ZL1 A6: Need Help with Consistency and Dial-Ins

[2013 ZL1 #7860]

This summer I have ran my 2013 ZL1 A6 in the 1/4 mile about 150 times. I have a stack of time slips that is 2 inches thick. But, never made it to the 2nd round of Eliminations...

I recently ran a personal best of 12.20 @ 114.30 with a 1.799 60 Foot (This is at Bandimere Speedway in Morrision, CO and with a Density Altitude of 8,500')

I did this run on the first pass of the day, at the hottest point in the day and after driving the car on the highway for 45 minutes to get to the track. (Car was warm!)
IAT2 was at 97 degrees at the start. Coolant temp was 205.

I then let the car cool for about 1.5 hours (with the fans and intercooler pump running, Supercharger is cold to the touch) and then make another pass. The IAT2 was 92 degrees at the start and the coolant temp was 189. The car ran a 12.564 @ 111.20 with a 1.874 60 foot.

I again let the car cool for about 2.5 hours (with the fans and intercooler pump running, supercharger is cold to the touch) and then make my first Elimination Run. IAT2 was 89 degrees at the start and the coolant temp was 184. The car ran a 12.565 @ 111.05 with a 1.869 60 foot.

I lined up against a 69 Chevelle that dialed a 14.58.
I dialed a 12.35 because the weather turned cool and I split the difference between my first run and my second run. But I did not come close to running my dial and lost (again). Just never caught him and he even ran .2 slower than his dial time.

The issue I have is in determining my Dial In Time for the First Elimination with this much inconsistency.

Hind sight says that I should have thrown out the first faster run and just dialed off of the second slower run but I have no way of knowing if that run was just an opps for that day and why it was so much slower.

1.) Is it common for the first run of the day in hotter weather and with a warmer car to be so much quicker and trap 3 mph higher?

2.) Is it better to have the engine coolant temp in the 200+ range and have the IAT2's in the 95-110 range at the start of the run? Or to have the car cooler and the engine coolant temps in the 175-185 range and the IAT2's around 90?

Is the car pulling timing because the coolant temp isn't high enough along with pulling timing if the IAT2's are too high?

3.) Any other advice from Veteran Bracket Racers? My ZL1 is a full 2 seconds faster than my last car I raced for 6 years but it is less consistent despite it being an automatic.

4.) Why did my trap speed drop 3 mph???

My Mods Are:
Stock Tune and 91 Octane
10% OD Lower Pulley (8.86")
Rotofab CAI with Big Gulp
Vmax TB
Rotofab Intercooler Coolant Reservoir
Mickey Thomspons 305/35/20 ET Street II (Ran them at 16 PSI)
Line Lock (Got a good burnout on all the three runs)
Car has 3,400 miles on it and it weight 4,305lbs with me in it and 1/4 tank.

I pull both ABS fuses and run the car in Tour Suspension Mode and have the transmission is Sport (shifts by itself). I launch at 1,000-1,200 rpms. (I have tried up to 1,500 but the car moves in the staging box and messes with my Reaction Time)

The car does an awesome burnout with the line lock and has no issues with traction. It just squats and pulls, no drama and no spinning. I have about 50 Go Pro and Iphone videos of this as proof.

Any advice or thoughts is greatly appreciated!

[2013 ZL1 #7860]

I will post the Go Pro Video of the faster run this week when I get a chance to upload it.

It was against my friend in another 2013 ZL1 Automatic with Headers and No Cats, Larger Lower Pulley than mine (unknown size), Injectors and Tune, 3,200 Stall Torque Converter, Intake and the same tires (DR's) at 18psi.

He ran a 11.669 @ 117.01 with a 1.588 60 Foot. Said he was about 600whp (corrected).

[Col. Brain]

Originally Posted by 2013 ZL1 #7860

This summer I have ran my 2013 ZL1 A6 in the 1/4 mile about 150 times. I have a stack of time slips that is 2 inches thick. But, never made it to the 2nd round of Eliminations...

Very good but are you recording this data in a journal? Do you know your Density Altitude etc?

I recently ran a personal best of 12.20 @ 114.30 with a 1.799 60 Foot (This is at Bandimere Speedway in Morrision, CO and with a Density Altitude of 8,500')

I did this run on the first pass of the day, at the hottest point in the day and after driving the car on the highway for 45 minutes to get to the track. (Car was warm!)
IAT2 was at 97 degrees at the start. Coolant temp was 205.

I then let the car cool for about 1.5 hours (with the fans and intercooler pump running, Supercharger is cold to the touch) and then make another pass. The IAT2 was 92 degrees at the start and the coolant temp was 189. The car ran a 12.564 @ 111.20 with a 1.874 60 foot.

I again let the car cool for about 2.5 hours (with the fans and intercooler pump running, supercharger is cold to the touch) and then make my first Elimination Run. IAT2 was 89 degrees at the start and the coolant temp was 184. The car ran a 12.565 @ 111.05 with a 1.869 60 foot.

The 205 to 189 temps can make a HUGE difference. And yes when the car is warmer it can run away (warmer oil has less friction - its even worse on iron headed motors)
The trick here is to hit 185 or 190 each and everytime you hit the water box. Go in at 190 and do the burnout the same time EVERYTIME. Your temps should be fairly consistent.

I lined up against a 69 Chevelle that dialed a 14.58.
I dialed a 12.35 because the weather turned cool and I split the difference between my first run and my second run. But I did not come close to running my dial and lost (again). Just never caught him and he even ran .2 slower than his dial time.

Yeah dont do that. Your first run should be thrown out and you should dial close to the last 2 runs (or the runs where your car was setup as close to identical as possible.

He was .2 slower because he bailed on the run to not break out since you were no where to be found

The issue I have is in determining my Dial In Time for the First Elimination with this much inconsistency.

Hind sight says that I should have thrown out the first faster run and just dialed off of the second slower run but I have no way of knowing if that run was just an opps for that day and why it was so much slower.

1.) Is it common for the first run of the day in hotter weather and with a warmer car to be so much quicker and trap 3 mph higher?

2.) Is it better to have the engine coolant temp in the 200+ range and have the IAT2's in the 95-110 range at the start of the run? Or to have the car cooler and the engine coolant temps in the 175-185 range and the IAT2's around 90?

Is the car pulling timing because the coolant temp isn't high enough along with pulling timing if the IAT2's are too high?

3.) Any other advice from Veteran Bracket Racers? My ZL1 is a full 2 seconds faster than my last car I raced for 6 years but it is less consistent despite it being an automatic.

4.) Why did my trap speed drop 3 mph???

1 - it is common for cars to run away when they start hot lapping at the end of eliminations. We had this problem the first year we raced but decided to stop off at the water station and cycle cold water through the motor after the run to speed up its cool down. (this was an iron block iron headed 427 bbc) - it worked. Our car would keep running 10.90s and other cars would break out.

You ran faster because your car was 20 degrees warmer.

2 - coolant temp is best where you think the car can have repeatability
If 190 is - great or it could be 205. Whatever the number always make sure that is where you are at going in.

3 - I think the additional heat from the blower can cause inconsistencies. I have noticed in the top dragster/sportsman ranks - the blower cars fly but it is normally the NA cars on nitrous that win/go more rounds. The COPOs and Cobra Jets use blowers to basically destroy A stock records.

Not saying you cant be consistent but its something else you need to keep "under control"

4 - once again get a weather station. We (my family) use a crew chief pro from don higgins. He has a lap top setup and a weatherstation we mount on our trailer. That is quite expensive but it did pay for itself in the way of 4 track championships, 2 2nd place points finishes, and a 9th place in 6 years of racing. With a handful of event wins.
We started out with their hand held unit. My suggestion is to buy this and a very good tire gauge! (Jegs has a nice digital one for about $70 but we have broken 3 of them over the years)

My Mods Are:
Stock Tune and 91 Octane
10% OD Lower Pulley (8.86")
Rotofab CAI with Big Gulp
Vmax TB
Rotofab Intercooler Coolant Reservoir
Mickey Thomspons 305/35/20 ET Street II (Ran them at 16 PSI)
Line Lock (Got a good burnout on all the three runs)
Car has 3,400 miles on it and it weight 4,305lbs with me in it and 1/4 tank.

I pull both ABS fuses and run the car in Tour Suspension Mode and have the transmission is Sport (shifts by itself). I launch at 1,000-1,200 rpms. (I have tried up to 1,500 but the car moves in the staging box and messes with my Reaction Time)

The car does an awesome burnout with the line lock and has no issues with traction. It just squats and pulls, no drama and no spinning. I have about 50 Go Pro and Iphone videos of this as proof.

Any advice or thoughts is greatly appreciated!

I may suggest slicks and skinnies (if allowed). You will run quicker but also more consistent.
You also dont need giant John Force burnouts either

tire psi - another big deal. Always check. If you run 30psi always run 30psi.

It really does come down to the little things

Good luck

[EvilZL1]

I cant even break low or mid 12s right now. My PB is 12.8. Can anybody help me with launching correctly. I had my coolant temps down to 169 maybe before the water box. My first run last week i ran a 12.93 with temps down in the 180, tire pressure dropped to 24-25 psi on stock goodyears, traction control off. dont know how to break this curse

[JackalopeZL1]

Post a time slip.. your launch is more than likely horrible.. you letting it shift?

[EvilZL1]

Originally Posted by JackalopeZL1

Post a time slip.. your launch is more than likely horrible.. you letting it shift?

yea im letting it shift. I know its the launch, has to be. I baby it out the hole to lessen the chance of wheel spin

[EvilZL1]

Sent from Wayne's Manor

[JackalopeZL1]

Originally Posted by EvilZL1

Sent from Wayne's Manor

What is your Elevation? DA? Slow start and low MPH in the traps For example my best I ran a 11.87/119 bone stock 1100DA

[JackalopeZL1]

Are you putting back to "M" and letting it auto shift? Some folks don't know that puts you in a first gear start vs second in "D"

[EvilZL1]

Originally Posted by JackalopeZL1

What is your Elevation? DA? Slow start and low MPH in the traps For example my best I ran a 11.87/119 bone stock 1100DA

also meant to include i was car 21. and Da fluctuates between 2000-2700. elevation is 243ft

[Mr. Nasty]

If all of your R/T times is like the on your slip you have more then your dial in time to worry about. Stage in deep that will help. You will have to put deep on your window.
Your R/T times cost you .53 of time over the other car. I know this dose not help with the car times but will help on your run with your times. Get the R/T down

I have been running the pro class with R/T at .100 and loss. Started staging in deep now R/T .033 to .009. Now I'm knocking out all out drag car and making a little money LOL

[JackalopeZL1]

Rt means nothing except if trying race another car period.. sit there for 10 seconds it means nothing for this guy's question. And if he is new to drag racing going deep will just make things worse for getting the basics down.

[Mr. Nasty]

Originally Posted by JackalopeZL1

Rt means nothing except if trying race another car period.. sit there for 10 seconds it means nothing for this guy's question. And if he is new to drag racing going deep will just make things worse for getting the basics down.

HEY DID YOU NOT READ #3

If he dose not have the basics after 6 years he will never have them. Not only did he ask about his car but also about bracket racing and R/T time means every thing that is where its won and lost. You cant start 10 seconds in the hole bracket racing.

[JackalopeZL1]

No. The guy who posted his time slip did not