Furthermore, the JMOD gives you a shift that is only as firm as your right foot wants it to be.
Around town driving yields shifts that are barely noticeable. faster, but not so firm you spill your coffee(with lower spring in). With lower spring out, you'll feel a little jolt at low rpms, but still, totally liveable.
But if you up the ante, and mash the go-pedal into the higher RPM's, the shifts get firmer as the rpms increase. its like a totally driver-adjustable shift. Want to break the back-end loose? mash the gas until shift point. getting up there in the rpms, but dont want to bark the back tires? back out of the throttle slightly, and enduce a slightly softer shift.
I know the JMOD is designed to speed up the amount of time between shifts. the pay-off, is firmer shifts at the same time.
The part about the article that most people miss is, the lower the torque your engine produces, the firmer the shifts will be. its as if more torque slips the tranny more, so the JMOD shifts arent bone jarring, like they can be in a stock motor-equipped car. Up the torque, soften the blow, so to speak.
as far as late shifts, the W in 4R70W stands for "wide" ratio. This means, a day and a half in each gear. I drive a Mark VIII, which has factory shift points at 6000 rpms at WOT. coupled with 3.08 gears, talk about a long lag between gears. My car doesnt even see third gear on the 1/4 mile!!! And thats a trap speed of 95.5 mph!!!
On my Mark, the ECU retards timing before the shift. The ECU gives the shift command at about 5400 at WOT. The shift solenoids react, and the tranny takes its time following orders. In the mean time, the engine seems to stop pulling "as hard" due to the timing drop. This timing drop feels like you just backed out of the throttle ever so slightly, as if to 'enduce' a shift.
A chip can change all that. Our 97 with SCT 4-bank chip has the timing retard effect removed, and line pressure increased. it pulls hard into 6000 rpms, and shifts clean/firm. So, my 94 with JMOD, Mach 1 TC, and a 98 tranny shifts harder than our 97 with chip. But my 94's timing still retards at shiftpoint.