D_M_A_N

I dont think it's so much the weight as it is the size on the 18's. I have superlight 18's but they still suck for performance, though they look better than smaller ones IMO.

Bigger wheels change the shift timing in autos, and it takes longer to get going. Less gas mileage too. I know there's some kind of equation you can use to get actual mileage out of oversized wheels, but I went from getting 32mpg with stock wheels to getting 22-25mpg with 18's. I dont think the equation will make up for 10mpg.

typhoonorchid

(I can't tell if your saying that the overall diameter of your wheel/tire package is bigger then stock?)

Anyway...It's 2 things: the bigger the rim the more weight farther out from the hub = bad for performance. And a heavier rim is worse than a lighter rim period.

Each pound you can lose off your wheel/tire package is like losing 10 pounds off the chassis.
On a M.T. Box each horsepower @ the wheels is pushing around about 26 pounds.

If you got some 11 pound rims you might be saving 10 lbs per rim!(x4) this would be equivalent to adding 15 hp @ the wheels.

It would show up on a dyno too.

stangdude22

I am suprised you are getting that kinda of milage, I have heavy 18s, I would say around 22-24 lbs. and I get around 28-30mpg.
Can wait to see what happens with 15lbs 16s!!

Kevtav

http://www.importtuner.com/powerpage...2003_scion_xb/

xb2bnvd

Im guessing no one else has been to the dyno...im lookin to take mine sometimes soon.
I got:
Strup header
Blitz axle back
Fujita short ram intake
Nology hotwires
Grounding kit (not sure if this does anything)

ShadowOnTheBayou

To the original poster: Is the header the only exhaust modification that you had? In other words, was it a header hooked up to a stock exhaust?

How does it sound? Any sound clips?

stangdude22

Well, I am getting a consistant 2mpg more withthe 16s

D_M_A_N

I have a Volant CAI, and stock exhaust.
The sound didnt change after I put the header on, at least that I could tell. Maybe just a tad deeper. The majority of my sound comes from the CAI. With the box around the air filter it sounds pretty mean, but as we all know, is not

I am still waiting on my ram air scoop that goes from the fog light housing straight to the CAI box. That should help a little more on power hopefully.

I do believe my MPG sux more with this header. Or my foot might have gotten heavier.
Probably the latter.

ShadowOnTheBayou

That's exactly what I wanted to know, man. Thanks!

I absolutely loathe the way these cars sound with aftermarket exhaust systems. It's just not my taste. I was thinking about getting a header, but I didn't want it to change the sound.

itsme

i wonder what i can my numbers are on a dyno.......how much does it cost to dyno your car? im onlee wondering cuzz i can keep up with friends 95 Acura Integra LS that has I/H/E/ and a stage 2 clutch....i can pull on him from first to third gear then after third he starts to walk me and then when we start to near 100mph he just leaves me........its that same thing every week.......yea i race him every week