Gearboxes- Anybody Swapped Gears Out?

[altezzaclub]

The massive gap between third an fourth is a pain in my K50, and I wondered if anyone had swapped the earlier gear sets from the Ke30/55 into a K50.

 

While a lot of people say the K40 and K50 have the same ratios, there are several different sets of ratios quoted, even in our Wiki.

 

Going the T50 path would have the same effect, but cost a bundle and give a lot of hassle with K-T bellhousings and heavy gearboxes.

 

So... anyone 'blended' a K40 and a K50 yet??

[Taz_Rx]

K40's have an even bigger ratio difference between 4th and 5th than a K50, so doing what you've suggested would make what you don't like even worse!!! :yes:

[altezzaclub]

K40's have an even bigger ratio difference between 4th and 5th

 

Read that again Taz!

 

Its pretty hard to find 5th in a K40!

 

Anyway, I assume you mean 3rd to 4th, and if its bigger you are right, it would be worse.

 

However our Wiki lists 3rd gear as-

 

K40 1.405

 

K50 1.435

 

and then it says-

 

Doug spotted that there are two different ratios across the series, listed below:

 

KE10, KE20, KE30, possibly KE55 w/ 4 Spd

 

..... 3rd 1.383 ......

 

If that ratio could be fitted into a K50 we would have a third that is closer to fourth.

 

For those who wonder about all this, it means that if I'm driving at just under 100kph in 4th I'm pulling about 3000rpm. I drop it into 5th and I'm cruising at 2595rpm. When I come to a hill I go down to 4th and get a 400rpm boost, which is great. But if the hill gets steep and I go for 3rd at 3000rpm it will jump to 4305rpm, which is too big a gap.

 

With that 1.383 3rd gear in there it would only jump to 4150, still too much but better than the stock K50 by 150rpm.

 

Irrelevent for all those people living in the flatlands! :laff:

 

I'm spoilt by the Altezza dropping 500-600rpm between most of its 6 speeds!

[Felix]

Put a 5k in it. More torque. Halve your gear changes.

[RainWarriorDregs]

not having a dig but why don't you like the gap. I dunno if its just me but i love winding 3rd hear out, haha, but i guess i'm trying to relive my childish days haha.

 

pretty much an irrelevant post.

:)

[altezzaclub]

Ah... ultimately I'd love a sequential 6speed out of the V8Supercars! Something that keeps it on peak power all the time. When you don't have much power you need to use it all the time!

 

I rallied Datsuns for years in South Africa, an the biggest improvement was when we shelled out lots of $$ and bought a factory close-ratio gearbox! That box was magic to drive with... a high first and a 1:1 fifth, with all the other gears close in between.

 

I'm hoping there is a cheap solution involving a lightweight gearbox for 'almost-stock' 4Ks, rather than worrying about blowing them up from to much power and using heavier or stronger boxes.

[camerondownunder88]

For gear box mods what you can do is machine off a gear from the shaft and make a new one and weld it on. That is how some shops modify K40-K50 for racing guys can be done I got a quote once from my machinist at work who used to do it he could do it at home for me for $400 per gear...not cheap.

 

Now this new gear when you get it made get them made wider thus making the load distributed more and thus stronger :)

 

also follow this link:

http://www.billzilla.org/rcar.htm#gearbox

 

Details moving gears in a K box to make it close ratio and a better box good read.

 

Cameron

[altezzaclub]

haha! Billzilla! He is absolutely brilliant! A maniac, but brilliant... Love his stuff.

 

I really need a gearshift with 1st where my 5th is and reverse in the same place as 3rd!! :laff:

 

..and I want his diff too!!

[philbey]

I rallied Datsuns for years in South Africa, an the biggest improvement was when we shelled out lots of $$ and bought a factory close-ratio gearbox! That box was magic to drive with... a high first and a 1:1 fifth, with all the other gears close in between

 

ahh the good old Option 1 box.

[Andy43]

I got one k40 with stud's in the bottom plate and a 2 to 1 ratio in 2nd and another with bolts in the bottom plate with a 2.2 to 1 ratio in second.

[altezzaclub]

Andy, that box with the tall second (2.0 to 1) should also have the tall 3rd, the 1.383

 

Do you think a 5th gear can be mounted on it? It would mean using all those gears inside a K50 box with 5th hanging off the back as usual. The idler gear set would have to run on the longer K50 shaft.

 

Have you stripped a 5speed? Any ideas of the comparisons?

[Andy43]

Andy, that box with the tall second (2.0 to 1) should also have the tall 3rd, the 1.383

 

Do you think a 5th gear can be mounted on it? It would mean using all those gears inside a K50 box with 5th hanging off the back as usual. The idler gear set would have to run on the longer K50 shaft.

 

Have you stripped a 5speed? Any ideas of the comparisons?

 

 

I'll confirm the 3 rd gear today on the 2 to 1 box.

I havn't seen inside a 5 speed box, I'm scrutineering a race meeting today if the rain stops, and where racing tomorrow I'll ask some of the other Corolla guys and see what I can find out.

Cheers

Andy

[altezzaclub]

Thanks mate- any info is a step forward.

[Andy43]

OK

I have checked the 3rd gear ratio and looks like its 1.38 to 1.

The box has a identifying sticker saying K1 KE30.

It has studs in the inspection plate and not bolts as later K40 did

The extension housing looks like its standard K40

The Main body has one extra rib and a channel cast into housing ( see pix difficult to explain )

Do you have a Gregory's K55 manual ? as it covers both K40 and K50, I can scan and PDF if you want.

I can also scan the Ke30 manual.

I have compared the layer shafts to those in the K30 manual and it looks different as the K50 extendeds into the extension housing.

Here's the pix

Cheers

Andy