but isnt it the gears that make you accelerate faster, thus turning a better time?

 

Smaller wheels and tires gives the same affect.

Andre

 

Only to a point, there is several variables involved in picking the right gear for 1/4. You have to consider your cars weight, power curve. You can't just put in a high gear set and expect it to perfom the way you may expect. Picking a gear that not only limits some shifting time but more importantly maximizes the duration and amount of your power curve with your cars weight. You could litterially take this info and find one precise gear that will give you the best possible exceleration in 1/4 for your car. You want to cross that finish at peak power/rpm. So you have some calculating to do to figure out which is the right gear for your car. High gear sets are fun around town and from stop light to stop light but aren't always the best choice for max accel over a given distance.

The general rule is more power = less gearing. For example a semi truck with no trailer doesn't weigh that much and it puts out roughly 700whp @1500trq and has gearing all over the place. Take a diesel VW bug for the sake of comparison both being low rpm engines and tell me who will get to the 1/4 first. Technically the semi should have much better power to weight but its high gearing is a limitation in motivating that power effectevly for exceleration. It can however pull a house down.

Other then some tight auto cross tracks and some added fun, in my opinion for these reasons I stated above there isn't any real performance reason to go any higher then a 4.44 gear in the S. N/A or FI if your looking to maximize your power delivery for max accel.

There is a nice gear calcular floating around that you can use to deturmine speed in each gear and can be vary usefull for assisting in deturmining the right gear for 1/4 distance racing.

 

But better because your also reducing overall unsprung weight= faster accel/decel/manuvering

 

Andre

 

Honestly I would go to 4.44 or stay stock. If my 4.57's blow I'll be 4.10's again

420rwhp S/C btw

 

this isn't true

with gears torque multiplication increases because of a changed rotation ratio

with smaller wheels the torque is still the same because the rotation ratio hasn't changed

 

I think your confused. The effect is the same but efficiency is much better then just doing a gear swap in the rear end. You can have the same effect by keeping the rear end stock and changing the trans gears also, but again the wheel/tire method is the most efficient. Just from the pure numbers stand point on paper, you can use the gear calculator to see that the effect of your tire size on your rpm vs speed is identical to the gear ratio's of your choice. Try it

For example these are some wheel/tire combinations that I have tried and these are the break downs of the effective rear end ratio they provided.

225/45/16 = 4.26

245/35/17 = 4.29 -current

215/45/16 = 4.33

245/35/16 = 4.48

 

^ now that i think about it, you do make sense..