One of my friends told me that turbo'd cars actually get better results when running bigger rims (....less tire). I thought that by running bigger rims, one would lose torque. hell i felt a diff when i changed from stock to 18's. So, is it true?

 

Depends, your friend might be referring to a larger diameter wheel covers "can" cover more pavement with one spin?

Maybe...I might be way off. But I do know the larger in size means more weight, generally.
So I personally dont care much about the flashy flashy, so I plan of going boost, keeping stock 17's and putting some bad ___ tires on em.

 

The wheels act as the truly final drive gear. If you increase the size of the wheels it'll dampen acceleration. It'll cause the engine to take more time to do the same amount of work so you'll technically have more time to maximize your tire's grip.

For all you people wanting a smaller (longer) final drive ratio, technically, you can just get some 22" DUBs.

You don't lose torque; it saps away your effective power.

It's all in the law of conservation of angular momentum.

Generally, you're going to want a different means of maximizing tire grip. You can slow things down with your pedal or you can slow things down by adding stuff to your car that makes it slow. Most of us here want to make the car, ultimately, faster.

Here's a quick experiment to test this law. Take a string of good length and swing something on it at a constant rate. With the same amount of force applied, swing the string with half the length and notice how fast it's swinging relative to before.

 

......what?? so what your trying to say is......

 

^^Smaller with better tires is better. Stick to the same size wheel, but wider. Like 18x8.5's with some good rubber, and you would be rockin and rolling.

 

turboed engines like to be in a "bind" . for example a n/a car will do great with 4.11 gears where a turbo car will not. a turbo car needs the engine to work hard = burn more fuel which generates heat energy and spools the turbo faster and makes it have a higher ceiling . so heavier wheels may actually help but not as much as staying light and just changing the diameter .

 

Take an introductory physics class. Many of the questions asked here can be answered with basic physics and sometimes, chemistry.

Whoever said that larger wheels are better for turbocharged cars isn't entirely wrong. The idea is to lengthen (make numerically smaller) the final drive ratio to maximize tire grip. I'm sure everyone here knows how easily the tC can spin the stock Potenzas. If you slow down your gas foot you'll notice that the tires don't spin so much. In fact, if you go really slowly on the gas, you'll notice that the tires don't spin at all.

By decreasing the final drive ratio (making the gears longer) it slows down how fast your axles get up to speed so you give your tires more time to cling on to the pavement.

Changing out the actual final drive gear isn't really easy to do so the next best thing, although a band-aid fix at best, is to increase the size of your wheels since the wheels act like the very last gear in the transmission. Having larger wheels will sap away power because it forces the engine to take longer to do the same amount of torque (power is a measure of how fast you can twist.)

Of course your friend probably meant larger wheels in the way that rhythmnsmoke meant - width. Wider wheels present more rubber to the pavement so, essentially, you'll have more grip.

Either way, if you want to go faster go with some light weight 17" wheels and get some good tires and forget all about angular momentum.