TB Performance Torsion Bar

[iso100]

I purchased a TB Performance Torsion Bar recently and here's my install and notes.

The bar arrived via USPS and came with the actual bar, two 8-point 1/2" bolts, two lock nuts and four washers.

Here's the bar as I received it:

I noticed that while the bolts have an OD of 1/2", the cups in the end of the bar have an ID of 3/4". The idea I guess is that you crank on the bolt and it dishes the washer up into the 3/4" hole, centering things and applying constant pressure to avoid eventual squeaking, etc.

I was curious to see if I could find a bushing to fit both the bolt and the cup so I went to the local hardware store. Low and behold, I found a bronze bushing that was exactly 1/2" ID and 3/4" OD. They didn't just drop right in, but a simple C-clamp easily pressed them in. Additionally, since they were shorter than the cups I still have the area at the end for the washer to crush in slightly when mounting.

The bar, the bolt and the bronze bushing:

Pressing in the bushing:

Top side (when installed) of the cup and bushing:

Bottom:

Now for the install I went to a buddy's house (That's not my Raptor) because he has air tools and ramps.

All the parts laid out and ready to install. You'll also need a 19mm/3/4" wrench and deep socket:

The twist beam is already drilled, so luckily all you need to do is drop the bolts through.

I quickly discovered that with my modifications (the bushings) the tighter tolerances made it impossible to push the bar all the way to the bottom (top) of the bolts with my bare hands. I had to use a C-Clamp to convince it that it's possible:

With only one clamp, I had to work back and forth.

I finally got the bar pressed down enough to show threads. Then I broke out the air hammer and drove the nut all the way down using a 19mm deep socket and wrench on the other side.

Finally I used a torque wrench and tightened the nut to 90ft/lb.

Finished product:

Impressions? HOLY CRAP. The car is on rails now. Immediate turn-in and it corners completely flat now. I honestly didn't expect this kind of roll-stiffness improvement. Highly recommended mod.

The bar can be purchased here:
http://www.tbperformanceproducts.com/ford-fiesta.php

 

[iso100]

First time running a chord through the traffic circle today and man, does it want to hang the tail out.

I might go out on a limb and say that if you have upgraded springs you might not want this as it makes things too stiff. I can't help but think that my bushing modifications made this stiffer than it would normally be.

 

[MKVIIST]

Looks like a real easy install. You think it would be too stiff with croilovers?

 

[iso100]

I think it could work well but for ultimate performance in Auto X or road racing you would be better off increasing spring rates in the rear to achieve the same end result but with more side-to-side bump compliance.

Of course, buying custom springs and installing is harder than 2 bolts and some ramps. I say give it a try if you're interested but be prepared for the rear to be much easier to break loose.

 

[MKVIIST]

Yeah I might just give it a try and see, if its too stiff I can always take it off.

 

[iso100]

Yeah I might just give it a try and see, if its too stiff I can always take it off.

Exactly. But be prepared to have to hammer out or press out the bolts should you choose to do the bushing mod like I did. The bar isn't sized exactly for the use of them and it's a tight fit.

I honestly didn't expect to feel this significant of a difference by installing a little bar into existing holes in the rear suspension. It's easily the best value (dollar per smile) mod I've done to my car so far.

 

[Chris G]

I have this thing on my car and am really enjoying it as well. Between this bar and the Pierce 2-point up front, the car feels really nice. Combined those two bars are less than $200 so it's almost a no-brainer for anyone that wants to improve the handling of their car on the cheap.

That is a pretty nifty idea with the 'bushings' - it looks really clean. My only other observation is that a lot of folks put the bolt down through the top. I did it the opposite way... not sure if that matters or not. I noticed there are some fuel lines above the beam that could potentially get in the way maybe if you are lowered, but on stock height it appears fine. I'll likely swap mine around when I'm under the car again in the near future just for some piece of mind.

 

[iso100]

I have this thing on my car and am really enjoying it as well. Between this bar and the Pierce 2-point up front, the car feels really nice. Combined those two bars are less than $200 so it's almost a no-brainer for anyone that wants to improve the handling of their car on the cheap.

BRB. Time to place an order at Pierce!

Which did you install first? This torque bar or the Pierce one?

 

[Chris G]

Installed the TB bar first then the Pierce.

 

[iso100]

Could you feel the incremental improvement after adding the pierce bar?

 

[Chris G]

Could you feel the incremental improvement after adding the pierce bar?

For me, it was steering feel with the Pierce bar. But that's just my opinion.

 

[iso100]

For me, it was steering feel with the Pierce bar. But that's just my opinion.

Yeah, that's what I meant. You could feel the bar's affect on improving steering feel. That's cool. I'll get one for sure.

I've noticed that roll stiffness is greatly increased but the car isn't appreciably more tail-happy. It almost seems like it has more grip than before and the speeds required to get the tail to hang out are faster too as a result.

Did you notice something similar?

 

[Chris G]

YEP - I am very happy with it. I also ended up getting the trunk brace and the cross member brace too. I personally didn't notice much with the trunk brace but am looking forward to installing the cross member brace in the near future.

 

[praecurvo]

Subscribed. Very interesting.

Only concern is might these braces make the chassis too stiff?

 

[iso100]

Subscribed. Very interesting.

Only concern is might these braces make the chassis too stiff?

For a performance vehicle there is no such thing as a chassis that's too stiff. You want all deflection in the suspension, not anywhere else.

Did you mean that maybe the rear suspension might be too stiff side-to-side after the torsion bar? That's different and is a matter of taste and driving style. When you hit a bump on only one side of the car you definitely feel it transfer into the body. It acts as if your rear spring rate were increased greatly. The ride on uneven bumpy roads is a bit bumpier. Turn in is immediate and crisp.

What I thought would happen is that the rear end would become too loose and walk around on me much sooner. That's not the case with my stock suspension. Instead, ultimate grip is greatly increased. Where a prior blast through a traffic circle would yield oversteer at 40, that limit is now far higher. The car literally feels like it's on rails now. When it does break away, it's just as smooth if not slightly less tail happy.

I hope that makes sense.

In have no other braces currency but just ordered the Pierce Motorsports 2-point lower bar yesterday. I believe it will compliment things nicely.

 

[Chris G]

Let me know how you like the Pierce bar.

 

[iso100]

Let me know how you like the Pierce bar.

Will do!

 

[praecurvo]

For a performance vehicle there is no such thing as a chassis that's too stiff. You want all deflection in the suspension, not anywhere else.

Did you mean that maybe the rear suspension might be too stiff side-to-side after the torsion bar? That's different and is a matter of taste and driving style. When you hit a bump on only one side of the car you definitely feel it transfer into the body. It acts as if your rear spring rate were increased greatly. The ride on uneven bumpy roads is a bit bumpier. Turn in is immediate and crisp.

What I thought would happen is that the rear end would become too loose and walk around on me much sooner. That's not the case with my stock suspension. Instead, ultimate grip is greatly increased. Where a prior blast through a traffic circle would yield oversteer at 40, that limit is now far higher. The car literally feels like it's on rails now. When it does break away, it's just as smooth if not slightly less tail happy.

I hope that makes sense.

In have no other braces currency but just ordered the Pierce Motorsports 2-point lower bar yesterday. I believe it will compliment things nicely.

Yes, I am concerned with the rear being much stiffer it may not perform as intended. Sounds like currently there's more tendency to understeer? You also mention roll is reduced, how about lean?

I am really looking forward to hearing your updates on the Pierce bar as well. What are you looking to achieve with the Pierce bar?

 

[iso100]

Yes, I am concerned with the rear being much stiffer it may not perform as intended. Sounds like currently there's more tendency to understeer? You also mention roll is reduced, how about lean?

I am really looking forward to hearing your updates on the Pierce bar as well. What are you looking to achieve with the Pierce bar?

It's definitely stiffer but I believe it still performs as intended. Generally, increasing roll-resistance in the rear will make it oversteer more/understeer less. It definitely doesn't understeer more. What happens is that it just rails right through the corner at a higher speed than before without hanging the rear end out.

In my opinion, roll == lean. They're synonyms. I can tell the rear is flatter and if there's any lean/roll it's mostly up front.

I wanted to get the Pierce lower bar to ensure front suspension geometry stays as intended with the new higher cornering limits and ability to corner much faster.

 

[Chris G]

I'm with iso... it seems to just GO through the corners... hard to explain