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AJ30 Jag engine / box install. Gear ratios?
magpies - 23/7/18 at 10:29 AM

Hi

I'm looking at fitting a Jag 3.0 V6 out of an S-Type along with a 5 or 6 speed manual gearbox.

I could do with knowing the gear ratios as I would then be able to work out what rear diff ratio I need

The existing ratio is a 4.2 (lsd) out of a Sierra, yes this is not ideal but the car was going to be used for sprints and hillclimbs

but now just going to be a road car. The existing engine is a BOA V6 Cossy and MT75 box which will be pulled and sold.


40inches - 23/7/18 at 04:02 PM

If you are using the Jag Getrag box, a 3.62 will work well, a 3.3 is better for motorway cruising.


magpies - 18/10/19 at 05:51 PM

cheers 40

I've put in the standard 3.64 that is usually fitted in the 7.5" diff - had the LSD swapped too.

'box is the early 5 speed Getrag 221

I'm using 8 x 17" wheels with 215/45/17 T1R's (may sell and fit Rainsport 3's)

I have a programmable speedo so no problem there.


magpies - 27/9/21 at 10:37 PM

Update:

The 3.64:1 diff is OK, gives near enough 20 mph/1000 revs in 5th.

That equates to 3500 at 70 which is a little high but bearable and a theoretic 144 top speed

It seems to like 3800 on motorways but the exhaust is a little loud - have done Bridgwater to Teesside at that.

Driven 4500 miles this year up to now.

It pulls very well from 25 in top.

Although I do have the 3.14 ratio I will not be changing at the mo.


CosKev3 - 28/9/21 at 03:19 PM

I'm running a RX8 6 speed with a 3.14 diff and mines ticking over at 2800rpm at 80mph
Exactly as I planned with it,sixth gear is like a overdrive


magpies - 28/9/21 at 05:21 PM

quote:
Originally posted by CosKev3
I'm running a RX8 6 speed with a 3.14 diff and mines ticking over at 2800rpm at 80mph
Exactly as I planned with it,sixth gear is like a overdrive


I think the RX8 'box is too wide for the TVR S chassis, not 100% so could do with the dimensions if available


CosKev3 - 28/9/21 at 05:36 PM

quote:
Originally posted by magpies
quote:
Originally posted by CosKev3
I'm running a RX8 6 speed with a 3.14 diff and mines ticking over at 2800rpm at 80mph
Exactly as I planned with it,sixth gear is like a overdrive


I think the RX8 'box is too wide for the TVR S chassis, not 100% so could do with the dimensions if available


It is a big box the 6 speed,much bigger than a Type9 gearbox.
Rx8 5 speed is much smaller than the 6 speed.
I've got a 5 speed I can measure up if you want?