Thanks doug, this on a standard UK rear diff, and not sure sure if it has the long gear or not. But I am being told but another source the gearing is about 90% that of a UK box. So fingeres crossed the gearing will be OK.

I am not looking to top out at 150. I just don't want to be at say 80mph, floor it to overtake/pull away from something on a open road, only to run out of revs and gears at say 100-110mph. With my power and revs it will pull 110 in a blink, so I could be looking at the redline to quickly if the gearing is too low. I need to top out no less than 130 really.

 

The box has the original ratios, so an 0.825:1 5th gear, as apposed to the 0.738:1 of the UK box.

If you assume 170mph on UK box, then 170/0.825*0.738=152mph

Paul

 

Job done ! Thanks again.

 

I meant to clarify, although stated already, the box in question has UK diff and transfer box so the final drive is same as UK.

 

How did you get the commander to read im mph Doug? I thought it wasn't possible?

 

it may say km/h but it will actually be mph if the speedo converter if the speedo converter is placed such that it effects the speedo signal to the ECU aswell as the dash cluster.

 

Would that not confuse the ecu or would you just map around that?

 

Best asking Andy as he fitted and mapped it. Took the reading from the commander as i thought it would be more accurate than the clocks.....

 

This is how the OE ECU's speed limiter is often raised, Its still set to 180 kph, but the signal coming in has been converted to mph. So speedo uses the kph clocks but now shows mph (hence the MPH sticker). AFAIK it has no effect on other areas of the ECU so no need to 'map around that'

 

I see.

Thats somewhat different to my setup. It has the speedo converter but still reads in k's on the commander. I guess the converter must have been fitted to the speedo only as before I went with the Apexi PFC the car was still limited to 112mph.

 

Gearbox in and all fitted. It feels strong but very nervous of it at the moment. The ratio's don't feel too short either so very pleased.

It difficult to tell now though as I have just added an induction kit was I suspected was holding back my power on my 2.5. Since fitting it at more or less the same time as the box. The car currently feels like a bullet, and pulling in the revs extremely quickly and packing such a punch low down and pulling so hard to the redline I am almost scared to nail it in third due to the torque and power its trying to put down.

At first I thought it was pulling in the revs due to a shorter box, but when I look at the speedo I would say its more down to a significant increase in power.

Will defo need to get this thing back on the rollers soon.