DTAForum.com - a forum for the DTA ECU

Hi,

I've recently fitted an S100 to our Caterham 'Busa hillclimb car to incorporate pneumatic paddle shift, which, with limited testing, worked reasonably well on our first outing.
However, we've missed a couple of downshifts. From our data logging, I think at least one of these missed shifts may have been attempted at mild part throttle.

We have a pneumatic blipper, but it is not inline with the throttle cable. it simply lifts the throttle open by about 20%. It looks to work OK as long as we're off the power.
Should we be able to change down with power on?
Do we really need a cable blipper?

Busa gear dogs are undercut as std and will remain locked in until unloaded so, no, unfortunately no 'power on' downshifts. Dog boxes really need an unloader, either ign. or clutch. The 'blipper' IMO only helps equalise the rev differential change in ratio's to prevent wheel locking - standard practice for bikers LOL!

have you selected the full throttle down shift option? blipper will not help in your situation, it is there for when the engine is in an over run condition and the dogs are locked in that condition due to the dog under cut mentioned above, the blip unloads the dogs. What you need to happen is the power to be cut by the ecu by spark cut/retard to unlock the dogs just like a full throttle upshift.
There is something weird in the settings for this, there is an rpm setting for the down shift but it only allows 0-100, which makes no sense. I have never used this feature.

That's a typo, Rob, it should be max throttle, not RPM. I'll update that.