K3-VET - what manual trans to use?

Eddie · October 18, 2018, 9:01am

Hey guys,
just wanted to ask what are the options when converting a YRV turbo to a manual. Mainly if there’s a box that will fit the K engine and withstand the torque of the stock (maybe modified in the future) engine.

Obvious options to me are:

YRV trans from the K3-VE
Sirion Gtvi trans (quite rare to find in Europe)

I’m conscious of the other models that had the K3, but are the transmissions the same, strength wise? Based on the gearing they seem pretty similar to me.

Any thoughts are welcome

Ace3001 · October 18, 2018, 11:21am

The best trans in my opinion would be one from a Daihatsu sirion rally 2 or 4.
They should be upgraded to match the output of the K3-VE2 (a tuned version of the K3-VE engine).

Mr_Gormsby · October 18, 2018, 11:28am

As far as I know almost all the same whether 3cyl or 4cyl. The difference is mostly the final drive. I have a few varieties here but am yet to pull them down to count the gear ratios. There might be a list of gear ratios here if you searched. Someone told me the L700 had closer ratios or a taller first than than any M100 based box, but I need to verify. With my EJ I’m using a EF-EL TRXX box as it has a lsd. One the one hand I’d like to go to a M100 or L700 based box and install an LSD. But really what I want is a Sadev ST-82-14. On the other hand if going to that expense a Sadev SL-75-LW might be within reach and I could build a space frame mid engine hillclimb car and put a L200 Mira body/facade over top. But that is dreaming and off topic. I do have both a M100 3cyl box and a M100 GTVi box. Sitting side by side you can’t tell them apart.

Eddie · October 19, 2018, 10:19am

EDIT
Unfortunately the EJ and K3 transmissions are not interchangeable,
as the bellhousings and starter positions are different.
END OF EDIT

So I think I have found a theoretical winner. As MR_Gormsby said, all of the EJ/K3 transmissions are basically the same (only difference being in 4th and 5th gear on some models), apart from the gear ratios.

1st: 3.182
2nd: 1.842
3rd: 1.250
4th: 0.917 (0.865)
5th: 0.750 (0.707)

So far I’ve found there to be 2 factory ratios for these boxes: 4.267 and 4.500

But then I stumbled upon a box from a Mira L250 (EJ-VE):

1st: 3.42
2nd: 1.95
3rd: 1.25
4th: 0.87
5th: 0.71
final: 3.94

Even though the gears are a bit shorter, with the longer final drive this
makes this the longest geared box I have found that should fit an EJ/K3.
Bellow it is compared with the longest EJ-DE/K3 variation from a L700 Mira.

Mira L250 box
L250

Mira L700 box
L700

Here for a comparison is the 4sp auto, the only factory option on the K3-VET
auto

As you can see, being a 4 speed the gears are horrendously long. I can’t
imagine how sluggish that must feel even with the turbo engine.

So to close this up then, the best option gear wise looks like to be the L250 box, as anything shorter wouldn’t employ the full torque potential of the turbo engine in my opinion. Also it should be the best for economy since the cruising RPM will be always lower. There is a but though.

Why doesn’t the L250 have the same box as the EJ-DE ones? For example: post 2004 sirions that have the K3-VE still have the same box as the M100/101 ones.

Does that mean that this box is an “updated” version of the EJ/K3 one?

Why would they put the longest geared box in the smallest and least powerful car (Although the L7 Mira also had the longest variant of it’s box)?

PS: this has become quite a bigger write-up than i imagined, sorry if it’s too long for somebody.

Mick · October 19, 2018, 3:11pm

Hi, in Germany I think we got the sirion M1 series with K3, EJ or EV engines. I have an old k3 gearbox here you can have, its defect, doesn’t select 2nd or 4th gear, but no big deal if you are going to swap the gearset anyway. You can have it for free if you pick it up or organise postage.

Eddie · October 19, 2018, 4:21pm

Hi Mick, i appreciate your offer, but the point of this search is to find the most ideal box from the factory so that i wouldn’t have to tinker with the ratios basically. Still thanks though

Mick · October 19, 2018, 5:35pm

The bellhousing is anyway different between the 1.0 and 1.3 as far as I know, the starter motor is on the other side of the block. Offer still stands if you change your mind. Im also curious if the info you have is accurate, because from what you say the L250 gearset with a 1.0 sirion final in a 1.3 housing would be perfect for me! Everything short and close, it would be ideal for slalom/autocross.

Mr_Gormsby · October 20, 2018, 4:17am

Wow, great info. Well done.

Mick · October 20, 2018, 5:03am

At the moment I hit redline in second at about 115, but this combo seems ideal for me. The engine wpuld remain between 4000 and 7000 so always between peak torque and peak power. And third gear wpuld have a better range, and 1 &2 would accelerate much faster.

Mr_Gormsby · October 20, 2018, 5:05am

I am going to look into one of these boxes for my L200 Mira soon. I’m after the closest 1-2-3rd I can find.

601to602 · October 22, 2018, 2:22am

The differences in part numbers between the m100s and the m101s are .

the bellhousing part of the trans case.
roller bearings imput shaft.
output shaft.
1st gear.
2nd gear output.
4th gear imput.
4th gear output.
roller bearing output.
differential gear.
All other part numbers are the same imput shaft, 3rd gear imput/output ,clutch hubs syncros etc.

601to602 · October 22, 2018, 8:45am

Gear ratios Available here.
Sirion M100s 3.181 1.842 1.250 0.916 0.750 4.500 final.
Sirion m101s 3.181 1.842 1.250 0.864 0.750 4.266 final.
Cuore L701s 3.181 1.842 1.250 0.916 0.750 4.266 final.
Copen L880k 3.181 1.842 1.250 0.916 0.750 5.545 final.

Close ratio box for reference. JDM.
Storia x4 3.090 2.055 1.518 1.058 0.750 5.545 final.
Boon x4 3.090 2.055 1.550 1.160 0.878 5.545 final

Eddie · October 22, 2018, 9:28am

Some really useful info here

Are there any aftermarket or OEM final drives (like 3,9) that will fit the Daihatsu boxes? Perhaps some toytoa ones?

Mick · October 22, 2018, 11:21am

So other than the x4 they all have the same 1 2 3, good to know. I was just looking at gearboxes, lucky I didnt buy one and find out the hard way
Looks like copen final is the way to go for me.
Do you know if the L250 ratios are confirmed?

Mr_Gormsby · October 23, 2018, 6:00am

Bravo, excellent bit of info. Thanks

Patrick_Hart · October 25, 2018, 4:22am

the m300 boxes and m1 from k3 engines will both fit
final drives from lots of boxes will fit with a litle massaging - just need a good gearbox fella to assemble for you

x4 m1 ratios obviously best, but the boxes are hard to find second hand and new they’re approx $1300 a gear to change over - so better to have custom gears cut to suit

then if you’re going to do custom gears then best to leave FD stock and go with a short 3/4/5th and have taller starting gear - changing second gear of course the most expensive of all hanving to change shafts

heaps of performance to be made with adjusting them tho!

Patrick_Hart · October 25, 2018, 4:27am

as far as handling the power - none of them ultimately will
especially if you let that beaut engine breathe!
i only know half a dozen reliable guys with these conversions - some have minced boxes fairly quickly
and some have done a fair few kays and still going okay
so there’s another vote for aftermarket gears

the stock fly and clutches are quite heavy as well - thankfully you can buy all these parts new if you want them

Mick · October 25, 2018, 4:59am

Hi Patrick, youve had a bit to do with gearboxes, do you know if the ratios listed for the L250 are correct?

Patrick_Hart · October 25, 2018, 7:54am

Yeah I think so. But internals of L2 and 5 are individual to themselves and even if you made them fit I don’t think they’d handle the power
If you’re after shorter starts I’d go fd switch then go down wheel size as much as you can.

Mick · October 25, 2018, 8:12am

I think L250 is the newer model, not the old L200. I think it has the EV or EJ so it should be the same housing as sirion?