Nizer

http://www.roadandtrack.com/new-cars...-one-he-raced/

http://www.roadandtrack.com/car-cult...d-sports-cars/


One of my favorites:

Jean

Pete,

Thanks, and great article

Area under the curve is a direct result of engine torque buildup, and engine torque buildup is a direct result of boost and compression on turbo engines. On the road, a broader torque area at low RPMs under high load (5th and 6th gear) is clearly a measure of turbo spooling speed and CFMs.

Turbo lag can have many definitions depending who you ask, technically, according to most technicians, it is the time it takes from depressing full throttle until boost onset, not full boost, and this time is in hundredths of seconds on these cars in lower gears.

To compare to the 488, on my 991 TT, it takes ~ 1 second or less from 0% throttle to 99.9% to reach from 1 to 2.2 bar absolute boost in 3rd. gear. This is based on datalogs.

From a driver experience side, as I mentioned earlier you simply cannot feel any lag in lower gears.. Could well be my old 993 days subjective lag benchmark!!


Amazing videos!

Apex-Monkey

Great links, thanks.

turbo8765

Floor it from very low revs in fifth gear and graph boost v rpm.

Below 3k revs there is lag, above 3k throttle response is good.

Petevb

Clearly there's spool-up time included in area under the curve, but the fact remains that "area under the curve" is not response. It's something else entirely.
Consider: take the same turbo engine and double it. Throttle response, the time between your command being given and the engine doing what you've asked, stays exactly the same. What you're showing is usually called "flexibility" or similar.
So the additional time it takes for the turbo to go from .001 bar positive to full boost is called what? More lag?

Good anti-lag systems such as those currently employed in WRC keep the intake plenum charged with pressurized air at all times, from sitting on the start line at "idle" on up. These engines function exactly like a normally aspirated engine of larger displacement. The difference between that and the way a regular turbo engine responds is the issue, and that delay is what WR is complaining about and what engineers are working so hard to eliminate.
I totally believe that. And the point is that one second is an eternity when you're trying to steer a car with the throttle. Imagine your steering wheel on a one second delay- you'd be feet off the apex on the first corner and in the weeds on the second. Worse yet it's on a variable delay- one corner it's one second, the next it's less than half a second.

In a 4wd or less powerful car it's much less of an issue, but in a very powerful RWD car steering the car with the throttle is exactly what you're doing as you approach the limit. It's nearly impossible the "ride the line" in a grip limited turbo car in the same way, and that's a lot of what I love about them. Given space I'm far more sideways than I'd planned to be multiple times a lap in a GT2, 1M, etc (when I'm feeling exuberant). It's huge fun, but it's also an issue...

Modern turbo cars are working to reduce lag largely by becoming more normally aspirated. Higher compression ratios, less boost, higher revs are all the norm. In doing so they approach the normally aspirated standard, but compared to actual standard (a larger normally aspirated engine) only positive displacement superchargers, WRC anti-lag or the electrically assisted turbos in F1/ Le Mans currently achieve it.

hf1

+1!!

JCtx

Mine too. THAT is driving. Even F1 circuits look like child's play compared to rally driving of the caliber of Rohrl. And that level of intensely focused driving goes on for hours and hours. Remember reading an interview where he was asked about his win in a competition among champions of other series (kind of an IROC), including F1, where he didn't finish by tenths of a second ahead of them all (as expected), but minutes. He said the difference is he was used to handling the car at the limit all the time. He obviously has unique talent, but said he was happy about that win because it gave rally drivers the respect they deserve (more like the respect HE deserved. He he). I bet it was humbling for the F1 drivers to get pummeled like that by somebody few knew.

Petevb

He is just so good. I've driven with other pro rally drivers on rally courses and I was able to keep up- mentally I could tell we were doing the same things, they were just a little bit better at some of them. And I know I'm about 1/2 second off the best SCCA national AX champs in an equal car we both know, not "close" but in the picture. But WR was just on a completely different level- it took about ten seconds to realize that I could practice for the rest of my life and I will never be that good. And he's 70.

ipse dixit

Maybe the issue is that we are comparing a turbo to a NA engine.

Sort of like asking why frozen yogurt isn't as creamy as ice cream. Well, because it's not ice cream.

Petevb

And soon we'll be comparing both to electric. I already am- my daily's electric, and compared to that my DCT seems unbelievably antiquated. Literally decades behind.

porscheguy119

What makes him so good? Besides the planning three corners ahead and car control, what - if you can put your finger on it - stood out to you? I mean little things, like holding the wheel and smoothness. That Sport quattro video is magical.

996FLT6

He survived through group B maybe? But WR is da man!!! Guy is smooth as silk. What was his prior education? Engineer? Mike

Petevb

Good question. I'll need to reflect on it, but I'll give you my blink:

Most guys get in a car and generally play tic-tack-toe. We see a corner and attack it. Get a bit better and we start to play checkers- car setup, tire management, reading and predicting a changing course. I can play a good game of tic-tac-toe and an ok game of checkers on a good day. In a clear moment I can analyze what needs to change, though it's largely a post-processing exercise: I drive the car in tic-tac-toe mode then go back afterwards, analyze, then try to write a script that lets me play a decent checkers strategy next game. Of course I'll usually blow a move or two and need to make adjustments.

Walter seems to play an entirely different level of game I can barely access- it feels like he's playing chess or even Go. There's a whole checkers game that I'm trying to master: not getting into the marbles in a braking zone, realizing the tires will be x amount hotter than last run, not getting greedy on corner entry and optimizing the line, driving on the traction circle. That stuff is very tough on the out-lap for me, easier on lap three. But all of that is simply a given in real time for WR- it feels like he's going to get every one of the things I'm striving for precisely correct without thinking about it or working at it whatsoever. The steering wheel is so still compared to what I'd be doing- 10% of the inputs, if that- it almost seems boring.

That seems to free his conscious mind to tackle another level of complexity. Is the setting sun changing the ice? Is the light drizzle improving intercooler performance? If I draw a perfect line between the next five linked corners how does adjusting the entry point three inches to either side effect the outcome?

I can't actually grade the results, I can only note zero mistakes in the game I know and catch glimpses of a game I don't. I do know I was attempting to have a cerebral conversation while we were at speed, and despite the fact that I wasn't driving I was very much the weak link. He was happy to contemplate my silly questions while balancing the car with one hand and casually doing everything better than I could conceive of...

I'm critical by nature and occasionally an amateur driving instructor- I'm used to giving critique. More than anything the fact that I couldn't really find fault was most sobering. If everything is as good or better than I can register then it's clearly off scale high, and I simply have zero reference to judge how high.

CAlexio

^^^^^
Poetic, you think WR reads rennlist? Cause I'm sure you just made a tear come down that old racer's eye.

hf1

+1