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Petrol engine? Don’t be a fool!

01/04/2014 14:39 |  Comments: 


Former car restorer, damper designer, rotary-engine guru and also an automotive engineer, but generally doesn’t talk much about his former activities. András is our mag’s Leatherman tool: when there’s a project no-one would poke with a stick, he’s the one usually assigned to carry it through. When he’s in Hungary, he works 16 hours daily, then every once in a while he disappears from the horizon. Last time he’s been seen in Auckland… Has a huge garage, lives with a girlfriend.

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I wouldn’t think twice if I had to choose a motor for a new car. Tell me, why should I buy a petrol engine?

Cars are running on petrol.” „Diesel is for tractors.” That's just bullshit, no matter how many still stick to these stupid statements. They should try one of those pretty little petrol engines and then, right after that, a diesel in the same car. They would have to agree that in most cases the diesel is much better, beyond all comparison.

It all started with the Note. The spiritless supercharged three-cylinder petrol engine was just crap after the diesel. It was followed by the Captur. It shook, rattled and jerked with the woeful 900 cc TCe. Right after that I took a seat in the Skoda Yeti 1.4 TSI. It sounded just like a diesel which is not exactly a compliment for a petrol engine. I admit that's a rather unfortunate selection of test cars and this constellation had a great effect on me.

On the other hand it's true that in the last 30-40 years diesel engines deserved their bad reputation. In the beginning, rough characteristics and moderate power came with thick black smoke. Then they gained some grunt, but lost reliability on the way, and not much later the disease, called Mondeo-phenomenon, threatened diesel-owners with horrible service costs. Long gone was the legend of the Mercedes engines running a million kilometres without bothering, plus we found out that diesel smoke causes cancer. And smells bad. All of this led to the popular belief that diesels are cheap at the petrol station, but expensive at the garage, and toxic anyway.

What happened meanwhile with the petrol engines? The simple, naturally aspirated motors which were really more reliable, easier, and cheaper to repair, are a rarity among today's new cars. On almost every new petrol engine, there's direct injection, exhaust gas recirculation and at least one turbocharger. Even the ignition coils, oxygen sensors and EGR-valves of some naturally aspirated engines could be a pain in the neck, but the cutting edge petrol technology is at least as risky as the diesel systems. Collective wisdom is dragging behind at least one or two decades.

In my mind, the slowly accumulated experience over the years came down to this: the fuel consumption of diesels may be attractive, but petrol engines are undeniably more elegant. They sound better, smell better, and are more pleasant altogether. It's like tractor drivers in rubber boots versus intellectual theatre visitors. The strange thing is, nowadays the intellectuals seem to wear rubber boots.

There were dozens of diesels in the last few months and years that made me say: Jesus, I'd prefer to own this one instead of a petrol sibling. Frightening, isn't it? And if diesels are more enjoyable - which they are indeed – something must have gone wrong.

Diesel engines made an incredible leap forward in the last two decades. They have much more low-end torque and are revving much more happily than before. Spontaneity was never a real problem for them, and the turbo lag seems to be much easier to handle for the engineers than in the case of the petrol engines. Okay, their fuel consumption doesn't decrease any more, but even stagnation is acceptable on this level.

At the same time, there are more and more petrol engines that aren't worth a shit. Before you start protesting, let me tell you that I also know some that are really good, but the trend points downwards: less and less cylinders, more and more turbo boost, and an incredibly increasing magnitude of problems. This is true from Dacia to Mercedes, there are only a few Japanese exceptions, but not for long, if you're asking me.

Let's see why we adored petrol engines. Because they were smooth-running? Listen to the cold-start of a TSI and you'll see that past tense is correct in the previous sentence. Because they were more fun to drive? Naturally aspirated engines will be soon extinct, manufacturers are putting bigger and bigger turbochargers on smaller and smaller engines, so you'll have to face even bigger turbo lag in the future. Because of their reliability? Read our tech articles and you'll see that some direct-injection petrol engines have even more severe problems than the dreaded common rail diesels: carbon build-up at the intake valves for example which can happen at 50k kilometres instead of at 150k as previously. Because their exhaust gases are less detrimental? Don't be so sure about that: direct-injection petrol engines are emitting a serious amount of particles that are similarly carcinogenic as diesel smoke.

While stringent laws force manufacturers to put more and more effective particle filters on diesel engines – which is a good thing - legislation only starts to recognise this serious problem of modern petrol engines. You say, a modern petrol engine consumes as little fuel as diesels? Look at the brand new Peugeot 308, European Car of the Year which takes more than 10 litres on 100 kilometres on shorter trips. Or at the Opel/Vauxhall Insignia which surprised us just today as I write this article with a reading of 15 litres. Let's be fair and say that the consumption of a turbo petrol engine depends very much on where and how you drive it.

I could find thousands of good and bad examples, but I feel that something has changed. When in a tiny little car like the Nissan Note or the Dacia Sandero clearly the diesel seems to be the better choice, when in a Mercedes E class you can hardly find a proper 6-cylinder which is obviously the only adequate engine, you have to rethink your prejudices. It's hard to find a reason for buying a new car with a petrol engine. There are no more universal wisdoms, you have to look at each model separately, and you better get used to the thought that the diesel will win the comparison. The worst thing is: not only because it takes less fuel, but because it's more fun to drive.

I don't know if the European exhaust gas norms or the CO2-emission laws have killed the petrol engine. It's just happened, at least here in Europe. In the bigger part of the world, in Asia, Australia and in America there are only a few diesel passenger cars. There's a different car culture, different legislation and I guess different problems. Anyway, if I had the choice in a new car today, in most of the cases I'd go for the diesel.

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