Torsion bars

[Matt49]

Obviously sprints use them and there is some debate in that world between torsion bars and coil-overs and I don't necessarily want to get into that debate. But I am curious if anyone has tried something like this on a late model or what people's thoughts are on why it would or would not work.

[Lizardracing]

I'd imagine someone smarter than me could make it work.
Torsion bars are more linear in rate than coil springs.

[MasterSbilt_Racer]

I'd imagine someone smarter than me could make it work.
Torsion bars are more linear in rate than coil springs.

The bar is, but geometry is what makes it non linear.

[JustAddDirt]

Dusty Chapman tried them in late 90’s at Brownstown and Twin Cities. I believe he modified a warrior chassis to use them. He was always thinking outside the box.

[Matt49]

Interesting...I know Dusty and have raced with him quite a bit. I'll have to ask him about his experience with it.

[JustAddDirt]

He and his father were pretty smart folks. Always trying something different.
Newer shock technology may lend a hand in getting it to work.
From what I remember they tried it on the rear. Not sure if they tried on the front.

[Brian Gray]

Was on one of Audie McWilliams cars a number of years ago. I actually know where the rear clip is believe it was on a early 2000 Rocket and if I not mistaken they made it illegal a number of years ago.

[Matt49]

I just found Lucas Oi rule 12.21.G. Springs must be made of steel. Torsion bars are not allowed in rear.
And UMP/WoO rule 15.10.A.2. Rear suspension must utilize either coil or leaf spring.

Neither say anything about the front. Now I'm really curious as to why that is.

[billetbirdcage]

I just found Lucas Oi rule 12.21.G. Springs must be made of steel. Torsion bars are not allowed in rear.
And UMP/WoO rule 15.10.A.2. Rear suspension must utilize either coil or leaf spring.

Neither say anything about the front. Now I'm really curious as to why that is.

It's been in most sanctioning bodies rules for as long as I can remember, that they were not allowed and that is going back to the early 90's. Most just said no torsion bars but like I said it did vary some.

[Dirtmod13]

I just found Lucas Oi rule 12.21.G. Springs must be made of steel. Torsion bars are not allowed in rear. And UMP/WoO rule 15.10.A.2. Rear suspension must utilize either coil or leaf spring.Neither say anything about the front. Now I'm really curious as to why that is.Probably because they were stock on the mopars from the factory. Pretty sure some old Chrysler guys tried running them when the old 70’s cars were actually a late model car.

[fastford]

i remember a guy running a Plymouth duster in street stock several years back , the stock duster bar was to soft so he took a newport bar, which was to stiff and kept turning it down on a lay some how till he got it where he wanted it , he won a few races with it.......

[Krooser]

We ran torsion bars at the old Waukegan Speedway back in the 60's when it was paved. Ran '57 to '64 Ford chassis... one car had four wheel bars the other just rears.

That was back when your innovations weren't hampered by tons of rules.

The cars were fast but not much faster than the guys on coil or coil/leaf suspensions. We had an 18" wide tire rule and those big meats made everybody quick if they had the horsepower. We ran big block Fords... the tunnel port 427 did blow away most of the Chevies but the guys I crewed with always broke something due to poor prep or maintenance.

The whole deal for us was trying to get the unsprung weight down... then we bolted on a 100# tire/wheel....

[Matt49]

Cool info, guys. Thanks!
My thoughts on it are more related to how it would "free up" the shocks to work a little more efficiently. From what I'm told (and I believe it), coil-overs put a certain amount of side load on the shocks and that creates unwanted drag inside the shock. Maybe I should just consider trying hydraulic spring perches rather than redesign an entire race car.

[JustAddDirt]

I would definitely go with the hydraulic spring perches. Before doing this definitely.
I am thinking of working on a Canti-lever 4 link. Get the spring off the birdcage.
I am a mod guy so nothing in my rules about it.(that I have ever seen)
I am going to definitely work on one for the rf shock.

[Mr.Kennedy777]

cantilever just on the left side?

[Matt49]

What I had drawn up is actually nothing like a sprint car torsion bar system but more like the way F1 does it. Using bell cranks where the center of the bell crank is on the torsion bar. To me, de-coupling the shock and spring is really something to think about. We talk on here quite a bit about how some of the pavement stuff is slowly adapted into dirt. I follow F1 closely as this is where the real "cheaters" are in terms of people looking to take advantages where the rules don't exactly define things perfectly. Very cat and mouse. Late model racing is getting more and more that way.

[JustAddDirt]

cantilever just on the left side?

Yes. That is my thought, lr only

[kiwi1955]

Looking back through some old threads and saw this. We will be assembling a cross torsion, 4 bar, open tube Super Saloon ( Kiwi Late Model) in the next couple of weeks. I got the chassis back from the powder coaters last week. This car is also set up to take a standard late model 4 bar coil over set up, closed tube, j bar etc. Our intention is to spend a day testing each set up and run with which ever is fastest. I will post some pics in a few weeks and would be interested to hear posters on 4m's thoughts.

[Krooser]

Keep us posted...

[hotshoe65s]

Matt.
It isn't necessarily a "torsion" bar, but Danny Drinan built a system that was pretty successful. He put it on a UMP mod in the late 2000's and was successful with it. Unfortunately it's been outlawed by about every sanctioning body.
http://www.dri-bar.com/

From my experience in NASCAR with anti-roll bars I don't see method of making it work very well in the rear of a modern day late model. With all that said, I could see it working on the front. You would need to have a lot of bar "slack" to allow it to roll on the RF, and then time it to engage at the correct point. Then you could clip the RF travel with the bar and run a softer rate RF spring.

[cjsracing]

Yes. That is my thought, lr only

Message SPark14 on here, he did this about years ago.

[over4T]

Late '80s when the rules were pretty basic and hard work & innovation could (occasionally) overcome the bucks I had a stock stub front clipped rule LM that we put a K member torsion bar setup from a California Highway Patrol Dodge on the front of an all fabricated chassis. Used rack & pinion steering from Ford Fairmont/Mercury Zephyrs that were $15 a pop at the local Pick 'n Pull. Rear was less exotic with stacked leafs and a pull bar.

Took about 2 years to figure out what we were doing as there was no one to bounce ideas off but eventually we got it to work pretty well and went to coilover mono leafs on the rear. Car was reaching it's potential and it got banned so I parked it for a couple years then reclipped it with a '76 Cutlass front end. It was never as good again and today, over 20 years from it's heyday, it still sits behind the barn. Maybe someday....

[kiwi1955]

As previously mentioned, here are some images of my set up. Thoughts?

[Austin34471]

As previously mentioned, here are some images of my set up. Thoughts?

Looks cool.. why the open rearend? And what was the thought process period? Coil springs do a pretty good job of what they are designed to do. Definitely outside the box

[fastford]

i like the looks of that , is it one torsion bar running all the way through or are they split and work independently of each other?

[Austin34471]

i like the looks of that , is it one torsion bar running all the way through or are they split and work independently of each other?

Split. Basically using torsion bars for springs.. I would like to hear the creator's thoughts on advantages he was trying to explore. Can appreciate the design/fab work regardless

[Kromulous]

I have read that Torsion bars offer a lot better spring rate, and progressive-ness? I guess increasing and or decreasing thicknesses of the bar in various places can give the bar some vary cool effects in the realized spring rate.

[Matt49]

i like the looks of that , is it one torsion bar running all the way through or are they split and work independently of each other?

They're split. You can see the stops on the opposite ends of each bar.
If they were linked, it would be an anti-roll bar design. I've seen that in combination with the independent left and right bars on the front of some sprint cars.

[Austin34471]

I have read that Torsion bars offer a lot better spring rate, and progressive-ness? I guess increasing and or decreasing thicknesses of the bar in various places can give the bar some vary cool effects in the realized spring rate.

Not true unfortunately. Torsion bars are very linear. Making the bar different diameters in different spots would not make progressive or digressive. It would be like a stack spring with no lockout. You could make it act progressively at the wheel by doing some motion ration stuff with the torsion arm i guess.. or just use springs. lol

[JustAddDirt]

As previously mentioned, here are some images of my set up. Thoughts?

Would love to see a pic of the entire car.
looks like you all do some really nice work (fabrication), and thinking outside the box.

Is the kind of car that has the transmission divorced from the motor, to help with rear weight %?

[fastford]

one thing to consider is where the energy is stored as compared to a coil over mounted higher in the chassis , and how it would effect chassis roll.

[kiwi1955]

I will post some pics of the car. No the transmission is not mid mounted. Most cars here do that because we have to run a steel block with the #1 plug in line with the centre of the balljoints. We have the block, heads, intake etc machined to get the weight down. 54-56% rear is achievable by doing this. My chassis builder does do nice work, the car is tig welded which always looks nicer.

[dirty white boy]

petty made them work on dirt in the 60s and 70s, pavement too! worked pretty good on road coarse as well! and is some what lighter and weight has a lower cg!

[CageFaraday]

Obviously sprints use them and there is some debate in that world between torsion bars and coil-overs and I don't necessarily want to get into that debate. But I am curious if anyone has tried something like this on a late model or what people's thoughts are on why it would or would not work.

We had a Custom chassis built by Frank McClendon back in 86' that was a torsion bar car. Worked pretty good, but the owner liked canti-levers better so we went back to that. After 2015 and the Ruling DLM overlords decided to illegalize everything, they threw out torsion bars as an option because they don't know what the he!! they are doing.

[CageFaraday]

Message SPark14 on here, he did this about years ago.

SPark did a "canti-lever" car, I bought his canti-levers...