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Old February 22nd, 2004, 07:22 PM   #1
TI (Alameda)
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GGR Time Trial #1 Wrap-Up

Well now that the first Time Trial has been over for a week, any stories to share?

There are some stories in the new GGR Nugget magazine: http://www.pca-ggr.org/nugget/Mar04Nugget.pdf

There are some photos online that various people took: http://pca-ggr.org/photos.html#021404timetrial

Here is my story:


(Photo by Ron Leppke)

Saturday

Saturday was only slightly damp in the morning and dried out quickly. The weather was fine all day. I was able to manage a 2:02.50, about a second slower than my best. Ed "Ed from Belmont" as you know him on the board, a Boxster class Tp driver, followed me for a couple of laps and noticed a couple of places on the track where I was doing things differently or just plain sucking.

In T1 I was not braking, just lifting and then heading up the hill to T2 scrubbing speed, and then downshifting to 3rd under light braking for turn-in. He suggested braking for T1 and downshifting to 3rd, then accelerating up to T2 already in 3rd.

In T7 I was not nailing the second apex and was swinging out very wide on exit. He suggested more throttle steering to get into the apex and straightening out the line on exit for a straighter shot leading into the approach to the esses.

I was also lifting on approach to the esses, while Ed suggested staying on the throttle longer and then lightly braking before turning in to T8. I figured I'd try his suggestions Sunday morning to see how they felt.

I'd taken tire temperatures a couple of times in the afternoon, trying to figure out what the right pressures should be. My older Griot's analog bleeder/inflater/gauge that I used to go by has drifted out of accuracy over time, so I've started using one of those cheap but accurate $10 digital gauges (its granularity of measurement is 0.5 pounds psi), but that means I'm having to recalibrate my tire pressure thinking because I'd been using inaccurate pressure readings for so long. I finally settled on accurate hot pressures of 35.5psi front, 38.0psi rear. My analog gauge was reading 3 to 4 psi higher than the digital gauge by now, so my old technique of staying under 40psi hot rear, with 2 to 3 psi less in front, would result in pressures a good couple of pounds psi lower than they should be.

Sunday

It didn't rain overnight as had been expected, to the track conditions were great on Sunday morning. I tried out Ed's suggestions.

The change to T1 didn't work out exactly, because even with what felt like a reasonable amount of braking at T1, I was still well over 90MPH--perhaps 100MPH--in the braking zone, so I was over the 3rd gear rev limit at the time I'd normally want to downshift. What I ended up doing was a combination of light braking in the T1 braking zone, letting the hill scrub off some speed as before, and downshifting to 3rd early in the uphill section once the speed had dropped into the 80's. Getting the downshift done between T1 and T2 felt pretty good to me even though it's a downshift in the middle a turn, because it allowed accelerating into the braking zone and not having to get it all done on entry to T2. In a race situation it might be better to do it the old way because it would prevent someone from passing in T1, but for pure lap time this is probably better because it probably helps T2 exit speed.

The change to T7 seemed to work well. I throttle steered to make sure I hit the second apex better, and this straightened out the line on exit, rather than swinging way wide and having to keep turning to get back on the straight line towards the esses. It seemed like things slowed down this way, but I suspect it's just as fast and probably gets to the esses sooner.

I also tried carrying my acceleration all the way to the turn-in point for the first ess (T8), braking lightly to bring the speed down to the right level, whereas I had previously just lifted off the throttle much earlier to avoid braking there at all. After doing this a few times, it became comfortable. I think I was avoiding it before because the esses have kind of scared me before, having seen more than one car upside down in the first ess when the embankment used to be right next to the track there, and knowing of acquaintances' cars that have suffered significant damage there when losing it in the esses. But as long as the braking is smooth and consistent, the esses feel fine carrying the speed deeper leading into them.

This got me down to a 2:01.74 and a bunch of consistent 2:02's and 2:01's during the first morning practice session, so I was already within a couple tenths of my personal best, and within a second of my "optimistic" timed run guess of 2:00.986.

Then in the second session I started to do consistent 2:01's, and on one lap I really nailed all of the high-speed corners. In T6 I got on the throttle nice and early and ran out of 3rd gear before the end of the rumble strip on exit. In T8a (the second ess) I got on the throttle early and flew down the hill. I glanced at the speedometer before braking for T10 and saw an indicated speed of nearly 110MPH, the fastest so far. Yet I stayed calm in T10 and did the right amount of braking, got back on full throttle early, and really powered out, hitting 100MPH by the end of the exit rumble strip. This was my personal best lap of 2:00.71. There was only one more lap and it had traffic, and then practice was over. That 1:59.99 is out there somewhere to be had!

Timed Runs

I was in the first half of cars gridded for timed runs. The weather still looked OK. I was waved out on track and did a moderately hard lap to warm up the tires and brakes, and then went for my two laps on the clock. The first lap started out bad as I went through T1 a little too hot and felt like I lost some time gathering it up as took the curve going up the hill. As I crossed start/finish to start my second lap, I glanced down at the Hot Lap timer display on my dash and saw that my first lap had been a 2:04.53. I couldn't believe the lap had been that bad! Had I really lost 2 or 3 seconds on my T1 mistake? It seemed unlikely. I knew I had to do a lot better on my second lap. The second lap was good. Not perfect, perhaps not exiting the high speed corners as well as on my best lap, but pretty darn good.

I crossed the finish line, got waved back into the paddock, and looked at the Hot Lap display: 2:04.53! Again?! Aha. The hot lap transmitter had obviously been removed before the timed runs, so I was looking at my last practice lap under traffic, not my timed laps. Ed told me he clocked one of my laps at 2:01 something. Alan picked up the timing slips a little while later and I found that I had turned a pair of 2:01's after all.

As we switched over to the second half of cars to grid for their timed runs, it started to mist very, very lightly as the first couple of sets of cars went out. While Ed was waiting on grid, Alan and I covered up Ed's gear with his tarp and packed our cars since we were done. At some point the drizzle got a little too heavy and they decided to take the 10-minute worker break early and hope the drizzle would stop. In the mean time, as many of us as possible took a couple of slow laps in our cars to try to dry out the track. By the time we came back in, the drizzle had stopped and the track had completely dried out. But it was still unclear if there would be time to finish all of the timed runs.

The next batch of cars went out, and after a couple of minutes I saw a red flag come out at the starter stand. We saw a white 911 parked in the esses with a cloud of white smoke surrounding it. The announcer said something about an engine fire. The safety crew arrived quickly and put the fire out, which turned out not to be too serious. Unfortunately, the car had dumped oil through the first half of the esses. This was going to be a long clean-up, delaying the rest of the timed runs enough that they couldn't possibly finish them on time.

So unfortunately, since not all of the cars were able to post official times, none of the timed runs counted for points or even for track records. That means that GGR does not have *any* track records for Infineon Raceway yet, since this was GGR's first trip to Infineon in six years. So although I still have the class Ti records at Thunderhill, Thunderhill in reverse, Buttonwillow, and Laguna Seca, I was unable to make it a clean sweep!
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Old February 22nd, 2004, 09:45 PM   #2
doug_d (Cameron Park, CA)
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nice write-up trygve. let's just say that i had a lot of fun. it was good to see the gang again. i improved on sunday (no timing, i just know it), but since i was at least 10 seconds slower than you on saturday, i'll grant you the clean sweep! i'm sorry the timed runs didn't go better. either way, i'm glad i left at lunch. got home in time to clean up the car and play with the kids all before dark.
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Old February 22nd, 2004, 11:13 PM   #3
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Quote:
Originally Posted by TI (Alameda)
So although I still have the class Ti records at Thunderhill, Thunderhill in reverse, Buttonwillow, and Laguna Seca, I was unable to make it a clean sweep!
Take heart. That just means when you finally do get to set the record it may be sub 2:00
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Old February 23rd, 2004, 09:31 AM   #4
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Tire Pressures

Trygve,

Great post!

You're running 245/17 front and 255/27 rear tires, right?

I'm running my original Continental OEM ice scates in 225/18 front and 265/18 rear. To try to get my car to balance, I run 34 lbs up front and 32 in the rear.

I assume that you're able to run more pressure in the rear because your tire sizes are closer. Is this correct?

Doug
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Old February 23rd, 2004, 01:27 PM   #5
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Yep, I am running Kumho V700 Victoracers at 245/45-17 front and 255/40-17 rear. My general sense is that the Kumhos like hot pressures in the high 30's -- over 40 and they get slippery. This usually means cold pressures around 30 if you find that you gain 8 or so pounds from cold to hot-right-off-the-track.

But the truth lies in what the pyrometer tells you and how you want the car to behave. My car is a stock '98 with the "P38" option which presumably is like the 030. It's common knowledge that in stock form, you can't get enough negative camber in front, so you get too much wear on the outside of the tire, and the temperatures will never be ideal. Still, you can measure the temperatures and aim for linear gradation across the tire, which will indicate ideal pressure given the camber limitation. You can't be super-accurate unless you do this on a skidpad, but you can get some benefit anyway at the track, by not taking a cooldown lap, and trying to get readings as soon as you come off track.

What I found was that at 35.5 front and 38.0 rear (hot), the gradation of temperature across each tire was linear. That would indicate that these pressures put the tire in contact with the road surface in the flattest way possible given the alignment. (I think the rears were actually even, and the fronts were of course hotter on the outside.) So if 35.5/38.0 are optimal for each tire, you can then add or remove air on any given tire to reduce its grip away from optimal to change the understeer/oversteer characteristics. Maybe if you drop a pound in the rear, the rears will lose a little grip, so the front will have gained relative grip, and the car will understeer less. I was pretty comfortable with the balance of the car, so I left it at 35.5/38.0.

Of course, each tire brand/model is different. I hear that the Michelin Pilot Sport Cups (another R compound tire that is more ex$pen$ive) prefers hot pressures in the 32-34 range. Sounds weird to me but that's because I'm used to the Kumho pressures and the factory street tire pressures.

Also, I presume that for autocrossing, since the tires never get a change to really heat up much, the cold pressures start much higher in order to reach the optimal "warm" pressures actually seen during each run.
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Old February 24th, 2004, 02:23 PM   #6
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I beat your Ti record at Thill. Oh wait, I needed an extra 50bhp to sneak under your time by about 2/10. Yeah, okay that's kinda sad. I shouldn't have brought it up.
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Old February 24th, 2004, 08:29 PM   #7
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You're right, that extra 50HP is why you are up there in class Ni (or Np), not Ti, Scott! Whew!! And the Ni record at Thunderhill is listed as 2:11.219, so you actually gotta find another second!

Kevin is faster than me now and I think he will definitely break the Ni record. And Ed and Alan will surely threaten the Tp records they don't already own.
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Old February 25th, 2004, 10:35 AM   #8
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I ran 2:11.9 in an Ni class car and that record was too hard so I bought a new car and prepped it for Np. The record in Np is just 2:11.7(ish) so getting that record in my new car would just be a matter showing up for a GGR TT. Actually, based on seat of the pants experience, I expect that to be the case for both records. Kevin has a leg up on me since his car is already TT legal and I haven't even installed harnesses much less any of the other stuff. Odds are my own times will not find their way onto the GGR website.
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Old February 25th, 2004, 02:45 PM   #9
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It's funny how sometimes a "p" class record is slower than an "i" class record. The p class allows more mods than i class, so of course it's down to the particular drivers. I'd almost say that if an "i" record is better than the corresponding "p" record, then the "p" record is essentially trumped. So you do need a 2:11.2

You mentioned that beating the Ni class record "would just be a matter (of) showing up for a GGR TT." Cheeky monkey. Probably true for you, with the caveat that you have to turn that 2:11 immediately with just one partial warm-up lap starting from cold tires. Oh and don't forget about Kevin C.! The TT format is a good test of consistency and the ability to turn a good hot lap on demand without the luxury of gradually working your way up to it. I've been fairly good about it, sometimes turning my fastest lap on the clock, but sometimes not. Personally I can probably only make a reliable guarantee of coming within 1 second of my best morning practice time. (Too much heat or a green track can make a personal all-time best impossible during the entire event sometimes, so I usually gauge my official time relative to my morning practice times.)

Enough blathering from me, you know all that! Hope to see you there, Scott!
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Old February 25th, 2004, 03:12 PM   #10
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Yeah, I realize that in addition to getting the car to pass tech, it is going to be harder to hit a good lap right when it counts. But I do generally hit my best time on lap 2 or 3 of any given session. And with my peak coming in August in Willows, I had to learn to peak in the morning, too. I believe it was 97 when I turned the 2:11.9.

Anyway, I can honestly say that my car is easily +1 second faster than my old car. I believe Kevin was running 2:15 and up when he was Ni so I think he'd agree. But just so we're clear, I want to clarify my liberal use of the terminology. I distinguish between holding a record and beating a record. If I run a 2:10 outside of a GGR TT, I will tell anyone who'll listen that I beat the Np (and Ni) lap records. If I ever do it during a TT and get recognized, I'll say that I hold the record.
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