I am not shure if i understood the benefits and disadvantages of the different gear ratios (like 3.42, 3.72, 3.9 . . .) All i know is that they get adverticed with better acceleration than the standard. I do have the 3.42 on my vette and realized that the max speed is not as high as from a friends C5( see my sig for details. He was at least 5-7 MPH faster). But i dont know his ration . . . So who can tell me the technical differences in the ratios and the benefits or disadvantages in regard of max speed, acceleration, fuel consm. and so on.

Any info is appreciated

Jochen


[Modified by Jochen, 2:35 PM 3/14/2002]


[Modified by Jochen, 2:46 PM 3/14/2002]

 

As far as I know ... a 2.73 will have a higher top speed ... but a 3.90 will accelerate quicker ...

Other than that .. I have no idea ... Sorry...

 

It's like this, The girls from Medellin are beautiful.The girls from Cali are gorgeous. Get it? Oh, You said gears, I thought you said girls!:D :D :D

Hola Jochen!!! y Lili


[Modified by BRADS C5, 4:04 PM 3/14/2002]

 

BRAD !!! nice to read from you . . . I hope you and Carolina are fine. We had a great time in Colombia and all was really really nice. Honeymoon on Isla Palma - What an island ! Like in paradise. I hope you will go to Colombia one day, it is a wonderfull country.

I send you a few Emails but havent got any replies. Maybe you changed your Email like i did. My new one is jlellesch@skydsl.de

I tried to contact dough, but he never answered on my mails. Hope you guys are good. We will be in Miami this May. I hope we will see us.

Take care, Jochen y Liliana

 

The amount of torque your engine puts out and is multiplied by the gear ration of the transmission and then the ratio of the rear.

So if you go from 3.08 ratio to 4.11 your torque to the wheels will increase by 4.11/3.08 which is 33%.

Now great you have 33% more torque! The drawback is that now in fourth gear 1:1 ratio at 6500 engine rpm you will turn 6500/4.11 =1581 wheel rpms instead of 6500/3.08 = 2110 wheel rpms which means you will be going 33% slower as well.

So you sacrifice top speed for more torque which usually equals better acceleration. This is not usually such a big deal in a car equipped with overdrive (unless you live in Germany and like hauling butt on the autobahn.)

You have to be careful, since you can over gear a car as well. In general, the cam, rear gears, and torque converter should be selected to match the powerband of the engine to the gearing.

hope this clears it up for you

 

To add to what Tim said, you eventually need to factor in air resistance generated with those autobahn runs. This is why you sometimes see cars running faster in 5th gear rather then 6th - theoretically the car should go faster in 6th, but it's running into so much air resistance that having the car in 5th puts the engine in the fatter part of the power band - engine is putting out more power which overcomes the gearing disadvantage. Also don't forget the size of your tires (the outside diameter) will factor into the equation. A bigger rolling diameter tire is like a gear change, since one revolution of the tire covers a greater distance than a smaller tire. As for gas consumption, you gotta love that big overdrive 6th gear that lets the engine loaf along at 75-80 mph. So, generally speaking, lower rear end (bigger number) equals faster acceleration, lower top speed, greater gas consumption. Think of a bicycle with a rear derailleur (sp?) with multiple gear sprockets on the rear wheel. You start riding using the big rear sprocket to accelerate faster or to climb a hill (more torque), but eventually you shift to a smaller sprocket with fewer teeth to go faster. Hope this helps and viel spass!!


[Modified by wamara, 4:25 PM 3/14/2002]


[Modified by wamara, 10:08 PM 3/14/2002]

 

To add to what's already been said, the gear ratio (like 3.42:1) indicates how many revolutions the transmission's output shaft must make to make the wheels revolve once .. at 3.42, the trans output shaft turns 3.42 times to turn the rear wheel once.

 

Wow, i already knew that in this Forum we have many good informed and nice people. But this shows me again that it is even more than only this.

Thank you for your detailed and "easy to understand for a german guy" explain !

Jochen

 

I am getting my gears changed at VetteWrench soon (waiting on Power programer). This is the best information I have had on "why" I am doing it. Thanks guys for the education. :cheers: