gear choice at perris & VV

[asr99]

We are going to build a street stock to race at perris and victorville next year and I was looking for some info on what gear ratio to run there.

[Jesse "Flash" Gordon]

I would most definitely have an answer to that. I ran both tracks this year. I run a 6:0 at Perris pulling about 6000 to 6100 rpms and a 6:50 at Victorville. I run Mastercraft Avenger GT's all the way around and on the right side I have 255/70/15 and on the left side I have 235/70/15. I also only have a 2 speed powerglide if any of that info helps? Trust me you will enjoy running both tracks. I truely like Victorville's track the best but Perris' track just feels more professional and all having the pits inside and the load P/A system. It all just brings an awesome atmosphere! Hope you have fun!

I have a car for sale if your interested or want to find out if my info is credible? here's the link.
The Famous #10 Street Stock

[Rowdy Burns]

Gear ratios is determined by what size tires you use and which gear you use in the transmission and the spec's for the camshaft / engine as to where the peak hp and torque is in the engine.

There is calculators online that can determine how many rpms a engine will turn at X MPH with y- sized tires.

Let's use a ficticious number just for the sake of a example. Let's say my 2009 Chevrolet Avalanche LT with P295 /70/20 inch tires spins 600 times in one mile.

That means that at 60 MPH - or one mile per a minute, the tire will spin at 600 RPM
s If the final gear ratio is one to one in the transmission, we would know that the engine would have to spin at about 2100 Rpm's if the final gear ratio was about 3:42


The reason for that is that you would have a slight loss due to the components spinning on the front of the engine that robs power from the engine. The weight of the torque converter and the rolling resistance of the tires as they go down the road.

If you could actually see inside of the tire as it spins - you would see a flat spot on the bottom of the tire that actually rolls as the tire rolls down the road. You would also loose some power due to the viscosity of the fluids in the transmission and the rear end and the drag of the brakes on the brake rotors.

So choose the RPM's that your engine runs best at - preferably on a engine dyno - but you could look at the cam card for the engine. Then figure out the diameter of the tire, - which you can measure the outside of the tire with a tape rule and then divide by one mile. Do the math and you can figure out which gear will work best for you.