As per the title, I’m looking for a gearbox that will bolt to the C1J and have a std LSD?
I’ve heard the RS225/230 box is reasonably strong and can source them in Australia reasonably easily.
Has anyone tried or have they just gone for the VAG boxes?
The 225 box is a PK6 box (The R26 had the ND0).
Both 6 speed boxes. Huge in comparison to a JB/JC.
The JB/JC can be bolted up to a 225 engine, by re-drilling the bellhousing holes in the block. But I dont imagine it can go the other way. Physically wouldn’t be enough bellhousing face on the block to bolt up to.
I’m probably going to end up with about 240/250hp in my Mk1 Megane, and plan to use a well sorted JC5 box. Can get a diff for them, and the bolt in plate to stop the circlip from jumping. Think that’s your only option without going crazy modified!
I think the VAG box requires a chassis notch also. Not sure how that sits with the Australian cop shop. 
What torque will a well sorted JC5 box handle and what does ‘well sorted’ mean in the JC5 context?
? 225 box is ND0-000 and R26 is ND0-020 (LSD). PK6 is big compared to ND0.
Renault spec says 200 Nm.
As mentioned above I don’t think the bellhousing will meet the block face as it’s diameter is so much bigger. You might be able to do it with an adapter plate though, if there is enough primary shaft length. The shifter would be easy as it’s cable, just mount the stick unit in the car. The driveshafts are significantly thicker so they would need to be a custom with the smaller ends to work in your hubs, and the clutch and flywheel package would need to be bespoke too.
If I were going to budget for it i’d be planning £2-£3000 to get it in and working.
I have my own CNC plasma cutter, so can cut an adaptor plate if need be. I even had some 10mm 6061-T651 plate!
However, I need to check how much room there is to the chassis leg. 10mm might be too much!
@kimbe is correct
225 used no LSD and was ND0 000
R26 has as diff and is ND0 020
I’ve got an RS200 F4R engine and PK? Box. That box is pretty big and a fair bit heavier too!
Someone is Aus is selling an NDO with Gripper diff, so would be perfect for competition work, IF it can be made to work!
Sounds like a pk6 box from the laguna.
Clio III RS200 has TL4-024 or later ones TL4-031 (240 Nm), but yeah, probably Laguna 2.0T box if PK6-xxx (53 kg, 320 Nm).
It’s a std Clio3 RS200 box, so i guess TL4?
In that case yes.
What are the different clutch sizes these boxes run?
JB3 - 200mm diameter.
JC5?
NDO?
TL4 - I can measure this.
PK6?
You mean the actual clutch plate?
Laguna 2 F4Rt 120kW / 125kW + PK6 = 230mm, F4Rt 150kW + PK6 = 240mm
Clio 3 RS 200 F4R+TL4 = 230mm
Megane 225/230 F4Rt + ND0 = 240mm
Thanks for all the info so far. This really helps. I’d like to get hold of an NDO box to size up. I might measure up the JB3s and TL4 that I have and draw some templates in CAD. That will help me oveylay and determine potential fitment. Integrated a clutch might be tricky without going to a custom 7.5".
Its a big chop on the chassis rail to get the ndo in with an f4r. You will need a bolt pattern adaptor, hydraulic clutch, custom shafts etc.
The more cost effective option would be fitting a quaife into the jb3, no chopping, no custom shafts and flywheel needed, and it can usually handle most powerful c1js.
The more I look at this the more questions it raises! I can get JB3s in Aus. So I don’t really want to spend the money on a diff only to see the box fail and it cost a fortune to get another one sent from the UK. Maybe a JC5 is a better starting point?
Jc5 will work OK If needs be. Run them until they dry up then look at other options.
I stand corrected. Not sure why I thought the 225 was a PK6.
Either way, PK6 and ND0 both have the same bolt pattern to the F4RT block.
Heres an idea of the size difference. Photo of Adeys, because all the photos I’ve got of my conversion are shit and taken out in the rain.
That is an F4RT block, re-drilled for a JB/JC bolt pattern.
