C4B4the04

Hi all

Installed the Pfadt trans brace last night. I cannot believe GM didn't include this part with the car from the FACTORY. Its that good. If you don't have one, you NEED one. Trust me, the car handles like a different animal. My only issue is a bizarre harmonic resonation that becomes unbearable at exactly 2400 RPM...

I took the stock damper off (that bell shaped round hunk of metal on the driver side) as per the instructions. Started the car after install and could immediatley feel the driveline is now more connected with the car (read as more noise in the cabin, but I have no interior so thats magnified). When you rev the engine, as soon as you cross the 2000 rpm line you start to feel a vibration. When it gets to 2400 its a drone in the car (idled or driving) that is literally impossible to think over.

I am at a loss. I think I am going to try putting the stock damper back on as I am sure this is what it absorbs. If anyone here is running the Pfadt brace AND the stock damper, did you have to mod the damper to make it fit back in place? I don't think I will but just wondering....hey its only two screws so its easy to put back on!


Thanks in advance, I try to give advice when I can....this time I need the help!
Cassidy

Aaron Pfadt

Cassidy,

The damper should have nothing to do with it. I wouldn't waste the time modifying it to put it back on.

It is probably an indication of an unbalance in your stock driveshaft. It might be that your rubber 'guibo' is failing.

Try the rpm test with the clutch in and out. See if there is any difference. If it is the same in both cases, probably it is in your clutch.

-Aaron

sami85L98

This is one of reason i returned back to wilfulone the moment i bought, it works but vibration was my concern, my car has 35k miles and never been raced or abused, but still was concerned about vibration, hope aaron and his team will take care of this vibration thingy and make this an awesome product, i wont be afraid to buy again once vibration taken care of.

WKMCD

We're taking one out of my car tomorrow. I get a hard vibration at 3k and up. It feels like a solid motor mount. In fairness, I had the RAM Dual Street rebuilt at the same time as the brace was put in but RAM assures me that the clutch was rebalanced after the rebuild. Removing the brace is the first step in diagnosing the vibes. TT rubbers are fairly fresh. It probably wouldn't be an issue on a track car but it is in my cruiser.

We'll see tomorrow.

Aaron Pfadt

I don't mean to sound defensive here, but our mount does not cause vibration. The soft factory mount may cover up something that is out of balance on your car - our mount will not.

If something is amiss in your powertrain this mount may bring it to light. Aftermarket clutches seem to be notorious for being out of balance. While the factory driveshaft and 'guibos' are balanced by GM as an assembly, if some component in that assembly has changed, things might not be up to factory balance specs.

Keep in mind that moving parts can cause noise and vibration. Our mount is made of aluminum and polyurethane and bolts in place - it may transfer vibration, but it is not the source.

I hope I'm not splitting hairs here. I just wanted to clarify.

-Aaron

Warp Factor

Well sure, if things didn't vibrate, there would be no need for all the effort car manufacturers take to isolate vibration.

Short-circuit their efforts, and what's likely to happen?

Aaron Pfadt

That is absolutely true. However, in the majority of the cases, the Pfadt mount system does not cause any undue vibration in the car. There are a few instances where it does. My feeling is that there is something abnormal with those cars.

-Aaron

Warp Factor

Factory cars, or anything for that matter, are built within a range of tolerances.

If it was me, I'd just say right up front that certain changes are likely to cause more noise/vibration. That way, you don't get disappointed people posting on a forum.

I have one vehicle with a solid mounted engine and transmission. With that in mind, extra care was taken with engine and driveshaft balancing. It doesn't vibrate in a way that can be felt, but you can sure hear a symphony from the transmission (which is really just a higher frequency vibration).

vsocks1

I have one of the original trans mounts from Pfadt in my 2003 Z06. I had NO increase of vibration after installation AND I removed the stock resonator on the rear! You guys may have another issue. Didn't Pfadt even offer a softer poly bushing after the original ones? If so...I have the harder one!

Warp Factor

I have no idea, but if so, could it indicate that there was an issue?

WKMCD

I have the softer bushings. I'm not saying the brace is the cause but it comes down to the clutch or the brace - both of which were changed at the same time. If the clutch was easier to take out first, I'd take that out first. Since it isn't, I'll put the stock brace back in and see what happens.

BTW: I don't believe the brace with no moving parts is the cause of the vibration but if it transmits a level that is uncomfortabtle to me - out it comes.

vsocks1

I'll guess your clutch then...hope you get it figured out!

Hall1836

Also had a vibration at about the same RPM, tried the brace with different bushings. Didn't have the vibration before installation, didn't have it between bushing changes when it was out. Don't have the vibration now, don't have the brace either.

rustyguns

i bet its the pilot shaft bearing in the flywheel

that gets installed wrong alot on clutch jobs..or worse..they don't put a new one in !!!!!!!!!

Millenium Z06

The mount is not causing the vibration, it is merely transmitting a vibration that is already there from 1 hard surface to another, like a solid motor mount or a poly u bushing.

This is also the reason that I have not gone to poly u control arm bushing to eliminate wheel hop. I did it in my Z28 and it stopped wheel hop dead but transferred alot of road noise into the car and rode a little rougher.

ncvettes

Well, you can keep the Pfadt tranny mount and empty your wallet chasing vibration sources, or you can just put the stock mount back in place and not lose your sanity. It's a cool device and all, but I had to pull mine off for the same reasons.

dagon138

Now see, If I discovered that I had something out of balance in my drivetrain. I'd be more apt to fix it, as it probably indicates something is WRONG. And having something broken on my car would drive me nuts.

But that's just me...
I don't wash and wax my car every weekend though, so what do I know.

ajg1915

Polyurethane bushings in the control arms will not increase vibration or road noises. All the bushings do is take out the deflection of the stock rubber ones.

Now if you installed poly motor or transmission mounts you would get increased vibration and noise transfer.

Warp Factor

It might, or it might not. Harmonic balancers are used on perfectly balanced engines to reduce torsional crankshaft vibrations. Unbalanced jackshafts are designed into some 4s and V-6es to reduce vibration inherent in the design.
Not all vibration comes from imbalance. There are also impulses fed into the drivetrain with each power stroke of the piston.

It's the deflection which helps isolate the car from road noise and vibration, in the same way that flexible drivetrain mounts provide less noise and vibration transfer. The flexibility of these attachments is a judgment call involving some tradeoffs.

There's a guy who posts in this section who has been been involved in noise and vibration reduction in new car design. Maybe he'll comment on these matters.

WKMCD

McLeod, Lowcash and Sneakelman came by the house this morning and put the stock mount back in. Guess what - no more vibration!

Thanks guys.