Launching a 700rwhp+ whale, need some help
01-27-2013, 08:00 AM
#1
Launching a 700rwhp+ whale, need some help I'm looking for some guidance on what options I have to launch my better at the drag strip. I attend the track once or twice a year, normally through a track rental I organize. Last time out, I was having issues with spinning off the line and not planting the tires. Below is a run down of the car and current suspension setup. Now before anyone shakes their head too much, I know this car isn't the most ideal to be doing this with. If there are a few things that will make a difference and allow the car to remain enjoyable to drive on the street, then that's a big win for me.
97 TA Convertible - 4085lbs with me in it.
700+rwhp
Procharger F1-A
Tick Lvl 3 T56
McLeod Street Twin
S60
Tires: Track - 27x10.5 Hoosier QTP - Ran them around 14-16psi hot / Front - 15x4 Hoosiers
Suspension
Front - Strange DA Coilovers - 300lb spring / Stock sway bar
Rear - QA1 DA / Stock TA Springs / UMI - 22mm sway bar, Adj LCAs w/ reloc brackets, Chassis mount torque arm, panhard bar.
I tried slipping the clutch and also letting it out quickly (not dumping) but I would still spin if I had the launch RPM above say 3500 or so. I likely should have disconnected the front sway bar and perhaps dropped the pressure in the rear tires.
Many have suggested that a rear drag bar will greatly help my situation however since I don't drag race all the time, I would ask if there are ones that can be easily removed and reinstalled in prep for a track day?
Any help and guidance would be greatly appreciated.
97 TA Convertible - 4085lbs with me in it.
700+rwhp
Procharger F1-A
Tick Lvl 3 T56
McLeod Street Twin
S60
Tires: Track - 27x10.5 Hoosier QTP - Ran them around 14-16psi hot / Front - 15x4 Hoosiers
Suspension
Front - Strange DA Coilovers - 300lb spring / Stock sway bar
Rear - QA1 DA / Stock TA Springs / UMI - 22mm sway bar, Adj LCAs w/ reloc brackets, Chassis mount torque arm, panhard bar.
I tried slipping the clutch and also letting it out quickly (not dumping) but I would still spin if I had the launch RPM above say 3500 or so. I likely should have disconnected the front sway bar and perhaps dropped the pressure in the rear tires.
Many have suggested that a rear drag bar will greatly help my situation however since I don't drag race all the time, I would ask if there are ones that can be easily removed and reinstalled in prep for a track day?
Any help and guidance would be greatly appreciated.
01-28-2013, 09:46 AM
#4
Remove the front sway bar first. Lower pressure to around 12-14psi, but the most important thing in my opinion is shock settings and launch RPM. You need to raise the launch RPM to at least 5500rpm or so and get the suspension dialed in with your shock settings and rear anti-squat/instant center values.
01-28-2013, 07:47 PM
#6
Where do you have the shocks set?
Stock springs ok.
Remove front sway.
Relo's on lowest hole?
Torque arm nose as high as possible?
Once you get hooking a little better with shock tuning and the tire pressure adjustments, you can take a look at the drag bar. Right now your car isn't launching hard enough to launch crooked, I'd imagine. Your car certainly has enough power and potential to benefit from the drag bars ability to provide a nice flat launch.
You can drive on the street reasonably comfortably with the drag bar as long as you remember it's not a handling bar and will hang the rear immediately upon throttle on.
Take good notes at the track. Notes are a valuable tuning tool.
Stock springs ok.
Remove front sway.
Relo's on lowest hole?
Torque arm nose as high as possible?
Once you get hooking a little better with shock tuning and the tire pressure adjustments, you can take a look at the drag bar. Right now your car isn't launching hard enough to launch crooked, I'd imagine. Your car certainly has enough power and potential to benefit from the drag bars ability to provide a nice flat launch.
You can drive on the street reasonably comfortably with the drag bar as long as you remember it's not a handling bar and will hang the rear immediately upon throttle on.
Take good notes at the track. Notes are a valuable tuning tool.
01-28-2013, 09:12 PM
#7
Where do you have the shocks set? fronts were loose on rebound, compression firm. Rears were the opposite. I def should take notes next time.
Stock springs ok. OK
Remove front sway. OK
Relo's on lowest hole? Middle hole. Would lowest be best for the track, middle for the street? Or would just using the lower be fine?
Torque arm nose as high as possible? have to check but believe so.
Once you get hooking a little better with shock tuning and the tire pressure adjustments, you can take a look at the drag bar. Right now your car isn't launching hard enough to launch crooked, I'd imagine. Your car certainly has enough power and potential to benefit from the drag bars ability to provide a nice flat launch.
You can drive on the street reasonably comfortably with the drag bar as long as you remember it's not a handling bar and will hang the rear immediately upon throttle on.
Take good notes at the track. Notes are a valuable tuning tool.
Stock springs ok. OK
Remove front sway. OK
Relo's on lowest hole? Middle hole. Would lowest be best for the track, middle for the street? Or would just using the lower be fine?
Torque arm nose as high as possible? have to check but believe so.
Once you get hooking a little better with shock tuning and the tire pressure adjustments, you can take a look at the drag bar. Right now your car isn't launching hard enough to launch crooked, I'd imagine. Your car certainly has enough power and potential to benefit from the drag bars ability to provide a nice flat launch.
You can drive on the street reasonably comfortably with the drag bar as long as you remember it's not a handling bar and will hang the rear immediately upon throttle on.
Take good notes at the track. Notes are a valuable tuning tool.
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01-28-2013, 09:46 PM
#8
Are the rear DA QA1's 12 or 18 position and do you know which clicks each adjuster is on?
The drag bar links attach to the chassis with a special bracket and stud whereas the 22mm attaches with factory style end links. The bar itself would be quickly interchangeable but the endlinks throw a wrench in it.
You can try the lowest hole on the relo's no problem.
Front shocks sound ok.
The drag bar links attach to the chassis with a special bracket and stud whereas the 22mm attaches with factory style end links. The bar itself would be quickly interchangeable but the endlinks throw a wrench in it.
You can try the lowest hole on the relo's no problem.
Front shocks sound ok.
01-29-2013, 05:34 AM
#9
Are the rear DA QA1's 12 or 18 position and do you know which clicks each adjuster is on?
The drag bar links attach to the chassis with a special bracket and stud whereas the 22mm attaches with factory style end links. The bar itself would be quickly interchangeable but the endlinks throw a wrench in it.
You can try the lowest hole on the relo's no problem.
Front shocks sound ok.
The drag bar links attach to the chassis with a special bracket and stud whereas the 22mm attaches with factory style end links. The bar itself would be quickly interchangeable but the endlinks throw a wrench in it.
You can try the lowest hole on the relo's no problem.
Front shocks sound ok.
So lowest hole on the relo and leave it for street and track driving?
Guess I will need to think harder about the rear drag bar.
01-29-2013, 09:43 AM
#10
The rear drag bar isn't going to make it go any faster. The shock settings, the location of the LCA's and front of the torque arm, and the rpm you launch the car at will.
Here is what I would do for a baseline:
-LCA's in lowest hole
-Torque arm in highest hole
-Front compression setting one click off of full tight
-Front rebound setting 4 clicks from full loose
-Rear compression setting 6 clicks from full loose
-Rear rebound setting 12 clicks from full loose
-Raise the launch rpm to 5500rpm
-Tires at 14psi to start
Now, a slick tired 6 spd. car needs to slip the tire off the line, hell any slick tired car needs to do this. You want to turn the tire over almost 2 full revolutions in a perfect world before the car moves. If it does this on those settings, tighten the front rebound setting one click at a time from there out until it either blows the tires off or slows down. If it slows down or spins too much go back to the setting that worked best. If it completely dead hooks the tire and does not slip or spin, does not break anything and does not stand itself on the rear bumper or try to, add some tire pressure and/or tighten the rear rebound setting and front rebound setting one click until it does.
If it spins excessively off the starting line on those settings and launch rpm then you need to loosen the front rebound setting and the rear rebound setting one click at a time and lower tire pressure 1psi until it hooks and just barely slips the tire off the line.
If it wads the tire up excessively and shakes, tighten the rear compression setting one click at a time until it doesn't. ALWAYS leave the front compression setting on full tight or in this case one click off of full tight. Since you have a 6 spd. car where the nose is going to drop during every shift, the tighter the front compression setting is the less the nose will drop after it transfers weight and gets that nose up in the air. This keeps weight on the rear tires for better traction and doesn't allow it to fall down as much or as quickly once transferred.
The best thing you can do is get a guy to video the rear tire and rear suspension from the side and then play it back in slow motion in the pits to see what it was doing. What you'll want to see is the rear tires separate away from the body of the car during the launch and the front end rise up at the same time to where as soon as the front end lifts up and transfers weight to the rear tires and gives it a sort of nose up look, the rear end is separating at that same instance pushing the rear of the body up and away from the car and planting the tire into the ground basically leveling the car back out. That is what I consider a perfect launch where the car goes slightly nose up for just a split second and then the rear separates and levels everything out.
Wheels up looks cool, but it's not as fast as being controlled and level. Also you don't want the rear end to squat, period. Hope this helps you out some!
Here is what I would do for a baseline:
-LCA's in lowest hole
-Torque arm in highest hole
-Front compression setting one click off of full tight
-Front rebound setting 4 clicks from full loose
-Rear compression setting 6 clicks from full loose
-Rear rebound setting 12 clicks from full loose
-Raise the launch rpm to 5500rpm
-Tires at 14psi to start
Now, a slick tired 6 spd. car needs to slip the tire off the line, hell any slick tired car needs to do this. You want to turn the tire over almost 2 full revolutions in a perfect world before the car moves. If it does this on those settings, tighten the front rebound setting one click at a time from there out until it either blows the tires off or slows down. If it slows down or spins too much go back to the setting that worked best. If it completely dead hooks the tire and does not slip or spin, does not break anything and does not stand itself on the rear bumper or try to, add some tire pressure and/or tighten the rear rebound setting and front rebound setting one click until it does.
If it spins excessively off the starting line on those settings and launch rpm then you need to loosen the front rebound setting and the rear rebound setting one click at a time and lower tire pressure 1psi until it hooks and just barely slips the tire off the line.
If it wads the tire up excessively and shakes, tighten the rear compression setting one click at a time until it doesn't. ALWAYS leave the front compression setting on full tight or in this case one click off of full tight. Since you have a 6 spd. car where the nose is going to drop during every shift, the tighter the front compression setting is the less the nose will drop after it transfers weight and gets that nose up in the air. This keeps weight on the rear tires for better traction and doesn't allow it to fall down as much or as quickly once transferred.
The best thing you can do is get a guy to video the rear tire and rear suspension from the side and then play it back in slow motion in the pits to see what it was doing. What you'll want to see is the rear tires separate away from the body of the car during the launch and the front end rise up at the same time to where as soon as the front end lifts up and transfers weight to the rear tires and gives it a sort of nose up look, the rear end is separating at that same instance pushing the rear of the body up and away from the car and planting the tire into the ground basically leveling the car back out. That is what I consider a perfect launch where the car goes slightly nose up for just a split second and then the rear separates and levels everything out.
Wheels up looks cool, but it's not as fast as being controlled and level. Also you don't want the rear end to squat, period. Hope this helps you out some!
01-29-2013, 10:57 AM
#11
The rear drag bar isn't going to make it go any faster. The shock settings, the location of the LCA's and front of the torque arm, and the rpm you launch the car at will.
Here is what I would do for a baseline:
-LCA's in lowest hole
-Torque arm in highest hole
-Front compression setting one click off of full tight
-Front rebound setting 4 clicks from full loose
-Rear compression setting 6 clicks from full loose
-Rear rebound setting 12 clicks from full loose
-Raise the launch rpm to 5500rpm
-Tires at 14psi to start
Now, a slick tired 6 spd. car needs to slip the tire off the line, hell any slick tired car needs to do this. You want to turn the tire over almost 2 full revolutions in a perfect world before the car moves. If it does this on those settings, tighten the front rebound setting one click at a time from there out until it either blows the tires off or slows down. If it slows down or spins too much go back to the setting that worked best. If it completely dead hooks the tire and does not slip or spin, does not break anything and does not stand itself on the rear bumper or try to, add some tire pressure and/or tighten the rear rebound setting and front rebound setting one click until it does.
If it spins excessively off the starting line on those settings and launch rpm then you need to loosen the front rebound setting and the rear rebound setting one click at a time and lower tire pressure 1psi until it hooks and just barely slips the tire off the line.
If it wads the tire up excessively and shakes, tighten the rear compression setting one click at a time until it doesn't. ALWAYS leave the front compression setting on full tight or in this case one click off of full tight. Since you have a 6 spd. car where the nose is going to drop during every shift, the tighter the front compression setting is the less the nose will drop after it transfers weight and gets that nose up in the air. This keeps weight on the rear tires for better traction and doesn't allow it to fall down as much or as quickly once transferred.
The best thing you can do is get a guy to video the rear tire and rear suspension from the side and then play it back in slow motion in the pits to see what it was doing. What you'll want to see is the rear tires separate away from the body of the car during the launch and the front end rise up at the same time to where as soon as the front end lifts up and transfers weight to the rear tires and gives it a sort of nose up look, the rear end is separating at that same instance pushing the rear of the body up and away from the car and planting the tire into the ground basically leveling the car back out. That is what I consider a perfect launch where the car goes slightly nose up for just a split second and then the rear separates and levels everything out.
Wheels up looks cool, but it's not as fast as being controlled and level. Also you don't want the rear end to squat, period. Hope this helps you out some!
Here is what I would do for a baseline:
-LCA's in lowest hole
-Torque arm in highest hole
-Front compression setting one click off of full tight
-Front rebound setting 4 clicks from full loose
-Rear compression setting 6 clicks from full loose
-Rear rebound setting 12 clicks from full loose
-Raise the launch rpm to 5500rpm
-Tires at 14psi to start
Now, a slick tired 6 spd. car needs to slip the tire off the line, hell any slick tired car needs to do this. You want to turn the tire over almost 2 full revolutions in a perfect world before the car moves. If it does this on those settings, tighten the front rebound setting one click at a time from there out until it either blows the tires off or slows down. If it slows down or spins too much go back to the setting that worked best. If it completely dead hooks the tire and does not slip or spin, does not break anything and does not stand itself on the rear bumper or try to, add some tire pressure and/or tighten the rear rebound setting and front rebound setting one click until it does.
If it spins excessively off the starting line on those settings and launch rpm then you need to loosen the front rebound setting and the rear rebound setting one click at a time and lower tire pressure 1psi until it hooks and just barely slips the tire off the line.
If it wads the tire up excessively and shakes, tighten the rear compression setting one click at a time until it doesn't. ALWAYS leave the front compression setting on full tight or in this case one click off of full tight. Since you have a 6 spd. car where the nose is going to drop during every shift, the tighter the front compression setting is the less the nose will drop after it transfers weight and gets that nose up in the air. This keeps weight on the rear tires for better traction and doesn't allow it to fall down as much or as quickly once transferred.
The best thing you can do is get a guy to video the rear tire and rear suspension from the side and then play it back in slow motion in the pits to see what it was doing. What you'll want to see is the rear tires separate away from the body of the car during the launch and the front end rise up at the same time to where as soon as the front end lifts up and transfers weight to the rear tires and gives it a sort of nose up look, the rear end is separating at that same instance pushing the rear of the body up and away from the car and planting the tire into the ground basically leveling the car back out. That is what I consider a perfect launch where the car goes slightly nose up for just a split second and then the rear separates and levels everything out.
Wheels up looks cool, but it's not as fast as being controlled and level. Also you don't want the rear end to squat, period. Hope this helps you out some!
After all that and some video footage you can decide if a drag bar is necessary. Once it's hooking well you may benefit.
01-30-2013, 08:14 AM
#13
No problem...try it out and keep the thread updated and if you can, I'm telling you video tape the launch and play it back in slow motion. It will allow you to be able to see exactly what the car is doing. You'll be amazed how much E.T. you can drop off with a 1.4x or even a 1.3x 60'.
Main thing is getting as much power in as early as possible. Since we race 1/8th mile around here, we don't have an extra 1/8th mile to make up E.T. or MPH on the back end. I learned how to set up the suspension on my car when it was cam-only and then nitrous. With that type of engine combination you HAVE to get it all in as early as you can. If you don't...you'll never run the E.T. you're after.
It will come in time, just take the tips I gave ya and put em' to good use!
Main thing is getting as much power in as early as possible. Since we race 1/8th mile around here, we don't have an extra 1/8th mile to make up E.T. or MPH on the back end. I learned how to set up the suspension on my car when it was cam-only and then nitrous. With that type of engine combination you HAVE to get it all in as early as you can. If you don't...you'll never run the E.T. you're after.
It will come in time, just take the tips I gave ya and put em' to good use!
