3.73v3.91 Sagaris Diffs

[mr sagoo]

I know this has been done to death and I dont want to go over old ground, but now that a few sag/350/tam owners have had their diffs gearboxs changed I was just wondering what the verdicts were. I still havent been able to confirm if I have a 3.46 diff in my sag (will hopefully get it jacked up this weekend to check for sure) although I suspect it is a 3.46,even though it is still bloody quick it would be nice for it to be even quicker, one thing iam sure of is that It doesn't have a cr box fitted,in a nutshell am I better going for a 3.73 or a 3.91, I will only be doing very occasional track days and no hill climbing etc just mainly road use for weekends etc.To make matters worse ex-works up in Blackpool have told me they can also get a 3.79 diff just to confuse me a bit more, finally is the cr box worth paying the extra for, approx £750.
Many thanks in anticipation.

[VARLEYHYD]

Try this spreadsheet from the gearbox man.

I've put the various figures in it for quick reference on the tabs

http://www.varleyhyd.com/images/gearspeeds.v2.xls


Hope this is of use

G

Edited by VARLEYHYD on Thursday 27th September 16:26

[YI8TVR]

Be carefull with the 3.9 dif as its easy to stretch your con rods with the ratio being so low.

You will need to fit a soft limiter or change up lights at just over peak torque and set the hard limiter to 7500rpm so as you dont cut the spark out.

[tail slide]

YI8TVR said:

Be carefull with the 3.9 dif as its easy to stretch your con rods with the ratio being so low.

You will need to fit a soft limiter or change up lights at just over peak torque and set the hard limiter to 7500rpm so as you dont cut the spark out.

Avoiding over-revving always sensible, but con-rod stretch ....... speaking from experience?

[Daftlad]

mr sagoo said:

I know this has been done to death and I dont want to go over old ground, but now that a few sag/350/tam owners have had their diffs gearboxs changed I was just wondering what the verdicts were. I still havent been able to confirm if I have a 3.46 diff in my sag (will hopefully get it jacked up this weekend to check for sure) although I suspect it is a 3.46,even though it is still bloody quick it would be nice for it to be even quicker, one thing iam sure of is that It doesn't have a cr box fitted,in a nutshell am I better going for a 3.73 or a 3.91, I will only be doing very occasional track days and no hill climbing etc just mainly road use for weekends etc.To make matters worse ex-works up in Blackpool have told me they can also get a 3.79 diff just to confuse me a bit more, finally is the cr box worth paying the extra for, approx £750.
Many thanks in anticipation.

I would personally not drop final drive lower than 3,73 with a standard gear box.

With a close ratio box I would advise the 3,91. I belive the CR box and short diff make the car what is should have been ex-works.

If your car has a 3,46 diff, 3000 rpm in top gear should be 80-81 mph indicated. 3,91 will give 70-71. 3,73 is between the two!! The change to the factory specified close ratio gera box will not effect these speed ratios as the 5th gear ratio is the same.

[bobd]

Done to Death - Done To Death
The 3:73 is just fine- or 3:79 if thats available either one of those will do you rightly.
And stop questioning Heath and Pauls judgement just do it!

[Daftlad]

pointless post scrapped

Edited by Daftlad on Friday 28th September 11:26

[bobd]

Exactly Daftlad this has been done to death and I agree with your comments.