Just got the Sag back - C/R Box and 3.7 diff...

[Don1]

.... Wow. I'll try to be subjective later, but wow!

[alex_gray255]

Yup, I know what you mean!

I had my gearbox and diff completely replaced/rebuilt to CR(++) spec and it made a real difference!

[crimbo]

From what I have read it makes a big difference from a CR and 3.4, is that what you had before?

[Buzz Billsberry]

Come on don.... as John Travolta once said..'Tell me more tell me more"!

Buzz

[S6 ROR]

As a matter of interest, what Diff did the Sag leave the factory with.
I have looked under mine, and it has a 3.73:1, but standard gearbox. Does that mean a previous owner has uprated the Diff?

[RedSpike66]

They were originally supposed to leave the factory with CR box and 3.73 diff (or so I'm told), but I have a 2006 price list in my possession that lists CR box as optional on Sagaris and Tuscan, standard on Tuscan S.... Old wives tail is that towards the end whatever was available went in, meaning some Sags left with standard box and 3.46 diffs...

[RedSpike66]

Speed/Gear Ratios (assume change up at 7500 rpm, and 255/35/18 tyres)

CR Box	3.46 diff	3.73 diff	3.91 diff
1st-2.43	66 mph	61 mph	58 mph
2nd-1.56	103 mph	96 mph	91 mph
3rd-1.24	130 mph	120 mph	115 mph
4th-1.00	161 mph	149 mph	142 mph
5th-0.8	201 mph	187 mph	178 mph

Std Box	3.46 diff
1st-2.95	54 mph
2nd-1.95	82 mph
3rd-1.34	120 mph
4th-1.00	161 mph
5th-0.8	201 mph

I think the idea behind CR box and 3.73 diff was fastest times for 0-60 (no gear change), 0-100 (one gear change, but revving to 7800rpm !!)

Edited by RedSpike66 on Thursday 8th September 15:52

[Robertjp]

Congratulations on the upgrade!

Its one i have been considering too! Cant say i would miss the top end speed at all!!!!!

So its made a noticable difference? What diff did you previously have in?

Can i ask where you had the work done and what the costs were? Please PM me if you dont want to post costs...but i would appreciate knowing.

[Targarama]

Exactly why I went for a 3.91 - my car doesn't have enough power to pull 201mph and 178mph is 'sufficient' top end

Meanwhile the car feels much more alive through the gears/in normal driving when you want to accelerate.

[Cliffedge]

My Tuscan 2 S is amongst some of the last to come out the factory, but with a standard box (should have been CR box), so I'm also interested to know what it would cost to have the correct box fitted, if anyone would be kind enough to let me know!

Thanks

[Don1]

Well I've been off driving something else today as well, and the Escort Cosworth is going to go.... but that's another story!

Right, did have the normal box and 3.4 diff in it (according to the gearing speeds on Mr Varleys excellent site).

Jason and the boys at Str8-Six did the swap. They are highly transparent on prices, give them a shout. Let's just say that they are the cheapest I could get an answer out of (not only that, they knew the cost straight away, no "I'll call you back").

Currently can't give it massive beans, as it's running in the new gear (oil change in 1k miles). But the seat of pants-ometer gives the following reading: 1st/2nd - not much change, but quicker. 3rd/4th the engine revs so quickly I first thought I had a slipping clutch. Seriously. 5th yes, you are sacrificing top speed, but it doesn't matter. Instant grunt when you put the foot down at motorway(+) speeds.

Conclusion: Well worth the money. The biggest change I have found so far to the car. That good.

Christ only knows what it's going to feel like with over 450bhp....

[Diablos-666]

What revs are you seeing at motorway speeds in 5th?

Regarding the diff, did you get a new one fitted or your current one re-built to the new ratio?

Wasnt RG offering a new 3.7 diff for £500 and an exchange? Not sure if that offer is still on though.

[Diablos-666]

Also,

What are thd advantages / disadvantages to the following

CR box + 3.7/3.9 diff

Std box + 3.7/3.9 diff

CR box + std diff

Hope the above makes sense

[Targarama]

Diablos-666 said:

Also,

What are thd advantages / disadvantages to the following

CR box + 3.7/3.9 diff

Std box + 3.7/3.9 diff

CR box + std diff

Hope the above makes sense

Do a search, this has been discussed a few times.

[RedSpike66]

Table above tells you most of what you want to know, but basically, both boxes have same 4th and 5th gear.
If you want the quickest accelerating 2nd and 3rd gears, (and 4th/5th) CR+3.91
If you want the next quickest accelerating 2nd and 3rd gears, (and 4th/5th) CR+3.73
If you do a lot of motorway cruising, and want best mpg, STD or CR+3.46 diff

Apparently, the 4.3/4.5SS Power upgrades can negate the need for CR box and/or 3.73/3.91 diff due to torque increase....

Edited by RedSpike66 on Thursday 8th September 22:14

[alex_gray255]

4.5S engine upgrade - on my list for next year. So, I'll see what it is like with the CR box and if it makes no difference then.

[D14 AYS]

It will be interesting(for me anyway) to see what the 4.5ss does the 1/4 in, I consistently did 12.6 with the old engine, Brighton speed trials Saturday http://www.brightonandhovemotorclub.co.uk/index.ph... I will let you know Just praying for a dry day Standard box(I think!) 3.7 diff.

[sportie]

I believe they just fitted whatever diff they had available at the time. I came from a Tuscan S to the Sag and was shocked at how slow it was compared to the tuscan.

I complained to the dealer and they discovered that the factory had fitted a tamora diff 3.44 to my CR box which was a £1,500 extra.So I bought a Tuscan S 3.7 diff and had it fitted, and like all who have gone down this route the increase in delivery was well worth it.

[BCA]

D14 AYS said:

Standard box(I think!) 3.7 diff.

I think that may be the best set up all round. We've got a standard box and 3.4 - it's a bit long in gearing IMHO... At Aintree last weekend we were doing a few tests; 7800rpm in third is 124mph for us!!

Forecast is still iffy to favourable... Hope it stays dry too!! Looking forward to it, just arrived in Brighton infact.

[Targarama]

BCA said:

I think that may be the best set up all round. We've got a standard box and 3.4 - it's a bit long in gearing IMHO... At Aintree last weekend we were doing a few tests; 7800rpm in third is 124mph for us!!

Forecast is still iffy to favourable... Hope it stays dry too!! Looking forward to it, just arrived in Brighton infact.

Yup, too longly geared to enable you to make use of the power of the engine in most driving situations. I found I was having to drop a cog to get some decent acceleration. No longer a problem. 3.91 with the standard gearbox is perfect for me, but I know if I got for a 4.3 or 4.5 engine conversion I'd switch to a CR box and a 3.4 diff again.