Will be dropping a 347 in my car in a couple of weeks. Have a built 8" with trac-loc. Also have a beefed up C4. Have 4 1/2 leaf springs and subframe connectors. Buddy of mine is recommending some traction bars in back to keep rear axles from rollling forward? under hard launches. I'm guess the car will be around 425/425. Mostly stret but would like to take to strip and see what it can do. Are these necessary and what is a good brand to get? thanks
Do I Need Traction Bars?
- Thread starter palerider94
- Start date
Yes.
Use Traction Masters, the real thing, not the cheaper fakes. You may have to do something about mounting them due to the subframe connectors, but it should not be a problem.
Traction Master Company
Use Traction Masters, the real thing, not the cheaper fakes. You may have to do something about mounting them due to the subframe connectors, but it should not be a problem.
Traction Master Company
They used to have a special bracket to attach to subframes, but with so many different types, I think they stopped. Without them, the TM bracket attaches to the rear frame rail above the spring eye. Typical subframe connectors attach in this spot, so you'll have to modify the front bracket to account for your subframe connector.
brianj5600
Active Member
You may not need anything. My car never wheel hopped even once and with good tires at the track it had no traction problems on 26x8 slicks or 275 drag radials. My car makes decent tq/hp and 60' in the high 1.50's.
the problem isnt the tires, wheel hop is properly called spring wrap. if the rear springs are ridged enough they wont wrap up and suddenly release. with stock springs and more than 250hp you need some kind of device to prevent spring wrap, and the traction masters bars are the best.
blown65
Founding Member
x2, I would hate to see where his pinion is pointing with a 1.50's 60' with nothing to prevent spring wrap. wow
It looks like the subframe connectors I vae will be in the way. Here is how someone else dealt with it. Not sure I like the idea of using bolts versus welding in.
Underrider Traction Bars
Underrider Traction Bars
There's an excellent diagram of this on the TM site I linked. Simple math, if your engine produces the torque, you'll wrap the springs, unless you add something to prevent it.
I like the solution in your link showing using the connector as the forward bar bracket. That's a really effective connection.
brianj5600
Active Member
He has done something to address spring wrap, 4.5 leaf springs. I did something to address spring wrap too. Mine have a stiffer pack made from stock stuff. I am going to build some home made traction bars for mine since it should make more power soon.
brianj5600
Active Member
I would not run TM bars, especially if the spring is not very close to flat at ride height. The TM bars will bind since an arced spring will get longer as it compresses. I still think the beefier spring packs will be ok with an auto.
actually no they dont, at least not enough to worry about. remember that the tmc bars are rubber bushed at both ends, and have pivot points as well, thus the small change in spring length at the front half of the spring is not an issue.
brianj5600
Active Member
A clutch changes everything. Automatic cars are far more forgiving.
Springs do change length or there would not be a shackle on the back. Here is something copied from Traction Masters web site.
• G–1 Polyurethane Bushings
Perfect fit to the original M–1 cast ends. Maintains optimal performance by eliminating bushing slop. Bushings are tough
cast polyurethane with exacting tolerances.
It does not sound like there is much give in the polyurethane bushings.
Nor is any needed. The length of the TM bar is calculated to swing with that change in length, so none is needed. TH switched to urethane years ago. One of the few places I'll tolerate urethane on a street driven Mustang.
blown65
Founding Member
I bet if you took video of your pinion area upon launch you would think differently.
65ShelbyClone
Founding Member
Yes, half of the length change happens at each end of the spring. Since the front mount is immobile, that means the axle is displaced rearward by half of the total change in length. The springs will actually wrap a little bit under normal compression with the TM bars "pulling" forward from under the axle. However, that may not be an issue if the front of the TM bar is mounted higher than the axle end. The axle end will move rearward as it sweeps upward when the suspension compresses and offset the forward "pull." I don't have any of the spring/TM bar dims in front of me, but we could be talking about changes of 1/2" or less.
brianj5600
Active Member
You had to add traction bars? Autos are not as prone to wheel hop and may not need them.
Some springs have more arch than others. Actually a flat spring gets shorter as they compress. The rod will be pushing back and the spring perch trying to move forward. Something has to give.
You may be right. It never spun, vibrated or broke anything? It will be addressed with the new turbo.
Coming soon!
Yes, half of the length change happens at each end of the spring. Since the front mount is immobile, that means the axle is displaced rearward by half of the total change in length. The springs will actually wrap a little bit under normal compression with the TM bars "pulling" forward from under the axle. However, that may not be an issue if the front of the TM bar is mounted higher than the axle end. The axle end will move rearward as it sweeps upward when the suspension compresses and offset the forward "pull." I don't have any of the spring/TM bar dims in front of me, but we could be talking about changes of 1/2" or less.
The angle of the bars actually push back as they move up. I dont see a one size fits all working with spring that have different arches. If the under rides cause wrap, they are binding.
