Torque spec in Nm for idle and drive belt tensioner Ba xr8

Hello,

Drive belt tensioner to engine block 19 Ft-lbs or 25.76 Nm
Intake plenum bolts to intake manifold 8.33 Ft-lbs or 11.3 Nm
Intake manifold to cylinder head 18 Ft-lbs or 24.4 Nm
Rocker cover to cylinder head 8 Ft-lbs or 8.5 Nm

Hope this helps.

Cheers, Boris

Much appreciated thanks Boris. Could I ask what's my differential ratio would be and what would you recommend i do to my differential ratio to get just a little more torque? which I guess will give me less top end speed which is okay.
And what cc injectors do my xr8 factory injectors have? as I'd like to get around 100cc-150cc more than my standard injectors and will I need to tune my ECU afterwards?

Hello,

Depending on which transmission is fitted to your vehicle, the rear axle ratio differs.

5-Speed manual 3.23:1
6-speed manual 3.46:1

So, if your vehicle is 6-speed, as it is a V8, then a swap to the shorter 5-speed rear axle should do the trick.

Why do you need to install bigger cc injectors?
Turbo/supercharging or possible Nos?
The injectors should be 21lb/hr so 220cc.
A return of the PCM would be required to run the bigger injectors efficiently.

Cheers, Boris

Thanks again Boris. So, if I have the 5-speed gearbox and I switched the differential to a 3.46 differential from a factory 6speed manual xr8 I'd get a little more torque than my 3.46 differential and 5-speed box factory setup? Will I also need to get my speedometer recalibrated too?

I want to run my setup NA only. I just want to be sitting on around 350kw Max to be safe from my stock 260kw atm.

Hello,

Swapping to the 3.46:1 rear end would give you longer legs so would reduce the low-down grunt.

I believe your best bet would be fitting the 6-speed gearbox. The gears are closer together and better matched.

5-speed
1st 3.38:1
2nd 2.00:1
3rd 1.32:1
4th 1.00:1
5th 0.68:1

6-speed
1st 2.97:1
2nd 1.78:1
3rd 1.3:1
4th 1.00:1
5th 0.8:1
6th 0.63:1

Hope this help.

Cheers, Boris

Now I'm confused Boris. Are you sure that's the correct information you have given me?

Sorry for the delay. I think what Boris was saying is the 5 speed with the lower (higher number value) gear and 6 with the higher gear are matched pretty closely so you are not going to get much difference in performance.

However, if you have a 6 speed with the higher gear (lower number) and swap lower gear then you are going to have more low-end torque and the RPM is going to be significantly higher in each of your 6 gears.

So, this will give better performance and throttle response but will hurt your fuel mileage as the RPM will be higher.

Hope this helps.