How much et from skinnys?
Here is where I meant to put this:
Here is how you test: I was in on a track rental test session yesterday. Always throw out the first pass. (Stood up on the wheelie bars too hard anyway) Then ran 10.024, 10.011, 10.007. Made my change, went 9.954. Changed it back, went 10.004. (We call that A-B-A testing.) I called that one a five hundredths improvement. If your car won't repeat like that, your going to have a tough time knowing for SURE what something is worth.
Here is how you test: I was in on a track rental test session yesterday. Always throw out the first pass. (Stood up on the wheelie bars too hard anyway) Then ran 10.024, 10.011, 10.007. Made my change, went 9.954. Changed it back, went 10.004. (We call that A-B-A testing.) I called that one a five hundredths improvement. If your car won't repeat like that, your going to have a tough time knowing for SURE what something is worth.
Me? Of course. I check the fuel in my fuel cel every pass with a yard stick with a black mark on it for proper level. I have to weigh my car every qualifying & competition round. Have to do that to know at what it will go across the scales. Every Stock and Super Stock racer I know lives by the weather station (DA calculator?). Always have the DA handy.
All runs were within two hours in the middle of the day. DA varied less than 100', worst being the last couple of passes. When you change it back, and the times change back (A-B-A), you know it's legit. Otherwise, ?
sweetbmxrider, so you race bicycles?
All runs were within two hours in the middle of the day. DA varied less than 100', worst being the last couple of passes. When you change it back, and the times change back (A-B-A), you know it's legit. Otherwise, ?
sweetbmxrider, so you race bicycles?
Last edited by Ed Wright; Jun 3, 2013 at 03:40 PM.
TECH Enthusiast
Joined: Jul 2008
Posts: 577
Likes: 1
From: League City, Tx
Nah, you just don't go to the track, make a pass then throw the new part on the car and call the next couple of passes the results. Everybody I race with make a few runs to make sure the car has settled in, and stopped picking up. They most always pick up after getting the engine oil warmed up (can make a big difference) get the Trans fluid up to temp (higher than normal street driving) and gear lube warmed up. Many racers have heaters in the trams, eng oil pan, and even the rear end. The only way to know for certain how much something is worth is A-B-A testing. I have never found more than 5 hundredths swapping fronts like that. Since he picked up almost half his gain AFTER the tire/wheel swap, it appears that is about what he found. That car isn't real consistent.
Ed, I agree with you on A-B-A testing for sure. I have not gotten THAT scientific with it.. My car is fairly consistent but considering it only goes to the strip 2-3 times a year, and usually 3-4 passes a night, its hard to really hone in on improvements. But swapping the skinnies on at the track ALWAYS results in 2 mph gain... Always.. The 1 tenth ET reduction is a general average and could be less considering my 60's can very by .05 on their own as it is, let alone with any changes made to the car..
For me, I just normally try to stage the car at 150* water temp or less, try to have the oil at 180* or so and the tranny/diff warmed up. Normally I drive the car to the track about 40 miles one way so everything is good and hot, I just cool down the coolant and intake and let it rip. The car almost always dead hooks, the converter is tight so not a lot of variation in launches and the tranny shifts itself. Not exactly a bracket car and damn sure not a stocker but its not completely all over the map either.. I generally try to race it in -500 to +500' air...any worse then that and I don't even race it because I know it will slow down 1-3 tenths.
Its just my pump gas weekend cruiser with highway gears and AC..not a race car. The one thing I know I can alway count on if I need a little extra is slapping the skinnies on it... 2 mph gain for 10 mins worth of work.
Me? Of course. I check the fuel in my fuel cel every pass with a yard stick with a black mark on it for proper level. I have to weigh my car every qualifying & competition round. Have to do that to know at what it will go across the scales. Every Stock and Super Stock racer I know lives by the weather station (DA calculator?). Always have the DA handy.
All runs were within two hours in the middle of the day. DA varied less than 100', worst being the last couple of passes. When you change it back, and the times change back (A-B-A), you know it's legit. Otherwise, ?
sweetbmxrider, so you race bicycles?
All runs were within two hours in the middle of the day. DA varied less than 100', worst being the last couple of passes. When you change it back, and the times change back (A-B-A), you know it's legit. Otherwise, ?
sweetbmxrider, so you race bicycles?
I'm not sure if you are being childish or what but no, I hurt myself with my bikes.
Just wondered why the strange screen name.
Not sure why people don't just use their real names.
Well would depend on the size of the "A" combo, like for a 5th gen, you are talking a 20x8 front and with tire you are like at 65 lbs. Go to 17x5 with front runner, that's like 31 lbs. So you lose some weight and rolling resistance.
I know from drag racing my 5th gen that if I pump up my stock front tires and decrease the contact patch the car is quicker everywhere in the slip.
I know from drag racing my 5th gen that if I pump up my stock front tires and decrease the contact patch the car is quicker everywhere in the slip.
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TECH Apprentice
Joined: Apr 2008
Posts: 392
Likes: 0
From: the race track
here is an article i read that compares running skinnies to just running wider street tires
http://www.dragzine.com/tech-stories...the-dragstrip/
http://www.dragzine.com/tech-stories...the-dragstrip/
TECH Fanatic
Joined: Oct 2005
Posts: 1,131
Likes: 76
From: olympia, wash
here is an article i read that compares running skinnies to just running wider street tires
http://www.dragzine.com/tech-stories...the-dragstrip/
http://www.dragzine.com/tech-stories...the-dragstrip/
here is an article i read that compares running skinnies to just running wider street tires
http://www.dragzine.com/tech-stories...the-dragstrip/
http://www.dragzine.com/tech-stories...the-dragstrip/
Bringing this back just to put in my 2 cents. I didnt do "ABA" testing but my 96 Camaro ran 13.8 consistantly multiple times separate nights. This was with the stock chrome 16" z28 wheels and 245 tires. I switched to 15x4" Weld RTs and 165 tire and ran 13.6 multiple times and one 13.5. No change in season, weather, temps, weight, mods, nothing.
I didn't read every page of this thread, but I read an article in Hotrod magazine years back about this. Tested steel wheels on a Chevelle or something and did back to back test w prostars on the front. It went 2 tenths faster and 2mph I belive.
