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Bracket Racing in Bradenton

2K views 8 replies 5 participants last post by  KJ392 
#1 ·
Trying it again today. I haven't been able to get to a T&T to figure out my issues with changing 60' (+- .03) since last time out. What the heck nothing to lose today. Tomorrow is a Runday Sunday at Immokalee so that will be where I will be able to change some things and see if I can get my 60' consistant. It would of been nice to test before racing but sometimes you have to go with the flow.
 
#3 · (Edited)
I changed a few things up. Increased my burnout by 1 second, heal down and ball of my right foot on the brake pushing on the edge of the brake peddle (very light pressure holding the car on the line) , left foot heal down foot lifted off the gas and just slam it down when I see my spot on the tree, No "leaning" or feathering of the gas.

My 60' were 1.847 1.840 1.844 1.864 1.851 2 time shots and 3 eliimations runs, Went -.004 red round 3

First 2 runs daytime, run 3 twilight, last 2 at night

I think I put the car in a hair too deep the last 2 runs.

I was racing at a Summit event which the track is usually very well prepped.

I'm reviewing my timeslips lol E1 I got the win running a 8.343 @ 68.43MPH on a 8.21 dial. I got a huge RT advantage which I haven't seen in years. I think something went wrong with my opponent. Brembo's are awesome at scrubbing ET. I calced that I would of run a 8.16 out the door. Car scrubbed a wapping .183 ET in the 1/8 and yes I was on the brakes hard and off the gas.
 
#4 ·
+/- .03 60' is real good for a car with all the nannies on (TC off). Tq mgmnt variation is usually a lot more than that. The 392 is very consistent when tuned and set up properly. What were your time trial ETs & MPH assuming you ran out the entire 1/8th?
I usually dialed a 7.95 to 8.01 @ 88 to 90 MPH very consistently in the late spring and summer (Summit Series). Winter was usually a tenth quicker. The correct DRs where you can dead hook is the key. Once you can tune her, she will only get more consistent but you may have to go to another DR. Reduced tq mgmnt and the A8 will be a challenge to hook but she should really fly.
 
#5 ·
Here are timeslips. I had a full tank of gas, front 41 lbs, rear 20lbs, shallow staged off second amber, off idle, short shifting at 5K. Very light brake pressure and heal down toes up off the gas.

First time shot was a good run. Hit my spot on the tree and all shifts. Ran it out the back door. That's how things should work out.

Second time shot was horrible. I missed the tree looked up at my light then missed the shifts. "Tossed" this one out. Car picks up when shifting beyond 5k.


Eliminations. I decided to dial soft and use the brakes (rather than lifting off-on the gas) to scurb ET. First time trying the brake peddle.

Round 1 I dialed a soft 8.25. The round was at twilight which is the hardest time to hit the tree. I went out first hit the shifts then looked and my opponent was way way back. I was hard on the brakes and lifted (instinct) off the gas. Still took way toooo much stripe but got the win light. I had a huge RT advantage and calced that the car would of gone an 8.16. I take my first time shot and subtract the 330' ET from the 1/8 and get a split time (2.88) I then add that number (2.88) to my elimination 330' run of 5.281 to come up with the 8.16. That is my gussestimate of what the car would of run out the back door. Seems like the car scrubed almost 2 tenths(.182) . That is amazng. It was a safe brakeing as the car didn't nose dive, lock the brakes, or turn sideways.

Round 2. Ok I decided to redial and put a 8.23 on the window. Felt the car would go 8.16ish. Went against a slower car (a seldem thing). I saw a white flash as my second amber was comming on which resulted in a bad light. Mid track (after completing all my shifts) I saw the win light on my side. I lifted off the gas (my bad but instincts) just before the finish line. I don't think I scrubed more than .006 and less than 1mph or so. Surprise the car slowed to a 8.240 Hummm The white flash was my win light on my side of the tree. I did feel that I went in a little too deep on that pass.

Round 3. Redial to a 8.27, I'm the slower car and get to go first. As I stage I just flicker the stage bulb. Bump again and feel its a tad deep. Oh well nothing to do but hit my spot. I hit the tree and feel like I hit my spot well. Do all the shifting well then take 3 taps on the brakes on the top end and cross agian a car length in front. I see the win light in the other lane. Drats I feel I took too much which caused the loss. Get the slip and see I went .-004 red. Yep a tad too deep. The car would of run a 8.20 flat out and I scrubbed .106,

On ward and upwards. The next day I made 12 runs at IRR. Yes the car scrubs .04 with each brake tap. Being able to scrub this much there is no reason for me to short shift the car. Next race I will be leaving the car in Auto mode and not worry about the car shifting into 4th at the mph cone. My focus will be taping the brakes to come back to take .010 -.019 MOV on the top end. That is withing my ability to see the opponent and finish line.

The other fix (an hour chat Monday morning with my bracket coach) is that if I once again put the car in a hair too deep is to push the brake peddle down hard. This will make the car react a hair slower and hopefully move my .-004 to a .00x light.
 

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#6 ·
You're getting there!

Yes, let the tranny shift - it will be more consistent.

I applaud your efforts to go 0.00x on the tree, but you'll probably go red more often than you need to, especially in street division. If you can consistently go .01 to .02 on the tree, you'll go rounds without risking too many reds.

Tapping the binders might get you .04 with a +/- .01 margin (in other words .03 to .05 will be the norm). It's extremely hard to be that consistent and rely on a single brake tap to scrub exactly 0.04 every time.

I know you like dialing soft, so I'm going to tread gently here. Once you figure out what the car runs flat out in time trials when auto-shifting, slowly ease into dialing a bit tighter. If the car starts laying down consistent passes, then use that to your advantage and start whittling down that cushion as your confidence in the car builds.

If you tree the guy badly, you'll be so far ahead at the stripe it won't matter, and then just lift/tap. But if you are both close on the tree (which typically occurs in the later rounds with the better racers), it will come down to whoever runs closer to their dial. The best racers will consistently run it right out the back without lifting and be within .01 or better each time.
 
#7 ·
In my experience the car will not be that consistent hot lapping. Here are my times from Fontana one day that ended up being 85-87 deg by the time I left in the afternoon. ALL runs dead hooked with drag radials. 9AM - after about a 45 minute cooldown :12.23 , 12.30 , 12.32 and 12.37 all back to back in 21 minutes. Seems about right. then I let the car cooldown for an hour and it ran 12.31. then I went back and put the stock filter in it and ran again 31 minutes later 12.56. By now it was darn hot outside. then 50 minutes later it ran 12.41 fully warmed up. SO I can only think that on the 12.56 run the cooling fans were cranked up. NOW you know why we want to dial soft. You can scrub SECONDS off your ET. But if you are .1 behind, you are toast.
 
#8 ·
Wow - that is brutal. It will be hard to go rounds with a car that inconsistent. Aside from introducing the variable with the air filter, the car is running about +/- .07.

With that said, I will say there is a clear trend of running slower with each successive pass with that 21 minute window, indicating heat soak - which you might be able to predict with some level of confidence if you watch the coolant temps and fan speeds closely on each pass. Further, the 12.31 after a 45 minute cool-down is smack dab in the middle of that previous group.

I would log coolant temp/fan speed against ET against DA and a pattern will start to emerge upon which you can base a predictive model. That car will be more consistent than you might initially suspect after you apply this predictive model, probably with a +/- .03 window which will be much easier to deal with on the big end.

I agree if you are going to bracket race a car which can't lay down predictable and consistent ETs, then you are forced to dial soft and line-up bumpers. For this technique to work, you must (repeat must) cut a better light than your opponent. If you cut a worse light and line-up bumpers, a break-out loss is a mathematical certainty.

Part of my recipe for success on consistent ETs was a thermal management ritual which I never deviated from. Hood always open, the same cooling fan time, the same coolant temp before the pass, minimum idle in the staging lanes, etc. When I was forced to deviate from this management plan in later rounds due to faster cycling of classes, I used my predictive model to estimate the slow-down due to running a hotter engine with more heat soak.
 
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