, all other factors held constant.

My understanding of physics is that speed is not relative but absolute, meaning 100km/h is the same in all cars irrespective of the engine capacity and all other relevant factors, such as forced induction or lack of, and transmission mode. However, I feel like I have this entirely wrong. What is your opinion?

2. In terms of safety, what is the effect of installing big wheels and wider tyres (ridiculously wide) on an SUV, bearing in mind that they are not low profile tyres?

3. Sometime ago you wrote an in-depth article about tropicalisation of cars. Would you mind doing a quick overview of the important points for those of us with a short-term memory?

Bryan

1. Engine capacity does affect road speed, but not in the way you describe here. Case in point: I was in South Africa last month to drive a variety of cars from General Motors. One of them was the Chevrolet Spark, which had a tiny 1.2-litre engine. Despite my best efforts, I only managed 175 km/h in it. It could not be pushed any further.

Enter the dragon, the Chevrolet Lumina SS, sporting a 6.0-litre V8 engine from the Corvette supercar. Five minutes after I took the wheel, I had hit a heady 240 km/h without even trying, which the little Spark could not do if its life depended on it.

However, power output aside (that SS was something else I tell you), when the convoy was cruising along at 120 km/h, ALL cars were doing 120 km/h and ALL speedometers showed 120 km/h. 120 is 120, whether you do it in a small aircraft or in a motorised wheelbarrow.

2. I am guessing that you mean the huge rubber lumps that are bigger than asteroids used by hardcore off-road enthusiasts, right? They make the car wobbly and are totally useless on smooth roads. Do not use them if you do not need their abilities. They are meant for wading through swamps.

3. Here are the pointers:

  • Modify the engine (compression ratios especially) for the sake of our low octane fuel.
  • Increase the capacity of the cooling system (bigger ducts, pipes, radiators, high capacity water pumps)
  • Toughen up the suspension.
  • In some cases, another coat of paint (or UV resistant lacquer) may also come in handy.