Low 1st Gear 904

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SuperStock

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I did a lot research, if I swap the Front Carrier, Front Ring Gear, Sun Gear from A999 to 904 I will have lower Gear Ratio on both 1st and 2nd Gear, the ratio will be 2.74/1.54/1 (904 stock ratio: 2.45/1.45/1)

I dont want lower on both 1st and 2nd Shift, I want lower ratio at 1st Gear only, like: 2.74/1.45/1

After study the 904, I release that if I want to lower the 1st Gear ratio, I will need bigger Rear Ring Gear and/or smaller Sun Gear. Are there aftermaket set that lower 1st Gear ratio only? Or anyone have modify 904 this way please let me know how did you do that?

I always think instead of Lower Axle Gear to help the car launch faster, Lower the 1st Trans Gear will do better job, what yours think?
 
1.54:1 is barely any different than 1.45:1. It would be more expensive and difficult to go through the trouble of trying to swap just the first gear. Besides the slightly lower 2nd gear makes the 1-2 'drop' not quite as bad as it would be with a stock 2nd gear, why do you want to keep it stock so badly?
 
MOPEkidD-3 said:
1.54:1 is barely any different than 1.45:1. It would be more expensive and difficult to go through the trouble of trying to swap just the first gear. Besides the slightly lower 2nd gear makes the 1-2 'drop' not quite as bad as it would be with a stock 2nd gear, why do you want to keep it stock so badly?
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I want lower 2.74 at 1st Shift because I it help launch car hard from zero, when car already moving it has momentum, so if I keep 2nd Gear Ratio higher(like 1.45 instead of 1.54) I believe it will make car go faster.

Lower 1st Gear will increase your chance in 1/4 mile, and also keep good MPG, thats what Im thinking.
 
aka474 said:
I want lower 2.74 at 1st Shift because I it help launch car hard from zero, when car already moving it has momentum, so if I keep 2nd Gear Ratio higher(like 1.45 instead of 1.54) I believe it will make car go faster.

Lower 1st Gear will increase your chance in 1/4 mile, and also keep good MPG, thats what Im thinking.
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You're right about the first part but I think you have the wrong idea about gear spread. When you shift gears the engine RPM drops depending on how different the two gear ratios are. When a car is accelerating, ideally the transmission keeps the engine revving as close to its peak power as possible. When you have larger spread between gears the engine has to slow down more between shifts, and unless you have a mild big-block with a tall but super-flat torque curve it will struggle to get back up to speed. This is even more pronounced with a hopped-up engine that doesn't make good low-end torque. Keeping the 2nd gear higher will make the 2-3 shift more 'effective' but will take away from the 1-2 shift.

Also the momentum of the car has nothing to do with acceleration; all that matters is the weight of the car + friction, being pushed by a force from the engine. How fast it's initially moving only affects the RPM (and thus the instantaneous torque) of the engine.
 
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