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Dyno challenges

Hi all, I figure I'm the only one here with an automatic 33s, but I'd still like to pick your brains on this topic.

Recently put the car on the dyno (dynojet), but was unable to get an accurate reading due to some issues with the automatic ecu. Traction control was disabled, along with all other safety features (by holding traction control button).

Regardless of being in manual mode the transmission will generally upshift when hitting the limiter. However when flooring the accelerator in 4th gear to execute a run, the transmission consistently downshifted into 2nd gear over a few attempts, the result was also the same when trying to hold 3rd and 5th gear respectively.

I expected the transmission to change gears and upshift...  but the downshifting was surprising and new to me. I am also unable to replicate this downshifting under heavy acceleration when driving on the road, so I cannot confirm if this is simply something the transmission is supposed to do.

Not sure if @CTC-Performance would have worked on the automatic ecu before... but i'd like to hear some thoughts from others on if this is the limitation of an automatic transmission or incorrect technique for the transmission on the dyno?

Hi St. Nick,
It's called 'kick down'. Nearly all torque converter automatics I've ever driven have this. Basically, going full throttle (stabbing the accelerator to the floor), invokes kick down in the automatic. It's quite normal... and depending on gear / load in your 33S... it will do exactly the same.

Whether this can be defeated is unknown on an automatic 33S (I have a manual). But, there might be an electrical switch that is actuated by the accelerator pedal on full travel (to the floor). You may be able to temporarily disconnect it. Other than that, I'm not sure how you can defeat this system. Maybe pulling a fuse?

As mentioned, I know nothing about automatic 33S's. Just some thoughts - that's all.

Thanks.

Thanks for the response Dazza,

I speculated something like that, and your explanation has helped me to make sense of the scenario. I definitely was not expecting that the transmission would 'kick down' with manual mode engaged... but I see now that this is the limitation of the mechanics/software of automatic transmissions in general.

I suppose the turbocharger has been a bit too forgiving with me lol - this really is a punchy little car.

I'll take a look into temporarily disconnect the switch... hopefully it is as easy as pulling a fuse. And not something as invasive as rewriting the ECU.

Many thanks. I understood a lot from this.