Final gear ratios

M

Marlon

Lifer
 Lancs.
Has anyone altered their final gear ratio to trade top speed for acceleration?
I’m not for one minute thinking about doing this, just idle curiosity after hearing an engineer friend who modified a VW Polo: He said that it was lightning fast off the line and that the trade-off in top speed was worth it.
I’m guessing that such a mod on a sports car would mess up the balanced acceleration through the gears and bugger up the torque curve.
 
A final drive can't change the torque curve. It won't change were the gears are relative teach other, all it will do is change change where they entire ratio set is 'placed' speed wise.

If you're willing to live with sitting at higher rpm there are big gains to be had as most modern cars are way over-geared.
 
I think the highest final drive is 3.73, compared with the 3.0si manual at 3.23.

At redline 1st 37/32, 2nd 64/56, 3rd 97/84, 4th 131/113, 5th 161/140, 6th 190/164

Would probably hamper 0-60 with the shift but perhaps some gains on the track once you're into 4th?
 
techathy said:
A final drive can't change the torque curve. It won't change were the gears are relative teach other, all it will do is change change where they entire ratio set is 'placed' speed wise.
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That makes sense.
 
Can't say for your car Marlon but IMHO the ratios on the ///M are just about perfect for the engine output. I'm happy to be out dragged by a 330d from 50-80 in top all day long, as that's not some thing I ever do. I tend to sit at 65 for hours on those rare occasions I use motorways. :)

The other side of this low torque motorway mode in top, is the pitch perfect scream through the other five ratios. Each new gear hitting home well above the 4.5 k Vanos zone and keeping the engine car and driver on an Adrenalin drip all the way to the other side of 170mph, were legality and space permits. :wink: :D :driving: :thumbsup:
 
By fitting a Drexler LSD with a ratio of something like 4.08 my E85 is now much, much faster in acceleration but overall mpg has dropped to 25 mpg. Top speed will have dropped, but still nowhere near anything that I am likely to achieve anyway! Acceleration is way faster than standard. :)
 
DLH said:
By fitting a Drexler LSD with a ratio of something like 4.08 my E85 is now much, much faster in acceleration but overall mpg has dropped to 25 mpg. Top speed will have dropped, but still nowhere near anything that I am likely to achieve anyway! Acceleration is way faster than standard. :)
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I remember you telling me about fitting an LSD at the TurnPike meet, didn't realise it altered the final drive ratio too :thumbsup:
 
Marlon said:
DLH said:
By fitting a Drexler LSD with a ratio of something like 4.08 my E85 is now much, much faster in acceleration but overall mpg has dropped to 25 mpg. Top speed will have dropped, but still nowhere near anything that I am likely to achieve anyway! Acceleration is way faster than standard. :)
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I remember you telling me about fitting an LSD at the TurnPike meet, didn't realise it altered the final drive ratio too :thumbsup:
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Yep, the final ratio is significantly higher than the OEM diff.
 
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