[cwebster]

The 26" Hoosiers helped me set a new ZL1 M6 bolt-on fast list record of 11.5000 @ 125.67
Otherwise the car is still bone-stock.


Actual diameter of the Hoosier 335/30R18x12 is 25.8" at 21 PSI.

See Help selecting replacement DRs for details on my decision process and Hoosier DOT Slicks vs MT ET Street SS for info on comparing, installing, and testing the Hoosiers.

Car Setup:

Rear: Hoosier 335/30R18x12: 21 PSI cold
Front: Goodyear 285/30R20x10: 36 PSI cold
Fuel: 93 octane E10 pump gas - 1st pass with under 1/2 tank (approx 8 gal)

[Summary]

Last Sunday was a near perfect day for drag racing with DA from -350 to -580. That helped offset the 12 MPH headwind. The track seemed well-prepared, at least in my preferred right lane. Not too crowded to get in 3 hot-laps at a time without shutting down to wait.

Even though I screwed up the first pass I still ended up with an 11.5 ET. It was surprisingly fast between gears. I forgot and left the nannies on after my 2-sec line-lock burnout. Then that strange engine oscillation (intermittent cut-out) came back after shifting to 2nd gear (watch the video). I gotta dig some more into that to find the cause. I'm sure it would have been a 11.3 or 11.4 pass if not for these things.

Just as I had predicted, the shorter tire gave me more power at the launch and the wide, sticky slick tread pretty much kept the wheels planted (except pass 5 in left lane). Even if I did get wheel slip in 2nd gear, it was easy to drive through and recovered traction quickly (except pass 5 in left lane). There's still a short bog on launch if it hooks right away but it recovers much more quickly and accelerates much faster between gears. If I can manage a slight wheel slip at launch while maintaining traction on gear shifts, given some "good air" I'm confident I can break into low-11 territory on nothing but tires.

Once again I've got to adjust my launch technique, shifting, and throttle application. The car behaves completely different with these tires. There's a lot more torque available so I've got to be ready to adjust the throttle after breaking free at the tree. It's so much quicker that I have to wait maybe 1 or 2 10ths sec longer after the 3rd yellow at launch to avoid a red-light. I also have to watch my tach closely to be sure to shift between 6500-6600 RPM. Shifts come up a lot sooner now so my timing is a little off. By the time I cross the finish gate I'm nearing the top of 4th gear, whereas I'd be only mid-way on the Goodyears or MTs.

Below are all the details for each pass, including links to combined PDR/Helmet/Rooftop video. No spectator videos this time. I couldn't get anyone to record them. As always, I welcome constructive criticism and helpful comments.

This YouTube playlist contains all the passes: 20180304 CPD Hoosier Slicks - M6 Stock record 11.5 @ 125 MPH

Let 'er rip!

--Cal


Time Slip Data:
(My 6th Gen ZL1 was Nr 04)

2017 6th Gen Camaro ZL1                      Opposing Lane
Seq  Time      R/T    60 ft  ET      MPH     Opposing Car         R/T    60 ft  ET      MPH   
  19 14:51:01  0.0040 1.8630 11.5779 124.33  LittleGreenCar       0.1386 1.6720 11.0511 120.29
  25 14:58:15 -0.0541 1.8581 11.5149 119.13  BlackChevyTruck      0.2910 3.1200 16.9719  93.72
  30 15:03:03 -0.1400 1.9219 11.5000 125.67  Black5thGenZL1       0.3480 2.1209 12.0720 121.57
  92 16:10:49  0.2859 1.9322 11.5480 124.61  BlackMustang         0.1621 1.9959 12.5230 113.58
  97 16:15:19  0.4849 1.9042 11.7759 122.35  RedMazdaHatch        0.6060 2.1220 13.0839 110.02
 103 16:20:35  0.3452 1.9388 11.8179 123.22  RedMazdaHatch        0.5370 2.1721 13.8550  74.47

[Lessons Learned]

1. Try to break the tires free on launch for short, slow wheel spin to hook 2500-3500 RPM.
2. Only use line-lock for 1st pass in temps below 55 F and only for a couple seconds.
3. If forced to use left lane, take care to line up with tire marks behind start gate, not in front. Otherwise, I'll be out of the groove to the right and spin wildly.
4. Pedal it if tires break free in 2nd gear but only enough to hook.
5. Watch tach closely for each shift - aim between 6500-6600 RPM.
6. Shift quickly and smoothly. More pulling force in 2nd & 4th. Just heel of palm for 3rd.


Time Slips 1-4



Time Slips 5-6


=============================================

20180304 CPD Pass 01 of 06 6th Gen ZL1 vs Little Green Car

20180304 Coastal Plains Dragway
Weather: Sunny, 52°F, wind N 13 mph (head wind), 43% humidity, barometer 30.14 in hg, DA -624 ft

Time Slip Data:

2017 6th Gen Camaro ZL1                      Opposing Lane
Seq  Time      R/T    60 ft  ET      MPH     Opposing Car         R/T    60 ft  ET      MPH   
  19 14:51:01  0.0040 1.8630 11.5779 124.33  LittleGreenCar       0.1386 1.6720 11.0511 120.29

Notes:

25.8" Hoosier DOT Slicks
Right Lane
2-sec Line-Lock burnout w/ rollout
Forgot to turn off nannies
Idle @ 2200 RPM
Launch @ 4000 RPM - Bogged
Dropped to 1000 RPM @ 10 MPH
Momentary wheel slip 1800-1600 RPM
Hooked @ 1600 RPM, 16 (15) MPH
Shift 2nd @ 6400 RPM, 60 (57) MPH
Engine RPM occilated 3 times between 4200-5000 RPM (lost 4-5 10ths)
Shift 3rd @ 6400 RPM, 86 (82) MPH
Shift 4th @ 6600 RPM, 117 (111) MPH
Finish @ 6250 RPM, 134 (127) MPH

# Shorter tires: (subtract 5% speedo error)

Stability control stayed on (nannies) while WOT but didn't intervene (PTM mode Race)

##!! Wow! Engine issues in 2nd gear and slow shift to 4th and still finished with ET of 11.5779

Combined Helmet/PDR/Rooftop Video:



=============================================
=============================================

20180304 CPD Pass 02 of 06 6th Gen ZL1 vs Black Chevy Truck

20180304 Coastal Plains Dragway
Weather: Sunny, 52°F, wind N 13 mph (head wind), 43% humidity, barometer 30.14 in hg, DA -624 ft

Time Slip Data:

2017 6th Gen Camaro ZL1                      Opposing Lane
Seq  Time      R/T    60 ft  ET      MPH     Opposing Car         R/T    60 ft  ET      MPH   
  25 14:58:15 -0.0541 1.8581 11.5149 119.13  BlackChevyTruck      0.2910 3.1200 16.9719  93.72

Notes:

25.8" Hoosier DOT Slicks
Ritht Lane
Rolling burnout
Idle @ 3000 RPM
Launch @ 3700 RPM
Dropped to 1100 RPM
Wheel slip 1100-2300
Hooked @ 2300 RPM, 23 (22) MPH
Shift 2nd @ 6600 RPM, 61 (58) MPH
Shift 3rd @ 6500 RPM, 83 (79) MPH
Shift 4th @ 6500 RPM, 117 (111) MPH
Missed shift to 4th - in gear @ 5500 RPM
Finish @ 6000 RPM, 129 (123) MPH

# Shorter tires: (subtract 5% speedo error)

##!! Incredible! Missed 4th and still finished with ET of 11.5149

Combined Helmet/PDR/Rooftop Video:



=============================================
=============================================

20180304 CPD Pass 03 of 06 6th Gen ZL1 vs Black 5th Gen ZL1

20180304 Coastal Plains Dragway
Weather: Sunny, 52°F, wind N 13 mph (head wind), 43% humidity, barometer 30.14 in hg, DA -624 ft

Time Slip Data:

2017 6th Gen Camaro ZL1                      Opposing Lane
Seq  Time      R/T    60 ft  ET      MPH     Opposing Car         R/T    60 ft  ET      MPH   
  30 15:03:03 -0.1400 1.9219 11.5000 125.67  Black5thGenZL1       0.3480 2.1209 12.0720 121.57

Notes:

25.8" Hoosier DOT Slicks
Right Lane
Rolling burnout
Idle @ 3600 RPM
Launch @ 3800 RPM
Red Light
Drop to 800 @ 8 MPH
Slight wheel slip 1500-1200-2000 RPM
Hooked at 2000 RPM 20 (19) MPH
Shift 2nd @ 6500 RPM, 63 (60) MPH
Short Shift 3rd @ 6100 RPM, 82 (78) MPH
Shift 4th @ 6500 RPM, 108 (103) MPH
Finish @ 6300 RPM, 136 (129) MPH

Momentary engine RPM oscilation between 6200-6300 RPM in 4th gear WOT just before slowing down.

# Shorter tires: (subtract 5% speedo error)

##!! Even with slight bog and short-shifting 3rd, still finished with ET of 11.5000

Combined Helmet/PDR/Rooftop Video:



=============================================
=============================================

20180304 CPD Pass 04 of 06 6th Gen ZL1 vs Black Mustang

20180304 Coastal Plains Dragway
Weather: Sunny, 52°F, wind N 12 mph (head wind), 40% humidity, barometer 30.13 in hg, DA -541 ft

Time Slip Data:

2017 6th Gen Camaro ZL1                      Opposing Lane
Seq  Time      R/T    60 ft  ET      MPH     Opposing Car         R/T    60 ft  ET      MPH   
  92 16:10:49  0.2859 1.9322 11.5480 124.61  BlackMustang         0.1621 1.9959 12.5230 113.58

Notes:

25.8" Hoosier DOT Slicks
Right Lane
Rolling burnout - tires bouncing
Idle @ 2800 RPM
Launch @ 3500 RPM
Drop to 800 RPM, 8 MPH
Slight wheel slip btwn 800-1700 RPM
Hooked @ 1700 RPM, 17 (16) MPH
Shift 2nd @ 6500 RPM, 62 (59) MPH
Slight wheel slip on shift to 2nd
Shift 3rd @ 6500 RPM, 87 (83) MPH
Shift 4th @ 6300 RPM, 112 (106) MPH
Finish @ 6300 RPM, 135 (128) MPH

# Shorter tires: (subtract 5% speedo error)

Combined Helmet/PDR/Rooftop Video:



=============================================
=============================================

20180304 CPD Pass 05 of 06 6th Gen ZL1 vs Red Mazda Hatch

20180304 Coastal Plains Dragway
Weather: Sunny, 52°F, wind N 12 mph (head wind), 40% humidity, barometer 30.13 in hg, DA -541 ft

Time Slip Data:

2017 6th Gen Camaro ZL1                      Opposing Lane
Seq  Time      R/T    60 ft  ET      MPH     Opposing Car         R/T    60 ft  ET      MPH   
  97 16:15:19  0.4849 1.9042 11.7759 122.35  RedMazdaHatch        0.6060 2.1220 13.0839 110.02

Notes:

25.8" Hoosier DOT Slicks
Left Lane
Rolling burnout
Idle @ 4000 RPM
Launch @ 3700 RPM
Dropped to 1200 RPM, 12 MPH
Spun wildly beginning at 3500 RPM - Never hooked
Shift 2nd while spinning
Hooked @ 5300 RPM, 70 MPH after momentary wheel spin
Shift 3rd @ 6500 RPM, 87 (83) MPH
Shift 4th @ 6600 RPM, 117 (111) MPH
Finish @ 6200 RPM, 135 (128) MPH

Should have let out throttle when wheels kept spinning before shift to 2nd

# Shorter tires: (subtract 5% speedo error)

From helmet cam it looks like I didn't center on the groove. Tracks beyond start don't line up with tracks before the gate. Left lane mostly narrow track vehicles.
Next time in left lane, note where tracks are before burnout or just stay in right lane.

Combined Helmet/PDR/Rooftop Video:



=============================================
=============================================

20180304 CPD Pass 06 of 06 6th Gen ZL1 vs Red Mazda Hatch

20180304 Coastal Plains Dragway
Weather: Sunny, 55°F, wind N 12 mph (head wind), 37% humidity, barometer 30.12 in hg, DA -404 ft

Time Slip Data:

2017 6th Gen Camaro ZL1                      Opposing Lane
Seq  Time      R/T    60 ft  ET      MPH     Opposing Car         R/T    60 ft  ET      MPH   
 103 16:20:35  0.3452 1.9388 11.8179 123.22  RedMazdaHatch        0.5370 2.1721 13.8550  74.47

Notes:

25.8" Hoosier DOT Slicks
Right Lane
Rolling burnout - wheels bouncing
Idle @ 3800 RPM
Launch @ 4000 RPM
Dropped to 800 RPM
Intermittent wheel spin btwn 800-1600 RPM
Hooked @ 1600 RPM, 16 MPH
Shift 2nd @ 6500 RPM, 61 MPH
wheel spin 1/4 sec at 5500 RPM
peddalled throttle
Hooked again at 4800 RPM
Short Shift 3rd @ 6000 RPM, 81 MPH
Shift 4th @ 6400 RPM, 113 MPH
Finish @ 6200 RPM, 133 MPH

Lots of wheel spin and short shifting
Should have added fuel for weight on this 2nd session

Combined Helmet/PDR/Rooftop Video:



=============================================

[waterman]

Nice detail. Great day at the strip; 11.5s. Looks like the M6 takes a lot of reps to gain consistency at hard launch.

As you mentioned, and I agree that the extra weight from more fuel in the tank may have helped you to hook up faster in your later runs. It looks like you are primed for some 11.3s net time out. Good luck!

[cwebster]

Originally Posted by waterman

Nice detail. Great day at the strip; 11.5s. Looks like the M6 takes a lot of reps to gain consistency at hard launch.

Yes because there are a lot more variables to manually control. You have to develop a sense for how the car is reacting to changing atmospheric and track conditions and respond immediately. Instead of a torque converter you modulate torque with the clutch and throttle. Instead of mashing the gas (Stab & Steer) you release clutch while punching the throttle then let up on throttle just enough to control wheel spin. Back into it watching tachometer in your peripheral vision (and/or listening to engine whine) so you can upshift at just the right moment. Quickly into the clutch, out of the throttle, shift, back out of clutch, back into throttle. All this while steering to counteract wind and drift and listening for anything abnormal. It has to be more like a reflex. It's not easy but it sure is FUN!!!

Originally Posted by waterman

As you mentioned, and I agree that the extra weight from more fuel in the tank may have helped you to hook up faster in your later runs. It looks like you are primed for some 11.3s net time out. Good luck!

Thanks. I'm pumped! I hope there are some more cool track days coming.

--Cal

[laynlo15]

Did you loose some mph?

[cwebster]

Originally Posted by laynlo15

Did you loose some mph?

I don't think so... in fact, I gained some over the Mickeys and I did as good or better than the stock Goodyears.


20180304 25.8" Hoosiers

2017 6th Gen Camaro ZL1                      Opposing Lane
Seq  Time      R/T    60 ft  ET      MPH     Opposing Car         R/T    60 ft  ET      MPH   
  19 14:51:01  0.0040 1.8630 11.5779 124.33  LittleGreenCar       0.1386 1.6720 11.0511 120.29
  25 14:58:15 -0.0541 1.8581 11.5149 119.13  BlackChevyTruck      0.2910 3.1200 16.9719  93.72
  30 15:03:03 -0.1400 1.9219 11.5000 125.67  Black5thGenZL1       0.3480 2.1209 12.0720 121.57
  92 16:10:49  0.2859 1.9322 11.5480 124.61  BlackMustang         0.1621 1.9959 12.5230 113.58
  97 16:15:19  0.4849 1.9042 11.7759 122.35  RedMazdaHatch        0.6060 2.1220 13.0839 110.02
 103 16:20:35  0.3452 1.9388 11.8179 123.22  RedMazdaHatch        0.5370 2.1721 13.8550  74.47

20180122 Stock 27.2" Goodyears

2017 6th Gen Camaro ZL1                      Opposing Lane
Seq  Time      R/T    60 ft  ET      MPH     Opposing Car         R/T    60 ft  ET      MPH   
6363 13:17:31  0.6088 2.0362 11.7154 123.86  Solo
6369 13:24:59  0.4550 2.1909 11.9729 122.32  LittleBlackCar      32.8454 none   none    none   RedLt
6372 13:28:10  0.3485 2.1941 11.9783 122.22  Solo
6449 14:44:22  0.5286 1.7052 11.1702  73.82  BlackBMW             0.5499 1.3605 12.0617  66.39
6467 14:57:52  0.6012 1.9852 12.0821 120.39  WhiteCorvetteVert    0.9262 2.0746 13.9533 109.52 RedLt
6479 15:07:40  0.4869 2.1677 12.0189 121.42  WhiteNissanZ         0.9020 2.2889 13.8457 102.20
6549 16:49:14  0.7485 2.1395 11.9787 121.89  SilverTurbo          1.0023 1.7473 10.8852 129.87
6569 17:07:14  0.5830 2.2191 20.4194  53.98  RedSuperBee          0.8537 1.7293 11.5915 117.31

20171217 Stock 27.2" Goodyears (pass 1-3) | 27.5" Mickey Thompsons (pass 4-6)

2017 6th Gen Camaro ZL1                      Opposing Lane
Seq  Time      R/T    60 ft  ET      MPH     Opposing Car         R/T    60 ft  ET      MPH   
  16 14:52:27  0.3121 ------ 11.8579 122.25  GoldNissanZ         -0.0131 ------ 12.8189  73.68 foul
  23 14:59:49  0.1748 ------ 11.6950 122.35  GreenMitsubishiTalon 0.5378 ------ 12.1280 123.73
  38 15:27:31 -0.0731 ------ 12.0653 120.61  BlackTaurus          0.1841 ------ 12.7680 105.13 foul
 123 17:01:45  0.1239 2.0932 11.9972 119.30  BlackCorvette       -0.0472 2.0961 12.4752 115.66 foul
 148 17:24:13  0.1960 2.0261 11.8691 119.66  PurpleScatCat        0.3000 1.8471 12.3599 112.55
 165 17:42:58  0.0830 2.2600 12.1451 119.95  GreenBoss302         0.0798 1.6099 12.1390 113.42

20170526 27.5" Mickey Thompsons

2017 6th Gen Camaro ZL1                      Opposing Lane
Seq  Time      R/T    60 ft  ET      MPH     Opposing Car         R/T    60 ft  ET      MPH   
1570 19:45:01  0.0881 2.3419 12.6670 118.75  #23 Red Corvette GS  0.1309 1.7800 12.4661 ???
1578 19:52:27  0.3379 2.0610 12.4421 ???     Solo
1641 21:17:56  0.2671 2.1470 12.3798 116.54  #21 White vert       0.5371 2.8229 15.5480 97.58
1656 21:34:46  0.0130 2.5261 12.6921 116.84  #49 Decal Car        0.5389 2.4570 15.4941 80.76
1573 21:53:26  0.3369 2.1951 12.4452 114.69  #56 Red Corvette Z06 0.4140 2.1600 12.9988 111.30
1687 22:07:41  0.0680 2.2610 12.3139 118.44  #56 Red Corvette Z06 0.2550 2.1492 12.9741 111.87
1693 22:14:14  0.0129 2.0341 12.0942 119.64  #27 Blue Car         0.3621 2.2110 13.9707 78.43

--Cal

[PRAY]

Congrats on the record.

[TheRealJA105]

Originally Posted by cwebster

Yes because there are a lot more variables to manually control. You have to develop a sense for how the car is reacting to changing atmospheric and track conditions and respond immediately. Instead of a torque converter you modulate torque with the clutch and throttle. Instead of mashing the gas (Stab & Steer) you release clutch while punching the throttle then let up on throttle just enough to control wheel spin. Back into it watching tachometer in your peripheral vision (and/or listening to engine whine) so you can upshift at just the right moment. Quickly into the clutch, out of the throttle, shift, back out of clutch, back into throttle. All this while steering to counteract wind and drift and listening for anything abnormal. It has to be more like a reflex. It's not easy but it sure is FUN!!!



Thanks. I'm pumped! I hope there are some more cool track days coming.

--Cal

Have you tried the NLS? If so are you losing too much traction on the shifts and that's why you don't anymore?

[cwebster]

Originally Posted by PRAY

Congrats on the record.

Thanks. It didn't change my position on the list, though - still at #8. I need to get better than 11.340 to move up. Maybe next time... this was the first time with the shorter Hoosiers. There's plenty of room for improvement.

Originally Posted by TheRealJA105

Have you tried the NLS? If so are you losing too much traction on the shifts and that's why you don't anymore?

Yes I have tried NLS and I like it. The problem is that I have to leave the nannies on to use it. I've found I can go faster turning all the nannies off (hold SC button 5-8 sec). The way I understand it, NLS only affects fuel and ignition while you have the clutch depressed at WOT. I've never seen it cause loss of traction in my experience.

--Cal

[Trackman]

I'm going to say the incredible DA had everything to do with your times not your tires. Now that your not so green go back and put your stockers on. I bet you may do a couple sub 2.0s on them now. Then you'll be ready for some 1.7's with the MTs.

[cwebster]

Originally Posted by Trackman

I'm going to say the incredible DA had everything to do with your times not your tires. Now that your not so green go back and put your stockers on. I bet you may do a couple sub 2.0s on them now. Then you'll be ready for some 1.7's with the MTs.

I doubt that! I realize it's hard to believe I could get such a dramatic improvement just from tires but I did the math, analyzed the data, made a prediction, and proved it right. Maybe the good air helped a bit but take a look at the time slip data in post #5 above. I've had other track days with negative DA. I certainly haven't improved my skill level that much in just a month or two. Go ahead and look at the time slilp data from all last year in my other track day posts. I don't keep secrets. Even my shitty runs are all there.

I've been wanting to improve my bone-stock time anyway so I may do my last 4 passes on stock rubber on my next visit 2 or 3 weekends from now. That'll show the same difference in 60ft and ETs. I know I'll never satisfy everyone. There'll always be someone that says "oh, well you just purposely sandbagged on the stock tires to prove your point." Anyway, I'm done with the tall MTs. I'm on 26" rears (or maybe shorter) from now on at the drag strip.

--Cal

[asthmamax11]

Nice pass and thanks for the thorough documentation. It will help others for sure.

I have a Hurst shifter with the pistol grip and I can shift much faster than with stock shifter. I was watching your shifting and I think it might benefit you.

[DFW1LE]

Everything else being equal the lower effective rear end ratio you get with 26" tires should come out on top for those 60' times for M6 cars. Another excellent write up.

[cwebster]

Originally Posted by asthmamax11

Nice pass and thanks for the thorough documentation. It will help others for sure.

I have a Hurst shifter with the pistol grip and I can shift much faster than with stock shifter. I was watching your shifting and I think it might benefit you.

You're probably right. I used to have a Hurst shifter in my '70 Nova SS 396 - loved that thing. Sure wish I had the buttery smooth synchros from the ole Muncie 4-speed "Rock Crusher" in my ZL1 M6 to go with it.

Originally Posted by DFW1LE

Everything else being equal the lower effective rear end ratio you get with 26" tires should come out on top for those 60' times for M6 cars. Another excellent write up.

I agree but you gotta have enough meat to put that torque to the pavement. Problem is that the extra traction works against me on the launch. It still bogs if I hook right away, although it recovers more quickly and accelerates faster with the 26" Hoosiers. Next time I'll focus on trying to get just enough wheel slip on the launch to move forward into the power band (about 2500 RPM) before it hooks. If I can do that and execute all my shifts on time, I should drop at least 2-3 10ths.

[cwebster]

Before I went to the track for this visit I match-marked my tires and rims so I could tell if they moved relative to each other. They did! Looks like they moved about 8-9" on each tire. I don't know what else I can do about it though. I don't want to drill and screw them in. I ordered these wheels with knurled bead seats and thought that would be enough. Maybe they just had to heat up and settle into the knurl grooves. I hope they don't slip much more. I'll mark 'em again before my next track day.

Left Wheel
(2 marks on opposite sides)


Right Wheel
(2 marks on opposite sides)


I didn't notice this until after I returned and put my wheels away in the garage. Any suggestions other than drilling and installing screws?

--Cal