Stage II ? with gear ratio.

[278cikiller]

Question on gear ratio. Iam running a stage II with a 206/212 roller cam,car has a brf tranny with a 3.90 gear and a 28.5 tire,Question is will i be alright going through the traps in drive or do i use over drive, Vavle flot on the cam card is 6200 RPM,any in put would be great thanks. This is the frist time out with the car going to a arm drop event with no time slips.

 

[nucnova]

Question on gear ratio. Iam running a stage II with a 206/212 roller cam,car has a brf tranny with a 3.90 gear and a 28.5 tire,Question is will i be alright going through the traps in drive or do i use over drive, Vavle flot on the cam card is 6200 RPM,any in put would be great thanks. This is the frist time out with the car going to a arm drop event with no time slips.

If you do the math at 6000rpm you would be at 130.49mph and at 6500rpm you would be at 141.36rpm. Lots of things come into play here such as converter slip, tire growth and etc. Make a pass and see if you need overdrive or not. Valve float is dependent on things such as spring pressure, weight of the valve train and ramp profiles so if your springs were set at what the cam card recomended it would be wise not to exceed that rpm.

 

[278cikiller]

If you do the math at 6000rpm you would be at 130.49mph and at 6500rpm you would be at 141.36rpm. Lots of things come into play here such as converter slip, tire growth and etc. Make a pass and see if you need overdrive or not. Valve float is dependent on things such as spring pressure, weight of the valve train and ramp profiles so if your springs were set at what the cam card recomended it would be wise not to exceed that rpm.

Thanks for the info,Ill have to keep and eye on things.

 

[ttypewhite]

Dan, you will not make it through in Drive for sure. That's very similliar to the setup I was running back in the day with my 3.90 gears and 200R4 tranny. I had to shift OD well before the ET line.

 

[bison]

I don't agree on the cam choice for the application. Peak power will be around 5400@30-32psi the way it sits. It should not need to be over 6000 ever with that cam. Gear the car to go 140mph@6000 with 5% slip.

 

[SCOOBY DOO]

I don't agree on the cam choice for the application. Peak power will be around 5400@30-32psi the way it sits. It should not need to be over 6000 ever with that cam. Gear the car to go 140mph@6000 with 5% slip.

Brian...what rear gear would you recommend?