6 cylinder vs. 4 cylinder turbo

Safety and low maintenance priority. Don’t need sporty. Hear turbo is o.k. with diesel, but can be a problem with a gas engine.

Which is better?

There are a lot of “ifs” here. Personally, I would chose a 6 cylinder non-turbo car over a 4 cylinder turbo, in gas or diesel. Turbos on gas engines are not necessarily more troublesome. Even Chrysler built a successful turb model in their gas powered K car series. However, there were a number of problems with the 4 cyl. Mustang turbo, and the driving style of Mustang owners did not help."

If you were an engineer or other concientious car owner, go for a turbo if you like that model. If car care is a bit of an afterthought to you, stay away from turbos, gas or diesel.

A turbo 4-cylinder diesel (IF YOU CAN FIND ONE) is an excellent way to go. Not to many companies offer them in the US yet.

Part of the problem with turbocharged gas engines is that they usually require premium gas and, unlike other engines that are premium recommended and can compensate for regular gas, if the owner uses regular in them it can severely damage the engine. This isn’t a problem with a turbo diesel.

All things being equal, the turboed 4 will generally get better mileage than a naturally aspirated 6 with roughly the same power rating, although it isn’t always the case for various reasons.

If you go with the turbo, definitely follow any requirements related to using synthetic oil and premium gasoline.

Different cars have different amounts of turbo lag. Make sure you’ve tried that out at various speeds during your test drive.

A boosted motor will experience more stress than an N/A motor. Probably use more gas too.

It all depends on the application by manufacturer and vehicle. What car are you thinking about?

Some negative statements here are true about turbo’s but only specific applications.

The 6 cylinder will probably have greater logevity (all things being equal). The 6 cylinder will likely have smoother power delieverly. Some turbos (particulary those that run alot of boost) suffer from turbo lag. Almost all turbos require the use of premium fuel. The turbo engine will get better fuel mileage most of the time, provided you’re not in the boost all the time.

That is sort of asking what flavor ice cream is best. Safety — about all I can come up on that one is Diesel fuel is less of a fire hazard vs gasoline. I believe most auto diesels currently in cars on the road today are 4 cylinder turbo VW’s like mine. (TDI = Turbo Diesel Injection)

I believe you will find more difference in maintenance and life, between different manufactures or different engines than you will find any real trends between gas and diesel or turbo or no turbo.

I would not worry about the engine first. Start by picking out a car you like and test drive the available engines that it comes in. Then check to make sure there are no known problems with the car or engine. I would not start by picking out an engine.

The turbo is NOT used all the time. Only when needed. When not needed (which I suspect 99% of the time) the 4 cylinder will give better gas mileage. I agree complete that they do put a bigger stress on the engine.

A 6-cylinder generally will have much higher torque…especially in the lower RPM range as compared to a 4-cylinder turbo. However a 4-cylinder turbo Diesel can have as much or MORE TORQUE then a gasoline 6-cylinder. In fact this type of setup is ideal for small to mid-size SUVs and pickups. Wish they were offered here in the US. Many are being offered in Europe and South America.

Take a look a SAAB for turbo info they have been using them a long time.

First, turbos are reliable as long as you maintain the vehicle correctly (this applies to diesels also). And, there is no relationship between these 2 engines and vehicle safety. Safety is related to the driver and the vehicle design.

A turbo-charged 4 kind of gives you the best of both worlds: good gas mileage when you are gentle and good acceleration when you need it. If you are looking at gas mileage, a turbo 4 will do better than just about any v6 when driven conservatively. A good 6 cyl engine will generate more horsepower, but not necessarily much higher torque at low rpms (for example, the VW 2L turbo gas engine develops 207 lbft from 1800 - 5000 rpm while the 3.6L v6 generates 280 lbft, but at 2800 rpm). Remember that the larger 6 also adds weight to the vehicle.

VW RECOMMENDS premium for maximum performance, and the engines will run fine off 87 octane fuel. So, it’s not true that you HAVE to use premium or risk damaging the engines.

One other thing to note is that normally aspirated engines are more sensitive to altitude. So, if you live in Colorado, for example, you won’t get as much of the rated torque (and therefore horsepower) out of the 6 as you would out of the turbo 4.

I can’t believe anyone is attempting to answer the question without knowing the specific manufacturer in question. That a 4 cylinder turbo and a 6 cylinder is involved means nothing-zero, zip, nada. Without knowing the specific cars or engines in question you simply cannot answer this question.

How about a non turbo 4 cylinder, some are pretty peppy.

There aren’t that many manufacturers that offer turbo charged engines in the US right now. The ones that do have a reasonbly long history with them, and know how to build them. These same manufacturers usually offer 6 cylinder engines in the same vehicle at a different trim level. What we are trying to show is that commonly accepted “truths” aren’t really true. But, of course, the specific engine is important for a detailed analysis as you state.

BTW, my comment about altitude is true no matter what manufacturer we’re talking about.

There aren’t many turbos offered in the U.S.!? I strongly disagree-it seems as though everyone is offering a turbo car at the moment. The Acura RDX, The BMW 1 & 3 series, The Mini Cooper, The MazdaSpeed cars, Audi A4, VW GTI, Chevy Cobalt, Subaru WRX and others, Saab, Mitsubishi, Etc Etc Etc.

A variation of this same discussion came up 54 years ago. Kaiser offered a supercharger(not a turbocharger) on its 1954 Kaiser Manhattan. The Kaiser engine was a Continental flathead 6. Kaiser’s advertisement called this power on demand. One had the economy of a 6 in normal driving, but when one needed power, flooring the accelerator kicked in the supercharger. The Kaiser with the supercharger probably did accelerate pretty well for the times. If one had the automatic transmission, the transmission was the GM 4 speed hydramatic. As for the economy, I’m not all that certain that the flathead 6 was all that efficient. My parents had a 1952 Dodge with the flathead 6 and a 1954 Buick with a V-8 engine and a standard transmission. The Buick got better mileage than the Dodge. Even with the supercharger, the Kaiser didn’t make it in the marketplace.

I have a 1987 Volvo 760T with a turbo charged 4 cylinder engine (cast iron block); it has more than 166K trouble free miles. It still has the orignial engine, heavy duty automatic transmission, turbocharger, intercooler, and rear axle. This engine/transmission combination was used by Sweden, Denmark, Norway, and
Switzerland police departments as a high speed police chase car to capture speeding motorists. This turbocharger has a water cooled jacket surrounging the turbo, and an intercooler. I have this car the routine maintenace described in the owners manual. Very well-built, well engineered car!

The 1987 Volvo gets better gas mileage than my 1996 Volvo with a 6 cylinder,
normally aspirated engine. Both cars produce about the same horsepower (even though the 1996 Volvo with 6 cylinder engine has a larger displacement engine).

I have two Volvos; both have more than 168,000 miles on them. I live in Denver and like to drive up the mountain roads on weekends during both summer and winter conditions. The 1987 Volvo 760 has a 4 cylinder gasoline engine with turbo and does not require synthetic oil or premium fuel. I still have the orignial engine, auto transmission, and turbo (noe have been repaired or replaced).

The 1996 Volvo 850 5 cyliner, normally aspirated, gasoline engine produces about the same amount of horsepower as the 1987 760 4 cylinder with a turbo. The 4 cylinder turbo engine gets slightly less highway mpg; both get about the same city mpg. The turbo lag is so small, it is a non-issue. Both engines have been trouble free.

The key to an engine’s long life–regularly scheduled maintenance!!