I currently have a Hotchkis non-adjustable poly/poly PHB on my car that I purchased and installed before I had plans on lowering the car. I ended up 2 months later lowering my car with Hotchkis springs and also installed Bilstein HD shocks. I know everyone suggests buying an adjustable PHB when you lower your car to help center the rear axle, but I have not purchased one because the rear looks like it is centered (I know eyeballing this isn't the best way).

After doing a search and reading what Trackbird and MitchTX have to say about PHB I found this post by Trackbird:

I have noticed that after I lowered my car I have a lot of "side-to-side" motion in the rear... especially noticeable at high speeds if you move the steering wheel back and forth. I first thought that my rear felt so loose because I was still running a stock rear sway bar and simply needed a bigger sway bar... but now I am begining to wonder if the side-to-side motion is a result of not having an adjustable PHB. Would I be wrong in thinking that my rear end being this loose is because my PHB is not adjustable and is therefore not long enough or not aligned properly?

Please help.

 

Not only will an adjustable PHB re-align your rear end, but it will also remove a lot of bushing flex you experience while using the stock bar. Changing to an aftermarket bar will help your rear feel more stable, but I can't say for sure if it's the only part to a solution for you.

 

If u have a poly/poly bar on there already an adj will not help. I think a bigger rear sway bar or more shock. I am told that the Bilstein HD is OK with stock spring rate but more is required with higher rates springs.

 

DOH! I totally skipped the part where he already had a poly/poly bar on there. Hah.

 

Yeah I already have a non adjustable PHB on there now. I guess my question is if I buy a adjustable PHB will it make any difference over my non adjustable one other than being able to center the rear axle?

 

Well, if you get one with heim joints, it will remove bind as well as being adjustable, but that's about it.

 

i think he means will it fix his problem with the way the car is driving. will he in other words be able to adjust it to were it drove like it was never lowered ect...

ofcourse the only difference is one is and one isn't adjustable, but will the adjustable one fix his problem...

from what ive read and i dont even have a lowered car, but i f'd my panhard bar up and need to get one myself, the adjustable one should infact help u recenter the rear, once the rearend is centered again the side to side **** ect will be gone and u will take full advantage of the nice handling you got ect.

if u decide to buy an adjustable one, pm me, maybe ill buy the one u have now, i really have no need for a nice one, just something other then stock ya know.

 

Well... I'm not the most knowledgable in suspension around here... or in anything for that matter. The side to side motion as far as I can tell could be caused by a variety of things. Can you tell if the waggle is in the suspension or are the tires scrubbing? IMHO, it is important for you to get an adj. PHB to recenter your rear and create the proper suspension geometry. With any luck, we'll hear from a more knowledgable source and nail this down.

 

It's definitly not my tires scrubbing.

I will let you know LS1_PNYTAMR if/when I get rid of my non-adjustable PHB

 

Ross, I'll let you install my phb tomorrow, while im doing my springs/shocks, if you want to see if that is really your problem.

 

I wouldn't put that ugly yellow thing on my car if you paid me. JK

Tempting, but I don't know how much I am gonna be around tomorrow. I think I will just order one and see if it fixes it. Thanks for the offer though Mark.

 

Read my post An ADJ PHB will not help. Bigger sway bar or more shock. koni!!!!!!!!!!!!

 

I plan on ordering a bigger rear sway bar soon. A bigger rear sway bar seems to make sense that it would help the side-to-side wag my car has... that is what I originally thought would fix the problem, but I just thought the PHB might have something to do with it as well.

You mention more shock (in the rear I assume?)... how would that help with the side-to-side motion I am having problems with? I thought shocks only helped with up and down movements rather than side to side? Not doubting you... just wondering.

Thanks for the replies.

 

I just got the Trackbird Enginering PHB. I felt a really big increase of rear end stability while conering and under heavy throttle. I run 315/35/17s. The bar helped evening out the tires allot. My rear end use to feel unstable and i use to feel the cars rear end wag side to side when doing hard accleration. And while crossing the traps at the end of the quarter mile. It use to feel really sketchy with slicks. Now it feels real stiff and a whole lot better now. I am gona get sway bars as well. https://ls1tech.com/forums/suspension-brakes/288941-stablizing-stiffing-rear-end.html

 

Interesting. Thanks for the info.

 

Intresting, hope it works out TTT

 

He went from stock one to aftermarket one. You are going from aftermarket to aftermarket. Apples to oranges comparisons. Of course his will feel 'more solid' cause there is less slack in the bushing. Under alot of hp the rear will hop all over the place with rubber bushings cause it was designed for less hp and it was designed for slack.

Post your whole suspension setup. This is critical in answering your question. This sounds like "I have an SES, what could it be?" And post the spring rates of your springs. Not everyone has them memorized. That's also crucial. It would help if you posted your specific goal and why you picked the parts you did. You might answer your own questions.

Spring rate is to control the car under fore and aft motion and it related to hp, traction, and weight. So you picked your spring rates based on that. And you kept in mind how lowering your center of gravity will affect the rest of the suspension components. All those precise calculations you've made were made to exactly match the rest of the car. Then you picked your sway bars to make the car corner nearly level, and balance oversteer/understeer to your driving liking. Then you carefully considered the weight distribuion, not just the weight. More weight on the rear, or less weight on the front will increase the need for a rear sway bar. This is why the front springs/shocks and sway bar is so much bigger then rear counterparts. There is little need for rear sway bar, but yet ppl still buy 21mm ones. Yes, I have one but it was bought during my crack cocaine days.

Your moving the steering wheel back and forth is like cornering. It kinda foreshadows what is happening during cornering. So when a car corners, it leans, twists the LCAs(if stock, mostly rubber bushing is being twisted first then the rest of the LCA, hence it's stamped not tubular so it will twist cause that's a good thing, it helps traction) which adds resistance to roll. If tubular LCAs, no twist of LCA, and if poly bushing, minimal twist of that bushing, which adds INIFINITE resitance to the roll. Something has to twist, but since nothing will it will lift up the inner part of your inside tire resulting in less contact patch and obviously less traction. But noone listens anyway and they all buy tubular poly/poly so I won't waste my time explaining more. Yes, those are great for drag racing, but don't cry about your street car then.

Now you have to relize how the PHR works. Go under the car and look. It's the only thing that directly opposed side to side movement. There is some slack in the bushing, but you took that away with poly bushings. Does it twist? Look again and imagine what would it take for it to twist. Do you need rod bushings? Imagine if it was longer or shorter, what would that do BESIDES move the rear? Your LCAs are fixed lenght aren't they? But you lowered the car. You moved the rear to one side. What would that do to the LCAs? Take 3 match sticks. Make a U. Move the one that connects them to one side keeping the open ends fixed. It might be minimal depending on the lowering. Are they even parralel to the ground anymore? Glue them together and move one side up without letting the other side twist.

And most of all have a nice day.

 

Nice info. Well explained.