8_wannabe

This is exactly what I do. I never thought of it as blip or rev matching, but I guess that's what it is. I'd bet about 98 percent of MT drivers do this but a purist like druck thinks no one on the winning side of the pond could possibly drive stick with anything tantamount to skill.

Kamala

We invented the assembly line and perfected interchangable parts (starting on a gun of course, the Colt). Keeps them backwards RX-8s quite a bit cheaper than if they were built one by one, eh?:D

mp5

It's called double-clutching and is required with transmissions that don't have synchros... not needed for most modern cars but will help save the synchros.

When you put the car in neutral, the input shaft of the transmission is connected to the engine but is disconnected from the output shaft (connects to the wheels). Blipping the throttle will increase the engine speed AND the input shaft speed to match the speed needed for the next gear. When the shifter is moved into place for the actual gear change, the gear teeth will engage smoothly without needing synchro help because the input shaft is already spinning at the right speed.

When you downshift without double-clutching, the synchros have to speed up the input shaft to match the gear you are engaging which puts wear on the synchros. Not a big deal since that's how the transmission was designed to work.

I haven't actually tried double-clutching myself. I think I learned it all from reading the web at some point.

lefuton

i believe you are looking for the layshaft. if you are in neutral, and have the clutch pushed in, giving a blip on the throttle will spin the crank faster up to the flywheel. the driveshaft will be spinning at whatever it happens to be while the layshaft, which is basically the clutch disc and pressure plate (depends how you consider this), is slowing down. so even if you revmatch the motor to what it should be, you are missing the middle part.

since i can't draw a picture here's the sequence of the drive train =)

crank -> flywheel |1| clutch disc -> layshaft -> one side of your gears |2| other side of your gears -> drive shaft -> differential -> wheels.

the clutch connects |1| and the shifter connects |2| ...so basically when you want to double clutch, rev match, or shift smoother you need to spin up all 3 parts.

visitor

ah, ok, that makes sense. so double clutching just saves wear on the syncro's. i assumed that when the clutch was depressed, the entire drivetrain was disconnected, didn't realize the middle part of the drivetrain.

druck

Yes, I'll acknowledge Henry Ford's contribution to manufacturing, especially as Ford own Mazda - but the RX8's engine is still built by hand!

Cheers
---Dave

wleonard

interesting.....learn something new here.

I have been driving manual trans since I was 15 (many moons ago) and never considered what goes in to double clutching. I drove an old 280z with the syncros worn out and was in effect matching rpm to drive train to slip the gears in.

Nice to see the explanation.

Also, enjoying my chukles on Ex British Empire folk lore.