G sensor , R33 series 2

[OJNZRG500]

Hi there , I'm new to forum and new R33 owner , based in NZ .

I have noticed this component under the center console , it has the red line through it . What does this component do , indicates what ?? 

Appreciate your collective help . 

 

[joshuaho96]

3 minutes ago, OJNZRG500 said:

Hi there , I'm new to forum and new R33 owner , based in NZ .

I have noticed this component under the center console , it has the red line through it . What does this component do , indicates what ?? 

Appreciate your collective help . 

 

The AWD or A-LSD system uses it to determine lateral g of the car and adjust the transfer case lockup or A-LSD lock pressure accordingly.

[Duncan]

If that is your G sensor in the pic, it does not have the high impact red line showing. 

If yours has a more obvious red section in the centre glass, it has had a high G impact. However, the shock indicator is physically separate to the actual g sensor electronics and is only an indication that the G sensor might be faulty. If your ATTESSA is working OK I would not worry any further

[OJNZRG500]

1 hour ago, joshuaho96 said:

The AWD or A-LSD system uses it to determine lateral g of the car and adjust the transfer case lockup or A-LSD lock pressure accordingly.

Thanks ,  I have A - LSD , and the sensor has the redline showing so will that mean that the A LSD wont be working ??

[GTSBoy]

29 minutes ago, OJNZRG500 said:

will that mean that the A LSD wont be working ??

No. Not necessarily. Duncan told you that already....

1 hour ago, Duncan said:

If yours has a more obvious red section in the centre glass, it has had a high G impact. However, the shock indicator is physically separate to the actual g sensor electronics and is only an indication that the G sensor might be faulty. If your ATTESSA is working OK I would not worry any further

My underline and bold emphases. Just substitute ATTESSA for A-LSD in your case.

But, if perchance your A-LSD was not functioning properly because of this failed sensor, then it is a prime opportunity to fling the smelly piece of crap in the bin (the whole A-LSD system) and replace with a diff that actually works properly.

[OJNZRG500]

11 minutes ago, GTSBoy said:

No. Not necessarily. Duncan told you that already....

My underline and bold emphases. Just substitute ATTESSA for A-LSD in your case.

But, if perchance your A-LSD was not functioning properly because of this failed sensor, then it is a prime opportunity to fling the smelly piece of crap in the bin (the whole A-LSD system) and replace with a diff that actually works properly.

thanks for that reply , what would be the test to understand if LSD was working / not working / functioning properly ??

[r32-25t]

Launch it and see if it goes straight or tries to wiggle it’s ass 

[Duncan]

haha yes, count the liquorice strips left afterwards. 2 strips good, 1 strip bad.

Sorry, I see your profile says r33 gtst, I had assumed gtr, didn't realise gtst with alsd had an attessa sensor too

[GTSBoy]

19 hours ago, Duncan said:

didn't realise gtst with alsd had an attessa sensor too

Yes, that's the primary input to seed the random number generator they use to decide the clutch actuator pressure in the diff.

[joshuaho96]

19 hours ago, Duncan said:

haha yes, count the liquorice strips left afterwards. 2 strips good, 1 strip bad.

Sorry, I see your profile says r33 gtst, I had assumed gtr, didn't realise gtst with alsd had an attessa sensor too

The A-LSD controller modifies the slope of the LSD lock pressure vs TPS curve depending on how much lateral g you pull. The more lateral g you pull the harder it locks up: https://sci-hub.se/10.1016/0389-4304(94)90219-4

Seems kind of suboptimal to have an open diff any time you let off the throttle but someone at Nissan thought that was a good idea.

[GTSBoy]

28 minutes ago, joshuaho96 said:

Seems kind of suboptimal to have an open diff any time you let off the throttle but someone at Nissan thought that was a good idea.

Reduces understeer. Remember, these are the same guys who came up with HICAS. It wasn't about making the best driver's car. It was about making something that sounded sporty and worked with very sub-optimal drivers.

[Duncan]

Not really fair, this was all mind blowing stuff back in 1987 or whenever the program started, and it was ahead of any other car of the day in multiple dimensions.

For sure, doesn't look great in 2022 though

[GTSBoy]

HICAS didn't look great by the time the cars were only 10 years old. It was already the butt of jokes about cars trying to kill people. I had to "fix" my HICAS upon commencement of ownership in 1999. That's only 10 years from first R32 release, 6 years from manufacture of my car. Bastard thing was dangerous. Wasn't worn out, just had a (deranged) mind of its own at anything above 7/10ths. And that's ignoring the occasional outright panic mode where it liked to crank the rear wheels to full lock at 80km/h.

Just not enough processing power, algorithmic development and designed experience (in terms of what actions are actually required, and what actions are definitely not required) at that point in time to create a system that was actually going to do what was on the wish list.

[OJNZRG500]

15 hours ago, GTSBoy said:

HICAS didn't look great by the time the cars were only 10 years old. It was already the butt of jokes about cars trying to kill people. I had to "fix" my HICAS upon commencement of ownership in 1999. That's only 10 years from first R32 release, 6 years from manufacture of my car. Bastard thing was dangerous. Wasn't worn out, just had a (deranged) mind of its own at anything above 7/10ths. And that's ignoring the occasional outright panic mode where it liked to crank the rear wheels to full lock at 80km/h.

Just not enough processing power, algorithmic development and designed experience (in terms of what actions are actually required, and what actions are definitely not required) at that point in time to create a system that was actually going to do what was on the wish list.

Did you use the bar lock out method?? . I got a bar that wasn't installed when I bought the car . i don't think the HICAS is working as fluids are all gone .

[GTSBoy]

30 minutes ago, OJNZRG500 said:

Did you use the bar lock out method?

Not initially, and also not ultimately. If the HICAS tie rod ends are in good condition, then the HICAS rack itself can serve exactly the same function as a lock bar. All that is required on an R32 to kill HICAS is to pull the smaller of the two loom plugs out the back of the HICAS CU. Stops working, no dash light (probably because the dash light wire is on that connector!!). The HICAS CU will lock the rack under a fault condition, meaning that it is "fail safe".....for a given definition of failsafe. I just happened to find a loophole (the small loom plug) that allowed me to exploit the design.

Later, I swapped the original HICAS rear subframe out for an A31 subframe with no HICAS. This is basically equivalent to fitting a complete HICAS eliminator kit (as opposed to just a lock bar). Lock bars keep the HICAS tie rods and they must be in good condition (ie the rod ends not worn). Eliminators can and should replace the original tie rods and the rod ends, replacing them with the sort of bushing that is used on the non-HICAS cars anyway. I just skipped all that aftermarket crap and went to an OEM Nissan solution to the same effect, that also happens to look completely factory, so that there are no obvious "steering system modifications", which would trigger raised eyebrows on a roadworthiness check. My car was going to have to go over the pits at Regency as part of the engine transplant that was happenign at the same time, and it sailed over without a word said. A lockbar or eliminator kit would possibly have got me in trouble.

37 minutes ago, OJNZRG500 said:

i don't think the HICAS is working as fluids are all gone .

There is no "fluid" iin R33 HICAS. This was the next generation of HICAS where the rack was electrically actuated.

[OJNZRG500]

15 minutes ago, GTSBoy said:

 

There is no "fluid" iin R33 HICAS. This was the next generation of HICAS where the rack was electrically actuated.

oh ok thanks for that .

[OJNZRG500]

As part of exploring G sensor and  A LSD i have found the leak in the the LSD pneumatic unit .

Seem like a repair has been tried before , un successfully !! Looks like a Pressure sensor of some kind .

Aside from binning the diff does anyone know what this part might be , as in genuine number and /or a non stock replacement part . thanks in advance .

 

[GTSBoy]

Yeah, it's the pressure switch.

All that goes in the bin. Of course, you'll need a new diff, casing, centre, etc.

[joshuaho96]

3 hours ago, OJNZRG500 said:

As part of exploring G sensor and  A LSD i have found the leak in the the LSD pneumatic unit .

Seem like a repair has been tried before , un successfully !! Looks like a Pressure sensor of some kind .

Aside from binning the diff does anyone know what this part might be , as in genuine number and /or a non stock replacement part . thanks in advance .

 

I don't think you can actually buy one separately as OEM. In theory you could get the whole unit sent off to Nismo for rebuild but the cost is hilarious: https://www.nismo.co.jp/heritage_parts/repair.html

If you are confident it's just the pressure switch and not anything else FPG sells the pressure switch by itself, not a direct fit but close enough: https://frenchysperformancegarage.com/products/fpg-nissan-gt-r-attessa-pressure-switch-replacement

[GTSBoy]

Just a caution - ATESSA switch point not necessarily same same as A-LSD switch's switch point.