Should I ditch my poly body bushings for Kirbans rubber?

[TURBOELKY]

I have summit polyurethane bushings installed but haven't driven the car yet. Wish I was more help.

 

[1986 Buick GX1]

I was able to chat with jdpolzin about the Prothane poly body bushings.
His feeling is the Kirban's rubber body bushings would be the best answer to your situation because of the poly bushings used throughout your suspension + motor mounts.

When running rubber suspension bushings or Moog replacements the Prothane body bushings are a great choice as they are not as stiff as the Energy Suspension poly's, but very close. He didn't think with your set up BuickMike there would be very much of a change going with the Prothane's.

I will edit my previous post to reflect the additional input.

 

[BuickMike]

Thanks! I emailed what I thought was Prothane customer support about durometer, but got a response stating that "prothanesuspensionparts.com" is a reseller and how to contact the manufacturer directly. I think that rubber will make a difference for me considering what else I have in play.

 

[1986 Buick GX1]

Summit racing carries Prothane products. I'm sure you can get their number from them.
Probably Jegs as well, whatever is your fav.

 

[LEGACY_GN]

Were these Prothane poly's? I've read the Prothane's are slightly softer than the Energy Suspension poly's.
jdpolzin has used these. PM him for his thoughts.

I have energy suspension and. I also have poly bushings throughout the suspension components and poly motor and tranny mounts. I use amsoil synthetic grease for everything and have zero squekes or rattles other than Windows when they are down. I did notice some vibration in floor pan after the poly transmission mount was installed but I think some of that is my factory driveshaft is out of balance. Find out once I install the cromoly. Other than that it's smooth so I'm at a loss as to all these reports of issues people have. I will also say I can dial in my shocks and I don't have them super stiff but firm. I'm sure of i turned them up it would be a harsh ride. For those with varishocks I'm running setting 7 front and 5 back on single adjustable. I also don't have low profile tires so that could be a lot of it too.

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[fitz3820]

I hate my poly body mounts - transmits too much jarring vibration for me, maybe I am just getting older Expansion joints, potholes, etc. are much more harsh - I bought Kirban's rubber mounts and am going to put them on soon. Some people don't seem to mind poly mounts - maybe you can get a ride in a car with them and decide?

 

[NY_GN]

I put poly body bushings in 2 weeks ago. Great on good roads, horrible on rough roads and potholes. I'm gonna have to reinforce my dash so it can survive. If I had to do it again, rubber mounts.

 

[Johnnie]

After all the knowledge I acquired by reading these posts, I ordered kirban's (rubber) kit. BTW He didn't sell me anything I didn't need. Can't wait to get it installed.
Thank you Mr Kirban for taking the time to talk with me.

 

[BuickMike]

Alrighty all, I finally got around to swapping the Energy Suspension bushings for rubber. Well...my GN is back to being a Buick.
Short story...it went from feeling like a '80's F Body to being a G Body again.

Long Story:

The goods are that it solved the vibration I felt, as well as whatever subsonic resonance that was drowning out my subwoofers. Also, it is not nearly so jarring when I am on rough roads or hit hard bumps. The rubber body mounts really absorb that. I really didn't mind the stiffness though. I actually liked it. I didn't like the vibration or resonance. Not that I could hear it, but when a pair of 10" subs are instantly muted when you start the engine, it is just odd. I also don't have the squeaks in the t tops that I used to. It still does not feel like a stock TR since the suspension and motor / trans mounts are poly or solid, but it helps.

The downside is that it feels a little floaty again and I'd mot a fan. I really did like some of the unibody like feel about it. Also, I feel this delayed body roll when I turn hard and it feels sloppy to me. I'm sure that some fender braces and reinstalling my joust bars will help a bit.

In the end, I'd say I prefer the rubber body mounts for a car that is going to mostly cruise or be on street duty. If my main goal was to auto-x or roadrace this car, I'd go with the energy suspension mounts in a heartbeat.

Hope this helps you all trying to make a decision.

 

[Chuck Leeper]

that only TTA folks get annoyed by HR motor mounts

I had 1 set, ONE TIME, sent them back. These were on my 86 GN. 1- 25 mi drive, my hands, and the cheeks of my butt were numb.
I put stock mounts back on, made a restraint cable system to the rear of the dr head, no issues..

 

[SpeedRacerX]

Alrighty all, I finally got around to swapping the Energy Suspension bushings for rubber. Well...my GN is back to being a Buick.
Short story...it went from feeling like a '80's F Body to being a G Body again.

Long Story:

The goods are that it solved the vibration I felt, as well as whatever subsonic resonance that was drowning out my subwoofers. Also, it is not nearly so jarring when I am on rough roads or hit hard bumps. The rubber body mounts really absorb that. I really didn't mind the stiffness though. I actually liked it. I didn't like the vibration or resonance. Not that I could hear it, but when a pair of 10" subs are instantly muted when you start the engine, it is just odd. I also don't have the squeaks in the t tops that I used to. It still does not feel like a stock TR since the suspension and motor / trans mounts are poly or solid, but it helps.

The downside is that it feels a little floaty again and I'd mot a fan. I really did like some of the unibody like feel about it. Also, I feel this delayed body roll when I turn hard and it feels sloppy to me. I'm sure that some fender braces and reinstalling my joust bars will help a bit.

In the end, I'd say I prefer the rubber body mounts for a car that is going to mostly cruise or be on street duty. If my main goal was to auto-x or roadrace this car, I'd go with the energy suspension mounts in a heartbeat.

Hope this helps you all trying to make a decision.

"Delayed body roll" sometimes means that while one portion of the suspension system was changed for expected improvement, an unmatched or "weaker" link in the system has materialized somewhere else.

I've learned a great deal about suspension systems over the last 7 years while gradually improving the factory system on my 2009 Pontiac G8 GT. Changing one section can affect another section not planned. On the G8, I found that upgrading struts, springs, end links, strut bushings and sway bars really improved daily driving handling and low and medium speeds, as well as, highway higher speed stability. Car was predictable to 160 mph. But push hard in turns, the car would not lean, then all of a sudden make a rear step out movement and unplanned tilt and then finally grab. It's very unsettling. What was happening was that all the force was now being transferred to the car's floating rear sub section, forces normally mostly absorbed by the stock sways, endlinks, bushings, shocks, springs, etc - all of which were replaced by me. So, the floating rear and it's rubber subframe bushings had to squash before the rear felt planted. Of course there are cures for that too but that would come at the expense of added NVH which I did not want so I stopped since I don't push the car hard in turns often.

So, just keep in mind that suspension is a system and touching one piece usually affects the rest.

The g-body suspension does need plenty of help though. Lol.

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[Steve V]

A lot of this is person preference. I don't use H&R mounts with poly body bushings. In the south roads are better than in the NE or snow belt so one has to consider this. I also did 1 car as a hybrid. Polys in the rear 1/2 poly/rubber under the driver/pass side and rubber on the core support. I have a very stiff front suspension -tubular arms and aluminum lower a arm bushings. Car rides nice is stiff but dash is quiet. I only did this because I got the set incomplete and hell it's my car.

Did a customers car in all poly and it immediately showed us the driveshaft was out of balance. Aluminum 3 in solved that.

Personal preference.....

 

[Johnnie]

The downside is that it feels a little floaty again and I'd mot a fan. I really did like some of the unibody like feel about it. Also, I feel this delayed body roll when I turn hard and it feels sloppy to me. I'm sure that some fender braces and reinstalling my joust bars will help a bit.

Mike , do you have any chassis bracing ? The ones I have installed helped out a great deal with the floaty feeling...

 

[eagleguy]

My ride became much stiffer just adding Bilstein's. Guess I will stay with the stock bushings as I am primarily on the street.

 

[BuickMike]

I have Bilstiens, springs (forgot which ones), rear frame brace, back seat brace, front frame brace (Grand Prix), poly rear control arm bushings on boxed lowers and UMI uppers, 1LE on stick lower fronts and solid on my ub machine uppers. I took the joust bars off because they were rubbing on my extended slic, but didn't really notice any difference when I had the poly mounts on. I still have the poly radiator support mounts. Not sure if changing those would do anything. I took my passenger HR mount off and put a softer insert on the DS mount. That made a decent difference. Ill bet I could have removed the DS mount and done a brace again, but I really like not chasing stuff rubbing like the DP since the motor sits rock solid. At this point I've found a happy medium.

 

[TURBOELKY]

Send me the body bushings you took out and I will properly dispose of them....thanks

 

[BuickMike]

Send me the body bushings you took out and I will properly dispose of them....thanks

LOL I plan on keeping them incase I build a g body auto x or drag car.

 

[Toby_Goodmk]

I put in Kirban's rubber body mounts/bushings and that was the best $45 investment I have made on my car. I have HR rear sway bar and upper and lower control arms, with UMI front upper and lower control arms. Lots of squeaks from the front end. Pretty sure it is the control arm bushings. I emailed UMI and they suggested that I make sure all my bushings were greased really good with synthetic grease. Now that the motor is out and it is finally warming up. I plan in doing that. I wish I would have left my stock control arms on. Not a bit of noise when I had all stock setup. When I put the big sway bar on the rear, after a while my rear stock bushings were ruined and started making noise.

I had the same issue. Need to loosen the nut, I know that sounds crazy but Ramey told me to do so. It fixed it.

 

[84TXGN]

An alternative is to run the poly bushings at the corners to add some stiffness and use the rubber bushings everywhere else to help with vibrations and comfort. Its probably the best compromise available.