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Discussion Starter #1
I know that they are intended to isolate some road noise and bumps etc but with all the raving about what the stiffer ones do, I just can't get my head around why they would be such a huge improvement. As far as I can tell, they are not much more than glorified spacers.

Now with that being said, since firmer seems to be better, is there a limit to that statement? I'm assuming that aluminum would not provide the isolation needed but what about materiels such as hard plastic like HDPE?

Just a few questions so I can justify the mod.

NAESS
 
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Discussion Starter #2
Weak or soft bushings will allow the body to flex and allow more body roll and shift of weight. Firmer ones help control that. Too firm and you transfer way too much pounding and vibration into the car and stress to the body.
 
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Discussion Starter #3
I'm sure you could turn up some info on a search, but this is worth discussing.

OEM "cabin comfort" criteria for any vehicle is a mix of many factors. Reality is, the Caprice was intended to have a fairly isolated passenger compartment, with as little intrusion of noise, vibration or harshness as the price point of the vehicle allowed to be spent on satisfying the requirements that ultimately come down to making the car acceptable to the customer base.

There is a big difference in a Caprice--a "family sedan" and a Corvette--a high performance sports car, for example, with different design and construction methods and criteria. Easy to see and understand.

The same is true to a lesser degree for a Caprice/Impala SS sedan and the 9C1 variant of the same vehicle. Spring & shock characteristics (stiffer or softer, valving design, different rate or load rating), tires (aspect ratio, tread design, recommended pressure), wheel size & width, and the body bushings (selected by rubber durometer, internal design--such as the number of voids-- length of spacers and lower cushion contact gap) are all selected/combined to meet specific performance parameters.

The differences appear to be quite subtle, and there are so many variables, it would be quite a task to become familiar enough with every different combination on any particular vehicle unless you worked (for GM) in the vehicle development area and had a good working knowledge of how the testing is done that determines each combination of factors. The OEM parts bin is full of parts the engineers and production people had to choose from when developing and building this car.

In the case of the Impala SS vs 9C1, it is easy to understand that the intended vehicle customer and use was distinctly different, enough so that the body mounting system got some special attention. Whether or not it was by accident or design, the Impala SS ended up with what most of us here on Forum seem to believe is an "inferior" combination of parts. Add to that the fact that we are now dealing with parts that have been in use for 8-10 years and in many cases are badly deteriorated. As enthusiasts, most of us will be of the mindset that we want the "best" on our cars, in whatever area (we) choose to focus, and the biggest factor is often whether the change is within financial reason. When we start modifying the car--engine mods, exhaust mods, changes to suspension, tire/wheel sizes and sidewall heights, powerful stereo systems, etc, we totally disrupt the OEM's tuning of the body mounting system as far as what will be felt in the driver's seat & passenger compartment.

So, it becomes a matter of whether the OEM has a good set of parts that can be identified as "best" or whether any aftermarket method may be superior--it will depend on what can be withstood in the driver's seat, and whether the specific use of the car will warrant the use of parts that impart a much more direct path for NVH "inputs" to the vehicle operator.

To answer your question, there IS a limit, but I really have no idea how a B-body would "behave" with hard plastic in place of the rubber mounts, but I do think you could notice the difference.

One thing to realize is that the factory parts may not always be available into the future, so if you have any notion that you want to maintain the OEM mounts as the vehicle ages, you should try to get your hands on those pieces now, even if you don't plan to install them for another 5 years.
 
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Discussion Starter #4
Poly/Graphite seems to be the extreem point that works the best. Metal is a disaster. Rubber too soft. The Energy Suspension kit replaces all the upper and lower bushings,including the factory deleted ones only if you get part #ens-34136g, the other pn's either delet some or don't use graphite impregnated poly. The 34136g produces a tighter car that feels more rigid with a little more vibration and noise coming into the interier.No free lunch,but a much better result than just doing the lower body bushing mod.
 
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Discussion Starter #5
One word to the wise, something to consider anyway. Installing all 12 bushings is a time consiuming afair, not overly compledx, however more time consuming than you might first think. I got a little lazy and decided to have the shop put them in for me, thinking it was a quick and easy job, when I picked it up they said it took a little over 5 hrs to do, and this is at $69 hr, with the parts I spent nearly $400. If I had known this project was going to cost me this much, I wouln't have done it, I would have put the money towards something more important like gears/posi or headers. If you are mechanical do it, but if you have to pay the shop don't do it.
 
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Discussion Starter #6
Lots of good info in this thread. Nothing groundbreaking but it is nice to see it all in one place...

The ES p/n 34136 is available from suspension.com for $98. I've done business with them before with good results. They're in CA. I believe it is a kit that only comes with body bushings and the price seems to reflect it.

The guy that runs the place seems like he is always 5 seconds away from turning into a cranky fart but never does so. His character comes through in the website as well. Its entertaining but I'd hate to see what would happen if I said the wrong thing.

Later,
Aaron

UPDATE: Summitt has the same kit for $81.39. Seems like a real good price even if you don't use all the bushings for the reasons Dodgercat specified. I think you would spend almost that much on the GM parts even at good guy prices if you only bought the deleted bushings. If you replace them all you will be money ahead.
 
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UPDATE: Summitt has the same kit for $81.39. Seems like a real good price even if you don't use all the bushings for the reasons Dodgercat specified.
I would recommend buying them localy. The AutoZone here can get them for about the same price as summit and I'm sure there are other chains or local shops that carry Energy Suspensing parts.... that way you won't get hit with shipping.
 
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Good idea Chris, I'll keep that in mind. I've pretty much given up on trying to get internet prices locally. If the price is the same it's usually a toss up between paying sales tax or shipping. Summitt has flat rate shipping, if I can afford it I usually wait for one large order and try to get it all done at once. I laughed when I got 4 15x8 wheels and a few small things shipped for $7.00.

Later,
Aaron
 
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Discussion Starter #10
One note- the lower body bushings are fairly easy to replace. The upper body bushing are the ones that are difficult and time consuming. You can easily DIY on the lower bushings in the driveway. The upper bushings takes alot more effort and know how. The lower ones are the ones which are missing fromt he factory on most ISS's.
 
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Discussion Starter #11
I wondered the same thing, Sublvr--assume you are referring to this comment:

"If I had known this project was going to cost me this much, I wouln't have done it, I would have put the money towards something more important...."

Not picking on you, Dodgercat....body mounting is pretty important, if the uppers are seriously deteriorated, it's no different than anything else--they need to be replaced, like tires, shocks, brakes, etc. Out of sight, out of mind, until its SO bad that you think the car is falling apart and you want to get rid of it. New body mounts can magically transform a car that has had every other suspension/driveline piece massaged, replaced/upgraded and the car still feels like its lurching down the road.
 
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Discussion Starter #12
ok folkSS, i want to do this long over due mod. both upper and lowers so what should i do, should i go with OEM/caprice bushing's or Energy Suspensions part #ens-34136g bushings.

what are the pro's and con's of either bushing please be specfic, i am not worried about pricing,shipping,taxes etc.., it makes no difference to me...
 
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Discussion Starter #13
UPDATE FOR MY UPDDATE:

I just got back from Auto Zone. I'll spare the details of the inept staff and just say that they wanted $98 plus $5 shipping (2 days) of free shipping for 10 days. Of course local sales tax needs to be added as well. I asked about pricematching Summitt and was told no can do.

Summitt looks like the way to go no matter what the situation. There is a considerable price differnece if you get some other items due to their fixed shipping rate.

Later,
Aaron
 
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Discussion Starter #14
Troy, the owner of the NAISSO Superstore tried the Energy Poly bushings on his SS. Bottom line is he hates them. The car pounds VERY HARD!
 
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Discussion Starter #16
I agree with Bob (RJI) wholeheartedly. Unless you are building a race car, you will be alot happier with the factory parts.

http://impalassforum.com/noncgi/ultimatebb.php?ubb=get_topic;f=16;t=000721

From the above thread--my post on Nov 10, 2001. No idea if all of these parts are still available.

(quote)
Due to the way I posted the P/N information for the 7B3 chassis body mount cushions, I may have created some confusion about what the correct parts are. Here is a better format, specifically addresssing what is needed to duplicate SEO (police) 7B3/9C1 uppers--note that the upper mounts on the Impala SS have nothing in common with the police package parts, listed here:

THIS LIST IS THE UPPER CUSHIONS

Qty 4 348080 Pos 1 & 3

Qty 2 330986 Pos 2

Qty 6 330942 Pos 4, 6, 7

Qty 2 488610 Pos 5

Qty 2 14085301 bolt (for #3 position only)

Use the above bolt in place of the longer bolt used with the production #3 mount on the Impala SS and standard Caprice.

Also, for any position that has no lower cushion on the Impala SS (#3 for sure) the flat washer installed in production should be replaced with a complete lower cushion, either the "Mueller" part or another 377801 (OEM production) cushion, which is specified on all lower positions for production in 94-96 cars.

I don't have a solid recommendation beyond what the factory does on the lowers at the moment--which used the same parts on 9C1 and standard Impala/Caprice. I am not sure what, if anything, the Mueller lower cushions will do with 7B3 upper cushions, but it can't hurt, I suppose.
 
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Discussion Starter #17
Navy lifter wrote:
note that the upper mounts on the Impala SS have nothing in common with the police package parts, listed here:

THIS LIST IS THE UPPER CUSHIONS

Qty 4 348080 Pos 1 & 3

Qty 2 330986 Pos 2

Qty 6 330942 Pos 4, 6, 7

Qty 2 488610 Pos 5

Qty 2 14085301 bolt (for #3 position only)


***** So what are the "correct postion number/part number" and "quanity of bushing for each upper positon" for the "Impala UPPER Bushing's" , all i see is the correct upper bushing part numbers for the 9C1's you say it has nothing in common with the Impala's.... and could someone tell me if the Impala has to replace the number 3 bolt??
 
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Discussion Starter #18
In the same thread, see my Nov 8 2001 posts:

This is a recap of the GM parts used on the 94-96 sedans, and all 91-96 wagons, with both upper and lower mounts/cushions listed. Remember that some of the positions on the Impala SS and standard Caprice do not actually have the lower cushion assembly I've listed (377801)--position 3 (* in chart below) being an example of the "missing" lower cushion. In place of the cushion is a flat washer. I don't recall which other lower cushions were not installed (or removed by bulletin).

Vehicle>>> 94-96 7B3 sedan 94-96 Impala SS 91-96 wagon
Upper/Lower
Mount
Position
VVV
1 U-348080 U-3524486 U-490724
L-377801 L-377801 L-457941

2 U-330986 U-3524486 U-490724
L-377801 L-377801 L-457941

3 U-348080 U-10201228 U-356941
L-377801 L-377801* L-457917

4 U-330942 U-3524486 U-330986
L-377801 L-377801 L-457941

5 U-488610 U-556755 U-488610
(upper only, no lower in any application)

6 U-330942 U-3524486 U-330942
L-377801 L-377801 L-457941

7 U-330942 U-330992 U-330942
L-377801 L-377801 L-457941

The bolt used in #3 on the Impala SS and civi Carpice is the LONGER bolt, due to the longer spacer that is part of upper mount 10201228.

Not sure what you mean in saying "tell me if the Impala has to replace the number 3 bolt??"

The bottom line is this:

IF you use the Impala SS upper mounts, stay with the long bolt in #3 position.

IF you use the 9C1 upper mounts, use the shorter bolt in #3 position--PN 14085301.
 
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Discussion Starter #19
ThankSS Mr. Bill that helps, waiting on dal for my parts to arrive..
 
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Discussion Starter #20
Is there any improvement over the 9C1 vs Impala SS bushings?
 
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