SL/R230: Roll Bar Picture
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MBWorld Fanatic!
Joined: Aug 2004
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From: Tallahassee, Florida
2006 SL600, 2001 S500, 1996 SL320
What for
I am going to a track that has mentioned all kinds of NHRA rules and one talks about the roll bar and convertibles. Don't know if they will allow me to run or not.
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Thread Starter
MBWorld Fanatic!
Joined: Aug 2004
Posts: 1,875
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From: Tallahassee, Florida
2006 SL600, 2001 S500, 1996 SL320
No No No
Originally Posted by ricky.agrawal
Good luck.
Hopefully they'll let you, I can only suspect that the extra weight over the rear wheels is a good thing for traction.
Hopefully they'll let you, I can only suspect that the extra weight over the rear wheels is a good thing for traction.
A roll bar will be mandatory in any full-bodied car running 11.00-11.49, or convertibles running 11.00-13.49 or dune buggy type vehicles running 12.00 &slower. Permitted in all cars. All cars must have neutral safety switch and reverse lockout. 3" Driver restraint system meeting SFI spec 16.1 mandatory if roll bar or roll cage is required.
Does or SL meet these requirements?
3" driver restraint????
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Joined: Oct 2004
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Originally Posted by StephenK
They may not let me run period. Top up or down. I am curious what others have run into with this.
A roll bar will be mandatory in any full-bodied car running 11.00-11.49, or convertibles running 11.00-13.49 or dune buggy type vehicles running 12.00 &slower. Permitted in all cars. All cars must have neutral safety switch and reverse lockout. 3" Driver restraint system meeting SFI spec 16.1 mandatory if roll bar or roll cage is required.
Does or SL meet these requirements?
3" driver restraint????
A roll bar will be mandatory in any full-bodied car running 11.00-11.49, or convertibles running 11.00-13.49 or dune buggy type vehicles running 12.00 &slower. Permitted in all cars. All cars must have neutral safety switch and reverse lockout. 3" Driver restraint system meeting SFI spec 16.1 mandatory if roll bar or roll cage is required.
Does or SL meet these requirements?
3" driver restraint????
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From: Orlando, FL
g
A guy with an SL65 had the same problem here at Bithlo. They said that he had to have a roll cage to run in the 11's. He tried to argue the point about the roll bar... they asked him to leave. I think it was in Automoblie Mag a while back 
It could depend from track to track depending on how lenient they are on their policies.
And with the top down isn't the drag coefficient increased by a fair amount?
It could depend from track to track depending on how lenient they are on their policies.
And with the top down isn't the drag coefficient increased by a fair amount?
Out Of Control!!
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I wouldn't think so. Isn't drag coefficent how much frontal area you have? I think putting the top up, or down wouldn't change that.
I guess though, there would be more air turbulence from the air not flowing smoothly over the car. I honestly have no idea.
I guess though, there would be more air turbulence from the air not flowing smoothly over the car. I honestly have no idea.
Senior Member
Joined: Jun 2004
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From: Central California Coast
2004 SL55, 2005 E500 Wagon
Originally Posted by ricky.agrawal
Isn't drag coefficent how much frontal area you have?
Cd = D/Ds
The drag coefficient is a measure of how slippery a car is compared to other cars of the same frontal area. Putting down the top doesn't change the frontal area, but it does change (increase) the drag and the drag coefficient.
Jim
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Originally Posted by CASL55
Drag coefficient is drag normalized to (divided by) the drag for a standard idealized shape of the same frontal area that brings all impinging air to a halt. The shape is a bit slipperier than a flat plate.
Cd = D/Ds
The drag coefficient is a measure of how slippery a car is compared to other cars of the same frontal area. Putting down the top doesn't change the frontal area, but it does change (increase) the drag and the drag coefficient.
Jim
Cd = D/Ds
The drag coefficient is a measure of how slippery a car is compared to other cars of the same frontal area. Putting down the top doesn't change the frontal area, but it does change (increase) the drag and the drag coefficient.
Jim
Senior Member
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From: Central California Coast
2004 SL55, 2005 E500 Wagon
Originally Posted by ricky.agrawal
Do you think it'll have a very severe effect on the 1/4 times, maybe enough to offset the advantage of extra weight (therfore traction) during launch?
That said, let me hazard an educated guess. I'm surmising that the part (in time, let alone distance) of the 1/4 that's limited by traction is much less than than the part that isn't. I also surmise that the dynamic transfer of weight to the rear of the car will be lower with the top down, since lowering the top will lower the center of mass of the vehicle. So the gain in static rear wheel weight will be at least partially offset by a loss in dynamic rear wheel force. But there will be more drag thoughout the run. I'd guess lowering the top wouldn't help 1/4 times. But I could easily be wrong.
One thing that will help is putting the driver's and passenger's seats all the way back, if the driver's feet can still reach the pedals.
Jim
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From: Ladera Ranch (i.e CaucAsia)
2005 SL600 Designo, Graphite Gray, Panorama Roof
Originally Posted by lorinserbenz
I think the 3" restraint is refering to a "3 Point" seat belt.
Readily available from Sparco, but it usually requires drilling to mount the anchor points, or at the very least, removal of the factory seat belts to use those mounting points (not practical in many cars).
And no, our roll bars do not constitute NHRA-legal roll bars. There's not enough "points," which simply described is the number of bars making contact with the car's chassis/floor.
We need something like this:
http://rds.yahoo.com/S=96062883/K=4+...ampics/33b.jpg
It's possible to make one, but it'd take alot of interior dissassembly and surgery to get it in, plus, the factory roll bar would need to be disabled or removed and overall, it's ugly.
My advice? Wait till all yoru mods are done, run as many passes as they let you till you're kicked off...then find another track.
