??? ABOUT RING & PINION SIZE

[JEFF69Z28]

HOW DO I FIGURE OUT WHAT SIZE RING & PINION I NEED.CAR WEIGH'S 3485 WITH ME IN IT. IM EXPECTING 7000 RPM AT THE END OF THE 1/4 MILE,TURBO 350 TRANS AND PROBALLY 4500 STALL.RICHMOND SAID 4.10,MOSER,STRANGE AND RANDY'S RING & PINION SAID 4.56,IM CONFUSED.I WOULD HATE TO PUT IN ONE GEAR AND FIND OUT I NEED ANOTHER.

[TopspeedLowet]

Tell me what Mile per hour you want to be at at 7000 in the traps and I can tell you in two min. don't leave out the tire roll out you have or will have

[JEFF69Z28]

120-125 mph

[dparker]

Jeff, whats your tire size?

[JEFF69Z28]

27x9x15

[TopspeedLowet]

4.33 is you your tire roll calculation was 84" this gives 7050 in the traps at 125. Hows that

[dparker]

A 4:56 at 7000 rpm and 27" tire would be 123.36 MPH. I think a 4:56 gear is what I'd run with your combo.

[JEFF69Z28]

great afr said the head and cam package i bought from them was good to shift at 71-7200 rpm.I was thinking 4.56 which is all i can find for my 8.5 10 bolt,where could I purchase a 4.30 ring and pinion?

[TopspeedLowet]

A 4:56 at 7000 rpm and 27" tire would be 123.36 MPH. I think a 4:56 gear is what I'd run with your combo.
How did you come up with such a different answer? Did you figure no slippage in the converter. the moroso scale does not factor this in FYI.

[dparker]

He's running a 4500 stall so the slipage will be minimal. I think the growth of the tire will off set the slipage of the convertor. I'm using a dragmath program thats been very close on actual numbers for me. A 27 in tire actually has 84.82 roll out.

[zipper06]

great afr said the head and cam package i bought from them was good to shift at 71-7200 rpm.I was thinking 4.56 which is all i can find for my 8.5 10 bolt,where could I purchase a 4.30 ring and pinion?

Right here, or Motive also makes them.

But i kinda wonder how you're going to put that much torque to the ground with a 9" tire and a car weighing almost 3500lbs.

Zip.

http://www.ringpinion.com/ProductDetails.aspx?ProdID=5428

[dparker]

Jeff has a 3500lb car I think I'd install as much gear as I could to get it out of the hole. ET is in the first 300ft.

[JEFF69Z28]

9" wide is all i can get for width in the 86 ss monte carlo,should i go to a taller tire?

[TopspeedLowet]

He's running a 4500 stall so the slipage will be minimal. I think the growth of the tire will off set the slipage of the convertor. I'm using a dragmath program thats been very close on actual numbers for me. A 27 in tire actually has 84.82 roll out.
I hear what you are saying but you come up with 400 RPM off using the same inputs and tire size I used. If you feel solid with your numbers ok, Good luck

[dparker]

I would but I think about a 29 to a 30in tall is all your going to be able to get without cutting your fender wells. For every inch you go up in height it will make about 5mph difference. So if you went to a 4:56 and was turning to many rpms you could always go up in tire height.

[JEFF69Z28]

THANKS FOR ALL THE INPUT.I THINK IM GOING TO GET A 4.56 AND IF IM TURNING TO MANY RPM'S I WILL GET A TALLER TIRE.

[JEFF69Z28]

I would but I think about a 29 to a 30in tall is all your going to be able to get without cutting your fender wells. For every inch you go up in height it will make about 5mph difference. So if you went to a 4:56 and was turning to many rpms you could always go up in tire height.IS THAT 5 MPH FASTER OR SLOWER?