Jump to content
SAU Community

Tractions Issues Gtr

GT-R32
 Share

Recommended Posts

GT-R32 Grand Master

GT-R32

Posted
Posted

I did a search and couldn't see anything on this.

My car is an R32 running HKS 2530 at 1.3 bar. I have a fairly choked exhaust with the stock dumps and front pipe. Power is basically unknown, it is pretty quick (I have a dyno of ~260awkw on the low reading mainline dyno in Canberra prior to replacing my cat). My car will come onto boost quite hard in 2nd and smoke the tyres up to high 7k rpm. Dramatic, but not the fastest way of forward movement. I drive like a Granny 98% of the time but I like to give it a hit now and then and wouldn't expect this in 2nd, nor is it especially legal. :P

I replaced the shit Nexens it had on it, with them the car would literally smoke all 4 at 100km/h. I figured it had to be the poor and balding tyres. I fitted 255/40/17 Toyo T1Rs to the TE37s all around which I've put several hundred kms on. It's slightly better but in second gear it's still hopeless, straight line is spins the wheels after 4500rpm.

Suspension is Bilstein shocks and unknown springs all around, with some changes to arms etc. as it came from Japan. The spring rates are of course stiff, but not overly so. The ride is quite compliant (certainly compared to a mate's WRX anyway). Camber is negative, but again nothing silly.

So my question is, WTF? How can a 4WD car with the same tyres struggle for grip when a mate's S8 RX7 (he runs a ported block + T04Z at 1.1 bar around 280rwkw) with the exact same tyres (basically the reason I bought them) have full grip?

Is there a certain set up that can cause this behaviour? It's got me beat. :)

Link to comment
https://www.sau.com.au/forums/topic/269209-tractions-issues-gtr/
Share on other sites
GT-R32 Grand Master

GT-R32

Posted
  • Author
Posted
Im betting its not spinning all four wheels, I think it'd only be spinning the rears and there is something wrong with your ATTESSA or more likely your transfer case.

The clouds of tyre smoke out the rear when held at throttle says otherwise... so definitely rears (ie. you are correct). You can feel when the front comes in as it progressively transfers and regains grip (perhaps 'all 4 wheels' was a touch of exaggeration but it certainly felt like that on the old tyres - but just more wheelspin). Perhaps that regain of grip was just natural and at all the 4WD aid... Thanks for the thought, I'll look into it. But something doesn't seem right. :)

Pezhead Grand Master

Pezhead

Posted
Posted

Yeah,

I'd be checking your transfer case. Firstly, they are tough but one good run at power where the rears slip but front doesn't will toast the clutch packs in the transfer case.

Try this, put the car on a jack (trolly jack with wheels) up until rears are just off the ground. Then slowly give it a little clutch to see if the fronts can pull the car forward. When my transfer case was stuffed it couldn't pull the car forward at all.

Also check the smell of the transfer case fluid. If it smells burned then that is a bad sign. Like others said, bleed and check the attessa system.

I did the plates in my transfer case which was expensive. Might be better off just swapping the whole transmission as I've seen a few for sale on the forums.

Best of luck.

some_cs_student Veteran

some_cs_student

Posted
Posted

Good luck, if your transfer case was really, dead, the car becomes un-drivable, when my one died, I could release the clutch and the car would not stall (clutch had 1-2mm left on it, transfer case was broken).

GT-R32 Grand Master

GT-R32

Posted
  • Author
Posted

Nah it's definitely working, in 2nd I'm getting 10kg/m which results in wheelspin. Whereas in 1st I get the full 50 which is no wheelspin (obviously less power in 1st too). I'll have a shop look at my suspension set up and then decide if I need a ATTESA controller.

djr81 Grand Master

djr81

Posted
Posted
Nah it's definitely working, in 2nd I'm getting 10kg/m which results in wheelspin. Whereas in 1st I get the full 50 which is no wheelspin (obviously less power in 1st too). I'll have a shop look at my suspension set up and then decide if I need a ATTESA controller.

The guage doesn't understand how shagged your attessa system may or may not be. It assumes it is working perfectly & displays how much front torque you would have if the system was working properly & the motoro was standard.

What frequently happens with Gt-Rs is the clutches in the attessa system wear. This causes the clearances in the system to become out of tolerance & you get a slow reacting system - ie more rear wheel torque than it should have. Given the system is old, slow to react & calibrated for a stock motor it is quite easy to end up where you are ie with a GTR driving like a GTST.

GT-R32 Grand Master

GT-R32

Posted
  • Author
Posted

I meant it's definitely working not because of the gauge, but because jacked up in the rear only it lurches forward just by letting the clutch out at idle. It may be slower or not as strong, but it's definitely 4WD still. I'll resist spending a bomb rebuilding the transfer case for now.

MrStabby Grand Master

MrStabby

Posted
Posted

You've been subjective with spring rates and camber in your post - what are the numbers?

Have you tried pineapples in the "traction" configuration? Although IIRC SK reackoned on 32 GTRs the "neutral" config was better, so maybe try both.

Risking Grand Master

Risking

Posted
Posted

Its the transfer case. Testing without load means nothing.

Get it put onto a 4wd dyno with torque split monitoring and id almost bet my race car's transfer case that yours is shot.

They become slow and end up with rear wheel spin. Eventually when its really rooted it wont drive off the jack. But at the moment its only slipping under load.

We re-build our cases with specially designed clutch plates every 48hours or so of use as this exact problem starts to occur on the circuit. Mines doing it atm and needs to be rebuilt.

On the road with genuine parts your transfer should last a very long time. Its not as an expensive excersise as some people think and in my opinion ANY R32 GTR which has not had it done should have it done.

GT-R32 Grand Master

GT-R32

Posted
  • Author
Posted
You've been subjective with spring rates and camber in your post - what are the numbers?

Have you tried pineapples in the "traction" configuration? Although IIRC SK reackoned on 32 GTRs the "neutral" config was better, so maybe try both.

Sorry it's running some camber - unsure how much. Spring rates again unknown :D . As per Japan basically... ie. no idea LOL.

Pretty sure it's the transfer case, like Risking said just slipping under load. Rebuilt for under $1k I would be happy, cs! I'll struggle here for that I reckon.

some_cs_student Veteran

some_cs_student

Posted
Posted

I personally went down the path of second hand (R33 transfer case), and paid $400 for a second hand transfer case to be fitted, in my case I it wasn't the clutch pack that went, it was a shaft...

GT-R32 Grand Master

GT-R32

Posted
  • Author
Posted
I personally went down the path of second hand (R33 transfer case), and paid $400 for a second hand transfer case to be fitted, in my case I it wasn't the clutch pack that went, it was a shaft...

It's gotta be clutches in mine. So rebuilt is preferred.

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
 Share
Go to topic listing


  • Similar Content

  • Latest Posts

    • Kinkstaah
      Mistakes were made, my R34 Story

      By Kinkstaah · Posted

      God damnit. The only option I actually have in the software is the one that is screenshotted. I am glad that I at least got it right... for those two points. Would it actually change anything if I chose/used 80C and 120C as the two points instead? My brain wants to imagine the formula put into HPtuners would be the same equation, otherwise none of this makes sense to me, unless: 1) The formula you put into VCM Scanner/HPTuners is always linear 2) The two points/input pairs are only arbitrary to choose (as the documentation implies) IF the actual scaling of the sensor is linear. then 3) If the scaling is not linear, the two points you choose matter a great deal, because the formula will draw a line between those two points only.
    • GTSBoy
      Mistakes were made, my R34 Story

      By GTSBoy · Posted

      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.
    • GTSBoy
      DeAgostini 1/8 scale BNR32 Nissan Skyline GT-R Nismo

      By GTSBoy · Posted

      That's hilariously putrid!
    • GTSBoy
      R33 Fuel Pump & Brakes after alarm swap

      By GTSBoy · Posted

      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.
    • Kinkstaah
      Mistakes were made, my R34 Story

      By Kinkstaah · Posted

      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.
×
×
  • Create New...