fleadh

For me, the data system allowed me to learn the appropriate fundamentals and trained me very early on on exactly what to look for in the "squiggly lines" (of course I didn't learn it on my own, JvO taught me). I can then apply that knowledge of what the data should look like with any data system I use or any vehicle I drive (slow GT's, fast GT's, prototypes, karts.. 99.5% of it is all the same) at any track and compensate for old tires, poor setup, etc. Seriously.. I have a super basic data system on my shifter kart and the data is nearly identical to what fast "big car" data should look like.

I don't claim to be a Pro or an idiot savant when it comes to driving or data systems. My point is simply, if I can do it, anyone can do it. And if you're not doing it, your not learning as fast as you could be. :-)

Personally, I don't understand how people like JvO (and other quality currently active professional drivers) aren't booked year around whenever they aren't racing. Combine a very basic data system with hiring them for an afternoon (if for no other reason than to set a "reference lap" and help you understand what and how to read the data) is invaluable if your goal is simply to be faster in anything anywhere. It's worth way more than a set of tires. I know we all want to save money at the track, but I know exactly what it costs and how much some of us pay to run... and I know exactly what the best Pro's charge for a day of their time. It's worth it. Do it.

Everyone learns a little differently, but the best guys will quickly help you figure out what works best for you (and adapt themselves accordingly). Not all the "fast guys" are good coaches.

My 2c anyway.

-mike

edit: just a final note, very very few drivers are ever within "tenths" of their cars full potential at any given time. i think people underestimate how much time is left in their car until a very good Pro drives it in anger. :-)

edit: i lied.. one more edit! here's a screen cap of my data from the last time I had the shifter kart out at sonoma. it looks the same as big car data. i'm sure anyone reading the thread that normally studies their own data can see all kinds of issues with the "white" driver (me). in my own defense, it was only the 5th or 6th time i've ever driven a shifter kart.. and the "red" driver is a very good professional kart racer who's been racing them for the last 20 years or so. :P



This was the first time I had kart data available. We didn't have it installed prior because I was just trying to figure out how to drive it, but I was getting frustrated with my lap times. I was driving it as hard as I could but I was still ~1.5s off the fast guys (over a 50s lap!) and couldn't find the times. As soon as we had the data, I knew where it was without anyone helping me. That 1.5s is hard enough to find that the "red" driver couldn't physically watch me drive and point out where it was.. we needed the data. IMO, that's the same problem with video when you're really trying to split hairs and find time. It's not granular enough.

Zuluracerx

^ Yep! Jack, you should get Kevin Roush to lay down a base line in your car. He helped me tremendously in exactly the manner Fleadh describes. He knows early 911's and he knows WSIR. He's also got that talent to speak to your abilities and adapt to other peoples skills and style. He can interpret data as well. You will not be disappointed.

Cory M

So where did you find the 1.5 seconds, what was the issue?

I sold my shifter cart a couple of years ago, sit was a lot of fun though and I hope to get another one sometime in the future.

Cory M

+1

I remember Kevin laying down consistent 1.26-7 laps for his entire stint during the POC Tibute to Lemans, in someone else's V3 car and in the dark!

analogmike

I have not read the whole thread but didn't see this brought up.

I do believe you have a stockish engine, it probably loses a lot of torque near the rev limiter. You may be losing speed on those two straights due to gearing, you might pull a little higher top end if you weren't so close to redline. My stock 2.7RS engine is like that.

JackOlsen

Mike, the engine is completely stock, save the oil pump. From a look at a 993 torque curve, it seems like shifting at or a little before 6000 rpm would probably be ideal. I should probably try moving my 4-5 upshift going into turn 8 a little sooner and see if it improves the acceleration line in my data.

But here's my update:

I went out last Friday to see if I could break my 1:27.04 record -- and didn't. Track conditions were ideal in some ways. It was under 50° until lunch time. There were only a few other cars on the track and the wind was only about 6 mph. But someone had ventilated their case the day before, and there was oil absorbant down from the middle of turn 2 to the exit of turn 4. There was also a lot of oil in the pits -- with no absorbant applied. The oil and powder compromised my cornering speed in 2, 3 and 4, and -- more surprisingly -- seemed to affect by braking all over the track. I don't know if it was in my head or not, but I'd guess there's a chance that the stuff gets up in your rotors when it's thrown into the air by the tires.

My times were pretty consistent -- and continued to rise as the day got warmer. I probably ran more 1:27s on Friday than I've run in all the years leading up to it.

Here's the best lap time and 'theoretical best' time (with the computer stringing together just the best segments) for each session:

1 Actual: 1:27.47 - Theoretical: 1:27.20
2 Actual: 1:27.54 - Theoretical: 1:27.23
3 Actual: 1:27.98 - Theoretical: 1:27.67
4 Actual: 1:28.17 - Theoretical: 1:27.56
5 Actual: 1:27.74 - Theoretical: 1:27.48

If I combine all the best segments from sessions 1, 2 and 5, my best theoretical lap would be a 1:26.73. That still makes a 1:25.99 seem like it's a long way off. But it makes a 1:26 seem do-able.

Here's video (with speed data) of my first session out. I run the 1:27.47 in the third lap.



In spite of not breaking my own lap record, I (pretty much) achieved four of the simple goals I set for myself.

1) I maintained more speed through turn 9 -- I don't usually drop below 100 mph from the end of the braking zone to the apex of the corner anymore. That said, I think I could still carry more speed through there -- and also be full on the gas sooner. But 9 is a dangerous corner, so I'm hoping for more incremental improvements, not a sudden fix.

2) I moved my 3-4 shift later, closer to the top of the hill in turn 6, which I think will probably make a small improvement to my rate of acceleration there. It's hard to say how much overall difference it made, though, since my top speed looked to be generally 1 mph (or so) slower than what I hit in my previous best lap.

3) I let go of hitting the late apex of 2 in favor of carrying a little more speed there and running a little bit wider. But this really wasn't even a choice, since there was so much absorbant sitting at that apex. It's hard to say what this got me, since the whole corner was compromised by the absorbant.

4) I had hoped to push my braking points for turns 1, 3 and 9 back a little. Again, it might be because of the absorbant getting on my rotors, front tires -- or maybe just my own skills coming up short, but I think I was braking earlier than previously, not later.

I made a rear sway bar adjustment before the last session, and I think it improved things. The drift upward of my lap times stopped with that session, even though ambient temps continued to rise.

I hope a better look at the data from the day will be illuminating. However, I've got young kids and we're traveling soon for Christmas and nothing is ready, so that better look won't come for a few days, still.

But if anyone has the time to watch the video and sees anything obvious in the video holding me up, I'd be grateful for any input. I want to go back one more time for testing before the end of January -- it'll be my last chance to break my personal record until probably the end of next year.

mark kibort

this is true only if you have maxed out the wing angle. if you are in the meat of the Lift range, the gurney flap will actually cost more drag for the same lift.

ditto Icemans assesement of the tires. slicks are addictive, but good A series can do the job too, but they are expensive too. see if Sofro has some garbage can pirellis he will sell you.

power curve might allow you to find more acceleration over all if you start shifting higher

Im by no means proficient at Willowsprings. (ran 1:27 once 10 years ago with a car that should run 1:24s) BUT, it looks like that advice to do some earlier apexing with some trail braking might be a faster way around that crazy race track! ping Mark Anderson at 928intl., he is probalby one of the faster guys out there with some really old and non tuned stuff, so his tricks might help. PM him. IM sure he would love to comment on your laps.

mark kibort

Even if you are losing torque, you are still in the high HP range of the engine. if so, its still more acceleration over all to hit the rev limiter. This means you have used more area under the HP curve. if you gear it to peak HP and then shift, your average would be less, so if you have less HP, you have less acceleration
acceleration = Power/(mass x velocity)
so, red line that sucker as much as you can if you want to run the fastest time possible. (Besides taking consideration a pesky corner that might force an untimely shift..... talking straight line performance here)
best performance will be just touching the rev limiter in whatever gear you are in on every straight.

Here is an example of a stock 993 vs chipped 993 dyno run. either way, both versions would pay dividends to be shifted at redline, no matter what!

JackOlsen

Baby steps toward the 1:25. I got a 1:26.88 at Willow yesterday.

ProCoach

Good. Incremental improvement...

Matt Romanowski

Nice!

JackOlsen

While waiting for the babysitter to get here this morning, I compared the data between my year-ago 1:27.04 and last week's 1:26.88 laps. The difference boils down primarily to the fact that I had a strong wind pushing against me on the main straight and at my back on the back straight on the more-recent lap. It cost me 4-5 mph on the front straight. On the back straight, it would have given me more than 1 mph if I hadn't blown the corner (turn 5) right before that back straight. In the graphic, you can see the mark at the braking zone for turn 5, where the speed delta is pretty huge (6 mph), even though the wind lets me more than make up for the error as I get up to 133.5 mph.



Here's a link to the un-annotated data, slightly more legible.

If I'd gone through turn 5 as I should have, I definitely would have been able to tap the rev limiter (for better and for worse) at 134-5 mph through turn 8. You can see the way the wind changes the time slip percentage between the slower lap (in blue) and the slightly faster one (in red).

You can also see that the theoretical number for the best pieces of both sessions is a 1:25.9, which is my ultimate goal. It's hard to say that's an actual number I can hit based on this data, since it's from two days a full year apart. But there's hope...

JackOlsen

And while I'm overthinking things, here's a side-by-side look at the two laps. They're 12 months apart, and the wind is an issue in the quicker one. But it's still interesting (to me, at least) to look at them this way.

jrgordonsenior

Winds at WS are common as you know and usually from the West/North West creating a crosswind/headwind slightly from the left as you head down the front straight. Occasionally it will reverse course 180 degrees blowing from the East and sometimes it will changes directions with in a few hours to really screw with your head. Like you, I like to wade through the possibilities and have my game plan for when the winds are strong enough to impact you car's attitude.

When it's from the West I know that I can carry more speed thru T1 as it will blow into my face as I exit the turn. Same with the entry to T2 as it pushes me back on-track. Turns 3,4,5, 6 are slower turns and not affected as much by the winds but T8 definitely is. Winds gusting from the West will try and push you off the outside of the track as you exit T8. We (POC) had 40+ MPH gust there last December and it was a little scary when you hit the inside bump mid corner. Conversely, they become head winds thru the exit of T9 as track-out onto the front straight. Consequently I've found I can carry more speed into T9 knowing the headwind will slow my exit and also push me back onto the track at exit. Of course all this reverses when the winds shift 180 degrees.....

We're there this coming weekend for our first race of the year and they're forecasting 15-20 MPH winds with stronger gusts. Oh well, it's Willow Springs....

4porsh

To cheat the wind have you guys tried staying track left coming off of nine down the straight then after start/finish line move back to track right for the set up for turn one? Buildings and wall may block the wind.