Turbocharge in cars, question.

[freebee]

I have a good example. Turbocharging is like plastic surgery. You can get larger breasts, but they are apt to be bouncy and strangely textured. But it works well on skinny women...and skinny women with big boobs are very attractive.

A naturally aspirated engine is like normally large breasts. However, normally large breasts are usually found in fat women. And large boobs, no matter how well shaped...when connected to a beer gut and thunder thighs do not work very well.

 

[Xenon14]

freebee,

ROFL!!!

 

[Evadman]

<< freebee,

ROFL!!! >>



Save some crack for me please!

 

[Grinchy]

I drove the Altima 3.5 (240 hp), and the WRX (22? hp), and the Jetta V6 (180?) and the Passat 1.8 Turbo (180). The Altima has an incredibly fun engine, but that car is the wrong application. FWD has no business with that torque. Horrible mix, and the suspension - gooey.
The WRX was fast, and fun. Drove it in the rain and no problems with getting the power to the ground. The Jetta was a good V6 in a rear drive, better than the same horsepower Turbo in the Passat, which lagged something fierce, and really didn't kick as much as it needed too - I'm guessing the Passat was too heavy.

Of all of them, since they all cost about the same (Jetta a few Thou less), the WRX is the winner. Interior is mildly horrible, but the engine and drivetrain and handling are all the best. The passat is a better cruiser, but the WRX was just fun, and the wagon has a lifetime of room in it.

As to which is better, the 240 n/a or the 240 turbo, the 240 n/a is more fun from 0-30. Then the turbo anytime after that. With a good turbo, it'll boost some at 15-20, and that really is good.

 

[Zenmervolt]

<<The Jetta was a good V6 in a rear drive>>

Hate to burst your bubble, but Jetta's front drive. (Unless you get the Jetta with AWD.)

ZV

 

[Cyberian]

<< 240 HP without turbocharging. But there are arguments fr both cases.

240HP without turbo means the engine is probably larger, or better designed. Also, it would be possable for that engine to possably make more HP if/when it is upgraded.

240 with supercharger, you have to wait for the Turbo to "spool up" The turbo does not put out any power at idle, because the impeller ( the fan that pushses in the air into the engine ) has to get up to speed before the power comes on. On the other side, the turbo will probably last longer, but you have to be sure to change that oil right at 3000 miles. Turbos eat oil for breakfast You may be able to modify the "waste gate" to get more boost. The waste gate lets excess air out of the forced induction process. Your waste gate is probably set around 6 psi. Crank that baby up to 30

<edit>
The 240 turbo includes the power generated by the turbo in that figure. >>

What does a Turbo do to oil that an N/A engine doesn't?

 

[slag]

It heats it up alot.. and can gunk up your turbo charger--called "coking"

It will break the oil down much faster than a N/A (normally aspirated) car.

Its like.. if you heat up anything too hot, eventually it turns into a goey sticky sludge.. thats the early stage of coking..

read THIS for info on coking and oil in general.

 

[Cyberian]

Got it.

I didn't realize that all Turbochargers used engine (crankcase) oil for lubrication.

 

[Emos]

That's why it's generally a good idea to use synthetic in a turbocharged engine, it won't break down as easily.

 

[Jerboy]

Ok for engines with identical maximum output(horsepower), naturally aspirated engines will be larger.

If you can force more fuel+air into cylinders, you'll get more power. It's easy to force more fuel by injecting more fuel. Turbocharger/Supercharger is the one responsible for forcing proportionally more air. Turbocharger is basically an air compressor powered by exhaust gas, so there won't be much boost until you have lots of exhaust flow. Supercharger is similar except it's powered from engine shaft.

Forced aspiration engines often sucks at low-end acceleration due to lack of low-end torque and turbo boost. Once you get the RPM up to certain value, it will match up well with larger naturally aspirated engines. This is the real petpeeve..

It gets better fuel economy and guzzles less gas at idle hence having smaller displacement and block size. This explains why it's very popular in Europe and Japan. In Europe fuel is very expensive, Japanese roads are narrow and super crowded and people spends long time idling in stop and go. An American V8 would literally gulp down fuel when you idle for a long time.

So to summarize the pros and cons:

Pros:
Alot of power for displacement
identical top-end power as larger engine and this is the determining factor in top-end speed.
better fuel economy
lesser idle fuel consumption
lighter

Cons:
More parts=more things to break
lacks low-end power and torque
hard on oil
sounds more like a ricer than roar of American V8

 

[Kadarin]

Someone commented earlier about preferring the naturally aspirated 240hp engine because it would make still more power with a supercharger or turbocharger added. This is true to a point, and that point is how the engine is designed. Engines with fairly low compression, using flat top or dished pistons (forged, not cast), and specific cam grinds (usually emphasizing higher exhaust lift and longer exhaust duration with a wide lobe spacing) lend themselves well to forced induction (the same rules apply to using nitrous oxide, where instead of using a compressor, the air is pre-compressed in a nice bottle). Engines with 10:1 compression or higher with domed pistons and poorly designed cylinder heads (like the awful Ford 5.0 castings with the extremely restrictive exhaust ports) don't work quite so well without help.

If I had the opportunity and the funding to put together a really fast street car, and I wasn't worried about smog, I'd probably build a turbocharged Ford 302 from the ground up with forged everything (pistons, crank, rods), and choose components with an eye toward the fitting them together into a complete package, from intake to combustions to exhaust.