CSR 260 differential R&R tutorial wanted.

[pethier]

My new differential arrived today! 

 

Since the CSR chassis is different, I expect finding a video tutorial is not likely, so I need all the help I can get.

 

The Quaife with the 3.62/1 gears is coming out to be set aside so my heirs can include it when they sell off my stuff.  

 

Going in this winter so I am ready for the autocross season in the spring:  All-new Ford Sierra case, 4.71/1 gears and Drexler LSD.  

 

Although I have done many mechanical jobs in my life (at least one of which people thought was impossible), I will not be offended if you describe the procedure as if I have never spun a wrench.  I would much rather be told stuff I already know than to be NOT told stuff I that I don't know that I don't know.

 

[Croc]

7 hours ago, pethier said:

4.71/1 gears and Drexler LSD.  

 

 

 

Am I reading that right?  Final drive changing from 3.62 to 4.71?  

 

Not sure what self-help video you need?  Switching out diff?  Just watch a regular Caterham diff swap video - the principles are the same albeit with a few quirks around mounting points.  

 

There are 3 phases of CSR chassis evolution surrounding the diff.

1) inception to 2009 - 2 mount points.  The problem with this approach is the torque of the CSR260 regularly ripped the mount points off the diff housing.

2) 2009 to 2014-ish - original 2 mount points plus two extra struts that come diagonally down through the boot area.  Originally optional then standard.  You used to be able to buy the extra struts via Caterham parts - no longer available

3) 2015-ish on - proper 4 point cage mounting

 

I don't know what year your chassis was - I vaguely recall it was a year older than my 2010?   If you only have 2 mount points then you really want to try to fabricate the extra struts that 2) involved.

 

You will want to research the torque measures required for the propshaft bolts and diff mounting bolts and the rear suspension bolts since partial disassembly is required.  

 

 

[pethier]

16 hours ago, Croc said:

 

Am I reading that right?  Final drive changing from 3.62 to 4.71?  

 

Not sure what self-help video you need?  Switching out diff?  Just watch a regular Caterham diff swap video - the principles are the same albeit with a few quirks around mounting points.  

 

There are 3 phases of CSR chassis evolution surrounding the diff.

1) inception to 2009 - 2 mount points.  The problem with this approach is the torque of the CSR260 regularly ripped the mount points off the diff housing.

2) 2009 to 2014-ish - original 2 mount points plus two extra struts that come diagonally down through the boot area.  Originally optional then standard.  You used to be able to buy the extra struts via Caterham parts - no longer available

3) 2015-ish on - proper 4 point cage mounting

 

I don't know what year your chassis was - I vaguely recall it was a year older than my 2010?   If you only have 2 mount points then you really want to try to fabricate the extra struts that 2) involved.

 

You will want to research the torque measures required for the propshaft bolts and diff mounting bolts and the rear suspension bolts since partial disassembly is required.  

 

 

Yes.  Changing from 3.62 to 4.71.  I'm an autocrosser, not a big-track driver.  I figure top end will be about 117 MPH.

 

Please point me to decent videos.

 

From the VIN, I believe the car is a 2007 model.  It certainly has the two extra struts that come diagonally down through the boot area.

[pethier]

Actually, the overall launch ratio with my new diff in the CSR will be higher than that in my other car.  I took the time to count the bolts going by to confirm the ratio on my Zetec car, and it counts out to 4.11 on the button.  I have to rely on published figures for the first-gear ratio on the T9 in my Zetec car and on the 6-speed in the CSR 260.  The entire range of the 6-speed is much smaller on the 6-speed.  Not only on the low end as seen there. Top gear on the 6-speed is straight-through, while top gear of the T9 is an 0.82 overdrive.

 

First gear overall launch ratios:

 

74PHIL 

5 sp    diff    overall
3.36    4.11    13.80
        

CSR 260 
6 sp    diff    overall
2.69    4.71   12.68

 

The current overall on the CSR 260 is 9.72, and that's not not all that great for launch required on most autocross courses.