Ya I guess faster shifting is a no-brainer if it’s possible. Would be awesome if APR could pull that off, as my car currently shifts nearly instantaneously. An effective LC setup would also be nice - not sure if GIAC’s tune has proven itself in that regard. Hadn’t thought about the RPM dipping issue. I’ll have to look back at some of my vids to see if I can spot that.
Who cares about faster shifting really. Let’s pretend that every single shift adds up to 0.150 seconds. Let’s now pretend that an upgraded shift time is 0.100 seconds. That’s a big change from an already ridiculously quick shift to something unheard of.
Now let’s pretend that for the time between shifts, the car doesn’t move at all. This will be fighting physics but I’m making a point. So, the car only accelerates while it’s in gear and comes to a dead stop while shifting…then resumes once the next gear is engaged at the exact speed it was at before the shift. I know, crazy, but follow along.
That means that on a stock trans car in the 1/4 mile, it stops accelerating for the 1-2, 2-3, 3-4, 4-5 (for quicker cars that get into fifth at the strip). So the total time it stops accelerating is 0.750 seconds. On a car with a modified transmission tune that shifts in a blistering 0.100 seconds, the car stops accelerating for 0.500 seconds. Difference in this world that doesn’t exist is a mere 0.250 seconds, over 1/4 mile, 5 gears and 4 shifts. Two tenths.
Reality? The cars do continue accelerating during shifts (the first few shifts anyway…and worst case scenario they are still making forward progress) so the time saved in the quarter mile will be a fraction of the 0.250 seconds in that ridiculous scenario. In other words, maybe half a tenth. This also applies to manual cars when people say they shift at 0.2 seconds vs joe blow at 0.5…they’re not going to pick up 3 tenths of ET per shift. It’s a fraction of that so trans/synchro destroying shifting isn’t as big a winner as they think.
Bottom line? Who cares about faster shifts. They’re already awesome and the gains won’t be worth it IMO. Let’s look at primetime’s list…
-
higher redline
(good one if it’s still gaining and the valvetrain/rods can handle the speed. How much more will you really get out of the car…because if it’s not up for the challenge of another 500 RPM or something you’re heading for an expensive repair or mod list to prevent that repair) -
rpm’s don’t dip after shift
(also good…not sure what this means though) -
LC that works, ie can cut better 60’s than I do launching off idle
(it’s not going to get faster because physics is determining how fast you get out of the hole with AWD/4000 lbs/400whp/400wtq/street tires…and you’re pretty much as fast as any car has ever been. Changing tires are the only way you’ll get quicker at this power level) -
faster shifting
(see above) -
true manual mode, I could care less about bouncing off the limter like others insist the car should do… My car for the most part has this already it just some times it will auto upshift when at partial throttle… if flogging the car it shifts when I pull the paddle or hit redline…
(you could care less means you care. I think you meant to say you couldn’t care less. aka you care zero, and there could be no less care than zero. Anyway, this would also be nice as this is what the RS cars do. Not sure why the S4/S5 DSG is so nannyish)
Saki, that is why it was #4 ;D
As for #2 watch one of my gopro vids if you get a minute… Sorry, I’m in the office otherwise I would link one… There is a slight hesitation/dip in rpm’s after the 2-3 shift, car drops to 5600ish rpm and then drops again to 5400ish rpm after shifting…
As for the LC one, I think a true LC could shave a little off of my 60’s but not much… To your point physics come into play… Also, even w/o an LC I would just as soon have the hesitation removed after launching that occurs at 3400ish rpm’s… car sits at that rpm for split second before advancing… probably some safeguard I would assume?
surprised CV hasn’t torn into a DSG for the B8 S4. He wrote a file for a VW DSG GTI about 5 years ago that was more than effective.
That’s why I stomp just as the second yellow goes out…big delay
The 2-3 clutch slipping was, at one point, fixed in a REVO revision of all things. At least that’s what was claimed a long time ago, but they did have the video to prove it. That was the same time they fixed launch control. It’s in AZ somewhere. It’s possible that has nothing to do with the DSG, weird as it sounds.
J
Faster shifting isn’t always the point of the DSG tune…done properly, it develops more fluid pressure and clutch pressure and releases harder and with less slip. There’s an argument that it will lengthen the life of DSG clutches.
True manual would be nice… and the 991 GT3 feature of clutch in when both paddles are pulled would be sweeeet. Maybe I can find a video of it somewhere, if someone’s made it yet. When you release the - paddle from a stop, it will “drop the clutch”.
There’s also the slight delay between using the paddle and the car shifting. I’ve gotten so used to it now, but it would be cool if a tune eliminated it.
^^ good point, that’s actual a pretty big delay compared to more sporting DSG from Audi and others I’ve tried.
The new pdk shaves seconds over a 997 gt3 around a road course. It’s that much of an advantage.
Saying quicker shifts is a dumb request means you only drag race your car.
You’re comparing a 991 Carerra 4s with PDK to a manual transmission 997 GT3? Different everything…not to mention manual vs. PDK
The post I made compared stock DSG vs. marginally quicker DSG.
who said ‘faster shifts are a dumb request’ again?
LOL, this is confusing. I think the comparison was only between a pdk 991 GT3 and a 6mt 997 GT3.
Hey, forgive me that I’m too lazy to search, but what are the advertised features of GIACs DSG tune?
J, I meant after the launch at 3400ish rpm, not cutting a good light in terms of reaction time… Here is a link that shows the hesitation at launch and after the 2-3…
This is what I could find:
I have had this issue as well Prime.
Same here
oh…i see prime/jones/db…you know it doesn’t always do that with mine, but it’s sorta like a clutch slip @3300, I don’t feel a hesisation when it fully releases. Hard to see on VCDS without better resolution. Would be nice to have that improved logging program available.
I wonder if that has something to do with the version of the APR tune that you’re running. I don’t think I have that issue - certainly not that pronounced.
Arin confirms where APR is at in their DSG tune in this post…
I also experience the occasional hesitation during the 2-3 shift and I have tiptronic, not DSG. It feels as if the engine bogs down. ECU torque limit perhaps?