[andrewskaggs]

I went bracket racing this weekend and I've noticed some trends with my car and was wondering what kind of experiences the rest of you have had.

Let me start by saying that I do have a manual transmission and I realize that my consistency isn't as good as it would be with an auto. I'm working on that problem as well...dropping off the c4 at my transmission builder this weekend.

As soon as I can get all of the transmission parts bought and installed, I'll also be buying a weather station and ET predictor (probably one of these: Computech Systems 1000 Computech RaceAir Pro), so I'll be better able to analyze the weather conditions and its effects on the car.

That said, my own evidence seems to suggest that humidity affects the car much more than temperature does. Almost every time I go to the track, my first run is the quickest of the night. As it gets later, the temperature goes down but humidity goes up and I start slowing down. This latest trip to the track, my first run was a 8.39 with a 1.72 60'. By the end of the night (5th run), I was running 8.61 with a 1.80 60'. What have you n/a guys found regarding temp and humidity as relates to ET?

I don't think engine temp is the big factor in this as it seems to slow down even when engine temp pulling into the burnout box is very similar. Between the first and second pass on Saturday, I had at least an hour of cooldown time with the hood open which should have been sufficient to get it back down close to where it needed to be. What do you guys do as a cooldown? The guys I usually race with have a generator and I have borrowed leaf blowers from them in the past to help with cooldown, but I'd like to find something that I don't have to rely on them for (if that is, in fact my problem).

My buddies with their race cars make me jealous. Their 65 Mustang with a 363 sbf on alcohol ran four 6.29s and a 6.30. I realize that their cars were built from the ground up for bracket racing and are going to be more consistent; I'm just looking for every little advantage for my poor little street car. lol

[06VistaBlueGT]

I've been logging my runs for a couple years now. Everything environmental plays a part in the performance of the car, some more than others. I will agree that humidity is a big factor. Engine temp and ambient temp are factors as well. This year i started logging track temp as well and that really seems to play a big part. DA is a factor too but not as big of a factor as I thought. To give you an example, the DA last Friday was around 2700ft. It never varied more than 100ft either way, however, ambient temp and track temp dropped and humidity went up. First run I ran a 13.19, track temp was 120. second run I did a 13.15, track temp was 104. Rest of runs were all 13.13. The track temp stabilized at 80 after sunset.

As for cooling the car, if it's going to be an hour or so between runs, I'll typically just shut the car off and let it cool on its own. If there is going to be less time, I'll turn my cooling fan on (I have it on a switch) for a few minutes. If it's going to be a really short turn around, the hood goes up and the fan will be on.

[andrewskaggs]

Yeah, I need to install a switch for my fan. What do you consider a really short turn around? < 20 minutes?

Thanks for the input. Reps.

[06VistaBlueGT]

Originally Posted by andrewskaggs Yeah, I need to install a switch for my fan. What do you consider a really short turn around? < 20 minutes? Thanks for the input. Reps.

IHRA and I think NHRA both require at least 15 minutes between runs so anywhere between 15 minutes and 1/2 an hour I'll have the hood up. It also depends on the weather. If it's 90 degrees, I might put the hood up and leave it up after each run no matter how long the wait is going to be. If it's 40, I won't bother with the hood, just turn the fan on during quick turnarounds.

[casper gt]

the hood up with an electric water pump & this cooling fan mod, Modular Revolution Forums

are all you beed to cool your car down IMO.


sitting behind my car in the pits with the high speed fan going, you can feel the heat coming out from under the back bumper/etc.

[andrewskaggs]

Cool. Reps for the link, casper. I'll definitely be doing that. You're running a Meziere pump, right?

[Tang Stang]

Originally Posted by casper gt the hood up with an electric water pump & this cooling fan mod, Modular Revolution Forums are all you beed to cool your car down IMO. sitting behind my car in the pits with the high speed fan going, you can feel the heat coming out from under the back bumper/etc.

x2. I run a Meziere pump and a switched auxiliary radiator fan on the Teksid-based stroker in my XR7. That thing cools off incredibly quickly in the staging lanes when I need it to.

[casper gt]

Originally Posted by andrewskaggs Cool. Reps for the link, casper. I'll definitely be doing that. You're running a Meziere pump, right?

yep, I have a meziere pump & I love it.

one thing though, if you decide to order one, don't get the meziere wiring kit they list for it, it's garbage.

[andrewskaggs]

I think I might've figured out why my car is falling off when it should be picking up as the temperature drops. I think my problem is too much traction. When the sun is on the track, it seems as if the tires slip just enough and my ET is better. As the track conditions get better, I start hooking harder and bogging--slowing down my ET.

I'm not going to overthink it too much trying to fix it at this point as the C4 will act completely differently. I'm getting antsy to get that in there. I'm very curious how it's going to affect my ET and MPH.

[06VistaBlueGT]

Originally Posted by andrewskaggs I think I might've figured out why my car is falling off when it should be picking up as the temperature drops. I think my problem is too much traction. When the sun is on the track, it seems as if the tires slip just enough and my ET is better. As the track conditions get better, I start hooking harder and bogging--slowing down my ET. I'm not going to overthink it too much trying to fix it at this point as the C4 will act completely differently. I'm getting antsy to get that in there. I'm very curious how it's going to affect my ET and MPH.

I have a TH350 and 4000RPM converter. My times are a couple tenths slower than when I had a stick but the reliability and consistency of the auto is sooo much better.

Also, I recently hooked up my line locks and 2 step to a switch. I use this combo when running No Box or Mod. The car is even more consistent this way. The only problem I'm having right now is finding my spot on the tree with the switch.

[andrewskaggs]

Yeah, I thought I might be a bit slower. That's fine so long as I can start going rounds.

I noticed you said line locks (plural). You have one on the rear as well?

[06VistaBlueGT]

Originally Posted by andrewskaggs Yeah, I thought I might be a bit slower. That's fine so long as I can start going rounds. I noticed you said line locks (plural). You have one on the rear as well?

No, typo on my part. Just on the front. I know a few who do have them on the rear but that is typically illegal.

[andrewskaggs]

How does it hold at the line with just the front brakes catching? Are you able to leave as high as you could if you were on the brake pedal?

[06VistaBlueGT]

Originally Posted by andrewskaggs How does it hold at the line with just the front brakes catching? Are you able to leave as high as you could if you were on the brake pedal?

I always try to launch at 2400 - 2500 RPM's. My converter flashes at 3100 so I'm pretty far away from that at launch to get a good run at the converter. Haven't had an issue with the back tires spinning yet.
When I set the line lock and floor the gas to come on the 2 step, the back end comes up a little like it's trying to push through the line lock but it never does. I'll see if I can get someone to take a video of it this weekend.

[JD mustang]

ive raced all year and i drop off through out the day as well. my runs would be quick at the beginning also. i could drop as much as 5 tenths and all the true bracket cars would still be close to their time trial runs. i tried every thing to be more consistent could not find it. auto is the way to go. to many variables to go rounds with a 5spd. you can do it but is difficult. i got 3 final 4's and 1 final this year but those days i treed people and had wiggle room at the end. go auto if your gonna bracket race. I wanna find another car so i can get to nationals next year. cant bring myself to pull the 5sp out its to much fun on the street

[andrewskaggs]

I have a c4 being built as we speak. I have most of the major parts...just have to pick up a spare console, shifter and a few odds and ends.

[06VistaBlueGT]

Originally Posted by andrewskaggs I have a c4 being built as we speak. I have most of the major parts...just have to pick up a spare console, shifter and a few odds and ends.

I remember the first time going down the track after converting to the TH350. By the middle of the run I was so disappointed because I felt I was going so slow. Got my time slip and it was 13.4?. By the end of the day I was down in the 13.2's. There is so much less to worry about with the auto, it's like a ride in the park. lol.

[andrewskaggs]

Originally Posted by 06VistaBlueGT I remember the first time going down the track after converting to the TH350. By the middle of the run I was so disappointed because I felt I was going so slow. Got my time slip and it was 13.4?. By the end of the day I was down in the 13.2's. There is so much less to worry about with the auto, it's like a ride in the park. lol.

Yeah. Do you have a brake in the car? I'm putting a brake in, but I will be running mostly footbrake still. I just want to have the option of running super pro if I decide I want to. I'm probably going to put an air shifter in with an RPM switch eventually, so it will be even more consistent.

[06VistaBlueGT]

Originally Posted by andrewskaggs Yeah. Do you have a brake in the car? I'm putting a brake in, but I will be running mostly footbrake still. I just want to have the option of running super pro if I decide I want to. I'm probably going to put an air shifter in with an RPM switch eventually, so it will be even more consistent.

No brake yet. Can't run slower than 11.99 in Top (Super Pro) at my track. I do have a line lock and a 2 step and have the ability to launch on a switch when running Mod or No Box. Just put that in last week and have been trying to get used to it.

[andrewskaggs]

Originally Posted by 06VistaBlueGT No brake yet. Can't run slower than 11.99 in Top (Super Pro) at my track. I do have a line lock and a 2 step and have the ability to launch on a switch when running Mod or No Box. Just put that in last week and have been trying to get used to it.

There are no ET breaks at my track. If I do decide to run Super Pro, the dragsters will be cursing me while they sit at the tree for 3+ seconds (1/8 mile). lol