Ph1 standard gearbox to Cup 129?

[Leslie Graham]

Hi all, need to take the box off my Ph1 and have been told the 129 box off the cup is a good upgrade?
Can anyone provide some info on this ref gearing and acceleration differences please?
Any experience in this having changed?

Many thanks in advance

 

[letsturboit]

I'd be interested to know this myself too.
R5 + 172 engine + cup gbox = weeee?!

 

[Budgie]

You wont notice the difference. Or at least, i didnt.

 

[scotiamr2t]

Daily driving i noticed almost zero difference except at motorway speeds. I did however notice a difference when using the car on track

 

[Leslie Graham]

You wont notice the difference. Or at least, i didnt.

Ah OK, very marginal then.
The Ph1 is ok but always worth looking at a possible upgrade

 

[Leslie Graham]

Daily driving i noticed almost zero difference except at motorway speeds. I did however notice a difference when using the car on track

Difference how? Very interested

 

[NorthloopCup]

You'll get marginally better acceleration and due to the cw&p ratio being different, it'll be slightly more lively on track as well due to being slightly higher up the rpm band.

 

[sburrell93]

I noticed a decent difference as well on track. Mainly between two corners at knockhill. I used to be able to just avoid the limiter in 3rd, but I'm now well into 4th along that section. I fitted a lightweight flywheel at the same time though which will have added to the effect. Ratios on the FD are 3.867 on the JC5-089 ph1 box and 4.067 on the JC5-129 cup box, or, roughly just under 200rpm difference at 70mph in 5th.

It's probably not enough to bother about unless you're removing the box for another reason IMO (refurb, clutch change etc). If you're doing other work that needs the box out though and can source a cup box then I'd go for it!

 

[Leslie Graham]

Yep, box coming out as have a clutch/box problem anyhow.
Had to replace engine earlier in year (161000 miles) so gearbox could probably do with being freshened up also.
Going well though for a very tired chassis.
Appreciate feed back lads

 

[NorthloopCup]

Yep, box coming out as have a clutch/box problem anyhow.
Had to replace engine earlier in year (161000 miles) so gearbox could probably do with being freshened up also.
Going well though for a very tired chassis.
Appreciate feed back lads

I've got a 129 box that I'll be refurbing and selling shortly if you're interested mate. Pm me if you are. This was my original gearbox, so I know the history of it and what it needs.