Questions About Turbocharged Cars

I'm think about buying a Mazda CX-7 but am a little leery of the turbocharged engine...I've never owned anything that was turbocharged. What special care and feeding to they require? How about reliability? They also recommend premium gas...what happens if you use regular? Does it just lose some power or does it do nasty things to the engine?

Reply to
M.M.
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With a turbo there are a few changes to keep in mind IF you want to keep it happy and not need to replace the turbo. One is to use a Synthetic oil and change it regularly (3-4K with a turbo is normal) Another is that if you just ran it hard and kept it making boost for a while DON'T just shut it down when you stop driving, let it idle a few minutes to cool the turbo and keep from burning the oil in the turbos bearings. The premium gas is REQUIRED with a turbo engine. They are tuned for more power and the turbo packs in more air/fuel mix. The higher octane fuel will resist pinging which will kill a turbocharged engine faster than it will hurt a non turbo. That is due to the increased relative compression that results from the turbo pushing in the mix. Use regular gas and you will discover just how expensive the parts of the engine are. Reliability is usually ok UNLESS you abuse the vehicle/turbo.

Reply to
Steve W.

I wouldn't know about that specific car, but be aware that 60+% of cars bought in Europe are Diesels. They all come with a turbocharger. Turbos themselves are known and straightforward technology.

The turbine sits in the hot exhaust and spins up to 150000 rpm at full load. It is ususally cooled by oil and/or water within the engine's respective circuits. The only bit of special treatment it needs to get is some time to cool down after running hard. If your trip involves pottering through a residential area at 30mph for the last mile, you'll be fine. If it involves running at 120+ mph for an hour straight and then stopping at a gas station, let it idle for a minute or two before you're shutting it off, so it can cool a bit. That is all.

cu .\\arc

Reply to
Marc Gerges

  1. Follow the owners manual for advice on gas octane rating.
  2. Do better than the owners manual when it comes to oil changes -
4,000 miles and use synthetic.
  1. Enjoy the car. With proper care and reasonable driving habits the turbocharger (and the rest of the car) should easily last beyond
200,000 miles.
Reply to
John S.

Why shouldn't he follow the owners manual for oil changes? Don't know what it says, but 4000 between changes seems ridiculous. There's no reason a car shouldn't go 5 times as far between changes.

Yep. And that would even allow for some fun :)

cu .\\arc

Reply to
Marc Gerges

Is it necessary to do the idle cool-down even when 100% synthetic is used?

Reply to
larry moe 'n curly

YES !

Reply to
Mike

It is not necessary if the last minute or two of your trip is at low speed and low power. The comparably cold exhaust gases at these conditions help cool it enough to not cause it any grief.

The Turbo, when under full load, turns hot enough to shine red. So when you've been driving under these conditions, you need to give it a minute or two at idle.

cu .\\arc

Reply to
Marc Gerges

Most owners manuals say 7,500 or so.

Well, lets do the math with your proposal. 4,000 miles times 5 equals

20,000 miles. So you are saying that turbocharged cars should be run for 20,000 miles before changing the oil and filter. It would be an invitation to early engine replacement.
Reply to
John S.

Depends on the cars, I'd say.

My last turbo charged car was a 2 Liter turbocharged diesel. Manufacturer's recommendations said I should change oil and filter every

2 years or 30000 km (which is something like 20000 miles). It didn't really strike me as odd. Considering the engine is used in lots of different cars and sold at the hundred thousands per year, I think the manufacturer probably knows what they are doing.

cu .\\arc

Reply to
Marc Gerges

Yes. Even synthetics can't take red-hot metal. It only takes 30 seconds, its time WELL spent.

Reply to
Steve

A great many turbo engines do not require premium gas at all. The boost management electronics has a knock sensor input and will bleed off the boost through the wastegate if knock is detected. Premium fuel just allows the engine to run at higher boost levels than it can on lower octane cordial.

This may not be true of all turbo cars but is definitely true of Saabs. Late models measure the post power stroke plasma ionization at the spark plug and hence don't use a knock sensor.

Reply to
Bhagat Gurtu

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