gday just got 2 free ke70's and both of em have 5speeds but 1's staying and the other going to be stripped. ive got the good old 4k-c with a 4 speed and the gears do bog down a bit on the change, so ratio wize would it be better to put a 5 speed in it and if so would it just bolt in ??

Ratio wise they're pretty much the same. A 5 soeed has an overdrive, which is beter on the highway. I.e: doesn't rev as hard on 100kph. 1-4 ratios are pretty much the same.

thanks and i 4got to say it's for motorkhana and khanacross so i need good ratio's!!

It's not going to make a difference really. If you want to get them closer without spending ultra dollars on custom gears, change your final drive ratio. (diff gears.)

so that means it wouldnt make a difference at all unless i changed the diff ratios and i'll only use 1st,2nd and 3rd i spose

In a nutshell. Yes.

Smaller diameter rear wheels for a quick gear ratio change ;)

lol ive already got 13 inches of space and ive got globes and hotwires coming that are 13 inches of space!!

This is what i have found with all the Ke70 diffs i have seen.

 

Ke70 Auto = 4.3:1

Ke70 4 speed = 4.11:1

Ke70 5 speed = 3.89:1

 

Correct me if I'm wrong ?

does it get driven on the street at all? or just racing?

 

if driven on the street, then definately go 5 speed, if just for racing, then go the 4 speed.. less weight you see ;)

 

also look for the 4.3:1 diff, that will help too.

 

strip the guts out of the car to make it lighter etc..

 

just out of interest toyota ae71, do you race at the bagshot track by any chance?

thanks alot man yeah sure do used to race the white ae82 but i took out the red ke70 2 meetings ago!!

My ke70 has a 4.1 and it is a 5 speed fitted from factory. The only time I has seen a 3.9 or 3.89 is in an AE71.

I have a 4.5 borg in my ke20, I was going to put it behide my 4age in the ke70. should be fun for awhile

 

Chris

As has been said, if its only for the track you wont need the 5 speed. When I was autocrossing, I would only spend about a third of the time in third. That was with a KE20, modded 5K and 4.2 diff. With a 4K I wouldn't think you would need three speeds let alone five ;)

 

Definetly try different profile tyres. The different height sidewalls will make a slight difference in gearing. The smaller the height, the more acceleration you will have.

 

Some other things to try if its only a track car - use thinner oils in the gear box and diff. In the past I used ATF in the gearbox.

thanks for all the info will do coz its due for some new rims and transmission and diff oil change

i believe 5spd boxes and 4 spd boxes have the saem gear ratios, jsut get a different diff if u want more acceleration