Jump to content
SAU Community

Recommended Posts

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

Link to comment
https://www.sau.com.au/forums/topic/91554-gearbox-ratio-change/
Share on other sites

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

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 :)

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

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.

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 .

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • Sounds like you've got an interesting adventure ahead here with local support if you have trouble! My guess is that, unboosted, you will be OK with a small upgrade like -9. What will happen is that once the stock ECU sees more airflow than it expects it will add a heap of fuel and pull a heap of timing to be safe because it can't understand how it could get that much air without there being an issue. You will see clouds of black smoke and it won't pull hard through the midrange and top end. So, overall it will be a bit frustrating but should be OK. If you are still nervous set the base timing back 2o through the CAS, but it will be even more sluggish everywhere. As said above through...this is not my guarantee your engine won't be blown into a million pieces, leaving you looking for very hard to find parts A better idea is get a computer with logging ASAP, wire in a wide band O2 sensor and a use remote tuner. I've done multiple cars this way and while it is not as good as a specific tune on a dyno they can get it 90% right. I'd suggest if you can afford an R33 GTR these days you can afford an ECU and tune. And if you can't afford that you sure won't be able to afford the rebuild if it goes bad in the meantime,.  
    • Yeah it would be nice if someone took the time to put that sort of information together, but there are a lot of variations in looms. I think you are making this way hard for yourself if you just want to get it running....sourcing an SR20 with the right wiring will be a billion times easier than matching the RB loom to an S15 chassis. If you do end up going this way, you just need to trace every wire in the loom with a multimeter, 95% of them will go to a location you can confirm at the ECU.....and then post it up for the next person who needs it  
    • Just top it up with water, and keep a general idea of how much you added. It is normal for water to be pushed into and pulled out of the reservoir through the cap, and it should not be more than half full or it will be likely to overflow when hot. Any decent mechanic can do a pressure test of the cooling system to confirm if you have a leak. Keep in mind if it is only leaking a little and when hot it may well evaporate before you see it hit the ground
    • I'd ask the shop what they used and use that. Mixing coolants is sometimes OK, sometimes not, and you have know the details of each coolant to know whether it's a good idea or not.
    • Is it alright to top up with just another green coolant?
×
×
  • Create New...