Controlling ATTESA PRO with Syvecs S8 - RB26 / BCNR33

[skylion]

Hi,

I'm attempting to control the 4WD system on my R33 GTR from my Syvecs ECU. First time wiring an output off the ECU, so go easy on me!

The ATTESA ECU (Pin 48) requires a TPS signal - from my research I've found its 0.5V (fully closed) to about 4.3v (fully open).

I have an spare output with a 2 pin Deutsche connector: IGN8 + 12v supply. The loom is custom built and sealed, so if 5v is needed. I would have to use my X10 instead.

Is the following correct?



Thanks.
Shah

[stevieturbo]

It might be safer with 5v ?

I'm sure you could add in a little 5v regulator close to the Atessa unit to drop the 12v down to 5v before the resistor. At least that way it should ensure you can never fire 12v into the Atessa unit ?
With most of that wiring adjustments at or close to the Atessa, so you can then use your 2 pin connector and 12v/output

I would imagine your existing 12v supply is just a vehicle supply, and not a regulated supply at 12v ? ie, so not an ideal to use for any controls, as it would vary as well with alternator charging etc ?

At least with a 5v regulator from the 12v....you will get a reliable 5v.

[skylion]

Good idea, I have a 12v to 5v regulator I can use to drop the voltage. Didn't even think of using it.

It's 12v from the ECU so it's regulated, but you are right I don't know if the ATTESA ECU will like 12v. So I will drop the voltage.

Thanks for the reply

[stevieturbo]

Where on the ecu is it coming from as a regulated 12v ?

There is only one output I believe that would offer that, which is the variable voltage supply. And it would seem odd to use that along with an output pin.

It's probably just an ignition based 12v ? as opposed to coming specifically from the ecu ?

Other option might simply be a bigger resistor, but again it would not be regulated, so could vary which you wouldn't want for a control you need t be repeatable and consistent

[skylion]

Yep, it's not a regulated 12v I was going by the supplied documentation that came with the custom loom.

I installed a buck resistor to lower output voltage from 12v+ to 5v and setup the PWM values on S8. All seems to work well.

Wired it to the 4WD ECU and checked the signal against TPS position all within the correct values.

All seems to be in order, appreciate the help.

[stevieturbo]

good job.