The Goods On Attessa

[IanB]

Okay, so this thread has two purposes.

First, I want to establish firmly the differences in peoples experciances and on paper between the 3. AFAIK R33/R34 has the same but R32 is different?

Secondly, I want to know just how much it really does for handling. Driving a R32 GTR myself, I have found that in most corner situations, it rarly puts any power on the front wheels whatsoever. Is it a constant system, even if massivly RWD bias (EG a constant 5% on the fronts at all times + whatever the computer decides to put on)? I have noticed that when I have the car up on a hoist, if I spin one of the front wheels all 4 wheels spin, whereas if I spin the rear wheels, only the rear two spin.

Also, what can be done to change this? I have heard of attessa controllers, where can I find more info on them?

I know this sounds like im trying to get spoonfed, but I searched this forum for quite some time before I posted this.

Thanks

Ian

//edit oh dear... I appear to have posted this in the wrong section... Mods, please move it? Thanks:)

Edited November 30, 2006 by IanB

[salad]

It is not a fulltime 4WD system. It is RWD most of the time and then when it needs more traction it splits some of the torque to the front. The maximum split is 50:50.

[IanB]

Hmm yes, I do know the maximum split is 50/50, what prompted me to ask about the full time thing is I have a RWD switch in my car, if I do turn it to RWD only, the steering in the front becomes a bit stiffer. Having come from a turbo FWD car, I think its because theres no power whatsoever on the front wheels, hence making the steering a bit less responsive.

What im more after is how to make the car more FWD-favourable to improve handling.

[Snowman]

IanB - I'll try my best to explain the system as I understand it as it's something I've been fiddling with recently.

As you mentioned the R32 system is different to the R33/R34 system in that the later models have an extra sensor to help increase the front wheel drive in times of loss of traction in the rear wheels.

But for you I'll explain how your system works and why the Raceworx Attessa controller (Found Here) will fix your problem rather than a fix split system such as the Grid TS Dancer.

In the R32 you have 2 G sensors. A longitudinal sensor detecting accelerating G-forces and a lateral sensor detecting cornering forces. What you should find in an extreme straight line force - such as a standstill launch you will be able to gain full FWD capabilities no problems.

However - what a lot of people don't understand is that the lateral sensor actually REDUCES front wheel torque. So basically as the car corners harder the amount of drive to the front will reduce allowing more RWD and the chance to basically power slide out (aka - the objective is no understeer). However in the R32's because there is no detection for wheel slip you can find it's far too much RWD especially if you have come from a FWD or AWD background.

So what the principle of the Raceworx Attesa controller does is that it is a voltage reducer of the lateral G-sensor. So basically as you start cornering hard the lateral G-sensor will be telling the Attessa to reduce front wheel torque. With the controller you will basically be able to reduce the influence of that signal to what ever level your style of driving prefers.

This type of system is much more preferable to a fix style system as it will still allow the benifits of an ACD unlike a fixed torque system.

Hope that helps a little and clears a few things up.

[Beer Baron]

good post snowman. just 1 point i'm not sure on is the wheel speed issue. I'm 90% sure the attesa ecu get's wheel speed input from all 4 wheel speed sensors so it does detect traction loss. maybe it doesn't react to it, but I was pretty sure that it does.

[Snowman]

See I haven't been able to get a definite answer on the "3rd" sensor in the R33/R34's. Basically the only answer I have been given which half makes sense is the traction loss one which is why I've been told you can't put the R33/R34's into RWD mode with a simple fuse pull.

Anyways - as far as Ian's problem with oversteer goes and his desire for more FWD the information regarding the lateral and longitudinal sensors is all right.

[Beer Baron]

yeah, it's all good. I understood that the main differences from 32 to 33/34 were another G sensor, and faster sampling rate of the ecu and preloaded clutch pack in the transfer case (this is why you can't run on 2WD in 33,34). all 3 models have individual wheel speed sensors.

[Duncan]

nah the 32 had 3 g sensors as well. They all have 2 fore-aft (longitudinal) and 1 lateral sensors....some info in the 32 workshop manual ppCH-57 onwards. From when I was talking to Nige andrew it looks like there is 1 or 2 additional sensors in the rear of the 34 but they are for the screen display only.

Also, it takes both wheel speed and g sensor input so you can get front torque from either wheel spin or from accelerating.

Ian for the rest of your questions - hopefuly most of the info is in the Group Buy thread in my sig, it looks like you may already have read some of it.

Certainly the 32 in particular is very tail happy for a 4wd....while it may be fun its not particularly fast....the controllers make a huge difference to this and Nissan must have agreed - they made the 33 and then the 34 substaintially more front biased.

[IanB]

Thanks duncan. I have placed an order for one of your units. However I dont want to wait until the new year, I am orginising some new break rotors and coilovers to go in at the same time and want this to go in as well....

Kinda like a kid in a kandy store, dont want to wait, but hey, who does?

Thanks for the well written posts.

[blind_elk]

There is also another input for the ATTESSA, from the TPS.

There was an article on Autospeed (sorry, dirty word for some), quite a while ago now, about how the G-sensors affect FWD.

[ebola]

Autospeed article summary:

turn G-sensor unit 90deg... effective round corners, loses straight line 4wd.

simple resistor pot - crude, but effective. (10k resistor into lateral line)

op-amp based unit (variable 2.5v clamp) - superb, and for sale in the $450 attessa thread.

its under the centre compartment thingy between the front seats.

[noone]

Sure that I read somewhere else or may have been on here even that the circuit in the Autospeed article doesn't work,

(seem to remember it was someone selling TSC (torque split controllers) who said this, can anyone confirm or deny this.

Edited January 3, 2007 by noone

[heller44]

Hmm yes, I do know the maximum split is 50/50, what prompted me to ask about the full time thing is I have a RWD switch in my car, if I do turn it to RWD only, the steering in the front becomes a bit stiffer. Having come from a turbo FWD car, I think its because theres no power whatsoever on the front wheels, hence making the steering a bit less responsive.

What im more after is how to make the car more FWD-favourable to improve handling.

What I am trying to chase down now is the same as what you experienced, heavy steering. It seems to be a fail safe condition on the speed sensitive power steering where it goes into the steering load that equates to approximately 60-70km/hr range. Unfortunatly mine is there all the time due to dodgy transplant wiring.

[PHATR32]

thats ive also been told.

one example is in the wet when i take off slow, I ride the clutch alittle and give it a bit of gas get the rear wheels to loose a bit of traction, the torque gauge instantly hits above 40, even though the car isnt even moving (easily under 5kph) it bogs down.

so I assume, that would suggest that attesa computer also gets its readings off the abs sensors, as well as the tps.

steve

good post snowman. just 1 point i'm not sure on is the wheel speed issue. I'm 90% sure the attesa ecu get's wheel speed input from all 4 wheel speed sensors so it does detect traction loss. maybe it doesn't react to it, but I was pretty sure that it does.

[ebola]

thats ive also been told.

one example is in the wet when i take off slow, I ride the clutch alittle and give it a bit of gas get the rear wheels to loose a bit of traction, the torque gauge instantly hits above 40, even though the car isnt even moving (easily under 5kph) it bogs down.

so I assume, that would suggest that attesa computer also gets its readings off the abs sensors, as well as the tps.

steve

Don't know about tps. My theory is speedo

From a complete halt, the front ALWAYS gets a fair whack of initial torque.

When moving, there is a delay.

also, if it was tps and g-sensor, you would get large front torque with any quick acceleration. try rolling along in 1st (no acceleration) and putting some light throttle on. Will be different to the initial torque from a halt.

also, it makes more sense to be speedo based. the only time a different to standard map would be needed is from a complete halt.

also, about the '50 in the wet' - as soon as wheelspin is detected (straight line), it fully engages the front wheels, and as long as there is any acceleration, it keeps it at 50. Don't know about what happens with corners. hadn't thought about it before... I'll have to try.

This is just my car (R32), so I speak from limited experience.

oh - and its _not_ 50%. read the gauge (yes, I'm pedantic)

EDIT - nope, I was wrong. Damn - I thought the theory was pretty good.

Edited January 9, 2007 by ebola

[PHATR32]

Don't know about tps. My theory is speedo

thinking about it you may be correct.

although as i mensioned above the car barely moves when the front wheels kickin, it totally bogs down.

around corners at high speed the ass end swing way out, but it goes the way the front wheels point. quite scarey at first.

[PHATR32]

well, looking at the diagrams in the 32gtr manuals, it doesnt show the input from the tps, although there are 3 wires coming from the ecu going to the attesa computer. I cant see what they say as the scanning is pretty bad.

also, the attesa computer controlls the abs, therfore the wheel sensors connect into the attessa computer. which i assume means the 4wd system uses the reading from the wheels.

steve

[heller44]

The three wires from ecu to attessa are:

Engine speed signal

Throttle signal +

Throttle signal -

James.

[IanB]

Since posting this I have installed a Attessa Hand controller/computer in my car. Its a nifty little unit that intercepts the signals from the G sensors, determines whats going on and sends out a fake signal to the attessa computer to get more or less FWD based on the conditions. As it only really uses the lateral sensor, you still get all your standard AWD for launching the car, traction control etc...

Has completly changed the feel of the car. I put it in as my first drivetrain mod, then put in coilovers and new breaks. The car now turns like a rex on steroids, and I can plant it in second right before the apex of a corner and come out without loosing any traction at all, and having the front wheels pull me through the corner.

info on it can be found in this thread, including photos of it installed in my car:

http://www.skylinesaustralia.com/forums/in...howtopic=126694

Other users testimonies:

http://www.skylinesaustralia.com/forums/in...howtopic=134113

Other devices made by ruzie engineering, including his AWD controller:

http://www.skylinesaustralia.com/forums/in...howtopic=147560

The device cost me about 650 all told, and it was installed by one of pauls friends who did a very tidy job.

[sewid]

nah the 32 had 3 g sensors as well. They all have 2 fore-aft (longitudinal) and 1 lateral sensors....some info in the 32 workshop manual ppCH-57 onwards. From when I was talking to Nige andrew it looks like there is 1 or 2 additional sensors in the rear of the 34 but they are for the screen display only.

Duncan the rear mounted G sensors on the R34 are probably not for the display only. The screen you talk about is only a Nismo option and not fitted to many cars from the factory (if any, possibly all aftermarket or dealer fitted) so it makes no sense that the factory put G sensors on the car to support an aftermarket item.

My car has these G sensors and I have not got the Nismo display nor do I have any G meter display in the car.