Torque arm watts link 4 link suspention vs 5 link suspention

[Roadrage David]

what are the pro,s and conns consirning serius road racing!!.

[Payton King]

Huge improvement over leafs. I am in the process of doing another car that will be more of a track car and I am putting the same suspension set-up in that car as well

https://static1.pt-content.com/images/pt/2011/08/DSCN3627-1.jpg

[cornfedbill]

I would have to second that one. A watts link with a torque arm seems to be the right setup for this application.

I am intrigued by the Mumford link in place of the Watts link. It allows a lower roll center in the rear while still maintaining ground clearance. I think it may be marginally better than the Watts link.

I would leave the 4 link for drag racing.

[exwestracer]

Bill,
The Mumford will give you a VERY low roll center. Maybe TOO low, unless you are really looking at tuning roll with a lot of rear bar. For years, I've started with an 8" R/C split front to rear, and had good results (without rear bars) in a number of different applications. The Mumford, as typically installed, would give you a rear R/C at or below the front. That's a BIG change...

[cornfedbill]

For years, I've started with an 8" R/C split front to rear, and had good results (without rear bars) in a number of different applications.

Ray,

When you say an 8" R/C split, I assume you mean that the front R/C is 8" below the rear R/C. Is that correct?

On my Nova with the G-mod and flatter than stock 225lb Afco leafs and a short lowering block, I believe I will be over that 8" target. I guess I will need to do some more calculations to bring the to R/C's closer together (or at least verify that they are close to 8" apart).

Thanks for the input.

[exwestracer]

Ray,

When you say an 8" R/C split, I assume you mean that the front R/C is 8" below the rear R/C. Is that correct?

On my Nova with the G-mod and flatter than stock 225lb Afco leafs and a short lowering block, I believe I will be over that 8" target. I guess I will need to do some more calculations to bring the to R/C's closer together (or at least verify that they are close to 8" apart).

Thanks for the input.

Correct.

I'm assuming a 27" rear tire and flat spring pack, Figuring rear roll center height in the usual way, I'm thinking around 11-12" for your Nova? Even with the G-mod, Unless the front is REALLY low (LCAs downhill to the frame), you are likely close or a little LESS than 8.

Keep in mind this is ALL a guess...

[cornfedbill]

Ray,

Thanks again.

I will have to get cracking on the calculations. My tires are stock diameter, just over 25". Yes, they are a bit small compared to may of the cars here. I am not planning to tub the car. I am also running without a stagger. All my calculations show a near 50/50 weight bias. I also don't have too much motor, only about 425 lb-ft of torque.

The springs will be pretty flat when loaded, so the rear R/C will be easy to measure.

Do you suggest I run the front LCA flat to the ground or a bit lower on the inside pivot? I was leaning towards a flat control arm in the static position.

Thanks again.

[killer69]

Huge improvement over leafs. I am in the process of doing another car that will be more of a track car and I am putting the same suspension set-up in that car as well

https://static1.pt-content.com/images/pt/2011/08/DSCN3627-1.jpg



https://static1.pt-content.com/images/pt/2012/07/Speed_Tech_59-1.jpg

https://static1.pt-content.com/images/pt/2012/10/DSC_1405-1.jpg

Nothing to add todayjust thought the 3 pics would look good together.

[Twentyover]

Huge improvement over leafs. I am in the process of doing another car that will be more of a track car and I am putting the same suspension set-up in that car as well

https://static1.pt-content.com/images/pt/2011/08/DSCN3627-1.jpg

I'm in process of trying to figure out if I want to replace my leafs, and if so, with what.

What makes you say the torque arm is an improvement?

[exwestracer]

I was leaning towards a flat control arm in the static position.



That's how I would set the ride height, yes.

[cornfedbill]

That's how I would set the ride height, yes.

Ray,

Thanks.

Your help may save me some trial and error. Now I just have to lay everything out to see how it will sit before I start the cutting process.

[Roadrage David]

Ok let me ask it again!.. Torque arm watts link 4 link suspention vs 5 link suspention what are the pro,s and cons of the 2 when compeard..??. wich one is preferd. we are not talking about leaf springs...

[cornfedbill]

I did not mean to hijack your thread.

The advantage of the watts link is a linear movement. While the watts link moves straight up and down (within its designed range), a panhard bar has a small side to side motion.

However, for serious road racing, the suspension movement is very small due to very high spring rates making the lighter panhard bar a good choice.

The same goes for the torque tube. It is a great system, but can be heavier than the 4-link. The torque tube is a better alternative when beginning with an existing chassis. Many kits can be bolted on with no welding.

Most bolt on 4-link set-ups compromise the length of the upper length and the adjustability that makes a 4-link so desirable. The fabrication required for an optimal 4-linke makes it less desirable for most builders of dual use cars.

With no concessions for a rear seat and no limits to the modifications, the lightest, but still strong, setup is a 4-link with a panhard bar.

That is what I have seen.

[Payton King]

My opinion is based on driving my car with leafs for 4 years and changing to system I posted. Ride is not even in the same ball park. The long torque arm have very little pinion angle change through the range of motion. Great forward bite and the longer arm resulted in no brake hop that you hear about with shorter arms. The watts link (same would apply to a panhard bar) lets you adjust roll center to either loosen the car or tighten the car depending on the track/course you are running. Bind free articulation. I could go on and on, so what do you want as far as info? Prior year my car ran 26-27th out of 80 cars at RTTH. Took my car back the next year with 5 miles on the new torque arm suspension and ran top 10 all day, think I finished 12th overall. I was dropping 1 full second to .5 second each run as I learned the car...just ran out of time and that was no tuning on the car.

Could I have done the same with the DSE...probably so. I like the design of the torque arm. I am sure Ray (exwestracer) would do a better job of pros and cons. There is a thread that speaks about torque arms, no sure I have seen one on a 4 link style like the DSE, not sure I have ever seen a 5 link. I know AME makes a 5 link but that is for running a 3 link and then removing the 3rd link and converting it to their tri 4 bar system...one for drag racing and one for road racing.

[exwestracer]

Ok let me ask it again!.. Torque arm watts link 4 link suspention vs 5 link suspention what are the pro,s and cons of the 2 when compeard..??. wich one is preferd. we are not talking about leaf springs...

Yeah, sorry. I was worried about where that was going. The torque arm is much better over a wide range of situations. BTW, the suspension is typically referred to by the number of front to rear links. So a system like Paytons is a "2 link with torque arm and watts". Your other choice would be a 3 link or 4 link with panhard or watts. The side links don't count.

[Roadrage David]

Ok guys i askt because we are building a all out road racer and use the BMR Torque arm suspention system with watts link. altho we have customized it . as our car is mutch lower.
also im a bit stuborn to go 5 link ore what ever its called.. My frind sais Go with the 5 link suspention its a 2 day job to build. but i dont whant to disreguard a nice piece of suspention that i bought and imported to europe. im of the upinion that altho it caries more weight with it , it can do the job just fine.. hensh my question Torque arm watts link 4 link suspention vs 5 link suspention !!. i like to know what both systems bring to the table so i can antisiopate in the rest of the build of the car.. https://www.pro-touring.com/showthread.php?93068-Project-quot-quot-Road-Force-One-quot-quot

[cornfedbill]

I reviewed your build link again. Nice ride!

Ray is the expert. He knows his stuff.

I agree that the torque arm suspension and watts link are great for all around performance and would be good for road racing.

I just depends on if you want to loose some wight and go to the 4 link. I would stick with a 4 link over a 3 link with that big motor and tires. I would prefer the stronger 4 link on my car if I had that much motor.

Since it is there, I would stick with the watts link even if you move to a 4 link suspension. A watts link has better movement for a car that turns both right and left. Panhard bars can favor one side over the other depending on how they are installed.

Either way you go, you cannot go wrong. The setup you have is a good setup and will perform well. Moving to the 4 link will likely only be a benefit because it can be lighter. The performance differential may be very difficult to measure.

[Norm Peterson]

also im a bit stuborn to go 5 link ore what ever its called.. My frind sais Go with the 5 link suspention its a 2 day job to build.
What exactly does this "5-link" arrangement look like, and for what car is it intended? I have a vague idea what Steeda's version for certain Mustang chassis looks like.

If all 5 links are connected at the same time, the axle is "overconstrained" and will bind under some conditions unless some very specific geometric "coincidences" are intentionally made to happen. Even then, you're dependent on bushing compliances once the suspension starts to move.


Norm

[exwestracer]

What exactly does this "5-link" arrangement look like, and for what car is it intended? I have a vague idea what Steeda's version for certain Mustang chassis looks like.

If all 5 links are connected at the same time, the axle is "overconstrained" and will bind under some conditions unless some very specific geometric "coincidences" are intentionally made to happen. Even then, you're dependent on bushing compliances once the suspension starts to move.


Norm

Norm, I believe from previous posts that David is including the lateral links in the count. I'm ASSuming he means a three link with watts. The only other option for a 4 link with torque arm would be a dirt Late Model style system with birdcages...

[Roadrage David]

my bad i ment the BMR torque arm suspention pacage. the way its on the car now. with the watts link. against a 5 link suspention. i alredy disided to stick with what is in the car now.. but i wanted to know wat the pro and conns of both systems are.

[exwestracer]

my bad i ment the BMR torque arm suspention pacage. the way its on the car now. with the watts link. against a 5 link suspention. i alredy disided to stick with what is in the car now.. but i wanted to know wat the pro and conns of both systems are.

Any sort of linkage suspension (3 or 4 link) will typically be easier to adjust the I/C and antisquat %; BUT the I/C will usually move further as the suspension cycles, which can mean a very different reaction to throttle or brake input depending on chassis position. The linkage suspension can offer slightly lower unsprung weight.