Using R32 Ecu In R33 Yet Retaining Vct And Idle Control

[nigelswazi]

Hi,

I have recently purchased a R32 ECU mapped to suit RB25DET tuned for the same mods as my car and installed it. Now as this is a R32 ECU there is no output to control the VCT so I believe I need to purchase a Vtec type controller to switch it off and on like the factory ECU would.

Now I have a question firstly regarding this, is the VCT controller on the RB25 just a on / off device that the ECU switches on or does it require a special pulsing signal or such like? I ask as I plan to just use a VTEC controller if I can. Will this work just as effectively as stock once setup?

Now the next question is regarding pinout differences between the ECU's. My car idles at 1500rpm and after spending hours on here searching it would appear a few pins are different on the ECU's

RB25 Pinout http://www.skylinesaustralia.com/forums/ip...ECU_Pinouts.jpg

RB20 Pinout http://www.skylinesaustralia.com/forums/ip...ECU_Pinouts.jpg

My question is which wires to move where? It looks like the Pin 54 output of the R32 ECU needs connecting properly to the R33 loom which says its not connected or whatever the NC stands for but which others as I would like it to behave just like normal.

Any information from someone that has done the complete conversion would be much appreciated.

Thanks in advance for replies.

Edited November 19, 2007 by nigelswazi

[paulr33]

hi nigel

the rb25 vct is based on TPS and comes on when throttle is opened, presumably past 0.33v on the TPS

once its past 4500rpm the VCT is no longer active and turns off.

/* RB25 VCT switching */

#define ON 1

#define OFF 0

#define VCT 1

#ifdef VCT

If (TPS > 0.33 && RPM < 4500) {

switchVCT(ON);

}

#endif

ive got an apexi VAFC coming my way and im going to try and use it to control the stock VCT

i dont think it will work but ill give it a shot. you can also check out the CAMCOM controller i think from buddy club or something like that - its on nengun.com under electronics

[nigelswazi]

From comparing the ECU pinouts the R33 loom covers all pins identically except for the following:

On RB20 ECU Pin 54 Throttle Valve Switch (Idle Connection)

On RB20 ECU Pins 56/57 Im assuming are the same as the R33 although every ECU pinout for the RB25 listed those too pins under different names AT/ABS/LSD Control Units for both.

Then the only difference is Cyl No 4 & 6 Injector GNDs are the wrong way around but if it is batch fire it won't make a difference if it is sequential then these should ideally be swapped. Then the R33 Pin 133 needs to be connected to a external VCT controller to maintain factory VCT specs.

Can anyone confirm what changes are required and give any good recommendations of VCT controllers

[paulr33]

camcon controller (should be fine)

apexi vafc (maybe)

gizmo have a camFC device (should be fine)

autospeed have a home-made device i think

dick smith / jaycar have a home-device relay switching device

[PM-R33]

Out of curiousity, why would you want to keep the variable cam timing? Doesn't it cause a bit of problems trying to tune with it for high horsepower applications? Like i hear about a lot of cars that push around 250-300 at the wheels and don't bother retaining the cam timing by either not tuning with it, or replacing the cam gear or cam. Can some one shed some light on this?

Cheers.

[nigelswazi]

Out of curiousity, why would you want to keep the variable cam timing? Doesn't it cause a bit of problems trying to tune with it for high horsepower applications? Like i hear about a lot of cars that push around 250-300 at the wheels and don't bother retaining the cam timing by either not tuning with it, or replacing the cam gear or cam. Can some one shed some light on this?

Cheers.

I would like to keep it as the low down torque has decreased quite noticeabley. I can tell the ECU is better once its on boost especially on my AFR guage its a way better tune I just want my low rpm torque to be optimised as I do a lot of city driving.

Does anyone know which pin on the R33 pinout is the same as Pin 54 Throttle Valve Switch on the RB20 ECU?

[AntsRB25]

I use a micro switch on the throttle body of my S2 RB25 connected to pin 54. When TB closed switch is armed. I had the same problem of high idle when I first connected the 32 ecu. This switch fixed the problem.

[PHaT MR30]

I am going to try and use the Aux output on my Microtech when the time comes, ill let peeps know how it goes, but I know this isn't PFC related or anything like that.

[nigelswazi]

AntzRB25 what type of switch was that? Do you have any pictures?

What about the Injectors pins 112 and 114 do people just snip the wires and swap them around or is the pinout information on the net just incorrect?

[Hotwire]

Nigel,

Lee here (bought the springs/top hats etc). How did you go getting the ECU running? Im thinking of purchasing a re-tuned RB20 ECU for my car also, and would like to know your experiences. Did you get it working ok in the end, and do you think it was worth the money to go this path?

Cheers

Lee

[AD2AV1]

From memory, doesnt the 32 ECU have a trimpod on the side of it to control its idle speed?

Also, I just had a dyno session yesterday and found that leaving the VCT unplugged gained me around 10kW and made my torque curve much stronger and smoother without any real hesitation down low, Im no longer a fan of VCT. 215.4kW @ rears on stock 33 turbo seals those thoughts for me.