question on gears
Thread Starter
Safety Car
Joined: Mar 2002
Posts: 3,729
Likes: 0
From: Vancouver, BC
question on gears
seems like 3.70 gears are highly desired from what i can tell. how would lower gears affect vehicle performance and what effect would higher gears have? thanks.
Melting Slicks
Joined: Dec 2000
Posts: 3,407
Likes: 2
From: Carmichael CA
Re: question on gears (SizzleChest)
Gearing depends on the engine, how many gears are in the transmission, and what you want to do with the car. If you only had one gear in the transmission and the car will be used for transportation on freeways with a maximum speed limit of 60MPH and the desire is for best performance then the rear end would need to be selected so that at the highest horsepower peak of the engine the vehicle will be traveling at the cruising speed of 60MPH to allow more load carrying and better throttle response and manuevering during the speeds that the vehicle will normally be driven at.
With that in mind consider that the highest HP will be around 4,500 RPM and the fuel efficiency will be terrible. So, if fuel efficiency is desired with everything else the same, then the rear gear should be selected so that the engine RPM's will be at the point where HP is just sufficient to keep the vehicle at the cruising speed of 60MPH.
If the vehicle is desired to go from zero to 60 as quick as possible, then the rear gear should be selected so that the sum of HP used during the acceleration is the greatest...this is usually where the redline of the engine is.
As you can see there is a lot to this. However, if you are interested in 1/4 mile drag racing then the rear gear should be selected so that at the end of the 1/4 mile your engine will be at redline in the highest gear. Keep in mind that higher gears will reduce your top end speed.
With that in mind consider that the highest HP will be around 4,500 RPM and the fuel efficiency will be terrible. So, if fuel efficiency is desired with everything else the same, then the rear gear should be selected so that the engine RPM's will be at the point where HP is just sufficient to keep the vehicle at the cruising speed of 60MPH.
If the vehicle is desired to go from zero to 60 as quick as possible, then the rear gear should be selected so that the sum of HP used during the acceleration is the greatest...this is usually where the redline of the engine is.
As you can see there is a lot to this. However, if you are interested in 1/4 mile drag racing then the rear gear should be selected so that at the end of the 1/4 mile your engine will be at redline in the highest gear. Keep in mind that higher gears will reduce your top end speed.
Melting Slicks
Joined: May 2001
Posts: 2,812
Likes: 4
From: Gig Harbor Wa
Re: question on gears (SizzleChest)
With all else being equal, switching to lower gears (higher number) such as going from 3.36 to 3.70 will give the feeling of more torque and power. This results in quicker acceleration. The downfalls are higher RPM for a given speed. This will lower fuel economy.
Switching to higher gears (lower numerically) will give better fuel economy because of the lower RPM for a given speed. Downfalls of this would be slower acceleration.
Switching to higher gears (lower numerically) will give better fuel economy because of the lower RPM for a given speed. Downfalls of this would be slower acceleration.
Thread Starter
Safety Car
Joined: Mar 2002
Posts: 3,729
Likes: 0
From: Vancouver, BC
Re: question on gears (70 LS1)
With all else being equal, switching to lower gears (higher number) such as going from 3.36 to 3.70 will give the feeling of more torque and power. This results in quicker acceleration. The downfalls are higher RPM for a given speed. This will lower fuel economy.
Switching to higher gears (lower numerically) will give better fuel economy because of the lower RPM for a given speed. Downfalls of this would be slower acceleration.
Switching to higher gears (lower numerically) will give better fuel economy because of the lower RPM for a given speed. Downfalls of this would be slower acceleration.
