Ok, let me set the stage. This old lady in newer Mustang GT lines up next to me at a stop light. I thought surely she won't want to race me but sure enough, as the light turns green she peels out. I caught up to her by 65mph and I thought I'll show you what my car can do and downshifted from 4th to 2nd (I think). I guess I was in a hurry and didn't match rev and next thing you know I am almost flying out of the front window -as if I hit the brakes hard-- and I hear my tires squealing. I was so embarassed. I am hoping my car didn't over-rev. I take it this happened because I downshifted too aggressively? I did this once before when I accidently shifted into 1st slowing down from 35mph... it felt like I slammed on my brakes... How bad is this on the car??
So, how do you execute a smooth downshift? You push in the clutch, downshift into lower gear, you blip the throttle, let out the clutch, and you floor the gas? Is that the correct order? Also, you shouldn't have to fully depress (ie. to the floor) clutch during shifts, right?
Thanks!
sbkim,
I would not worry about over revving the car once or twice. I have friends who have done it from time to time and their cars are fine.
I think you meant you shifted from 3rd into 2nd instead of 4th if you were trying to catch her.==> The easy fix for the 3-4 shift would be to put your elbow into the 3-4 shift alignment point after the 1-2 shift. THat way, the 2-3 shift is straight up and the 3-4 shift is straight back.
As far as a smooth downshift is concerned, there are a couple of things you want to keep in mind.
1. You need to be smooth as to not upset the car.
==> If you downshift at a speed above the redline of the engine for that gear, the rear wheels will lock up a. potentially spinning the car, b. if they grab the car can over rev and exceed the capacity of the valvetrain: when this happens the valve springs can no longer keep the proper timing between the valvetrain and the pistons. To the degree the top and bottom end become out of synch, will determine the overall degree of damage to the engine.
2. You must know the speed limit of the car for each gear: Obviously you do not want to exceed the speed limit in any gear.
==> If you are above the limit, you must use the brakes to slow the car before releasing the clutch
Heel and toe downshifting is how race car drivers match the revs while slowing the car quickly and downshifting at the same time.
Heel and toe downshifting is simply 1. Brake(inner ball of foot on brake pedal) 2. Clutch in 3. Downshift 4. Blip throttle(with outer ball of foot) 5. release clutch
After this sequence, depending on the timing, the engine revs should be almost perfectly matching the exact engine speed at that MPH if you just happened to be going that fast in that gear in a normal street driving situation.
A sidenote here is that in normal street driving, you should always downshift in reverse order from the gear you are in at the moment, ie 5-4-3-2-1.
Without the ability to heel and toe, and skipping a gear in the downshift sequence, you are always in danger of spinning the car.
As far as how far to depress the clutch is concerned, you only need to go the distance to the floor that allows for the full disengagement of the clutch.
This is only for people who have mastered basic shifting.
Trying this at home so to speak without sufficient skills could lead to ruining synchros and grinding the teeth off gears when you make a mistake.
Definitely not worth it IMO.
Up and downshifting is a rythm that is learned and felt whose speed can be incrementally increased based on feel.
I am back!!!
