Gear Ratio Question??

[paco]

Is there any way we can change the gear ratio in our transmisions??
I Know you can do it with differencials. I was wondering if you could do it in our cars.

[manybrews]

if its an automatic, no. the PCM monitors the ratios 100 percent of the time to check for proper shift quality, timing, and verify its not slipping.

if its a manual, you could.. if you could find some other ratios.

frankly, the ratios are damn near perfect. why would you want to change them?

[paco]

because it takes too long to shift. Wouldn't the car be faster if the ratios were shorter. It' hard to explain. But think of it like with the tires.- If you put bigger than stock tires, the car is going to start slower if you put smaller it's going to start faster. What if we could change the gear in the axle (the one that makes the tire spin) for one that has more teeth. Wouldn't that make the car go faster.
Because you know that our cars are slow starters. If this can be done it would help a lot.
I don't know if I made any sense but I can barely undestand it, I have been talking to a friend of mine that used to race bikes for a living and he was telling me about this and about how much it helped him in his 1/4 mile time.
Any help would be appreciated.

[Auto-9]

You're right, if the gear ratios were shorter, it would be quicker to shift. However, remember that's what manual trannies and continuously-variable trannies are for...thus if you shorten your ratios you'll need more gears to attain higher speeds. Changing your overall wheel/tire diameter is not recommended because you'll have to recalibrate it...and refine tune the gearing that the engineers have already done for you.

[paco]

No,no man. I understand what you are saying but, that is not what I meant. We wouldn't need extra gears for higher speeds because we would already be going really fast. Look at this:

Transmission Gear (turns)-----------Gear connected to tire (turns)
a.- 1--------------------------------------.50
b.- 1--------------------------------------.75

These are no real numbers, this is just an example but which way would be faster? b
Now, my question was how can we make our cars go from a to b, with our real numbers of course.
I hope this makes morse sense. But on Monday I'm going to go to a performance transmission shop, I know a guy that works there and we'll see if this is something that can be done with our cars.

Oh and by the way, my friend that raced bikes, he went from 9.90s to 9.10s after he did this to his bike.

[manybrews]

if you numerically raise the ratios, you will end up with better acceleration. the trade off is higher RPMs at the same speeds you were at previously. this in turn raises emissions, drops milage, and may limit your top speed if you run out of RPMs before you run out of gears.

[paco]

I think this would hapen if you change both gears, but what if you only change the one that makes the tire spin. If I could add a gear with 5-10 more teeth there. All that you said wouldn't hapen. The only thing that would happen is faster acceleration.

[RollinBishiStyle]

Just go play Grand Tourismo 3 and change the gear ratio on a car for better acceleration, that will show you the problem with it. :orangeno:

[manybrews]

<div class='quotetop'>QUOTE(paco)</div><div class='quotemain'>I think this would hapen if you change both gears, but what if you only change the one that makes the tire spin. If I could add a gear with 5-10 more teeth there. All that you said wouldn't hapen. The only thing that would happen is faster acceleration.</div>
no.
there is always a trade off. ESPECIALLY if you just change the final drive ratio.
anytime you switch any gears of any driveline, you trade RPMs for torque, or vise versa.

[paco]

alright, I agree with you. But you think it wouldn't be worth it. I mean, how often do you drive at 120mph. I'll still look into it and we'll see what happens. Thanks for all the input.
Whenever I have any results I'll get back to you guys.

[Auto-9]

<div class='quotetop'>QUOTE(paco)</div><div class='quotemain'>I mean, how often do you drive at 120mph. Â*</div>

You have no idea :laughing:

[FRCFD6]

not to burst you guys' bubble, you can change gear ratios, but to get a reliable setup, expect to spend at least 5-15000 for a custom set of gears. the tooling alone for the gearsets are not worth it changing a whole transmission.

[T-O-P]

Our tranny's aren't very tough anyway, so you might wanna consider beefin the tranny up too .. I would do other mods before gear ratio's.