Misc. questions for experienced DragRacers (car insurance, vehicles, idle, convertibles)
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I have some questions on things which ive been curious about and id appreciate it if you experienced Racers can help :
1. If a particular cars maximum torque occurs at 4,000 rpms, is this the rpms that you want to shift at ?
2. When a car that has nitrous is getting ready to launch, is the nitrous energized at this time , or, afterward ?
3. At what level does a car require interior roll bars ?
4. Why dont the front end on Dragsters lift everytime , given the miniscule weight up front ?
5. If a terrible accident occurs whereby the DragRacers car goes into the stands and kills someone, whos Insurance comes into play : The Track or the DragRacers ?
6. Have you ever totally lost control on a run ? What happened ?
yes
2 Nitrous is a complicated science, to involved to explain here. check this Nitrous Oxide Injection F.A.Q.
3 Different speeds attained designate if and what type of roll bar is required. Look.! NHRA-legal Roll Bar - Crankshaft Coalition Wiki
4. The perfect run is getting the engine combination, clutch, tires, etc, set up for the optimum coefficient of friction, which means the front end lifts very little. Pulling the front end hurts ET's. You want to achieve mimimum tire slip, and mimimum front wheel lift. Many different factors can cause wheel stands, none of which are a good thing. In the perfect storm, dragsters can flip completely over. It was not uncommon in the early days. Today they have wheelie bars to prevent to much front wheel lift.
Go to NHRA.com and learn all about drag racing. We're right in the middle of the '08 NHRA drag racing season, watch for the races on most Sundays. No races this weekend.
2008*NHRA POWERade Drag Racing Series television schedule (http://www.nhra.com/tvschedule.asp?y=2008&s=POWERade - broken link)
I have some questions on things which ive been curious about and id appreciate it if you experienced Racers can help :
1. If a particular cars maximum torque occurs at 4,000 rpms, is this the rpms that you want to shift at ?
2. When a car that has nitrous is getting ready to launch, is the nitrous energized at this time , or, afterward ?
3. At what level does a car require interior roll bars ?
4. Why dont the front end on Dragsters lift everytime , given the miniscule weight up front ?
5. If a terrible accident occurs whereby the DragRacers car goes into the stands and kills someone, whos Insurance comes into play : The Track or the DragRacers ?
6. Have you ever totally lost control on a run ? What happened ?
Thanks for your time.
I'll try to make this less than 10 pages. Some of this can get complicated
1. Shifting is normally done according to HP curve not torque. Drag racing vehicles are light enough that torque is not critical. Shift point would depend on HP curve of engine. Look at it like this. Lets assume curve is linear. 100HP @ 1000 RPM 200HP @ 2000, 300 @ 3000, 4000 @ 4000. Than it starts to drop 300 @ 5000, 200 @ 6000. If you reach 4000 and shift where will it drop to. If it drops 1000 rpm you would be better off shifting @ 4500. It would slowly fall off and when you do shift it will be close to peak HP.
2 Nitrous is purged before race starts to remove any liquid nitrous. Nitrous is not normally energized until car is moving. You can normally make enough HP to spin the tires without nitrous, Add it when it will produce forward motion not tire spin.
3 NHRA requires roll bar if your car is 11.49 or quicker, over 135 MPH or 9.99 or quicker requires a roll cage.
4 300" wheelbase and power application. Assuming you are talking about the cars you see on TV. The clutch management system is designed to keep engine speed constant while applying more clutch to increase speed. The long wheelbase applies leverage and that front wing is amazing effective over 100 MPH. Those cars are going that fast @ 60 ft.
5. Insurance is carried by track and organization holding race. Read the fine print on your ticket.
6. Left the starting line in my 53 Studebaker. It normally carried the front wheels for 40 -50 feet. When it came down the steering shaft had pulled out of the steering box. Car turned right and T-boned the car in the other lane. Car sustained damage to front end and subsequently suffered engine damage. Eight thousand dollars (out of my pocket) and many hours later it reappeared, lighter, better looking, more powerful and faster.
As an addendum to #5. Todays tracks and cars have safety features that make driver injuries rare. Spectator injuries are even less likely. Engines and transmissions are enclosed in blankets designed to keep pieces contained. Concrete guard rails are shaped to keep cars on racing surface. Drag racing vehicles have momentum going the direction of the track, not turning and striking walls at right angles.
Last edited by studedude; 05-22-2008 at 06:53 PM..
The answer for #2 ; NOS is generally used when the engine is pulling a load, 2nd or 3rd gear in many cases. That is what I did. Answer to #4; Looking at a dragster an average person would not know it but the rail is NOT SQUARE. This was the case with my rail. I had a 180 in wheelbase VW dragster, frame built by a FUNNY CAR builder Steve Rhoades. The purpose for this is that on launch one front wheel hopes to still touch the pavement due to the high torque of the engine. Strange, the experts did not give you an answer to #4 before me. Owning one is the only way you would know that answer. Watch NHRA on Sat/Sun and observe the camera long shot on launch of the rails and you will see the front ends rise differently, one wheel higher then the other. Hope info helps. Steve
But what goes up, must come down....even if it is a little violent...
I think also for #4 not only do some cars have wheelie bars to keep the nose down, but also if you think about it, if the car did a huge wheel stand down the track, I would think that would mean increased wind drag on the non aerodynamic underbody which would mean lower times.
Wheel stands are IMO for show and for idiots that don't care if their car gets destroyed while riding on it's bumper or worse when it slams back down into the pavement. Just look at the above pics.
And if you get into an accident at a track, don't expect regular car insurance to cover it. Drag racing is very risky business.
No bad information anywhere here, but I can answer for the ametuer bracket racer perpective for #1 and #2:
1.) Shift to stay in the cars torque curve, which may vary based on type of trasmission you have, it may also vary from gear to gear. Keep in mind when you shift that your car then drops a couple thousand RPMs. i.e - your max torque is at 4,000, you shift from 2nd to 3rd at 6,000 RPM which brings you down to 3,000 RPM or so, below your torque curve but still a good compromise. You can bring sceince into it..or you can just play around with different shift RPM's and see what works right. Keep in mind your valve train limits, most small blocks don't like over 6000 RPM too much, after that you tend to experience valve float.
2.) Nitrous - I woudln't recommend engagin nitrous at launch unless you want melted pistons. One thing that happens is your RPM jumps above the safety level real quick, another thing is the cylinder pressure is too low. But, some racers have multi-level systems, etc.
3.) Additional info: For convertables with soft tops I think you need a rollbar for 13 seconds. You need a helmet for any car 13.99 and under (I've been kicked off several times for that, now I have one).
No bad information anywhere here, but I can answer for the ametuer bracket racer perpective for #1 and #2:
1.) Shift to stay in the cars torque curve, which may vary based on type of trasmission you have, it may also vary from gear to gear. Keep in mind when you shift that your car then drops a couple thousand RPMs. i.e - your max torque is at 4,000, you shift from 2nd to 3rd at 6,000 RPM which brings you down to 3,000 RPM or so, below your torque curve but still a good compromise. You can bring sceince into it..or you can just play around with different shift RPM's and see what works right. Keep in mind your valve train limits, most small blocks don't like over 6000 RPM too much, after that you tend to experience valve float.
2.) Nitrous - I woudln't recommend engagin nitrous at launch unless you want melted pistons. One thing that happens is your RPM jumps above the safety level real quick, another thing is the cylinder pressure is too low. But, some racers have multi-level systems, etc.
3.) Additional info: For convertables with soft tops I think you need a rollbar for 13 seconds. You need a helmet for any car 13.99 and under (I've been kicked off several times for that, now I have one).
Actually they lowered to 13.49 for convertibles this year. As factory cars get faster NHRA has had to change some times so people will not have to put a roll bar in a brandnew bone stock car.
On #3 NOS, I never had a problem with any piston melting as the power in the combustion area did a number on the rods, egg shaping them in 4, 1/4 mile passes on Sun. Mon AM I pulled heads/pistons and rods for inspection and had to resize bottom end of rods and replace with new Rod bearings which I normally did after every race day anyway. Small insurance. You can have a engine idleing, hit the NOS button and watch the tach jump to 6 grand in a sec. Wow, just loved the sound/performance. Steve
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