Gear Ratio?

FrankM · 02-04-2016, 03:05 PM

I am going to be ordering a 12 bolt from Moser for my 95 Firebird Pure Stocker. Using the online calculators like Wallace Racing seems to indicate with a 28" tire the right gear would be a 4.56. Assuming the car runs right it should be in the 110-115mph range. Are my calculations right or do I need less or more? Keep in mind this is a Pure Stocker with restricted valve springs so can't handle high revs.

Thanks,
Frank

RobbieRacer · 02-04-2016, 03:55 PM

My bracket car had a 28" tire, went 116 MPH and was turning 6400 RPM if that helps.

FrankM · 02-04-2016, 09:05 PM

That does help, thanks.

Eman · 02-07-2016, 01:23 PM

I'm looking at changing gears in my 3rd gen bracket car. The Wallace calculator doesn't seem to allow for converter slip, assuming you have an automatic. I run 29" tall tire and a t350 with 4.50 gear and at 100mph in the 1/8th my car is at 5900-6,000RPM. Wallace calculator says 5213 for my gear/MPH.
Wallace uses MPHxGear Ratiox336 divided by Tire Height=RPM

Rsmith38 · 02-07-2016, 02:56 PM

Slippage on my low HP stocker (8" converter) is about 6%.

02-04-2016, 03:05 PM	#1
FrankM Junior Member Join Date: Jan 2009 Location: Columbus, OH Posts: 98 Likes: 0 Liked 3 Times in 2 Posts	Gear Ratio? I am going to be ordering a 12 bolt from Moser for my 95 Firebird Pure Stocker. Using the online calculators like Wallace Racing seems to indicate with a 28" tire the right gear would be a 4.56. Assuming the car runs right it should be in the 110-115mph range. Are my calculations right or do I need less or more? Keep in mind this is a Pure Stocker with restricted valve springs so can't handle high revs. Thanks, Frank

02-04-2016, 03:55 PM	#2
RobbieRacer Member Join Date: Jul 2012 Location: Phoenix, Az Posts: 320 Likes: 17 Liked 118 Times in 41 Posts	Re: Gear Ratio? My bracket car had a 28" tire, went 116 MPH and was turning 6400 RPM if that helps.

02-04-2016, 09:05 PM	#3
FrankM Junior Member Join Date: Jan 2009 Location: Columbus, OH Posts: 98 Likes: 0 Liked 3 Times in 2 Posts	Re: Gear Ratio? That does help, thanks.

02-07-2016, 01:23 PM	#4
Eman Member Join Date: May 2014 Location: E TN Posts: 470 Likes: 16 Liked 133 Times in 76 Posts	Re: Gear Ratio? I'm looking at changing gears in my 3rd gen bracket car. The Wallace calculator doesn't seem to allow for converter slip, assuming you have an automatic. I run 29" tall tire and a t350 with 4.50 gear and at 100mph in the 1/8th my car is at 5900-6,000RPM. Wallace calculator says 5213 for my gear/MPH. Wallace uses MPHxGear Ratiox336 divided by Tire Height=RPM Last edited by Eman; 02-07-2016 at 01:27 PM.

02-07-2016, 02:56 PM	#5
Rsmith38 Member Join Date: Mar 2011 Posts: 186 Likes: 0 Liked 28 Times in 15 Posts	Re: Gear Ratio? Slippage on my low HP stocker (8" converter) is about 6%.