Car lovers

[geek4life]

For all the car lovers out there...

Starting to idly shop for a new car. Mainly looking at sport-sedans. Pretty open-minded: I've considered everything from the Subaru Impreza to the Mercedes-Benz C230 sport sedan. I'll probably be less open-minded when it comes to affording and/or financing it, but we can all dream Wink

Anyway, a lot of sport-sedans are equipped with either turbochargers or superchargers. I can look up the technical definition of each device on Google, but that doesn't tell me what I really need to know: what do they feel like? More power all over the powerband, or a spike high in the band? What are the consequences to the machine? Reduced fuel mileage, more engine wear, more expensive maintainences? First-hand experiences with turbo or supercharger equipped cars is the best, but all responses are welcome.

 

[OS]

s/c or turbo effect on powerband is all in implementation and/or design. There's no fixed guidance for this.

 

[SynthDude2001]

My car's got a supercharged engine...I don't really know much of the technical specs either, but it's definitely a lot more powerful over the whole range - my last car had the exact same engine, except non-supercharged.

I'm sure there is more engine wear or something, but I'm not really a car person so I'm not going to try to explain stuff I don't understand.

Fuel mileage is not bad at all, I think my current car is rated at 17 city/25 highway, compared to 18/28 for my last car.

 

[jagec]

For the most part, superchargers are designed to give more power over the whole range, and turbos give you more power at higher RPMs. As for the machine, a forced induction engine will certainly get lower fuel mileage than an equivalent engine which is not forced induction. It's not a horrible drop, but worth considering. Check out fueleconomy.gov for fuel mileage listings.
Engine wear isn't a real huge issue. Anytime you increase the power output on the same internals, there's a bit more wear, but it's not enough to concern yourself over. Maintenance cost shouldn't change either, but you DO have to be a lot more picky about ALWAYS changing your oil and filter on time (synthetic oil helps a lot for forced induction), not driving the car hard when it's still cold, and if you drive it really hard, give it some time with the engine running to cool down before shutting it off. This is because turbos and superchargers get REALLY hot, and if you shut off the engine, that stops oil circulation, which may result in pretty much baking the oil that's in there.
Finally, you can't put Regular into a forced induction car. Always, always use the grade recommended in the owner's manual or higher.

 

[OS]

Originally posted by: jagec
For the most part, superchargers are designed to give more power over the whole range, and turbos give you more power at higher RPMs.

that's not really true any more. Those 1.8T audis and VWs make max torque at like 1900 rpms.

 

[Zenmervolt]

Originally posted by: jagec
For the most part, superchargers are designed to give more power over the whole range, and turbos give you more power at higher RPMs. As for the machine, a forced induction engine will certainly get lower fuel mileage than an equivalent engine which is not forced induction. It's not a horrible drop, but worth considering. Check out fueleconomy.gov for fuel mileage listings.
Engine wear isn't a real huge issue. Anytime you increase the power output on the same internals, there's a bit more wear, but it's not enough to concern yourself over. Maintenance cost shouldn't change either, but you DO have to be a lot more picky about ALWAYS changing your oil and filter on time (synthetic oil helps a lot for forced induction), not driving the car hard when it's still cold, and if you drive it really hard, give it some time with the engine running to cool down before shutting it off. This is because turbos and superchargers get REALLY hot, and if you shut off the engine, that stops oil circulation, which may result in pretty much baking the oil that's in there.
Finally, you can't put Regular into a forced induction car. Always, always use the grade recommended in the owner's manual or higher.

Superchargers do not require idling after driving hard. And modern turbochargers are often liquid-cooled and also don't require idling after driving hard.

ZV

 

[flot]

Generally speaking, superchargers make more power over the entire rpm range, so there is not a big difference in driving.

Generally speaking, turbochargers make more power at HIGHER rpms, usually starting in the 2300-3300 rpm range. So typically turbocharged cars will have more of a "kick" as you accelerate, but less grunt off the line.

In either case, it'll depend on the overall design of the system. But I think it is safe to say that turbos will have more of a power peak. Either can produce anywhere from 30%-100% more horsepower than the same engine without forced induction.

Neither is especially bad, but since you are basically adding additional complexity outside of a normal engine, it is fair to say that you should expect a slight increase in maintenance costs. (if for no other reason, than because you now have a turbocharger/supercharger which could go bad) Both will likely require premium fuel. The supercharger may have an internal oiling system that needs to be changed from time to time or could feed off the engine oil. Turbos typically feed off the engine oil. In either case, you'll need to be more religous about oil changes because unlike your engine internals which are spinning at 6000 rpm, the turbo may be spinning at 60,000 rpm.

In today's products, there's no reason to expect a turbocharged or supercharged car to have any sort of significantly reduced lifespan. It used to be that turbos were only expected to last 50k-80k miles, but my 91 twin turbo was still on it's original pair after 13 years / 160,000 miles.

 

[jagec]

Originally posted by: OS

Originally posted by: jagec
For the most part, superchargers are designed to give more power over the whole range, and turbos give you more power at higher RPMs.

that's not really true any more. Those 1.8T audis and VWs make max torque at like 1900 rpms.

Which is why I said "for the most part". That's how things are usually tuned, but using the correct sized turbo you can make power wherever you want it.

Or you can twincharge, or go the TT route, but that gets complicated.