since its the season for disclaimers, here is mine: i'm an occasional trackie so my pbox data is next to pointless since line consistency blah blah is non-existent with the lack of practice.
There were however interesting data points from the log which showed one of the risks of heel and toe. These come especially when the blipping is done where there is a tendency of poorly done heel and toe that brake pressure is reduced due a portion of force being directed to blipping of throttle.
I feel the action, even with a slight over blip, helps to smoothen the downshift transition. Overall, I'd do it. The benefit of reducing gearshift shock to the drivetrain and better traction are huge plus points I can't ignore. Whether i'm a good enough driver to wring out these benefits, only the times will tell.
I'd also like to share an experience of mine. When I complained of clutch slip to a certain well known workshop, the famous owner-mechanic-driver (X) asked me to show him how I drove to determine if it was clutch slip or driver error as he was convinced there was no such device as CDV (clutch delay valve) which I claimed to be causing clutch slip at high rpm quick shifting. As most owners of my ride will know, the CDV is actually present. X then claimed I was reading too many forums and shouldnt believe everything I read as it was probably a US issue but not applicable for JDM cars like mine.
I then drove the car and did my usual shifting albeit with a bit of messy shifting as I was still very new to the car (<3mths). I was then heavily criticized by X and then was asked by X if he could drive to show me the "way to drive". What I saw surprised me as when X upshifted at high rpm, he would ease off the clutch rather slowly thereby using the clutch much more than I did.
The downshifting was even more of a shocker when he began clutching in, dropping gear, blipping then slowly letting out the clutch (edit: he kind of slips the clutch as the revs dip to make the shift smooth) so the rpm dropped smoothly with the clutch release. That seemed more a clutch slip technique than the heel toe I knew which required an accurate blip with quick release of the clutch.
The classic moment came when we stopped and he told me that he felt no CDV present, he said AP2 clutches usually lasted <1 yr due to enthusiastic driving (my stock clutch lasted 3.25 yrs) and that my driving was ridiculously damaging to the transmission components so if I continued this way, I would end up with a broken transmission in <1 yr. It has been 3.5 yrs now and my transmission is problem free except for a 10 dollar gearshifter bushing. A Used Oil Analysis of my gearbox and rear differential fluid at the 2.5 yr mark showed minimal traces of metal particles thus proving my transmission was in excellent condition.My gearbox was opened up and visual inspection proved the same.
Although we could attribute it to many reasons but I've heel and toed or rev matched every single day of driving my car and I truly believe its helped keep rev mismatch wear to a minimum. It took a while to get used to the ratios but its pretty much second nature and smooth about 90% of the time. I related and demonstrated how I downshifted to a few qualified driving instructors and they have validated my heel toe as proper technique.
I do recommend it to all drivers. Sadly, with the advent of clutchless paddle shifter boxes with auto blipping, it seems likely the heel toe may soon go the way of the dinosaur. Nevertheless, for those who enjoy driving manuals know that a heel toe can be both fun and beneficial when performed correctly
