edcmat-l1

I just wanted to comment on this, as I'm the guy that wrenches on and tunes Kevin's car. I'm also the one that suggested it may be the trans mount.

The vibration in Kevin's was not a balance type vibration. The car didn't shake. It was more of a harmonic resonance. A "buzzing" if you will. I was the one that told him it felt more like a solid motor mount than a balance issue. Kevin agreed.

It's been my experience over 25 years of building performance cars, most of that time professionally, that most of the time when you use solid or poly mounts you end up transferring a certain amount of vibration to the chassis/body.

sneakelman

No problem Kevin, you know you always got an extra pair of hands on call.
The brace is a nice piece, but for that price, there should be better bushing options. That poly just transmits, instead of dampening, vibration. Also, the design should be a little easier to install/remove. Took only about 20 minutes to put the stocker back in place, and bolt everything back up once we FINALLY got the unit out.
Glad I could help, always a pleasure my friend.

McLeod

Any time Kevin. What's the next mod.

Lowcash

No problem. It beats working on a paper.

It was a PITA installing it and a PITA removing it. Damn those 8mm allen bolts.

:

JUSTIFIED C5

I just bought the mount and installed it two weeks ago. I have the same issue happening. I'm a tech at a dealership and yesterday I put it on the lift, took it all apart again hoping the harder poly bushings were in the mount and I would install the softer bushings. Got it out and guess what, the softer bushings were already in there. I will say the mount works great, car feels different in a good way and the best thing is I don't have anymore "wheel hop". I have a Cartek clutch, which was balanced at TPIS when my 427 was built. I have not checked my torque tube bushings yet so maybe I have a bad bushing or two. Its just weird that a lot of us are having the same issues. On one hand I'm happy about the mount but the vibration feeling I'm dissapointed in. If I would have known it would be this way I would have thought a little harder before buying it. Guess i should have researched a little more...

ajg1915

Solid mounts will cause some vibrations.

Maybe a thin sheet of rubber between the rear cross bar and the mount would lessen the vibration.

Eric D

When you reinstalled the original differential mount in Kevin's car did you also reinstall the tuned absorber on the left side of the differential case?

WKMCD

It's in there.

ncvettes

I think Pfadt ought to have a 'street' line of their products. Take their motor mounts and increase the size to accommodate larger (& tad softer) bushing mass. Same with the tranny mount, plus softer end pads as well. And coil overs for the street to me would be a no-brainer. Let's face it, the 'race engineered' stuff is excellent and works, but how many of us are so hard core that we would want to live with the side effects everyday? Well, on this forum you never know!

Get to work boys.

Eric D

Yep!! If they were to rework them enough they might get them almost as good as the stock units.. Sorry, could help myself..:o

WKMCD

That's exactly what I was telling someone yesterday. I think the brace is a great idea and as designed a worthwhile addition to a track car. The vibration is just out of character with how I want my car day to day. I think benefits close to the current center poly bushing could be accomplished with a softer (rubber) bushing there for street use. There's not enough meat to do that as currently designed.

Anybody want to by a PFADT tranny brace?

K RIPPER

theres always a trade off in the quest to improve performance,more H.P.? gotta put up w/choppy idle f/cam, better handling? stiffer/harsher sometimes twitchy ride.I had wheel hop prob.adj. shocks then pfadt brace when brace was put in what a racket but I knew brace didn't cause noise how could it? Come to find bellhousing had cracked as a result of wheel hop was told by many brace made f/noisy ride but I was convinced of its usefulness and as i was putting car back togather I decided if noise/vibration was too much I was going to make the brace work since no replacement ends were avail.f brace I was going to try stabilizer link(aka sway bar) end link bushings as they are available in several states of compressability(hardness?)soft rubber hard rubber poly ect I also toyed w/the idea of cutting some strips of rubber from the sidewall of a tire to replace the ends on the pfadt brace. What I'm trying to say instead of cruicifying pfadt take their idea and improve it its a good idea and it works w/some trade offs this is what hot rodding is all about,modifing for your specific use.You can buy all the best parts money can buy and have a bitchen ride but the guy that tweaks and modifys those same parts to make them work better he's the one that comes in first.By the way after reassembling my car the only noise was some gear noise from trans which was within acceptable range, although I had given some thought to that I had toyed w/the idea of adding some petrolem modifyers(stp)in small amounts to see if it would help but it was unnecessary.Myself and my mechanic/racer friends have a saying "would you die in the desert" if your car broke down in the desert would you wait for somebody to rescue you OR would you use what you had on hand along with your ingenuity and get yourself out of the predictament. the same applys don't work the way you want it take the bull by the horns use some of that american ingenuity we're famous for.P.S.Aaron Pfadt, great idea,well made, beautiful CNC machined anodized part but kinda $$$$we know ya gota pay for an idea but look around OBX headers ring a bell your part could easily be made in china if theres a market for it or a machine shop could knock them out if theres a demand.I rather you stay in business and continue to supply us with domestic made productsfor our hobby. Don't shoot yourself in the foot.

vsocks1

Now that was a struggle to read...

WKMCD

What a diatribe..

There are many things I could do to my car. I could cut a huge hole in the hood and run an 18 inch tall NHRA blower but that's not what I want for my car. I could jack the body up and put a Jeep undercarraige on it - but that's not what I want from my car either. Both of those mods would serve a purpose for someone. I also don't want a car that vibrates over 3k RPM and is less fun to drive.

If you've been around here awhile you should know there are not a lot of things I won't do to my car to make it like I want it. This was just not one of them. It's a good piece but in my opinion more suited for track use - period. I'd love to see Aaron come out with one more appropriate for the street that uses a rubber bushing at the pivot. You may not get 100% of the benefit but if you get 75% and no vibration it's still a winner for people like me.

K RIPPER

Iwasn't going to answer but it seems you clearly miss the point diatribe? well it is long but it is not critical or satirical in a nutshell a good piece that could be made to,or modified, or otherwise altered to suite your individual needs and to do it yourself.If its not for you fine but it is clearly superior to the factory piece performance wise and if made to work w/o the short comings all the better. the reference to NHRA blowers and jeeps I don't get it.My post was in no way a response to your post. I was satisifed with the part and just wanted to point out that for those who encountered problems the part could be made to work in an acceptable manner

Warp Factor

My feeling is that a part sold as a bolt-on to a factory car shouldn't need a lot of dinking. If it's sold as a component for a race car or a fabricated car, that's a different matter.

I realize that people have posted in various threads that the car feels different, but what actual evidence is there that it is superior to the factory piece?

A louder exhaust, red floor mats, or a "carbon fiber" console might make my car seem faster. A skillful money grubbin' ***** sittin' in the passenger seat would do even better, if I was into fooling myself.

ajg1915

Based on the design of the C6 rear cross member and differential design, GM sought a better way to stabilize the rear differential by creating a mount on each side of the differential instead of just a single center mount.

The Pfadt piece for the C5, sought to do the same thing that GM did for the C6, the only issue (difference) is Pfadt did it by using a harsher (solid) mounting method which is why many owners with the Pfadt mount are experiencing vibration noise transfer.

A piece of 1/4" rubber mounted between the cross-member and the Pfadt mount would probably eliminate 95% of the vibration noise.

Unlike most frame vehicles there are no body mounts (poly or rubber) used to isolate the chassis from the body, nor are there any absorption materials used in the cross-member or frame mounting areas.

The lack of any absorption material makes any noise carry in the C5 / C6 vettes in my opinion.

Warp Factor

I'll let the GM engineer here address any differences between the C5 and C6 differential mounts.
Yes, performance vehicles often cut it really close when it comes to vibration and sound isolation versus performance. In my opinion, the Vette engineers made some intelligent compromises. Under most situations, road noise is quite tolerable. On rough or grooved road surfaces, I can't have a conversation with a passenger without yelling.

I think we all know that mainstream auto engineers are capable of creating cars that can pull some fantastic G forces. The question becomes, "How many buyers will purchase such a car, given the loss of creature comforts?"

Almost any of us can go out and purchase a fast econo-rail (for drags), or a go-cart (for giggles and lap times). They're not all that comfy. How many recreational miles are put on these compared to Vettes?

ajg1915

To be honest with ya, where are you legally going to use the handling capabilities of a C5 or C6 vette. I don't think there are too many places where you can ever max out the "G" force of a vette legally on the street.

Much of the performance mods we do on our cars is for bragging rights or guys who run at the track in either the 1320 or roadracing categories.

I know that I will never use what I have built except in some off-road excursion.

None of this really affects me since I'm going with a C6 Z06 differential in my C5 and thus will be using a C6 cradle and mounting system.

Millenium Z06

Yet that exactly what they did. RR crossings were harsher and road noise increased slightly. Overall, the trade off wasn't much, certainly not enough of an annoyance for me to take them out but I could defiantly tell a difference when I took rudder ones out and the PU were in.

The deflection that the rubber ones had is exactly why I too them out but just like here, that same rubber that allowed for some deflection also adding some cushioning or insulation.

Like someone else said, maybe if the part had a bigger softer rubber isolater then it would work better for non track only cars.