718 4.0 - short ratio kit?
- Thread starter edseds
- Start date
Changing 3-4-5 without changing 2 has the effect of bringing 3 closer to 2 and the result is almost like 2x 2nd gears.
So might work for you if just want to shorten those gears 3,4& 5 for track, and bring those ratios closer together ...but actually the real ‘issue’ with the stock ratios on the road is with 2nd. So you’ll have 2 boxes in 1... long 1&2 and then short stack 3,4,5, then a bigger gap than OEM from shorter 5th to OEM 6th
Also if we’re nitpicking, OEM 6 is a little short for relaxed motorway speed cruising... and being a touch longer would be even better for economy there also. But overall I’d say it’s fine for a fun car.
1+2 are on the main shaft and so it’s not a very easy change and not sure there are any well know options to help here.
GT Gears have a full custom gear set including 2nd which they supply to Deman Motorsports in the US for their 4.5L builds. I do believe this is available to buy though.
CW&P ‘final drive‘ is the other way.. this effectively shortens all ratios, but does not address the gap of rev drops between ratios. Also you are increasing the effective torque through the crown wheel... so over time this could become a stress point with aggressive/used as intended use... so something to bear in mind. Also the cost of going this route is comparable to a custom gear set anyway, depending on who you go to.
I think people should really think carefully about exactly WHY they want to change the gearing... options available means it not straight forward, cut and dry.
I know of a couple cars that have had this done... CW&P via RPM and custom 3,4 & 5 via JZM. Customer were happy in both instances, but they then didn’t keep the cars for very long after moving on to other metal... so didn’t really get a long term view.
So might work for you if just want to shorten those gears 3,4& 5 for track, and bring those ratios closer together ...but actually the real ‘issue’ with the stock ratios on the road is with 2nd. So you’ll have 2 boxes in 1... long 1&2 and then short stack 3,4,5, then a bigger gap than OEM from shorter 5th to OEM 6th
Also if we’re nitpicking, OEM 6 is a little short for relaxed motorway speed cruising... and being a touch longer would be even better for economy there also. But overall I’d say it’s fine for a fun car.
1+2 are on the main shaft and so it’s not a very easy change and not sure there are any well know options to help here.
GT Gears have a full custom gear set including 2nd which they supply to Deman Motorsports in the US for their 4.5L builds. I do believe this is available to buy though.
CW&P ‘final drive‘ is the other way.. this effectively shortens all ratios, but does not address the gap of rev drops between ratios. Also you are increasing the effective torque through the crown wheel... so over time this could become a stress point with aggressive/used as intended use... so something to bear in mind. Also the cost of going this route is comparable to a custom gear set anyway, depending on who you go to.
I think people should really think carefully about exactly WHY they want to change the gearing... options available means it not straight forward, cut and dry.
I know of a couple cars that have had this done... CW&P via RPM and custom 3,4 & 5 via JZM. Customer were happy in both instances, but they then didn’t keep the cars for very long after moving on to other metal... so didn’t really get a long term view.
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