Auto rev match saves my bacon
 

After 15 track days, I finally missed a shift!

This past weekend I was at VIR and made an error during downshifting at the end of the front straight. Rapidly slowing to prepare for corner entry, I went to shift from 5th to 3rd and accidently selected 1st!

Fortunately, the throttle blip RPM rise (which was uncharacteristically high) clued me in that something wasn't right and I refrained from letting the clutch out and instead pulled the shift lever back to neutral before going to 3rd. I looked at the PDR data and found that had I let out the clutch (in 1st), I would have exceeded the redline by quite a bit. Had I not been using auto rev match, I would not have known I was in 1st rather than 3rd until I let the clutch out.

Long live auto rev match!

Yeah that could have been very expensive!!!

I know rev match was created to keep the rpms up for a smooth down shift, but in this case I have found it can be a life saver.

WOW! Glad to hear disaster was averted!

Why were you going 5 -->3 instead of 5 -->4 -->3? This is a very bad habit you're developing my friend. And a dangerous one as you just found out. The advantage auto blib gives you is that you can just drop a gear at a time and do it faster than your current foot skills allow.

No cutting corners in becoming a better driver.

Thanks for the thoughts. I appreciate your approach is a common one (downshift through every gear), but it's not a hard and fast rule that you must downshift through every gear. If you read a lot or watch instructional videos by pro drivers you'll see that some say it's debatable whether you down-shift only one time before corner entry or instead drop through each gear. You aren't doing it for engine braking, so it really doesn't matter.

In this instance (5th to 3rd) slowing from 135 to 45mph, going to 4th in between would not have made anything less dangerous, as I would have been doing the downshift at round 90-100 mph and if I missed the shift (as happened when I went grabbed 1st instead of 3rd), I would have grabbed 2nd (instead of 4th) and that also would have over-revved the engine.

I tend to disagree. Hard to shift into 1st when you shift into a bottom row of gears :search: Also 135 - 45 is a TON of braking time to shift down a gear a time to be honest.

Couple thoughts.. First, you're wasting time being in 5th at only 135mph if your tires/gearing are stock. I can almost guarantee you'll be going faster at the end of the straight if you stay in 4th (stock limiter in 4th is 142 mph). Free time. Then you will only need to downshift one gear anyways.

As far as skipping gears, I've never seen (or heard of) ANY pro driver either skip gears themselves or recommend someone else do it. It's just not proper technique.

OK. Humor me. So both of you say it's "proper technique" to downshift sequentially (and more than 1 gear if necessary).

Can either of you explain why? What is to be gained by downshifting two gears individually (effectively twice) rather than simply downshifting 1 time to the final desire gear?

Ok.. Well the "proper" way to downshift for a corner is to do the downshift as soon as the rpms drop enough that you can go to the next lower gear without over reving the engine. So to do it perfectly would be to hit the exact red line of the engine on the downshift. If you need to go down another gear, you do the exact same thing again. This maximizes engine braking, slows you down faster and/or can save your brakes a small amount.

At the level of us poor schmucks doing trackdays and hpde's does it really matter? Probably not, but that doesn't mean you shouldn't try to do it the "proper" way anyways.

Plus the odds of dropping it from 5th to 1st decrease, since you are forcing yourself from the odd gears (upper row of gates) to even gears, and that it’s straight up into the odd gear you intend. It is safer not to skip gears as your experience shows.

Give this a quick read. Ross Bentley on Speed Secrets answering a question about whether it's better to skip gears on downshifting or run through them sequentially.
https://speedsecrets.com/should-i-sk...-downshifting/

You might be surprised by the answer (if you ignore the sidebar issue of heel-toe that also gets commentary). And yes, he's a pro.

In his answer, Ross makes it sound like skipping on downshifting can be an additional challenge because of the timing and trying to match revs. I guess I'm "cheating" by using the auto rev match, but I can live with that as it does it better than I could do, with less wear on the drivetrain parts.

I still can't understand your logic here as to why 5th to 4th to 3rd lowers the risk of over-rev.

If you shift from 5th (upper gates) to 4th (lower row of gates), with a down-left-down movement, you face the risk of accidently shifting to 2nd (lower row of gates). I don't think that's any different than going from 5th to 3rd (down-left-up), where you risk shifting into 1st. Either way, the consequence of missing the intended gear and winding up 1 more column gate to left will result in over-revving the engine given the car's speed at the moment you are attempting the downshift (100+ attempting to go 4th and accidently grabbing 2nd; 60+ attempting to go to 3rd and accidently grabbing 1st).

Is there a reason to believe that a down-left-down movement from 5th is more likely to land in the intended gate than a down-left-up movement?

I want to make sure I’m understanding something. Did the computer only blip the throttle to the redline?

Yes auto rev will blip the throttle as soon as you downshift even before you let off the clutch.