R32 Gtr 4wd Constant

[Big Amph]

Hey guys and girls, i'm having a bit of a problem with my 32 GTR. For the past few months whenever i drive the car with more than say, 50% throttle, the gauge shows power going to the front wheels, i've

had new tires put on (bridgestone adrenalines)...

nearly 12 months ago had a set of 17x9in driftek rims put on...

taken it to a mechanic who changed all the sensors and ran a diagnostic, no fault codes...

but...

when he put on a set or R34 rims the problem stopped...

i've re-checked the drifteks, they are all the right sizes, i just can't seem to get my head around the problem...

Have i missed anything???

Any help is greatly appreciated...

Cheers

Amph

[heller44]

the drifteks were all the same size? tyres were all the same brand model and size?

why I ask is that I have 17x8.5's all round, with 235/45/17's all round. With different brands front compared to rear the 4wd was trying to engage just cruising, felt like a pulsing at 100kph and could see a blip each time on the gauge. swapped front to rear and it is gone. Takes bugger all to make a difference.

james

[Big Amph]

the drifteks were all the same size? tyres were all the same brand model and size?

why I ask is that I have 17x8.5's all round, with 235/45/17's all round. With different brands front compared to rear the 4wd was trying to engage just cruising, felt like a pulsing at 100kph and could see a blip each time on the gauge. swapped front to rear and it is gone. Takes bugger all to make a difference.

james

Yup they are all the same size, had that re-checked today, tires are brand new and were bought all together...

there is no pulsing at any speed, just the more speed you build and the further you put your foot down the more torque it sends...

[blind_elk]

If you are accelerating, then ATTESSA will get a signal from the longitudinal G-sensor (and maybe the TPS) and apply torque to the fronts. If you are simply cruising at >50% throttle, then you have a problem if you are getting front torque (sorry, don't know how to solve it if that's the case).

[Big Amph]

Today i put the original 16in tires on, it made it a little better, but it's still showing front torque at high speed and say 50% throttle...

ITS GIVING ME THE S**TS!!!!

but thanks for the feed-back, anybody else have similar problem???

[IanB]

that sounds to me like attessa doing what it normally does.

It will bring torque onto the fronts under mid - heavy acceleration. Basically anything sufficent to generate more then a few pound of boost. This is normal, my car does it and the half-dozen or so other GTR's I have driven also do this. Its to stop you from loosing traction under heavy acceleration. If you wanted a RWD car, you should of bought a GTST.

[cmoney]

How wide were the R34 rims?? Maybe you need some wider & heavier rims, sounds like the system is thinking it is losing traction early. Could be that the rims are narrower & lighter confusing it maybe....

[DSTROY]

sounds pretty normal to me, i think the ATTESSA works from throttle position also, so if your slightly accelerating the car will put some preload on to the front wheels.

[Big Amph]

Even on light throttle applications??? 3rd or 4th gear less than 3000rpm...

what about on the freeway, say 110km/h, drop it to 4th and it starts to send power to the front...

and the faster you go the more power is being transfered.

it wasn't like this when i first bought it, in the beginning it would come in when you put your foot down, but when you were moving at a fast pace (say 80km/h +) and back off, the re-apply the throttle there would be no more front drive...

i've had it up to 180km/h (on a track of course) and there is still power being sent to the front wheels...

that just doesn't seem right....

[cmoney]

Yeah that does sound like something has changed. Maybe take it to your local tuning shop, get them to have a look & ask them. Maybe also, a japanese wrecker on the odd chance that they have heard of this problem before. Where abouts are you located??

[blind_elk]

Sounds perfectly normal. The acceleration G-sensor is also a deceleration G-sensor. There is also input from the TPS to ATTESSA.

Were the new tyres fitted to all 4 rims?

[MrStabby]

Sound normal to me too IF you're accelerating. If your cruising then i would expect torque to be 0.

it wasn't like this when i first bought it, in the beginning it would come in when you put your foot down, but when you were moving at a fast pace (say 80km/h +) and back off, the re-apply the throttle there would be no more front drive...

That sounds strange. As elk says, if the g sensors are registering then some torque should go to the front. Unless of course you're cornering as well, where the system puts less drive to the fronts to prevent understeer. The other thing that will push torque to front is wheels slipping (or wheels that appear to be slipping to the system, ie when the circumference of the wheels is different front to back, or if your diffs have different ratios....)

[CeJay]

can the tyre shop compare the rolling diamaters of each tyre? I had a similar problem, 4wd engaged on half throttle, was due to the rolling diameter being 8mm smaller on the rears, attessa thought the rear wheels were losing traction.

[Big Amph]

Yeah all the tires were put on at the same time, the rims are all exactly the same size and shape (no buckled rims)

it just seems odd that whe i put the original tires and rims back on it still had the problem (not as obvious as with the drifteks)

I've only noticed this problem in the past 2 months, since then i've also changed to tein super-street coilovers and DBA slotted rotors at the front, in regards to the suspension i was told about getting the car weighed so they can adjust the coilovers to evenly distribute the weight...

could that have an effect on the atessa???

thanks for all the help so far guys, appreciate it...

cheers

Amph

[blind_elk]

the rims are all exactly the same size and shape (no buckled rims)

What about the tyres? Same manufacture? Same design? Same width? Same profile?

Tried swapping wheels F->R?

[Deano45]

What about the tyres? Same manufacture? Same design? Same width? Same profile?

Tried swapping wheels F->R?

Try what he is suggesting. The attesa system also uses the abs senses on each wheel to sense the wheel speed. As suggested earlier, it may be thinking that the rear wheels are slipping as they are spinning slightly faster than the fronts. Are the new tyres all from the same batch? Check the rolling circumference of each tyre. You can do this youself, by putting a mark on the sidewall, roll the tyre one full circumference and measure.

[Big Amph]

What about the tyres? Same manufacture? Same design? Same width? Same profile?

Tried swapping wheels F->R?

Yeah tires all exactly the same, tried swapping, made no diference...

[CeJay]

does the 4wd light ever come on?

[blind_elk]

Then I restate that it appears to be working exactly as designed. I have no idea why it didn't (appear to) work before. As for your new suspension, if anything it would cause an error in ATTESSA.

If the AWD light comes on, then you have an error, and you will not get torque to the fronts, no matter how hard you try.

[Big Amph]

does the 4wd light ever come on?

No never, the hicas light use to come on every now and then, but that stopped when i topped up the fluid resivour in the back...

The last place i took it to said that there was a difference of less than 4mm over the rolling diameter of all the wheels, i dont think the atessa can be that sensitive.. otherwise you'd have to change the tires front and back every few weeks...

and it's still doing it with 2 sets of wheels and tires...

the original 16's (which never had a problem when i bought the car with them on) and now the 17's