Zoomspeed

I may be getting some drag radials before I goto the track this week.

How do I launch with drag radials?
with drag radials how long am I suppsoe to burn out?
Am I suppsoe to go through or around the water box?

I'm still a newbie, only been to the track one time so far, so any other info would be cool too.

Thanks

Cetchup

dont use the water box. With drag radials you will bring water up the track with you, and that is a bad thing...

Import Convert

only use the water box with slicks

martini

drive AROUND the water box, not through it. and yes, do a burnout (on the dry burnout box) to get your tires warmed up.

jimlab

Actually, that's not precisely true...

If you have street radials, there's no use doing a burn out because your tires won't hold the heat (stay sticky). With the complicated tread patterns, you will bring water with you to the starting line and reduce your traction, so avoid the water box.

With drag radials, the tread patterns are much simpler, and if you're going to do a burn out (and you should), you DO use the water box. The water box is there to save your drivetrain by reducing the strain of getting the tires spinning, especially with big slicks.

If they have a debris barrier behind the water box, drive around it and then straighten the car out. Typically a track official will direct you to back up towards the water box, dip your tires, and then motion you forward just out of the box for your burn out. If there isn't a barrier, drive straight through, and watch the track official for instructions.

You'll quickly eliminate the water with your burnout if you hold for a good 5-10 seconds. The first pass on drag radials, I would do a ~10 second burn out, shifting into 2nd gear to get more tire speed (and save the engine), and then let up on the brake and let the car "come out of the hole" on its own, letting off the throttle. Don't dry hop the car on the way to the line, it isn't necessary. Only newbies dry hop.

On subsequent passes, I only did a ~4-5 second burnout just to heat the tires up a little and clean them off. If you do massive burn outs each time, you'll quickly eliminate the traction the tires afford by over heating them. The oils in the rubber will come to the surface in excess, making the tires slippery instead of sticky. You'll also heat cycle the rubber too much, and they'll wear out much more quickly.

Some people recommend dropping air pressure into the high teens to low 20s, but you'll have to find your own magic combination. Start with ~25 psi or so and go down a couple psi from there until you find what works. If you have to drive an extended distance after drag racing and there isn't a service station in the immediate vicinity and the track doesn't have air, invest in a portable air station to air up the tires so that you don't drive on them "flat".

Your launch will depend on your power and what the tires will hold. You'll have to experiment with that too, until you find what works. Start lower in rpm and if the car bogs off the line when you dump the clutch, raise your rpm until it doesn't. Keep raising it until you blow the tires away on the launch, and on the next run you'll have a good idea of where to let go. Or, you can slip the clutch at a higher rpm and ease into full throttle, but this is obviously hard on the clutch.

Hope that helps.

jimlab

Actually, I should revise that a little. The track may not want you going through the water box with drag radials, so follow track rules. However, I do recommend using the water box if you want to save unnecessary wear and tear on your car.

Doing a dry burn out on the street and doing a dry burn out on the launch pad of a drag strip are two completely different things. The drag strip launch pad is concrete, usually with built up rubber residue if they don't clean it periodically, and has likely been treated with VHT or another traction "adhesive" spray at one time or another, probably repeatedly. Doing a dry burn out on that surface is very hard on the car. It can be done, but you're better off avoiding it if possible.

Zoomspeed

thanks for the info.

If I get these, I'll be getting kumho V700 drag radials and my mods are in my sig if that helps any.

So for the launch wat RPM should I start experimneting at?

jimlab

The RX-7 doesn't have enough low end torque to carry a launch from low rpm without bogging, so you'll have to start around ~2,500 rpm, probably, and see what happens. If it bogs, move up. If it spins, move down, or ease into it by slipping the clutch. Whatever nets you the quickest 60 ft. times.

Zoomspeed

thnaks for all the help jimlab, you sure did alot of typing.

The last time I was at the track (last summer) I only got to run 2 times, and I got no secondary boost with no time slpis, so I don't know how well I did.

So, this is still pretty much gonna be my first time, I'm not expecting to do well, I'll be happy if I get a low 14.

NickSimcheck

Jim basicly covered everything but I would like to point one more thing out... ALWAYS roll out! If you don't you'll tear up your rearend. Have fun at the strip!

Nick

martini

Every drag strip I've been to (which, admitedly, is only two), has enough room in the burnout box (not the launch pad) between the water and the lauch pad (even the part of the launch pad for the long funny cars). Thought this could be because I mostly just attend the import events, and the track officials don't exactly care much about the import people, and may be insufficiently watering the box.

I usually pull around the water box, straighten the car out, back up to just in front of the wet spot, and clean off my tires.

jimlab

You're right, there is space between the water "box" and the actual launch area for burn outs, but all the cars with slicks are doing their burn outs there, and most of the serious drivers treat their tires. It's pretty sticky, even between the water box and the "launch" section, if you've ever walked it. If you have drag radials and they've already been heated, you'll really be stressing the car to get them spinning without a little water.

You may drop from a high enough rpm that you get the tires spinning first thing, but that's not an option for the automatic cars, and once again, its hard on the car. The differential mounts and PPF don't appreciate it, that's for sure.

jimlab

That's why I said "and then let up on the brake and let the car "come out of the hole" on its own, letting off the throttle." above.

More likely it will just kill the engine, and the only thing that will suffer is pride...

Zoomspeed

Man I hope I that doesn't ahppen to me. thanks for all the help guys, hopefully I can pull some decent times.

RedFD

This is probably a stupid question.... but are you supposed to use the brake while burning out? I never do.. and i dont understand how that would work.

NickSimcheck

Oops, sorry duble post.


Mods: DELETE THIS POST

NickSimcheck

I'm not sure about Mazda rearends but in any posi rear it will burn the clutch up. I know you already said you should roll out but I was just stressing the point.

Zoomspeed

yes, I think you ahve to sue the brakes unles you have a line lock. At least thats what I had to do last time I went.

jimlab

To hold the car in place for the burn out, you'll either have to "sidestep" the brakes (get on the brake quickly after you get the tires spinning, and hold them just enough to keep the car from moving) if you have a manual transmission or hold the brakes and do a "power brake" by flooring the gas pedal if you have an automatic. Both of these methods will wear the rear brake pads more quickly and create quite a bit of heat in the braking system, but they work.

Ideally, a line lock should be used to allow you to lock the front brakes only and allow the rear tires to spin without pulling against the brakes. A line lock is a solenoid which holds pressure in the brake lines even after the brake pedal is released, while the actuating button is held down. If you hold the brakes, push the button to lock the fronts, and then pump the brake pedal a couple times, you'll get maximum held pressure in the front, and none in the rear, which is perfect. They cost about $80-120 and you can find them at JEGS, Summit Racing, or other vendors.

You can't just floor the gas pedal after dropping the clutch and let the car move, because you'll likely be disqualified if you pass the starting line and don't have a 9-second (or quicker) car, and there will likely be a track official who will be pretty ticked off that he had to jump out of the way. You need to hold the car in one place and do a controlled burn out after the track official signals you that it's OK to begin, and let off on the brakes while the tires are still spinning. The car will hook and jump forward, "coming out of the hole", and you let off the throttle so that your momentum will die before you reach the starting line.

Ease forward to the starting line and inch forward until you light the yellow "pre-stage" bulbs on the tree. Creep forward until the yellow "stage" bulbs are lit, and you're ready to go. Don't worry about what your oponent is doing, unless he gets to the line first and you're competing against him. If he staged first, when you break the beam to illuminate the stage bulbs on your side, the tree may start the countdown very quickly, so be prepared.

However, if it's not a competitive race, forget the tree and just launch whenever you feel like it after the light turns green, or before, if you don't care. A red light won't stop the track sensors from timing your run, and if you're not concerned with reaction time and just trying to get your launch down, a red light doesn't matter. Or, you can just "sit" and take your time, and concentrate on perfecting your launch after the green bulb has illuminated. It takes the stress out of the situation if you ignore the other driver and just work on your own fundamentals.

lane_change

iTrader: (20)

My biggest problem while doing a burnout was that my car wanted to roll through my brakes and it would start tracking sideways which made getting out of it alot tougher because I was facing the wrong direction sort of. I think I need new brakes. It is all new to me as well since I came from a 97 GSX so the waterbox was a no-no place and I never had to do a burnout so I am still learning. Do you guys have both the brake and clutch held down with the same foot and then let off the clutch or do you just get off the clutch and then press down the brakes? I tried both ways and ended up with the same result. I need to practice more but I don't want to just do burnouts in town. Thanks

Zoomspeed

to do a burn out I just rev the engine up, drop the clutch and and quickly stomp on the brake while holding the throttle as well.

SWEET!! I just realized I'm over a 1000 posts. My avatar says I have no life (how true)