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Discussion Starter · #1 ·
Hello all,

I have searched this topic quite a bit and looked through the FSM, but I cannot find a the answers I am looking for.

I have transplanted the running gear out of a GTR32 into my S14 240sx and am having trouble finding out exactly how the attesa pump, pressure switch, and solenoid work together to produce X amount of line pressure. Since I do not have the attesa computer or sensors, my torque bias will be set manually to a certain front torque percentage, but only be engaged under certain conditions. Don't want to burn up that transfer clutch pack.

Even after looking at the diagrams in the FSM and reading through countless 4wd threads, I still do not understand how all 3 of the aforementioned components work together. My limited understanding is this and please correct me if I am wrong:

1. The pressure switch tells the pump to operate to maintain pressure until it is closed.

2. Voltage to the solenoid determines line pressure and therefore front torque bias? If so, how does it perform this? Does it change the amount of pressure that engages the pressure switch?

I suppose my main question is how the pressure switch is controlled. If I know how to change the amount of pressure that the switch engages at, I will know how to adapt the system to my car.
 

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On stageas which have pretty much the same attessa system (except it has less sensors) there is an ecu to run the system .
The stagea system is simpler so is probably easier to fit . It only uses a g sensor and the abs sensors for input readings and also has throttle position sensor readings to the awd ecu. There is also a connection from the std ecu to the awd ecu which may have to be hardwired ,
 

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Discussion Starter · #3 ·
On stageas which have pretty much the same attessa system (except it has less sensors) there is an ecu to run the system .
The stagea system is simpler so is probably easier to fit . It only uses a g sensor and the abs sensors for input readings and also has throttle position sensor readings to the awd ecu. There is also a connection from the std ecu to the awd ecu which may have to be hardwired ,
I understand pretty well how the stock system works in the big picture, but since I will not be using an attesa ECU, I need to find out how the attesa computer goes about controlling line pressure. I.E., how does the motor know when a certain line pressure has been reached? I assume the pressure switch grounds out telling the attesa computer that the pressure has been reached. But how does the attesa ecu get the pump to stop at certain line pressures. Some instances call for more or less than others, but how does it do this?
 

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Best of luck trying to get the attessa working WITHOUT THE MAIN COMPONENT - THE ECU
The point is thats exactly what the ECU does .The way it works things out is complicated which is why it has a computer.

Put simply the ECU takes readings from all four wheel sensors (on a GTR) and the G sensor and the throttle postion sensor and processes them

Cant see how it will work without these ( but if you know better I am happy to be educated)
.
 

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Wouldn't it be much easier to have attessa ecu running, and use a controller to modify front bias?
As GTR awd system isn't permanent (like wrx or evo), your method would lead to permanent 4wd... which would lead to many under steer moments if it's life is destined for the twisty stuff.

But if you already know this and still want to go ahead, find out what drag guys do (I assume this is what your focusing on), as a lot seem to have setups similar to what you speak of (ie. eliminate attessa ecu and manually controll pressure pump)
 

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Discussion Starter · #6 ·
Hmm, didn't know you guys were such debbie downers!

The ecu simply modifies the solenoid circuit load to vary the pressure switch's closing pressure point (I believe and am trying to find out). My torque % will be manually selectable, but only operable under certain conditions (similar to the Attesa ECU). Perhaps I wasn't clear earlier, but the system I just defined is not permanent 4wd. I'm pretty sure we all know what this can lead to with driveability and longevity of the transfer case clutch pack. Converting the car to a stock attesa system would be pretty expensive and difficult given the availability of the parts in the states.

From what I have read of the drag AWD guys: They do have a manually controlled torque%, but they don't do so via electronics as I am speaking of They are usually controlled mechanically some how, but those who do control them electronically still have to use the attesa ecu anyways. With my setup, you could still use a standalone ecu to control the solenoid circuit via a PWM signal using a map created from several sensors (albeit not my end goal).

I suppose my question is asking if anyone has any knowledge of the circuit design that controls the pressure switch.
 

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The Drag guys that have ditched the electronic 4x4 have a "Hand Brake" lever that they pump the system up hydrolicly (spelling...?) to get a set amount of pressure to the front wheels, Then by about 1/4 track they release it to go back to 2wd.

The not so supercar drag guys still run all the electronics and G-Sensors, And run items like the HKS drag modules to preset the amount of 4x4 with release times etc.

....Like the guys above have said, I think your are pushing sh1t if you think you can get the attessa system to work like it should without the ECU and G-Sensor. Once you have that going in the car, it is very easy to adjust how much drive you want buy using a Rusik or Skylab torque split controller.
 

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Hmm, didn't know you guys were such debbie downers!

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Have I missed something ?

You come onto a new forum asking for help because you dont understand (your words) the ATTESSA system but when we offer help you call us dds

Far from it I was actually suggesting a way round your problem but you have chosen not to even look at it

I will try once more to help

AFAIK you need an attessa system and ecu to use the torque split box . You cant use it to control something thats not there. On a GTR this means you need 4 wheels sensors and a G sensor to get the ecu to even start working.

I did try to explain the stagea system would be much easier to fit as it does not need the GTR wheel sensors but as you obviously know better so maybe I should just not bother .
 

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Discussion Starter · #9 ·
Have I missed something ?

You come onto a new forum asking for help because you dont understand (your words) the ATTESSA system but when we offer help you call us dds

Far from it I was actually suggesting a way round your problem but you have chosen not to even look at it

I will try once more to help

AFAIK you need an attessa system and ecu to use the torque split box . You cant use it to control something thats not there. On a GTR this means you need 4 wheels sensors and a G sensor to get the ecu to even start working.

I did try to explain the stagea system would be much easier to fit as it does not need the GTR wheel sensors but as you obviously know better so maybe I should just not bother .
Wow, you guys seem pretty slow. You don't seem to understand what I am asking and only provide criticism to boot! Lets go ahead and lock this thread up since this is pointless.
 

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I understand completely

You have joined the forum because you want a cheap shortcut to fit a complex awd system to a car not set up for it

You have decided there is a simple solution to this problem even though you have said you dont fully understand the system

People that do understand it have said they dont think its possible the way you want to do it and have tried to suggest alternatives but thats not good enough .

You say you have been critised but infact that was only because you spat your dummy out when it was suggested (very nicely) that it was not possible and you were given a suggestion which you did not even bother to think about.

Now thats pointless.
 

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Julio,
You could make a curcuit to pump preset amounts of pressure (Hydrolic) into the 4x4 system, and then pump them out....That would be reasonably easy, But it would be crap for the curcuit as you would be set to a certain amount of 4x4 all the time, as appossed to when you need it.

Getting it to work like it does from factory without the ECU and sensors would be nigh on impossible.
The way they work from factory is the ECU takes readings from the throttle,G-Sensor and wheel sensors and decides how much 4x4 you need to keep you on the black stuff.

I know you think there must be a way to do what Nissan have done with some bits from Radio Shack.....But I think not.
 

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Hello all, not to resurect a seemingly painful thread...

I am performing a very similar conversion as the originator of this thread. However, I have the ATTESA ECU, The G Sensors, ABS Sensors, etc, all from an R33 GTR. However, I am missing the ATTESA pump.

Fortunately, some years ago I purchased a complete R32 rear subframe for the stronger differential. Will this pump work correctly with all of the R33 electronics? I'm assuming it will, but I want the experts to verify.

Cheers!
 
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