Question about shifting

[NickCats]

In my quest to become a better driver, I am about half way through Skip Barber’s “Going Faster – Mastering the Art of Race Driving”. I am currently reading the chapter about downshifting, and the book mentioned that in a race car you should put the clutch in, shift to neutral, let the clutch out, blip the throttle, put the clutch in, shift into gear, and let the clutch out when downshifting ( double clutching ).

It then goes on to discuss not shifting into neutral between shifts, and blipping the gas while the clutch is depressed between gears. It mentions that the blip is more effective if you shift into neutral and release the clutch rather then just depressing the clutch.

I am sure they are talking about race cars, but I would like to practice this during daily driving to be more adept when and if I ever get the chance to race. My question is with our cars is there any advantage to letting the clutch out in neutral when blipping the gas or is simply blipping the gas with the clutch depressed sufficient ?

From page 97 :

When the engine isn’t directly connected to the input shaft of the transmission, which would be the case if you let the clutch out, the blip isn’t as effective at speeding up the input shaft. There is some drag going on between the motor and the input shaft, and a blip, even with the clutch depressed, will speed up the shaft some. The blip is much more effective, however, if you positively connect the engine and input shaft by letting the clutch back out in neutral.

Hope this makes sense…

Thanks !

Nick

[racer_d]

That is a practice called "double de-clutching".

Race cars typically have "straight cut" gears. Passengers have "curved" gears, and synchonizers. The job of the syncrhos is to make double de-clutching obsolete.

Can you do it without harming your car? Yes, absolutely. It is also an integral skill in heal-toe downshifting. But, it is not necessary.

The goal of "blipping the gas" is to ensure that once you downshift into the lower gear, the engine will already be spinning at the correct rate. It makes for smoother downshifts.

[John V]

Rev matching = essential.

Double declutching = waste of time with a synchro box. The synchros are faster than you are, and that's what they're in the trans for. Use 'em.

[Sammy]

When you go to shift you should hit the brake real hard before letting out the clutch.

(You and DJ are going to be on my heels at autocrosses soon enough so I need to edumicate you on the proper technique.)

[John V]

If you're autocrossing and shifting more than once, you're doing something wrong.

[Sammy]

Originally Posted by John V

If you're autocrossing and shifting more than once, you're doing something wrong.

I usually agree with this statement but we have run some pretty small courses with tight 180's and garage boxes which unless you have a torque monster it is tough to get out of quickly. It seems to be a hit and miss depending on the course layout. The bigger groups like Chicago and Milwaukee always have a long course and I've never had to shift more than once.