EFI University

bing · Joined: 03 Aug 2008 Posts: 25

For all Dynapack operator, do you have oscillation problem with load control?
Did you able to resolve the problem or how?

Most of the time it happen to 4wd race vehicle, S4 , Subaru STI. But no problem with EVO.

Thanks in Advance.

Brian

Dad · Joined: 16 Feb 2009 Posts: 21 Location: No fixed address

You have tried changing the weight setting?

bing · Joined: 03 Aug 2008 Posts: 25

bradyzq · Posted: Wed Jan 25, 2012 9:59 pm Post subject:

Are you sure that the front and rear hubs are spinning at the same speed at the beginning of the dyno pulls?

If they're not, you will have a problem.

The solution is to load the car smoothly before the run starts. Launch from F3 can help here. Activate it from the F10 screen.
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bing · Joined: 03 Aug 2008 Posts: 25

Not just happen to one car, it happen to couple race subaru, the problem is the normal street sub i have no problem at all..

I check all hub rpm are same and it will work smooth with F2 mode.

bradtpt · Posted: Thu Apr 05, 2012 4:38 pm Post subject:

I realise this is a late reply but I only just joined the forum today. I'm a tuner from Australia and use a Dynapack 6042 setup (4000 rear pods, 2000 front pods) and have encountered this exactly as you've described only on the Subaru's.

The vehicle I was tuning was running an aftermarket ECU etc and had the 6 speed transmission with Subaru's DCCD (Driver Controlled Center Diff). It turned out that the solenoid for the DCCD had not been connected as we'd run out of outputs from the ECU. With no power to the solenoid the center diff would effectively "open wheel" allowing the front and rear wheel speeds to vary with little or no resistance and hence we'd see awful oscillations like you described.

The fix was to simply apply power to that solenoid which would effectively lock up the center diff and we were able to go about tuning quite happily after that. Your customer will find some big improvements to the handling of his Subaru in low grip situations if you install a center diff controller or if it's possible with the ECU you're running to setup a PWM output to drive the solenoid so you can progressively increase the lockup with throttle position. Don't leave it just passively powered all the time! This will make turning the vehicle on grippy surfaces difficult at low speed and can lead to other problems.

Hope this helps anyway, check it next time you see the car.

bing · Joined: 03 Aug 2008 Posts: 25

All the Subaru we tune have stock controller, i have try to set it to full lock, it seems not the source of the problem, i think it is more like the PID control of the software or calibration on dynapack. where there are Heavy, custom and light. but i found that i use light at all time.

I have also experience same with 2wd vehicle as well, its an Turbo RX8 too.

Thanks,

Brian