Anonymous, Thanks for the reply. In another thread I saw where it was stated that this piece is setup a lot like a z-link coming off the pull bar to the right front. Now this rule states no floating, pivoting, or rotating mounts associated with the pull bar. I am unsure on the purpose of this piece, I would assume to pull the right front frame behind the tire/wheel "up" allowing to turn off the corner?
I have drawn out several designs and simulated the effects they would have on the performance of the race car. At the PRI show in Indy, Rodney Sanders car was there but there was NO cantilever pull bar on the car. I will say that the pull bar on that particular car was about six feet long. On that pull bar, there were 2 urethane bushing/coil spring torque link devices, one at each end. There was no mid plate on this chassis, which allowed room for that particular pull bar to attach up by the engine area on, towards the right side of the frame. The diameter of the pull bar itself was about 3 inches. It was something to see, I must say.Now to the tech part.A pull bar dampens the wrap of the rear end. Axle wrap is a result of torque that comes from the forward rotation of the tires. The amount of dampening is controlled by the torque link. If a solid bar is used, there would be no dampening, and the torque coming from the tires would be instantaneous upon the chassis, providing that the tires are not spinning. If the tires are spinning, the torque coming from the forward rotation of the tires would not promote much axle wrap. If properly used, a pull bar will help the rear tires maintain traction and give you more speed down the straightaways. In the corners, the attitude of the car is different than down the straights. We all know that. At entry, there is chassis dive. In the middle, the car is rolling upon its axis and the right side of the car is often lower to the track than the right side of the car, causing the suspension components to be in transition. And then there is exit, where the suspension again transitions to go down the straightaways. The idea, is to have enough dampening to prevent tire spin. If the tires spin, forward progress slows down and you lose some momentum as the car adjusts from traction, to slip, back to traction. First, you have to maintain traction. If the tires spin, you go no where fast. So keep the tires from spinning. That is the first step. Once that is established, you can progress into the other effects that a well configured pull bar can help you obtain. Most concentrate on preventing wheel spin and stop there. We cannot do that because the pull bar does much more than prevent wheel spin. When the tires are hooked up, the rate of pull causes the torque device to become bound, the pull bar then acts as a solid component. When this happens, the chassis will begin to lift vertically. The vertically lifting of the chassis causes the center of mass of the car to rise also. The center of mass does not move only vertically, it also moves rearward a little bit giving the car more rear percentage. The increase of percentage helps keep the rear tires firmly planted to the track so you can obtain maximum forward speed. When the driver slows the car for entry, the increased rear percentage begins to diminish, allowing the car to move back to the more balanced amount of weight distribution required for the car to go through the corner at its best potential to minimize loss of momentum. Now that we know that the pull bar will lift the chassis, we need to direct the loading gains/losses. If the pull bar runs down the center of the car,equally between the LR and RR with no lateral displacement, the loading gained from the chassis lift will be evenly distributed to the rear wheels. For instance, the chassis mount for the pull bar is more to the right of centerline, more weight will be taken from the RF of the car and put upon the rear wheels. Since the LF of the car naturally wants to lift due to the rear end walking up under the car, the RF becomes more loaded. The idea is to take away the added loading of the RF, to help keep BOTH FRONT WHEELS more equally loaded. The excess loading is then transferred to the rear wheels, helping them keep contact with the track and propel the car forward minimizing dreaded tire spin. When the driver slows for cornering, the loading transfers back to the front wheels, putting the percentages back where we want them, so the car is balanced through the corners.Thats how I see it.Look forward to the feedback from others out there that are trying to educate themselves and improve their racing programs. Those of you who want to stir the pot and cause teenage drama, please keep your comments to yourselves. Thanks Zach
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I also looked at Sanders car at PRI. We were there after hours and crawled under to look at that contraption of a pullbar he had on it. Our conclusion was it was a fake no functional piece put on just for PRI. We bounced the suspension and it never moved. It was ultimately a solid bar with a bunch of crap slid on it to make everyone wonder what it was. That was my take on it anyway.
He or someone else must have had something going on last year that called for a rules change / clarification.
8.8 Only one (1) mechanical traction device is permitted. Only one (1) pull bar or one (1) lift arm is permitted. No other options will be permitted.
8.8.1 Floating, pivoting and/or rotating mounts or brackets of any sort (connected or associated to the pull bar or lift arm) are not allowed.
8.8.2 Lift Arm is defined as solid steel triangulated bar that is connected at the top (with one heim) and bottom (with one heim) of the rear end housing, extending forward where it is connected to a shock (that may utilize only the heim directly related to that one shock (ONE ON EACH END), shock spring coil over combination (that may utilize only the heims directly related to that one shock (ONE ON EACH END) and a limiting chain (with or without a biscuit for cushion). Only one heim is permitted in this configuration. One stabilizer bar is permitted to locate the front of the lift arm from left to right in the car.
8.8.2 Pull Bar is defined as a continuous assembly (that may or may not contain a spring or biscuit assembly located in line to absorb torque) that is connected to the top of the rear end with one heim and extends forward to a solid mounting point located on the chassis where it is connected with one heim. The mounting location at both the front and rear of the pull bar may be adjustable but must remain constant during competition. Cannot be adjustable by driver during race.
I also looked at Sanders car at PRI. We were there after hours and crawled under to look at that contraption of a pullbar he had on it. Our conclusion was it was a fake no functional piece put on just for PRI. We bounced the suspension and it never moved. It was ultimately a solid bar with a bunch of crap slid on it to make everyone wonder what it was. That was my take on it anyway.
The pull bar on that car was a functional device. It can be obtained through Right Foot Performance Products.
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You will have to show me that one , because I cant seem to find what I looked at and had my hands on in there 2015 catalog, and it wasn't that Accell/Decel System stuff either.
You will have to show me that one , because I cant seem to find what I looked at and had my hands on in there 2015 catalog, and it wasn't that Accell/Decel System stuff either.
I have the catalog sitting by the computer at the house. When I get home I will provide the part #s
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Question, how is something legal in the pits, not legal once you hit the gas? The cars are only legal in the pits, my deck height and wheelbase are way off on the gas... How can something be legal in the pits but not on the track?
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can you all up date this wording as to why and what car ran it
Originally Posted by QQQQ
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