Jump to content
SAU Community

Recommended Posts

I have a R33 RB30det with a 4.39:1 dif ratio 5 speed and when driving down the freeway at 110ks an hour its reving at about 3300rpm which is way tooo high.

Idealy I would like to change 5th gear ratio to bring the revs down to somethng like 2300rpm at 110ks an hour or even less. The engine is very tourquey at that rpm and should handle it fine. Is it possible to do that ?

Or do i spend the money on the diff and change it to a 3.8:1 or 3.9:1 or something to bring the revs down ? the 3 litre would like this anyway..... I have access to a cheap R33 rear end so I could get one changed to a long ratio and keep the 4.4s for racing..... or change 5th gear and have the best of both worlds ?

I do lots of freeway driving and would like to bring the fuel consumption down also.

Anyone have any ideas how much it will cost to do modifications for those 2 senario's and what would be the best option. No i dont want a 6 speed and I would like to take the car drag racing every now and then.

The car will have 300rwkw + once it awakens so once i sort this issue out it should be good.

So the question is.. Does the box get a long 5th gear or the diff gets a long ratio or i just keep putting the extra $$$ into the tank for all my long trips.

Link to comment
https://www.sau.com.au/forums/topic/102505-where-do-i-put-the-money/
Share on other sites

Just put in either the 3.7 or 3.9 ratio crownwheel and pinion in the diff. It will make the most diifference to bring the revs down and get taller gears.

I hate the 4.3 with my 3lt, as first is useless, and will be going to a 3.9 hopefully when money permits...

Edited by Bl4cK32
Just put in either the 3.7 or 3.9 ratio crownwheel and pinion in the diff. It will make the most diifference to bring the revs down and get taller gears.

I hate the 4.3 with my 3lt, as first is useless, and will be going to a 3.9 hopefully when money permits...

any idea how much it will cost ???

my first gear is useless tooo !

SR's with r200 rear ends run 3.9s i think.

Maybe it's worth buying a full unit second hand, swapping out your internals (or even getting an aftermarket lsd) and selling off the 4.4 r33 diff on nissansilvia to some wannabe drifter?

any idea how much it will cost ???

my first gear is useless tooo !

best bet is to try the wreckers, or one of the importers of the forum. You can just fit the cw & pinion (keep you current centre), or fit the new ratio to a 1 (or 1.5 or 2) way centre.

From memory a couple of hundred dollars might be about right. Trouble is you may have to buy one in the whole housing still, cos people dont like to separate the diff parts.

S13 auto and manual ratios are 3.9 or 3.7 (i cant remember which one is which :D)

Food for thought but depending on the intermediate gear ratio spread maybe ~3.7 for wide ratio (GTST/GTS25T ~ 3.32 1st) or 3.9 for closer ratio taller 1st set .

Anyone know the ratios for aftermarket gearsets - 2.9 1st and rest std works well in the Aust spec 260Z , I really hate the 1-2 spread in most Nissan boxes ie around 3.2-1.9 .

I think the VLT Comode used a wide ratio version of the GTS25T box ie 3.6 1st but with tall 3.45 diff gears .

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

    • Nah, that is hella wrong. If I do a simple linear between 150°C (0.407v) and 50°C (2.98v) I get the formula Temperature = -38.8651*voltage + 165.8181 It is perfectly correct at 50 and 150, but it is as much as 20° out in the region of 110°C, because the actual data is significantly non-linear there. It is no more than 4° out down at the lowest temperatures, but is is seriously shit almost everywhere. I cannot believe that the instruction is to do a 2 point linear fit. I would say the method I used previously would have to be better.
    • When I said "wiring diagram", I meant the car's wiring diagram. You need to understand how and when 12V appears on certain wires/terminals, when 0V is allowed to appear on certain wires/terminals (which is the difference between supply side switching, and earth side switching), for the way that the car is supposed to work without the immobiliser. Then you start looking for those voltages in the appropriate places at the appropriate times (ie, relay terminals, ECU terminals, fuel pump terminals, at different ignition switch positions, and at times such as "immediately after switching to ON" and "say, 5-10s after switching to ON". You will find that you are not getting what you need when and where you need it, and because you understand what you need and when, from working through the wiring diagram, you can then likely work out why you're not getting it. And that will lead you to the mess that has been made of the associated wires around the immobiliser. But seriously, there is no way that we will be able to find or lead you to the fault from here. You will have to do it at the car, because it will be something f**ked up, and there are a near infinite number of ways for it to be f**ked up. The wiring diagram will give you wire colours and pin numbers and so you can do continuity testing and voltage/time probing and start to work out what is right and what is wrong. I can only close my eyes and imagine a rat's nest of wiring under the dash. You can actually see and touch it.
    • So I found this: https://www.efihardware.com/temperature-sensor-voltage-calculator I didn't know what the pullup resistor is. So I thought if I used my table of known values I could estimate it by putting a value into the pullup resistor, and this should line up with the voltages I had measured. Eventually I got this table out of it by using 210ohms as the pullup resistor. 180C 0.232V - Predicted 175C 0.254V - Predicted 170C 0.278V - Predicted 165C 0.305V - Predicted 160C 0.336V - Predicted 155C 0.369V - Predicted 150C 0.407V - Predicted 145C 0.448V - Predicted 140C 0.494V - Predicted 135C 0.545V - Predicted 130C 0.603V - Predicted 125C 0.668V - Predicted 120C 0.740V - Predicted 115C 0.817V - Predicted 110C 0.914V - Predicted 105C 1.023V - Predicted 100C 1.15V 90C 1.42V - Predicted 85C 1.59V 80C 1.74V 75C 1.94V 70C 2.10V 65C 2.33V 60C 2.56V 58C 2.68V 57C 2.70V 56C 2.74V 55C 2.78V 54C 2.80V 50C 2.98V 49C 3.06V 47C 3.18V 45C 3.23V 43C 3.36V 40C 3.51V 37C 3.67V 35C 3.75V 30C 4.00V As before, the formula in HPTuners is here: https://www.hptuners.com/documentation/files/VCM-Scanner/Content/vcm_scanner/defining_a_transform.htm?Highlight=defining a transform Specifically: In my case I used 50C and 150C, given the sensor is supposedly for that. Input 1 = 2.98V Output 1 = 50C Input 2 = 0.407V Output 2 = 150C (0.407-2.98) / (150-50) -2.573/100 = -0.02573 2.98/-0.02573 + 47.045 = 50 So the corresponding formula should be: (Input / -0.02573) + 47.045 = Output.   If someone can confirm my math it'd be great. Supposedly you can pick any two pairs of the data to make this formula.
    • Well this shows me the fuel pump relay is inside the base of the drivers A Pillar, and goes into the main power wire, and it connects to the ignition. The alarm is.... in the base of the drivers A Pillar. The issue is that I'm not getting 12v to the pump at ignition which tells me that relay isn't being triggered. AVS told me the immobiliser should be open until the ignition is active. So once ignition is active, the immobiliser relay should be telling that fuel pump relay to close which completes the circuit. But I'm not getting voltage at the relay in the rear triggered by the ECU, which leaves me back at the same assumption that that relay was never connected into the immobiliser. This is what I'm trying to verify, that my assumption is the most likely scenario and I'll go back to the alarm tech yet again that he needs to fix his work.      Here is the alarms wiring diagram, so my assumption is IM3A, IM3B, or both, aren't connected or improper. But this is all sealed up, with black wiring, and loomed  
×
×
  • Create New...