Q's Regarding R32 Gtr Drive

[DLUD3R]

Hey guys, i'm looking into perhaps buying an R32 GTR later on in the year, and i'm currently looking into what's available and what I should be looking for. I've had a look at some ads and seen the term 'suicide switch' thrown around. Now, as far as I know (not very far, but still) the GTR's are constant 4WD. There wasn't much information, but the general gist I got was that this particular GTR had a switch where you could switch between full 4WD and RWD. My previous understanding was that it was possible to stop the power going to the front wheels, but only by stuffing around with some of the drivetrain mechanics.

I don't want to waste too much of your time with newb questions, so in short, what i'm looking to confirm is:

- The R32 GTR is constant 4WD?

- Is it possible (with the right electronics knowledge) to build in one of these 'suicide switches' that allows you to manually enable/disable the front wheels at will?

Thanks

[scathing]

None of the GT-Rs are constant 4WD. They're only 4WD on demand.

The difference between a GT-R and your average "part time 4WD" shitbox is that, when its not in 4WD, the GT-R drives the right set of wheels for a sports car.

On an R32, pulling a fuse will disable the ATTESSA from working. So you could quite easily install a switch to do the same thing.

[DLUD3R]

Ok, i've done a bit more reading, just to make sure I understood it...

By default, the GT-R will send the torque to the rear wheels only? When the ATTESA ecu detects slip on one of the rear wheels, it then re-distributes some torque to the front wheels to keep the car under control (Thus creating 4WD)?

Hate to be a pest, but I was having one of those stupid little arguments about it and somehow we ended up with $20 on the table, so I need to be 100% sure ^_^

[Links]

That's a very generalised way of looking at it..

not only does it look at slip - but current speed, angle of the steering wheel, Throttle, and probably another couple of things than it engages the front wheels..

the R34 are alot smarter and tend to predict what you are going to do..

go take one for a test drive.. see how it goes, watch the torque gauge..

[DLUD3R]

Awesome. So it really just looks at multiple factors and enganges the front wheels when it thinks it's necessary.

I was thinking about test-driving one, but i'm not buying that soon and I don't like to waste people's time.

Anyway, thanks for the help guys, I think i've got it understood now. Yay.

[scathing]

Thanks Links. I'd forgotten about that (too long since I looked up or talked about ATTESSA).

Aside from detecting slip, the car knows from its other sensors where in a corner you are.

Assuming you have traction all the way through the corner:

On the straight its RWD. Under brakes and on turn-in its still RWD, which preserves its response and steering feel as the front wheels are not being corrupted by torque.

Once you pass the apex and get back on the power, the ATTESSA will funnel some torque to the front to pull you out of the corner, even if you have full traction. That will let you feed more power on as well as well as improve the power split to keep the car neutral as the rear tyres aren't being overwhelmed by demands on it.

Its all about maximising the amount of grip all four tyres can offer you by only putting torque to them when you can and when its needed.

I could write a longer post on it if you want, but you'd be just as well served Googling for it.

[Topaz]

- Is it possible (with the right electronics knowledge) to build in one of these 'suicide switches' that allows you to manually enable/disable the front wheels at will?

Thanks 

I have an old Japanese GTR video that shows 2 R32 GTR's partially enabling the front wheels using a switch (for a drag). Its all in Japanese so I don't know what they are on about but with the right electronic mind and skill you can enable the front wheels permanently.

The 2 GTR's 'front torque guage' needle peaked at different levels so theres obviously a fair bit of knowledge needed to get it where you want it....but I guess it can be done

[scathing]

It works off a variety sensors. And, just like plugging in an SAFC to do light tuning on your ECU, if you modify the signal the ATTESSA controller gets from those sensors you can control the way it behaves.

[DLUD3R]

Well I was only really referring to enabling/disabling the whole attessa system (turning the GTR into a constant RWD), but turning it into a constant 4WD sounds more interesting...

Would permanently enabling the front wheels have any disadvantages as far as traction or the genaral handling are corncerned? Power output would also be the same, only spread over all 4 wheels, yes?

Maybe I should stop pestering people on forums and go do some research myself, hehe

[scathing]

One of the best things about a GT-R is its adaptive drivetrain. You get power where you need it, when you need it. Making it permanent 4WD would kill a lot of the benefits in terms of handling.

[DLUD3R]

Mmmm, having done a bit of reading on how everything works, it seems stupid to try to change it at all. I'm gonna have to take one for a test drive when I get closer to a purchase (have a small loan that needs to be paid off first), but i'm pretty much sold. The challenge will be to find a fairly stock one in decent condition.