Altessa Sending Power To Front Too Easily?

[Tabs]

Hi guys my r32 gtr sits around 1/4 on the torque gauge when crushing around 100kms my gtr in NZ and my old gts4 didn't do this unless I had different size tyres on the rear !!

I removed the 4wd controller it had in it and still is sending power when light throttle on the Hilway ??

Any ideas ??

Cheers

[GTSBoy]

Have you looked for fault codes?

[niZmO_Man]

Does it return to 0 when you lift off? Probably mismatched rolling diameters.

[djr81]

They all put a little bit of torque forward at light throttle at that speed. The system is fine.

[niZmO_Man]

No it shouldn't. It should be 0 until the car detects slip.

Check tyre pressures.

[Piggaz]

No it shouldn't. It should be 0 until the car detects slip.

Check tyre pressures.

Wrong.

[Tabs]

^{Havent checked fault codes yet about to do that now>}

^{Does it return to 0 when you lift off? Probably mismatched rolling diameters.}

^{yip returns to 0 when back off, and I checked tyre pressures and pumped up to a nice firm 38psi 235/40/r18 all round, it does have 10inch wide on the rear and 9"on front.}

^{the same thinig happened to my gtr in nz when had 18's on front and gtr 16s on rear}

^{why does my previous 2 4wd skylines r32 gts4 and my other gtr in nz it would read 0 unless under bumpy roads or accerating or sliping, while cruising at 105kms.}

Edited June 25, 2013 by Tabs

[MrStabby]

Wrong.

R32 = no preload

R33/34 = preload

No?

OP - it should only send power to the front under heavy acceleration or slip. You're probably wearing it out driving it like that.

[Tabs]

yeah im turning key off-on most the time ( put in rwd mode till come to a stop ) to prevent extra wear plus extra fun of rwd

I have a power fc ecu would that effect the tps for the 4wd??? fi adjusted tps from .9 to .48v

putting the 4wd in diagnostics do you have to turn a screw like the engine ecu or something??

with reds on no led on ecu in the boot (passenger side)

[GTSBoy]

Wrong TPS value can cause shenanigans. It absolutely should be less then 0.5v at closed throttle.

Just google the procedure to put it into diagnostics, or look in the GTR manual. Or, take it to a mechanic who has a good scan tool and just hook it up and surf around in the computers. Much easier.

[KiwiRS4T]

If you have 10in at the rear and 9in at the front the the rolling circumference will be different - the 40 in the size is a ratio not a height and so they will have different heights.

[niZmO_Man]

That tyre size is too narrow for one. I had exact same problem when I put bigger tyres on the rear of my car. Try a different set of wheels if you can, one with same sizes all round.

But, do a diag first (I'm sure there's a procedure around here).

Wrong.

How am I wrong?

[KiwiRS4T]

Sorry didn't notice that you had the same tyres on different rims. Your rear tyres are illegal in NZ. Minimum for 9in is 235 ( I have 255s on mine) and minimum for 10in is 255 and ideally should be 265 or 275.

If you want to keep the tyres get a set of 4 8in rims or else ditch the lot and start again.

[djr81]

No it shouldn't. It should be 0 until the car detects slip.

Check tyre pressures.

Wrong.

R32 = no preload

R33/34 = preload

No?

OP - it should only send power to the front under heavy acceleration or slip. You're probably wearing it out driving it like that.

Clearly there is some contention about how much front wheel torque is supplied at cruising speed. I have found in the 32's I have run that there is a little supplied at about 100km/h. So I dont think any fault codes will show and I dont reckon there to be anything wrong with the system. AFAIK the attessa works in conditions other than large front/rear wheel speed differentials.

[niZmO_Man]

Yes that is true. But the small amount of front torque doesn't register on the gauge. Unless my ATTESSA is not working as well as it should, hence my question of how am I wrong to say that the needle should be at 0 until the car decides to send torque to the front wheels. I may sound like a dick online, but it's a genuine question lol.

When I had 245/40 front and 245/45 rear tyres, every bump sent the gauge to ~10. I had to lift off so it would relax down to 0 again.

Bit off topic, with the R33/R34 GT-R's, does the torque gauge read 0 during cruise, even though there is preload on the front wheels?

[blind_elk]

^{235/40/r18 all round, it does have 10inch wide on the rear and 9"on front.}

^{the same thinig happened to my gtr in nz when had 18's on front and gtr 16s on rear}

How many f*****g times do we have to state that you need same size tyres on same size rims on all 4 corners?

Stretching a 235/40 tyre onto a 10" rim will force the rolling circumference of that tyre to be smaller than a 235/40 on a 9" rim. Result = ATTESA chaos.

The added advantage of this setup is that you can easily even out tyre wear by swapping F<>R at regular (say 5k) intervals.

[jiffo]

Yes the R32's system works in conditions other than simply wheel speed difference, but cruising at 100 under light load, nope.

Moderate acceleration without rear wheel slip will show some front torque due to the "G" sensor input.

But as for tyre sizing, I can't understand what's so hard to understand.

Forget theoretical rolling diameters, get the bloody tape out and check circumferences.

It's surprising how similar looking tyres can still be quite different in circumference.

Put the small ones on the front.

And read up on the manual, it's all in there.

[Tabs]

Thanks for above comments

I agree with no preload and should read around 0 when crusieing at 100k

Also makes sense about 235 stretched on 10" rims personally I got the car like that and have been destroying the tread to get better tyres as they are a shit compound and I'd perfer stock gtr r32 rims or after r34 gtr rims bbs rims with gold don't do it for me despite what my mates recon thru are worth and how awesome they recon they look !!

Factory gtr rims here I come !!!

[MrStabby]

There's a sweet little thing called logic;

Sending power to the front when your rears are slipping = sensible, since your rear wheels are slipping...

Sending power to the front when you're accelerating hard = sensible, since your rears maybe be about to break traction because your accelerating hard

Sending power to the front when you're cruising at speed = no apparent benefit, so why do it? They don't do it, except for the preload. They noticed that the R32 system didnt react as quickly as they'd like, so its a bit of a hack to reduce latency. You dont see pre-load on the gauge tho, because its so close to zero.

FWIW, i've never noticed the torque gauge being non zero when cruising.

[datsun_1600]

Yes the R32's system works in conditions other than simply wheel speed difference, but cruising at 100 under light load, nope.

Moderate acceleration without rear wheel slip will show some front torque due to the "G" sensor input.

But as for tyre sizing, I can't understand what's so hard to understand.

Forget theoretical rolling diameters, get the bloody tape out and check circumferences.

It's surprising how similar looking tyres can still be quite different in circumference.

Put the small ones on the front.

And read up on the manual, it's all in there.

I've done a lot of messing around the G-Sensor - for sure, if it's not calibrated, it will cause what you are seeing. I've even done it deliberately for some tests. Although if it's as bad as you say, I would expect it to throw an error.