what do i need to get 12 sec slip? have 1000 bucks!
11-20-2006, 07:15 PM
#31
3rd Gear Member
Join Date: May 2005
Location: tx
Posts: 927
RE: what do i need to get 12 sec slip? have 1000 bucks!
This is from modular depot. Believe Bill Putnam wrote this up. Their forums are down right now so can not verify, the author.
Five Components to a 12 second NA GT
--------------------------------------------------------------------------------
Before reading on I just want to say that this is basically geared towards drag racers not your average enthusiast looking for 12s on street tires with no real changes to the car. Not that it canāt be applied to someone looking for that but this is geared more towards the people out there looking for 12s and willing to work for it.
1.) Power ā If you listen to some old school drag racers they may say you need at least 300+RWHP to hit 12ās in most cars. In some heavier cars that may be true but fact is suspensions are more refined these days and cars donāt weight 4,000 lbs. Most PI headed cars will hit the 245-255RWHP mark with basic mods (Pulleys, Timing Adjuster or chip, O/R H or X, K&N or other type of high flow filter and although not a power modā¦gears 4.10s or 4.30s). For a bolt on GT this is enough power to get the car into the 12s after you follow the other steps. Keep in mind more power will make it easier to reach your goal or help offset more weight (see next section) but it can be done with less.
2.) Weight - You basic 5 speed coupe without driver weights 3250lbs. So with an average driver weighing about 180lbs that puts your race weight at 3430lbs. At that weight and a power to weight ratio of .075 you would need 258RWHP to hit 12ās. Power to weight is the power of your car (rear wheel) divided by race weight of the car. Using my car when I broke into the 12ās first time I was making 246RWHP and had a race weight of 3250lb, which worked out to a .075 power to weight ratio or .075RWHP per pound of the car. From what Iāve seen a car can get into the 12s with a .075 to .080 P/W ratio. So if your race weight is 3430lbs then 3430 * .075 = 257.25RWHP. As long as you keep this ratio in the .075 to .080 range you are fine plus keep in mind you can drop weight instead of adding power. An example of this is a car with a 3000lb race weight could break into the 12s with 225RWHP (close to stock power on a GT).
Now Iām sure some of you are asking about weight reduction. Basic weight reduction would be rear seat delete, removal of spare tire, jack, tire ironā¦these would knock a good 70-80lbs from the car. Add a set of welds or light weight race wheels and you are looking at another 60-80lbs. For more information about specific weights and more ideas look hereā¦ http://users.adelphia.net/~mustang-9...0Reduction.htm
3.) Suspension - I feel that this component has the most leeway so to speak. Iāve seen near stock suspension cars get good weight transfer. I honestly believe a car that meets the other requirements could hit 12s on the stock suspension. However those of you that want to get an edge should read on. First thing I would do is look at springs since most of us want a better stance but still want weight transfer. For that look at fox body 4cyl front springs I usually look to the junkyards for these but most buy stock replacements at a local shop (avoid Moog brand though they are taller than stock specs). For the rear end I go with fox body v8 rear springs cut anywhere from a Ā¼ to 1 coil to level out the car. Just keep in mind that itās easier to cut too little than too much spring.
Next I would highly recommend a pair of sub-frame connectors welded in to tie the chassis together. Hard launches on slicks will twist the body and this will help keep it straight. Last piece to really help out is struts I went with Lakewoods because they are readily available and affordable but adjustables can be used as well if you have the budget for them. 70/30s and 90/10ās both work well and I stick with fox body specific struts since the car is lowered. Fox body specific springs are Ā¾ā shorter than stock SN-95 springs so the lower fox body specific struts are shorter.
4.) Traction ā Iāll cut to the chase here and just skip over street tires and drag radials and go right to slicks. Not that it canāt be done on these tires but it will take more power, more patience and much more writing on my part so weāll stick to slicks. Cars in this weight range and power level only need a 26x8.5x15 ET Drag for traction. Itās close to stock tire height and is more than enough to make our cars hook on the track. A better suspension will result in better 60 foot times but even on stock suspension a good burnout on slicks will not spin unless the track is poorly prepped or fluids are on the track. Some people opt for cheap steel wheels which I donāt necessarily recommend since you are keeping extra weight on the axles. This opens you up for possible breakage so I would go with a weld wheel instead even if itās a pair of used ones for track only purposes. Regardless a 15x8 with 5 on 4.5 bolt pattern and 5.5 backspacing will fit perfect, or if you insist on a wider tire like a 10ā then a 15x10 with 5 on 4.5 bolt pattern and 6.5 backspacing will also work on our cars.
5.) Practice ā This is one component that you canāt buy at any store, you can learn it from a text book and you canāt ask your friends about you simply have to get out there. Iām not saying everyone should be like me and hit every test and tune but donāt expect to make one trip and bingo your in the 12ās. I race on slicks for 3 months before hitting my first 12 second pass. Going to slicks alone was a big change that I had to adjust to before I got the hang of and learned to shift better, etcā¦ Take your time, get comfortable in the car and have fun with it. Do that and youāll achieve your goal.
Now that you know the key components to get into the 12ās you have to keep it all together. ļ In the above situation I would highly recommend an aftermarket shifter just to help keep the transmission alive longer. The biggest weakness in the above is the differential and axles. Not to say they canāt take some abuse because they can, mine went almost a full year of launches on slicks before breaking. I would look at a set of 31 spline axles and an Eaton or Ford 31 spline differential beefed up to keep the back end in one piece.
Five Components to a 12 second NA GT
--------------------------------------------------------------------------------
Before reading on I just want to say that this is basically geared towards drag racers not your average enthusiast looking for 12s on street tires with no real changes to the car. Not that it canāt be applied to someone looking for that but this is geared more towards the people out there looking for 12s and willing to work for it.
1.) Power ā If you listen to some old school drag racers they may say you need at least 300+RWHP to hit 12ās in most cars. In some heavier cars that may be true but fact is suspensions are more refined these days and cars donāt weight 4,000 lbs. Most PI headed cars will hit the 245-255RWHP mark with basic mods (Pulleys, Timing Adjuster or chip, O/R H or X, K&N or other type of high flow filter and although not a power modā¦gears 4.10s or 4.30s). For a bolt on GT this is enough power to get the car into the 12s after you follow the other steps. Keep in mind more power will make it easier to reach your goal or help offset more weight (see next section) but it can be done with less.
2.) Weight - You basic 5 speed coupe without driver weights 3250lbs. So with an average driver weighing about 180lbs that puts your race weight at 3430lbs. At that weight and a power to weight ratio of .075 you would need 258RWHP to hit 12ās. Power to weight is the power of your car (rear wheel) divided by race weight of the car. Using my car when I broke into the 12ās first time I was making 246RWHP and had a race weight of 3250lb, which worked out to a .075 power to weight ratio or .075RWHP per pound of the car. From what Iāve seen a car can get into the 12s with a .075 to .080 P/W ratio. So if your race weight is 3430lbs then 3430 * .075 = 257.25RWHP. As long as you keep this ratio in the .075 to .080 range you are fine plus keep in mind you can drop weight instead of adding power. An example of this is a car with a 3000lb race weight could break into the 12s with 225RWHP (close to stock power on a GT).
Now Iām sure some of you are asking about weight reduction. Basic weight reduction would be rear seat delete, removal of spare tire, jack, tire ironā¦these would knock a good 70-80lbs from the car. Add a set of welds or light weight race wheels and you are looking at another 60-80lbs. For more information about specific weights and more ideas look hereā¦ http://users.adelphia.net/~mustang-9...0Reduction.htm
3.) Suspension - I feel that this component has the most leeway so to speak. Iāve seen near stock suspension cars get good weight transfer. I honestly believe a car that meets the other requirements could hit 12s on the stock suspension. However those of you that want to get an edge should read on. First thing I would do is look at springs since most of us want a better stance but still want weight transfer. For that look at fox body 4cyl front springs I usually look to the junkyards for these but most buy stock replacements at a local shop (avoid Moog brand though they are taller than stock specs). For the rear end I go with fox body v8 rear springs cut anywhere from a Ā¼ to 1 coil to level out the car. Just keep in mind that itās easier to cut too little than too much spring.
Next I would highly recommend a pair of sub-frame connectors welded in to tie the chassis together. Hard launches on slicks will twist the body and this will help keep it straight. Last piece to really help out is struts I went with Lakewoods because they are readily available and affordable but adjustables can be used as well if you have the budget for them. 70/30s and 90/10ās both work well and I stick with fox body specific struts since the car is lowered. Fox body specific springs are Ā¾ā shorter than stock SN-95 springs so the lower fox body specific struts are shorter.
4.) Traction ā Iāll cut to the chase here and just skip over street tires and drag radials and go right to slicks. Not that it canāt be done on these tires but it will take more power, more patience and much more writing on my part so weāll stick to slicks. Cars in this weight range and power level only need a 26x8.5x15 ET Drag for traction. Itās close to stock tire height and is more than enough to make our cars hook on the track. A better suspension will result in better 60 foot times but even on stock suspension a good burnout on slicks will not spin unless the track is poorly prepped or fluids are on the track. Some people opt for cheap steel wheels which I donāt necessarily recommend since you are keeping extra weight on the axles. This opens you up for possible breakage so I would go with a weld wheel instead even if itās a pair of used ones for track only purposes. Regardless a 15x8 with 5 on 4.5 bolt pattern and 5.5 backspacing will fit perfect, or if you insist on a wider tire like a 10ā then a 15x10 with 5 on 4.5 bolt pattern and 6.5 backspacing will also work on our cars.
5.) Practice ā This is one component that you canāt buy at any store, you can learn it from a text book and you canāt ask your friends about you simply have to get out there. Iām not saying everyone should be like me and hit every test and tune but donāt expect to make one trip and bingo your in the 12ās. I race on slicks for 3 months before hitting my first 12 second pass. Going to slicks alone was a big change that I had to adjust to before I got the hang of and learned to shift better, etcā¦ Take your time, get comfortable in the car and have fun with it. Do that and youāll achieve your goal.
Now that you know the key components to get into the 12ās you have to keep it all together. ļ In the above situation I would highly recommend an aftermarket shifter just to help keep the transmission alive longer. The biggest weakness in the above is the differential and axles. Not to say they canāt take some abuse because they can, mine went almost a full year of launches on slicks before breaking. I would look at a set of 31 spline axles and an Eaton or Ford 31 spline differential beefed up to keep the back end in one piece.
11-20-2006, 07:20 PM
#32
6th Gear Member
Join Date: Apr 2005
Location: Wilmington, NC
Posts: 5,608
RE: what do i need to get 12 sec slip? have 1000 bucks!
ORIGINAL: PerformanceRed4.6
i have gears, tb, plenum, pulleys, cai, shifter, bbk o/r x pipe,bbk lt headers, flowmaster catback for now! zex nitrous kit 125 shot right now, prob. leaving out something but i ran a 13.5 n/a. i want a n/a 12 sec slip.
i have gears, tb, plenum, pulleys, cai, shifter, bbk o/r x pipe,bbk lt headers, flowmaster catback for now! zex nitrous kit 125 shot right now, prob. leaving out something but i ran a 13.5 n/a. i want a n/a 12 sec slip.
31 Spline Axles
31 Spline LSD
MT Drag Radials
11-20-2006, 07:58 PM
#34
5th Gear Member
Join Date: Jul 2004
Location: Pittsburgh/Dayton
Posts: 3,062
RE: what do i need to get 12 sec slip? have 1000 bucks!
Driver mod.
You seem to want everything with nothing. You have basically full boltons other than some simple suspenion mods theres not much you can do except a power adder to get there.
You seem to want everything with nothing. You have basically full boltons other than some simple suspenion mods theres not much you can do except a power adder to get there.
05-16-2008, 07:34 AM
#35
2nd Gear Member
Join Date: Apr 2008
Location:
Posts: 197
RE: what do i need to get 12 sec slip? have 1000 bucks!
definetly suspension work even with a stock gt suspension will help with a quicker launch. rule of thumb is beef up suspension then brakes then hp. you get a good suspension set you should drop at leat 3/10ths or more on the quarter. then lighten it up as much as want.
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