First time at the drag strip was UGLY
10/15/11, 08:00 PM
#21
Shelby GT500 Member
If your looking to get your reaction time, 60 Ft time and launches perfected... might i suggest finding a 1/8 mile track closer to home if you can. saves ya a 2 hour drive each way and you get to practice what needs to be practiced.
10/15/11, 09:05 PM
#22
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i ran with all the factory settings, pass number 3 was a 12.8 pass number 4 12.5, factory tires never changed a dam thing, wanted to see what i could do in full factory trim..... next time, drag radials, UPR control arms, front soft, back hard to start, gonna play with back settings, still makes more sense to me if the back i squats.... angle of the car sais more weight on rear tires, but i'm still amateur also lol. i got alittle more power now also thanks to mister MIKE DEZ and some tuning CAI and some mufflers..... oh and dont forget the other OLD trick ill be disconnecting the front sway bar for better transfer
10/15/11, 09:24 PM
#23
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Unreal, how many readers do you think understand your reference to Density Altitude (DA)? Really... If you want to use terms you may think are common, how about explaining them to others on our Forum who are acronym challenged. And then explain why a first time drag racer needs to even worry about DA. It was his FIRST time at the 1320 (uh thats a quarter mile in feet). Sheze, cut him a little slack...
.
Shane: I copied this from another forum to explain what I meant by DA,, Example, my track I run at is @ 900 ft, But with weather this summer most track days It was like at 2900 ft with weather considered. This takes track runs of 12.8 down to a actual run of 12.5 or better, Some people in Colorado run at 6000 ft so they have 14 second runs are normal.
Heres a explanation I found to help understand
Density altitude ( for our purposes ), is basically a means for describing how the weather conditions are going to effect our engines performance.
Look at it this way, if you enclose a 1 foot glass cube at sea level, in that cubic foot volume of air there is going to be so much oxygen. If you do the same thing on the top of mount everest there will be less oxygen in the air. Why would that be? air has 21% oxygen. well the air on mount everest is ,much less dense (less tightly packed), thus there is less molecules of oxygen in that cubic foot volume of air.
What effects density altitude?
Barometric pressure. Think of the atmosphere as a land mass...some places it is high, some places it is low. if you take your glass square and stretch it to the top of the atmosphere..if the atmosphere is significantly higher...there is more gas molecules pressing down, thus the pressure is higher, and the density is higher. if you go up in altitude...the column of air above you is decreased in height...so your actual barometric pressure measured right where you are at is less. ( thats why you shouldn't use sea level corrected BP's in calculating the DA ).
Temperature.
Guess as temp goes up the molecules get more active, and the gases expand some, so less oxygen molecules per volume measurment.
Humidity.
Water is a contaminant! it displaces potential air molecules.
Basically the DA formula takes the wetaher conditions, and then gives you a number that says. your current weather conditions are the equivilant to xxxft altitude in a standardized column of air.
the lower the DA the better!
Barometric pressure...the higher the better
Temperature...the lower the better ( offset by problems with track hooking when temp gets too low)
Humidity...the lower the better.
When you calculate DA correctly you should not correct for altitude, if you use the station pressure at the track...your actual track altitude is reflected in that.
Heres a explantion I got from another forum,
10/16/11, 07:42 AM
#24
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one of the other guys that was there recorded my fast pass against that truck:
that truck launched so hard it wasn't funny. I totally wasn't paying attention concentrating on not spinning, which didn't help at all lol. I didn't take down all the stuff the DA calculator i fond needed, but i remembered some of it and used the data from the next day i could find since the weather was similar. Looks like corrected the pas was a 13.1 at 112 and some change so very close to the real numbers.
that truck launched so hard it wasn't funny. I totally wasn't paying attention concentrating on not spinning, which didn't help at all lol. I didn't take down all the stuff the DA calculator i fond needed, but i remembered some of it and used the data from the next day i could find since the weather was similar. Looks like corrected the pas was a 13.1 at 112 and some change so very close to the real numbers.
Last edited by ShaneM; 10/16/11 at 07:44 AM.
10/16/11, 10:20 AM
#25
Bullitt Member
Shawn, very good explanation for density altitude and hopefully others will begin to understand the significance of running at high,hot and humid strips. It does make a difference to engine power and thus ET (elapsed time). Obviously the same is true for track events as well.
Did not mean to pick on you and you have certainly corrected and defined your acronym to the benefit of all of us. Thanks!
Did not mean to pick on you and you have certainly corrected and defined your acronym to the benefit of all of us. Thanks!
10/16/11, 10:31 AM
#26
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Shane I know what you mean, I race in a all Mustang club.
When I go to the track for Test and Tune days, you can be lined up with just about anything,
A few months ago I was lined up with a car soo loud I coulndt even pay attention to my RPMs or launch , I was lost. Needless to say my reaction time was real late and I spun like crazy.
Distractions are hard to ignore.
When I go to the track for Test and Tune days, you can be lined up with just about anything,
A few months ago I was lined up with a car soo loud I coulndt even pay attention to my RPMs or launch , I was lost. Needless to say my reaction time was real late and I spun like crazy.
Distractions are hard to ignore.
10/16/11, 10:37 AM
#27
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Shane this makes it easy to figure,
Just drop down menu for your track, and the date, and all the weather conditions are already there, then hit calculate and it will give corrected DA,
Then enter your track times and it will give you your time if you were at better weather and a sea level condition.
http://www.dragtimes.com/da-density-...ect+ET+and+MPH
Just drop down menu for your track, and the date, and all the weather conditions are already there, then hit calculate and it will give corrected DA,
Then enter your track times and it will give you your time if you were at better weather and a sea level condition.
http://www.dragtimes.com/da-density-...ect+ET+and+MPH
Last edited by UnrealFord; 10/16/11 at 10:38 AM.
10/16/11, 01:21 PM
#30
Bullitt Member
I would second Shawn's recommendations.
You want high(er) tire pressures in the front to lower rolling resistance. (Not necessarily to shift weight on which you rely on the suspension to do). You can do this in two ways 1) smaller tires i.e. look at the front tires of fuel/funny cars or 2) run higher pressures. (or both).
One caveat is make sure you do not exceed the maximum rated tire pressure stated by the manufacturer on the sidewall.
You want high(er) tire pressures in the front to lower rolling resistance. (Not necessarily to shift weight on which you rely on the suspension to do). You can do this in two ways 1) smaller tires i.e. look at the front tires of fuel/funny cars or 2) run higher pressures. (or both).
One caveat is make sure you do not exceed the maximum rated tire pressure stated by the manufacturer on the sidewall.
10/16/11, 03:54 PM
#31
10/16/11, 04:33 PM
#32
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I disagree, People disconnect there front stabilizer bar in front or remove it entirely to get front end up .
http://www.dragstuff.com/techarticle...uspension.html
Mike Canter of Outlaw Pro-Mod fame had this jewel of a post post years ago that I saved where he detailed the following sequence that you should watch for:
"This should be the sequence of events seen on the video. Right at launch the front should start to come up before any forward movement or the car.
The rear of the car with this added weight transferred from the rising front will lift very little but it should not go down (squat). An inch or two is normal and can be best seen by looking at the relationship between the top of the slicks and the rear fender lip.
This one or two inches of rise will indicate that the rear of the car is lifting and pushing harder on the tires while the front weight is being transferred (for every motion there is an equal and opposite motion).
If the front of the car does not rise first then the front shocks are too stiff or the rear shocks are not stiff enough.
If the rear of the car squats right away then the rear shocks are too loose.
I have found through slow motion video tape that if the rear shocks are too loose the rear tire actually bounces on the initial hit and will break loose almost right away. I stood next to the car pointing the camera right at the rear tire. It was amazing to watch. I kept on tightening the rear shocks until it stopped which was just below mid point of the adjustment. From all that I have seen the rear shocks should never be adjusted less that half way because of rear squat and tire bounce."
The rear of the car with this added weight transferred from the rising front will lift very little but it should not go down (squat). An inch or two is normal and can be best seen by looking at the relationship between the top of the slicks and the rear fender lip.
This one or two inches of rise will indicate that the rear of the car is lifting and pushing harder on the tires while the front weight is being transferred (for every motion there is an equal and opposite motion).
If the front of the car does not rise first then the front shocks are too stiff or the rear shocks are not stiff enough.
If the rear of the car squats right away then the rear shocks are too loose.
I have found through slow motion video tape that if the rear shocks are too loose the rear tire actually bounces on the initial hit and will break loose almost right away. I stood next to the car pointing the camera right at the rear tire. It was amazing to watch. I kept on tightening the rear shocks until it stopped which was just below mid point of the adjustment. From all that I have seen the rear shocks should never be adjusted less that half way because of rear squat and tire bounce."
Last edited by UnrealFord; 10/16/11 at 04:42 PM.
10/17/11, 06:13 AM
#35
Bullitt Member
I disagree, People disconnect there front stabilizer bar in front or remove it entirely to get front end up .
http://www.dragstuff.com/techarticle...uspension.html
Mike Canter of Outlaw Pro-Mod fame had this jewel of a post post years ago that I saved where he detailed the following sequence that you should watch for:
http://www.dragstuff.com/techarticle...uspension.html
Mike Canter of Outlaw Pro-Mod fame had this jewel of a post post years ago that I saved where he detailed the following sequence that you should watch for:
"This should be the sequence of events seen on the video. Right at launch the front should start to come up before any forward movement or the car.
The rear of the car with this added weight transferred from the rising front will lift very little but it should not go down (squat). An inch or two is normal and can be best seen by looking at the relationship between the top of the slicks and the rear fender lip.
This one or two inches of rise will indicate that the rear of the car is lifting and pushing harder on the tires while the front weight is being transferred (for every motion there is an equal and opposite motion).
If the front of the car does not rise first then the front shocks are too stiff or the rear shocks are not stiff enough.
If the rear of the car squats right away then the rear shocks are too loose.
I have found through slow motion video tape that if the rear shocks are too loose the rear tire actually bounces on the initial hit and will break loose almost right away. I stood next to the car pointing the camera right at the rear tire. It was amazing to watch. I kept on tightening the rear shocks until it stopped which was just below mid point of the adjustment. From all that I have seen the rear shocks should never be adjusted less that half way because of rear squat and tire bounce."
The rear of the car with this added weight transferred from the rising front will lift very little but it should not go down (squat). An inch or two is normal and can be best seen by looking at the relationship between the top of the slicks and the rear fender lip.
This one or two inches of rise will indicate that the rear of the car is lifting and pushing harder on the tires while the front weight is being transferred (for every motion there is an equal and opposite motion).
If the front of the car does not rise first then the front shocks are too stiff or the rear shocks are not stiff enough.
If the rear of the car squats right away then the rear shocks are too loose.
I have found through slow motion video tape that if the rear shocks are too loose the rear tire actually bounces on the initial hit and will break loose almost right away. I stood next to the car pointing the camera right at the rear tire. It was amazing to watch. I kept on tightening the rear shocks until it stopped which was just below mid point of the adjustment. From all that I have seen the rear shocks should never be adjusted less that half way because of rear squat and tire bounce."
Shock setting 1 for the fronts (and inflate to max allowed sidewall pressure) and 4/5 for the rears (and lower pressures to recommendations given in the previous post).
But experiment for yourself and see what you think....
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