Anyone have any experience using Polygraphite body mounts? I am installing a pair of Detroit Speed & Engrg (DSE) weld-in subframe connectors in my '69 vert and am concerned with the performance of the polygraphite mounts. Once I tie the frames together, the mounts will be "permanently" installed and I can not easily replace them. I know there have been discussions here on polygraphite suspension bushings, but I have never heard much about body mounts. I am getting ready to install these, so any warnings or recommendations would be gladly received.

Todd

I suggest you go over to the Team Camaro website or refer to David Pozzi's site on 1st Gen Camaro suspensions. He autocrosses his car.

Pozzi\'s Motorsports

From what I remember from all that suspension info, poly body mounts will still flex too much for weld-in subframe connectors and it will be bad.

I believe the suggested method is to use solid Del-a-lum body and subframe mounts.

I would check into the Gobal West Del-a-lum as you'll never have to mess with them after the fact as you may years down the road with rubber or Polygraphite... that would be the way to go in this case I would think?

You can compensate with the rest of the bushings if you need to get a smoother ride... or better yet by using a wider profile tire...

Unless you are going for all out handeling, then the ride stiffness is what your looking for, and then I'd also use the Del-A-Lum suspension bushings etc...

But yes, I'd go with the solid body mounts at this point.

Brett - 67 Drop Top 455!

What about a car without subframe connectors, will the Polygraphite bee a good choice for subframe body bushings??

There is always a RAGING debate on that question. It comes down to personal choice.

Take for example the "slammed" mini-trucks and ricers I see everyday. Ever watch the occupants of those vehicles as they drive down the street? I swear their teeth are going to rattle out. Either they don't seem to mind or they aren't going to admit that the ride is terrible - BECAUSE IT'S COOL. Yeh, right.

Some people are happy with poly everything, some people rubber, some people a mix. The problem is that you want to get it right the 1st time as you sure don't want to take the car apart again to make changes.

I am an engineer by trade and after everthing I read, I went with rubber subframe mounts and poly suspension bushings. I figured I could tighten up the handling but still isolate myself from the vibrations to a degree.

In the rear, I went poly on my spring mounts but rubber isolation pads between the axle and the springs. I figure that I will limit spring twist/deflection at the bushings but I am isolating vibrations at the axle mounts (which don't flex and therefore would not compromise handling). What I am looking for is a muscle car that handles really well (I have installed tubular upper and lower control arms and a 1-1/8" front sway bar too) but won't ride like my 25 year old 4X4 truck.

Unfortuately I have yet to get the car back on the rode to test, but then I only drove it twice before taking it apart and would not remember how it rode (with shot bushings) anyway.

If you go over to the Team Camaro or Dave Pozzi's website, you will see that Pozzi is a HUGE fan of Del-a-lum suspension bushings with solid aluminum body mounts. The theory is that unibody cars have the front subframe welded to the body and it works. Me? I am too afraid of spending years working on a car just to find out it rides like a skateboard.

Thanks for the replies! I spoke with the folks from DSE and they recommend using the solid mounts. Apparently, there isn't a great amount of difference in the ride between the polygraphite and solid mounts and obviously the solid mounts would not degrade over time. Even if I would want to replace them, they say you are be able to manipulate the frame to get the mounts out without having to undo the welds. I ended up ordering the solid mounts. . .

The solid mounts I think are a good choice with frame connectors. True, it will feel a little more like a Mustang, but our suspension is still a better design.

The reasoning behind solid subframe mounts when using frame connectors is so you dont twist the rear frame rails up.

Looks like a few of you already beat me to it on this one, but I'll add my $.02 anyway to back them up.

Just to clear up some confusion… the del-a-lum bushings referred to are control arm bushings that are solid with a nylon insert for low friction and wear properties. These are great for handling by the way, and don't hurt the ride.

As far as the body mounts, you want solid aluminium bushings. Not rubber, not polyurethane. Why? Both rubber and poly flex. Since the front to rear subframes are now tied together, that flexing motion in front becomes a huge moment arm at the rear. Over time, you'll fatigue where the rear subframe meets the body floor pan. So the end result will be the connector weld breaking? Probably not, but it's worse than that. What will happen is micro-cracking on the floor pan next to the weld where the rear subframe meets it. Not a good situation (they'll get bigger over time).

Both DSE and Competition Engineering sell solid bushings which they say are required for use with subframe connectors.

The other point would be that poly is not gong to last forever, and as you said, it'll be a bear to replace them unless you cut your connectors off. The solid aluminium with a coating should last the longest.

I replaced mine with solid aluminium and there was no noticeable harshness difference before and after. These will also improve handing and make the steering feel more connected. Unless you're doing a stock restoration, I'd avoid rubber or poly mounts regardless of using subframe connectors. Just stay away from stiff shocks and springs - your ride should be very nice.

Look for my installation instructions here:

/forums/ultimatebb.php?ubb=get_topic;f=23;t=002175#000000

I agree with all of that BUT polygraphite will last past your life expectancy. They don't degrade like rubber and they are are harder than a hockey puck. Our cars flex all the time anyway due to the nature of the unibody. Polygraphite mounts are darn near solid so don't get nervous if you have them with subframe connectors, they are very compatible. Keep in mind that connectors are more for horizontal movement not lateral. Body mounts contol lateral movement. You can mix and match depending on how much lateral movement you want.
Jim