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12 hours ago, Justracing44 said:

Can someone explain the coil car. What exactly do they mean rather than bars? Also, is it to the point where teams will need a coil car, and a car on bars?

You are able to switch from bars to coils with pretty much any car, but now Bicknell - and I think Troyer as well - are building coil specific cars with no rack to switch to bars. 

Assuming you have a car with a rack, switching from coils to bars would take a night in the shop to do, it's not something you can do at the track - at least not properly. 

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You can go from bars to coils at the track if you setup and scale on coils at your shop first.

I agree it would be difficult to go from coils to bars at the track.

 

This happened back in the early 2000s for a while but then it went torsion bar for a long time. The shock technology is so good now I doubt bars will be used much at all in the near future.

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28 minutes ago, scottnorwood said:

The shock technology is so good now I doubt bars will be used much at all in the near future.

Just curious why shock technology affects the choice between bars and coils?

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For years coils were tried and attempted, some seen good results, years back Alan Johnson dominated a 100 lapper at Utica in a Jake spraker 1j car on coils, but they were tough to predict on rougher surfaces. The shock technology today makes a coil car much more controllable, and predictable. Coils are more “accurate” for lack of a better term, bars are so hard to keep consistent, but they are much more forgiving as well. We now have progressive springs, we stack springs in order to change rate at different areas of the track where shock travel speed is either higher or lower than average. Guys are changing shock valving at the racetrack and flat out understand them more than in the past. For a long time shocks were considered “fine tune” adjustments. It could take you from a 3rd place car to winning.....now they are one of the most advantageous adjustments, and can take you from winning to 15th in a hurry. Unfortunately these advancements have forced most teams to have a shock deal, and a 10k dyno in shop to be competitive, spring smashers will become a must have with the coils becoming the spring of choice. Fortunately it will cut back on cost being that most teams don’t get much more than a few weeks on a set of bars, that are 100-200 bucks a piece depending on brand. 

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2 hours ago, rpm72x said:

For years coils were tried and attempted, some seen good results, years back Alan Johnson dominated a 100 lapper at Utica in a Jake spraker 1j car on coils, but they were tough to predict on rougher surfaces. The shock technology today makes a coil car much more controllable, and predictable. Coils are more “accurate” for lack of a better term, bars are so hard to keep consistent, but they are much more forgiving as well. We now have progressive springs, we stack springs in order to change rate at different areas of the track where shock travel speed is either higher or lower than average. Guys are changing shock valving at the racetrack and flat out understand them more than in the past. For a long time shocks were considered “fine tune” adjustments. It could take you from a 3rd place car to winning.....now they are one of the most advantageous adjustments, and can take you from winning to 15th in a hurry. Unfortunately these advancements have forced most teams to have a shock deal, and a 10k dyno in shop to be competitive, spring smashers will become a must have with the coils becoming the spring of choice. Fortunately it will cut back on cost being that most teams don’t get much more than a few weeks on a set of bars, that are 100-200 bucks a piece depending on brand. 

We were changing our bars every 4 weekly races...

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4 minutes ago, DIRTCar97 said:

We were changing our bars every 4 weekly races...

Yea that’s the problem with them, every once in awhile you get a good set of bars that can last 8-10 events, but they are so hard to keep track of. There are a few torsion bar dynos out there, but almost all of them only check a bar on the compression side, which is not where the bar problems normally occur. I have only seen 1 myself, that rates the bar through the rebound side of the wrap as well. 

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18 hours ago, rpm72x said:

For years coils were tried and attempted, some seen good results, years back Alan Johnson dominated a 100 lapper at Utica in a Jake spraker 1j car on coils, but they were tough to predict on rougher surfaces. The shock technology today makes a coil car much more controllable, and predictable. Coils are more “accurate” for lack of a better term, bars are so hard to keep consistent, but they are much more forgiving as well. We now have progressive springs, we stack springs in order to change rate at different areas of the track where shock travel speed is either higher or lower than average. Guys are changing shock valving at the racetrack and flat out understand them more than in the past. For a long time shocks were considered “fine tune” adjustments. It could take you from a 3rd place car to winning.....now they are one of the most advantageous adjustments, and can take you from winning to 15th in a hurry. Unfortunately these advancements have forced most teams to have a shock deal, and a 10k dyno in shop to be competitive, spring smashers will become a must have with the coils becoming the spring of choice. Fortunately it will cut back on cost being that most teams don’t get much more than a few weeks on a set of bars, that are 100-200 bucks a piece depending on brand. 

agreed; that's a good explanation.

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One thing l don't understand. Hope its not a dumb comment here. How is it that a vw beetle from the 60's can have original bars in it and not sag yet aftermarket bars are junk/weak in a matter of weeks/months? The spring rate on a vw bar can't be that far off considering the weight of the car us probably less than a modern modified. The arm is a similar length and the length of the bar us similar too. They used that basic suspension for eons doing everything getting groceries to super high dollar guys pounding across the desert in the baja 500. If a dirt car bar cant last 300 laps how are these bars whether oem or aftermarket lasting 500 miles across the desert much less thousands and thousands of miles in other applications. I get that they have failures too but it seems like the mod/sprint failure rate is way out of whack compared to other guys that have used torsion bars for years also. Feel free to slam me if l'm a complete idiot lol 

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47 minutes ago, special k said:

One thing l don't understand. Hope its not a dumb comment here. How is it that a vw beetle from the 60's can have original bars in it and not sag yet aftermarket bars are junk/weak in a matter of weeks/months? The spring rate on a vw bar can't be that far off considering the weight of the car us probably less than a modern modified. The arm is a similar length and the length of the bar us similar too. They used that basic suspension for eons doing everything getting groceries to super high dollar guys pounding across the desert in the baja 500. If a dirt car bar cant last 300 laps how are these bars whether oem or aftermarket lasting 500 miles across the desert much less thousands and thousands of miles in other applications. I get that they have failures too but it seems like the mod/sprint failure rate is way out of whack compared to other guys that have used torsion bars for years also. Feel free to slam me if l'm a complete idiot lol 

A northeastern dirt modified puts out 8—10 times the torque of a Volkswagen. 

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58 minutes ago, special k said:

One thing l don't understand. Hope its not a dumb comment here. How is it that a vw beetle from the 60's can have original bars in it and not sag yet aftermarket bars are junk/weak in a matter of weeks/months? The spring rate on a vw bar can't be that far off considering the weight of the car us probably less than a modern modified. The arm is a similar length and the length of the bar us similar too. They used that basic suspension for eons doing everything getting groceries to super high dollar guys pounding across the desert in the baja 500. If a dirt car bar cant last 300 laps how are these bars whether oem or aftermarket lasting 500 miles across the desert much less thousands and thousands of miles in other applications. I get that they have failures too but it seems like the mod/sprint failure rate is way out of whack compared to other guys that have used torsion bars for years also. Feel free to slam me if l'm a complete idiot lol 

Your not an idiot in anyway....most likely the torsion bars in all the applications you mentioned weakened and or are no good long before they are no longer used. The bars being used in the Baja 500 may have lost 50lbs of rate in mile 5 but your not going to change them. In some applications bars provide for a stronger, more durable suspension design than coils. In our style racing, we typically run shorter races multiple times a week on reasonably consistent surfaces. The cars are on scales usually before each event, so noticing a difference in bar response while making adjustments, sag in ride height, abnormal movement of weight or strange driver feel will be more recognizable because of the constant monitoring of the bar. Our cars are heavy, with lots of power, if the tracks are rough in anyway that bar is getting a workout, a piece of spring steel has “memory” , each time you twist that steel it loses some...along with rate, usually somewhere midway through wrap, these changes in the torsion bar are hard to stop and harder to exactly determine. There have certainly been thousands of torsion bars replaced that were not bad, but it’s a variable that most teams would rather be safe than sorry about.

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Also, the bars used in a modified are extremely soft compared to a street car or baja vehicle, in other words much heavier and robust.

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2 hours ago, special k said:

One thing l don't understand. Hope its not a dumb comment here. How is it that a vw beetle from the 60's can have original bars in it and not sag yet aftermarket bars are junk/weak in a matter of weeks/months? The spring rate on a vw bar can't be that far off considering the weight of the car us probably less than a modern modified. The arm is a similar length and the length of the bar us similar too. They used that basic suspension for eons doing everything getting groceries to super high dollar guys pounding across the desert in the baja 500. If a dirt car bar cant last 300 laps how are these bars whether oem or aftermarket lasting 500 miles across the desert much less thousands and thousands of miles in other applications. I get that they have failures too but it seems like the mod/sprint failure rate is way out of whack compared to other guys that have used torsion bars for years also. Feel free to slam me if l'm a complete idiot lol 

Made in Germany vs Made in America

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7 hours ago, Josh Bayko said:

A northeastern dirt modified puts out 8—10 times the torque of a Volkswagen. 

The torsion bar doesn't transfer torque. It just holds the car up.

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6 hours ago, oilman said:

Also, the bars used in a modified are extremely soft compared to a street car or baja vehicle, in other words much heavier and robust.

Not too many race buggies are 2500lbs. Lighter cars equal lighter bars. I'm not hung up on dune buggies. It was just an example l used because they've used torsion bars for years and years. That being said a heavy car with light spring rates would be harder on bars. Thanks for the reply. 

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2 minutes ago, special k said:

The torsion bar doesn't transfer torque. It just holds the car up.

Yes and no.....while they do not exactly transfer power....any high horsepower heavy vehicle will be harder on suspension components than something lighter and far less powerful. 

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1 minute ago, rpm72x said:

Yes and no.....while they do not exactly transfer power....any high horsepower heavy vehicle will be harder on suspension components than something lighter and far less powerful. 

I knew it would be a grey area answer lol. The mod would cycle the bar more than others due to all the chassis pitch due to the soft suspension. But the torque should be irrelevant. 

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7 minutes ago, special k said:

I knew it would be a grey area answer lol. The mod would cycle the bar more than others due to all the chassis pitch due to the soft suspension. But the torque should be irrelevant. 

I understand where your coming from....

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6 hours ago, rpm72x said:

Your not an idiot in anyway....most likely the torsion bars in all the applications you mentioned weakened and or are no good long before they are no longer used. The bars being used in the Baja 500 may have lost 50lbs of rate in mile 5 but your not going to change them. In some applications bars provide for a stronger, more durable suspension design than coils. In our style racing, we typically run shorter races multiple times a week on reasonably consistent surfaces. The cars are on scales usually before each event, so noticing a difference in bar response while making adjustments, sag in ride height, abnormal movement of weight or strange driver feel will be more recognizable because of the constant monitoring of the bar. Our cars are heavy, with lots of power, if the tracks are rough in anyway that bar is getting a workout, a piece of spring steel has “memory” , each time you twist that steel it loses some...along with rate, usually somewhere midway through wrap, these changes in the torsion bar are hard to stop and harder to exactly determine. There have certainly been thousands of torsion bars replaced that were not bad, but it’s a variable that most teams would rather be safe than sorry about.

Thanks for the detailed answer. I'm thinking longer bars (think chev trucks or dodge car front bars) would be better for longevity but l think they might have slower rebound response. Going back to the vw world. The rear bars are relatively short and are a similar diameter to a modern race bar except they are solid. The fronts on the other hand are blades of steel clamped together. I'm assuming its so it can have a light rate and last a reasonable amount of time.

 

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Most guys are running solid bars here..atleast the guys left using them. They are anywhere from .900 to 1.00 inch bars. Some guys were using the Strange engineering gun drilled bars, but they seemed to be harder to judge for rate. A gun drilled bar has more spring memory because of the added external surface area, thus creating a stiffer spring rate out of the same diameter bar. 

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1 hour ago, rpm72x said:

Most guys are running solid bars here..atleast the guys left using them. They are anywhere from .900 to 1.00 inch bars. Some guys were using the Strange engineering gun drilled bars, but they seemed to be harder to judge for rate. A gun drilled bar has more spring memory because of the added external surface area, thus creating a stiffer spring rate out of the same diameter bar. 

Thanks for all the info on the subject. Ttyl8r

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There's a lot more to it than just coil springs, though the technology on them is more advanced than what it was when they were last "the hot setup". (FYI the night of Danny Johnson's come from last victory at Rolling Wheels in our other car can be partially attributed to the fact that we wanted to try coil overs on the back of a car, but didn't want to change the car we had been running because of how good it ran). So anyway, along with coil overs, the panard rod has been moved to the left side and the rear radius rods have been shortened. Things are a little complicated right now, but basically they're trying to build rear roll steer into the cars similar to what the late models are doing. Right now there's a lot of experimentation going on to try and find out what the "hot setups" are with this style of rear suspension, but I think it will get simplified once things get sorted out more. The cars actually drive a little differently, it doesn't sound right to say you have to drive them "harder", but I guess that's the best way to explain it. 

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