Fredeee

Ok... total newb question here. My first 911 (I have a '24 4 GTS). It has a feature called "auto-blip" which, from what I understand, helps you rev-match on downshifts. For those like me who have driven manuals for a billion years and never heard of it, the engine engages when you shift into gear, not when you pull off the clutch. It's weird, especially for those that are used to downshifting to slow the car or just simply downshifting when entering slower traffic. Question, who in God's name actually uses this (it's default in Sport and Sport Plus) or am I completely out of touch with how the 911 drives.

breny4104

I'm not an expert, others will chime in with better answers I'm sure, but I'll give it a try...
1. Auto blip makes for a smoother downshift, without the initial lurch.
2. Racers would use heel-toe shifting - one foot on the break and on the gas at the same time to rev-match. The lurch caused by downshifting without rev-matching while in a curve can cause the rear end to lose traction.
3. with auto blip, you still slow down with engine braking but it isn't as sudden initially.
4. it's a sports car and rev-matching helps on the track.

BaxterPup

As I don't possess the skill of Walter Rohrl to dance on the pedals for blipping the throttle myself for smooth downshifts, I have auto-blip on all the time and love it!

Fishah

Have you just not been rev matching your downshifts all these years?

The system works brilliantly...

Also, the engine does not engage when you put it in gear... The computer revs the throttle to match road/transmission speed, but doesn't actually engage with the drive line until you release the clutch.

Wilder

It was very awkward for me too at the beginning, but given I only drive in sport and I don't change the settings every time I get in the car, I've gotten used to it and come to like it. It still feels like cheating sometimes but hey, at least it's not PDK.

Fishah

Oh, it absolutely is cheating 🤣

BTDubs

I'm excited to try it out eventually, but auto-blip has kept me in normal mode so far. I'm still in the break-in period and when I put it in sport or sport+ it auto-blips to over 4000 RPM on some downshifts.

Fredeee

Full disclosure, this is not only my first 911, but also my first "race car". So the closest I've come to "rev matching" is finessing the clutch for smooth shifts. I figured this is more of a learning opportunity for me, so I really appreciate the feedback. I'm in the same boat as BTDubs in this thread, still in break in and was worried about the RPMs when driving normally. I'll stay there for now and ween my way into the right way to drive this thing.

Fishah

Rev-matching is not just for "race cars". Ideally, any vehicle with a manual transmission should be driven this way. In the past before Synchronesh transmissions became the normal, rev-matching and/or double clutching could be required.

Yes when performing high performance driving, especially in the rain, rev matching is absolutely mandatory.

Ultimately though for any type of driving, if you're not rev-matching your downshifts you are putting unnecessary stress on your driveline.

In case you're unfamiliar with why, just imagine the scenario of what happens when you don't rev match. Your wheels are spinning at one speed, and your engine is spinning at a much slower speed. When you release the clutch without rev matching, the clutch has to work harder to bring everything to a matching speed again. In rainy conditions or when downshifting in a corner, this can cause the rear end to lock up as well.

By bringing the revs up before you release the clutch, the engine and rear end are already matched in speed so when you release the clutch the whole process is much smoother on the drive line.

Fishah

Totally fine. Won't hurt it.

BTDubs

Agree 100% and I've always tried to match the revs. It does feel weird when the car does it for me, though.

masmole

In anticipation of my soon-to-be-built T which will be the first car with auto-blip for me, I've got a question about how it actually works...

Previous manual transmission car that the T is replacing is a 997.2 GT3 that I've been driving for 13 years. I'm so used to rev-matching and heel-toeing the GT3, even for daily street driving that I feel it's a habit that will be hard to break. Say I drive my new T in sport mode, what happens if I forget the auto-blip function and do a manual rev-match downshift or heel-toe rev-match under heavy braking while the car is also trying to auto-blip. Does the auto-blip system override and just ignore my own throttle blip inputs? Or would that result in over-revving since I would be adding more revs than needed to the auto-blip rev-match?

alin2

Blipping the throttle manually during an auto-blip rev match won't add more revs as the throttle isn't "additive" unless you push the throttle more than a normal rev match blip.

981KMAN

On my 2022 Boxster GTS 4.0L, the Auto Blip system ignores my throttle blip (input) unless I give excessive throttle input (incorrectly). Then it will rev the engine to my higher input. It is a great training tool for beginner Heal-Toe folks

null

You have a GTS. My understanding is one of the benefits of that model is that you can disable the auto blip. Just turn it off! I wish I could do that with my inbound 4S....