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Gearbox Ratio Change

Haysey
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Haysey Grand Master

Haysey

Posted
Posted

Im sick of 3000rpm at 100kmh..... in 5th gear...

has anyone changed their ratios in the box? or anything else that will solve the high revving problem.....

at the moment the car uses more petrol on the highway then in the city.... lucky to get 200km from half a tank!!!!!!!!

soooooooo sick of it!

Ed

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Cubes Grand Master

Cubes

Posted
Posted (edited)

lol..

Imagine the poor souls with their R32's running a RB30DET's.

I'm always reaching for 6th.

The tacho is actually a little wrong, the pfc h/c states ~2800rpm for 100km/h. It is still too high though.

I will be dropping a S13 3.9:1 diff in mine, there is also available a S13 ~3.7:1. Really depends what you want, I want to keep the 'sports' feel so 3.9:1 is the highest ratio I will go.

The VLT has a longer 5th gear, throw a vlt g/box in to the r32.

Edited by Cubes
Sydneykid Grand Master

Sydneykid

Posted
Posted

100 kph is 2,750 rpm with a 4.363 diff (R32GTST) a 0.759 5th gear and 245/45/17 tyres.

100 kph is 2,600 rpm with a 4.1 diff (R32GTR) a 0.759 5th gear and 245/45/17 tyres.

100 kph is 2,500 rpm with a 3.9 diff (S13) a 0.759 5th gear and 245/45/17 tyres.

100 kph is 2,400 rpm with a 3.7 diff (S13) a 0.759 5th gear and 245/45/17 tyres.

As you can see there is not much difference, I suspect that you will improve the fuel economy far more by spending the money (that a dif change would cost) on some tuning.

;) cheers :)

paulr33 Grand Master

paulr33

Posted
Posted

check your 02 sensor as well, nuturious for angry fuel economy. if i do all highway driving i get over 400k's to a full tank and thats sitting on 100km's in 5th gear so it sounds like you arent going into closed loop mode or your sensor is dead

Cubes Grand Master

Cubes

Posted
Posted

I've just used my trusty gearcalc program.

@100km/h in 5th.

225 x 50 x 16" tyres.

4.36:1 Diff - 2782rpm

4.11:1 Diff - 2621rpm

3.9:1 Diff - 2487rpm

3.7:1 Diff - 2360rpm

So for myself running a 3.9:1 a drop of 300rpm, the diff needs replacing anyhow.

The biggest benifit will be picking up approx 9km/h in second gear and ~13km/h in third. Especially with the rb30det this will be handy. :)

Should I go the 3.7 that will be ~14km/h in second and ~20km/h in third I pick up.

discopotato03 Grand Master

discopotato03

Posted
Posted
I've just used my trusty gearcalc program.

@100km/h in 5th.

225 x 50 x 16" tyres.

4.36:1 Diff - 2782rpm

4.11:1 Diff - 2621rpm

3.9:1 Diff  - 2487rpm

3.7:1 Diff - 2360rpm

So for myself running a 3.9:1 a drop of 300rpm, the diff needs replacing anyhow.

The biggest benifit will be picking up approx 9km/h in second gear and ~13km/h in third. Especially with the rb30det this will be handy. :P

Should I go the 3.7 that will be ~14km/h in second and ~20km/h in third I pick up.

Hi Cubes , how do the numbers run for the manual VLT ? I think the final drive was 3.45:1 but it used a 3.6 1st wide ratio box and 205/60/15 ? Also how does the weight stack up compared to a typical RB30DET R32 2wd ?

Cheers A .

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