Can anyone tell me the ratios for a 5 speed corolla gearbox. We run in speedway with a 4 speed in second gear with a 3.9 diff and was wondering if a 5 speed in 3rd gear would be a better option for speed.

Off the top of my head I think I read on here that the only different between the K40 and K50 is the 5th gear (all the other ratios are the same). I could be completely wrong though. Feel free to correct me someone.

from what i hear on here, the ratios on each gear are the same 1-4 in both boxes, the 5 speed is essentially an overdrive gear added onto the 4 speed box to make the 5th gear.

someone will probably correct me if i'm wrong.

 

Edit: beaten to the point.

Edited June 12, 201115 yr by dzach23

http://www.rollaclub.com/board/topic/49536-does-the-k50-dominate-the-k40/

 

Some of the responses say:

 

1st: 3.789

2nd: 2.220

3rd: 1.435

4th: 1.00

5th on the 5 speed is 0.865

 

 

And:

 

Later (KE70) 4speeds and 5speeds are the same. The 5th is an overdrive gear stuck on the back outside the gearbox itself. 5th is nice on the open road, it just drops the revs a few hundred at 100kph. As soon as the revs hit 3000rpm going up a hill its time for 4th.

 

The earlier 4speed had a 2nd and 3rd closer to 4th, which would also be nice. 2nd is 2.022 and third is 1.384 One day I'd like to take the internals of an early box and stick it all inside a 5speed.

 

The diff ratio affects cruising speed also. I'm using an auto diff at 4.3, the manual runs a 4.1 So mine is quite perky around town but revs a bit higher on the open road.

There's the only difference Steve-

 

Early boxes run a 2nd of 2.022 & later ones have a second of 2.22. So an early box will give you more speed for the same revs, unless you're using one already.

 

I haven't sorted out if its possible to combine the two, but I doubt it as the layshaft gears are all machined on. Otherwise you could get a high 2nd and a low third together!

 

How about a 4.1 diff and using third?

Thanks for your help everyone. The main goal we are looking for is top speed. If the ratios are the same from 1st to 4th in both boxes their isn't really an advantage by switching to a fivespeed? What would be the best way to get the most drive out of the car? Gearboxes we have tried are 4.3 4.1 and 3.9 we have always used a four speed gearbox and most generally run 2nd gear with a 3.9 however we feel that we could get even more drive out of the car. Thoughts anyone?

If you're using 2nd with a 3.9 diff, you will have to look at things like auto diffs from celicas. They were down to 3.4 and 3.6 in the '82-'85 models. I'm not sure what they released in Aussie.

 

The usual diffs are the 4.3 and 4.1 & 3.9, so the next speed up with a Corolla diff would be third gear with a 4.3.

 

If you want to start welding the mounts onto other diffs you can get old Volvo diffs from 3.7 downwards, but although it will extend the top speed you can pull it will slow acceleration. Then you run into wheel stud changes..

Would it be an advantage to try and source a panel van diff - 4.5:1 - and run in third?

What would be the best way to get the most drive out of the car?

Are you looking for more torque/pull out of the corners or more top speed?

 

If you go up in the diff ratio go from 3.9 to 4.3 you will have more torque out of the corner, but higher rev's on the straight, And vis versa if you go down in diff ratio the revs drop and you have less torque/pull in 2nd gear.

 

What mod’s are you allowed to the motor in your class?

Can you balance the motor and change the cam to run at a higher RPM?

Also are you allowed to run stagged tyres like sprint car can? This will give you better direction and grip mid corner to late corner

Are you looking for more torque/pull out of the corners or more top speed?

 

If you go up in the diff ratio go from 3.9 to 4.3 you will have more torque out of the corner, but higher rev's on the straight, And vis versa if you go down in diff ratio the revs drop and you have less torque/pull in 2nd gear.

 

What mod’s are you allowed to the motor in your class?

Can you balance the motor and change the cam to run at a higher RPM?

Also are you allowed to run stagged tyres like sprint car can? This will give you better direction and grip mid corner to late corner

yes we have a larger cam in, the car will rev to about 7500rpm.

Thanks people. we will look into your suggestions. Cheers.