Stick Cars:gear Swap Results

rickster · 12-05-2007, 12:42 PM

i would like to see the results of rear gear swaps

60',et,mph

stick cars only please because i'm running a clutch car
thanx

Jeff Lee · 12-06-2007, 12:56 PM

I can say this; over-gearing can have as much negative impact as under-gearing.
Your question is to broad and vague for anybody to provide help.

rickster · 12-07-2007, 09:27 AM

what i'm looking for is an example of a gear swap,from not enough to optimum

which would help starting line leverage,and keep the motor in the powerband thru the lights

how does it effect 60',et,mph??

come on guys [4.88 to 5.13] [5.13. to 5.38] or better yet [4.88 to 5.38]

each car will react different to these changes,but i'm just looking for trends

thanx

Jeff Lee · 12-07-2007, 10:58 AM

As the engine specs changed over the years (cam primarily), I saw improvements going from 5.13 to 4.88 in D/S. I had the 4.88's in when I converted the engine (just the engine) to SS/H. I went faster when I later placed the 5.13's back in the car (I only run a 29.5" slick). I'm now placing 5.38's in the car but am going to a slightly larger tire. You just need to do the math on gears to the RPM your engine works best at. Heck, there are 455 pontiac's that are fast, really fast and only run a 3.73 gear in D/SA. I know turbo cars that have 3.90 gears. So, sorry, it all depends!
A general rule of thumb on a stick is 1st gear x rear gear should be around 15.00. Try that and see if that helps. But do the math!

gmonde · 12-07-2007, 10:12 PM

this all depends on hp vs torque the bigger cubic inch engines can run a higher gear ,even though the cam shaft may have a crazey duration ,smaller engines need a lower gear to perform,this is not news to most but,stockers try to run out the end on rpm and some times big cubic inch engines suffer,i put it like this ,i had a 455 buick, i could throw the brick on the gas pedal and it wouldnt rev past 5000 rpm free wheel no matter how long it sat there,it wouldnt blow up ,it would 60 ft like crazy but you where i high gear way before the 1/8 and you where hanging ,each application is different good luck gmonde

Adger Smith · 12-09-2007, 01:32 AM

Rear gear & tire size for finish line RPM & MPH. Transmission gear ratios for leave & split times.

acme383 · 12-15-2007, 07:16 PM

the best thing i did this past year, was go from a 4.88 to a 5.13. sixty foots dropped and so did et. my car has a 98" rollout on the tire with a 500cid stroker leaving at 6800-7400rpm.

12-05-2007, 12:42 PM	#1
rickster Junior Member Join Date: Nov 2004 Location: torrington,ct Posts: 13 Likes: 0 Liked 0 Times in 0 Posts	Stick Cars:gear Swap Results i would like to see the results of rear gear swaps 60',et,mph stick cars only please because i'm running a clutch car thanx

12-06-2007, 12:56 PM	#2
Jeff Lee VIP Member Join Date: Jul 2007 Location: Anthem, Arizona Posts: 2,766 Likes: 0 Liked 3 Times in 3 Posts	Re: Stick Cars:gear Swap Results I can say this; over-gearing can have as much negative impact as under-gearing. Your question is to broad and vague for anybody to provide help. __________________ Jeff Lee 7494 D/S '70 AMX

12-07-2007, 09:27 AM	#3
rickster Junior Member Join Date: Nov 2004 Location: torrington,ct Posts: 13 Likes: 0 Liked 0 Times in 0 Posts	Re: Stick Cars:gear Swap Results what i'm looking for is an example of a gear swap,from not enough to optimum which would help starting line leverage,and keep the motor in the powerband thru the lights how does it effect 60',et,mph?? come on guys [4.88 to 5.13] [5.13. to 5.38] or better yet [4.88 to 5.38] each car will react different to these changes,but i'm just looking for trends thanx

12-07-2007, 10:58 AM	#4
Jeff Lee VIP Member Join Date: Jul 2007 Location: Anthem, Arizona Posts: 2,766 Likes: 0 Liked 3 Times in 3 Posts	Re: Stick Cars:gear Swap Results As the engine specs changed over the years (cam primarily), I saw improvements going from 5.13 to 4.88 in D/S. I had the 4.88's in when I converted the engine (just the engine) to SS/H. I went faster when I later placed the 5.13's back in the car (I only run a 29.5" slick). I'm now placing 5.38's in the car but am going to a slightly larger tire. You just need to do the math on gears to the RPM your engine works best at. Heck, there are 455 pontiac's that are fast, really fast and only run a 3.73 gear in D/SA. I know turbo cars that have 3.90 gears. So, sorry, it all depends! A general rule of thumb on a stick is 1st gear x rear gear should be around 15.00. Try that and see if that helps. But do the math! __________________ Jeff Lee 7494 D/S '70 AMX

12-07-2007, 10:12 PM	#5
gmonde Senior Member Join Date: Nov 2007 Posts: 615 Likes: 56 Liked 165 Times in 59 Posts	Re: Stick Cars:gear Swap Results this all depends on hp vs torque the bigger cubic inch engines can run a higher gear ,even though the cam shaft may have a crazey duration ,smaller engines need a lower gear to perform,this is not news to most but,stockers try to run out the end on rpm and some times big cubic inch engines suffer,i put it like this ,i had a 455 buick, i could throw the brick on the gas pedal and it wouldnt rev past 5000 rpm free wheel no matter how long it sat there,it wouldnt blow up ,it would 60 ft like crazy but you where i high gear way before the 1/8 and you where hanging ,each application is different good luck gmonde

12-09-2007, 01:32 AM	#6
Adger Smith VIP Member Join Date: Dec 2001 Location: Texarkana Ark/TX Posts: 2,446 Likes: 575 Liked 880 Times in 311 Posts	Re: Stick Cars:gear Swap Results Rear gear & tire size for finish line RPM & MPH. Transmission gear ratios for leave & split times. __________________ Adger Smith (Former SS) Last edited by Adger Smith; 12-09-2007 at 01:33 AM. Reason: S.P.

12-15-2007, 07:16 PM	#7
acme383 Junior Member Join Date: Mar 2005 Location: chitown Posts: 55 Likes: 0 Liked 0 Times in 0 Posts	Re: Stick Cars:gear Swap Results the best thing i did this past year, was go from a 4.88 to a 5.13. sixty foots dropped and so did et. my car has a 98" rollout on the tire with a 500cid stroker leaving at 6800-7400rpm.