Q's about cars [Archive] - Grand Am Owners Club Forums

Pte Socks

03-24-2003, 10:00 PM

well i have a couple of questions about cars in general and about my car.. so i posted it here hoping to get the best results.. k my questions are as follows
1) what does a 99 GA se1 run stock for the quarter mile? ive heard a couple of different answers ranging from high 16's to mid 15's... does anyone know the what is the truth?
2) what does torque differences mean in a car? like there are 5.0 stangs with 220 hp and 300 ft/lbs of torque.. theres my ga with 170 hp and 195 ft/lbs and there is a 2001 celica with 180 hp and 130 ft/lbs.. what would the differences in torque be performance wise
3)rpms.. i dont really know how this affects stuff.. but ive come to the conclusion that higher is better but i dont know if that is correct .. ie celica gts 180 hp@7600 rpms compared with a ga se of 170@4800 rpms. again... looking performance wise
4) and last.. gear ratio.. and once again.. celica gts is 11:1 compared with 99 ga of 9.5:1. and once again.. performance wise.. hopefully someone can answer my questions about these..

TA^Guy

03-25-2003, 01:50 AM

Originally posted by Unrealoaded
1) what does a 99 GA se1 run stock for the quarter mile? ive heard a couple of different answers ranging from high 16's to mid 15's... does anyone know the what is the truth?
If the SE1 is a V6 it should run high 15's to 16's at sea level.

2) what does torque differences mean in a car? what would the differences in torque be performance wise
Torque simply put is a rotating force. Torque equals force (combustion) multiplied by distance (connecting rod). The engine produces torque by rotating the crank. Torque is that actual force that moves the vehicle. The more torque, the quicker the vehicle will acclerate.

General rule of thumb, the larger the motor the more torque you can make. This is why you hear the saying "No replacement for displacement" and "bigger is better", and for the most part it is true. Look at your examples. The 4 cylinder Celica makes only 130ft/lbs, a V6 GASE makes 195ft/lbs, and a V8 Stang makes 300ft/lbs. This great difference but yet their hp ratings are all with-in 50hp of each other.

Now you know torque is the actual force I think it's safe to tell you that hp is basically a equation of work done as a result of torque. 1 'HP' is equal to 33,000 foot-pounds of work every minute. So to do 1 hp of work you must move 330lbs 100ft in one minute. To find hp from torque you must multiply your torque by the engine rpm and then devide it by 5,252. (Torque x Engine speed) / 5,252 = Horsepower.

3)rpms.. i dont really know how this affects stuff.. but ive come to the conclusion that higher is better but i dont know if that is correct .. ie celica gts 180 hp@7600 rpms compared with a ga se of 170@4800 rpms. again... looking performance wiserpms (revolutions per minute) vary on each motor. Higher RPMS aren't always better. Most your real power (see torque above) is made at lower RPMs. Once you off and moving the hp is the oull at the topend that you feel. But just because your making 170hp at 4800rpms doesn't mean if you goto 7600rpms doesn't mean you'll make anymore power. Actually higher roms is what will kill a motor faster due to incressed friction, incressed pressure and force on the rotating assembly. Remember revloution that pistion must change direction. Some cars are built to reach their peek hp at higher rpms this is why your peek hp varies from car to car. Lighter rotating internals helps to allow higher rpms, along with tigheter tolerences and stronger internals. Once reason my .6 liter 4 cylinder in my motorcycle redlines at 13,250rpms.

4) and last.. gear ratio.. and once again.. celica gts is 11:1 compared with 99 ga of 9.5:1. and once again.. performance wise.. hopefully someone can answer my questions about these.. [/B]
What you listed is not gear ratio. It's the static compression ratio. Static meaning the ideal compression under perfect conditions. This will vary slightly to actual compression due to things like air density, fuel density, etc. When a piston travels down with the intake valve open it creats a small vaccume and draws air/fuel into the cylinder. On it's way back up it compresses it just before the mixture is ignited by the spark plug. So basically 11:1 means that 1 unit of air is compressed into a 11th of it's original size. The more it's compressed, the more consentrated engery there will be avalible.

Now gear ratio or also known as final drive ratio related to the differental. Gears are simple machines, with a gear reduction, the output speed can be reduced while the torque is increased.
As a example a car using a larger gear reduction of 3.73:1 (low gears), the driveshaft will turn 3.73 rotations to each rotation of the tire. This will allow for quicker accelration, but lower top speed.
A car using taller 2.73:1 gearing will rotate the driveshaft 2.73 times fo revery tire rotation. Typically result in slower acceleration but higher top speed.

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If I forgot anything or left anything out please excuse me. I jus t worked 12 hours and had to run somewhere important after work. Basically I had a really long day. Hope it helped. :)