Pfadt Trans brace and harmonic resonation without stock damper
10-01-2009, 02:45 PM
#61
Burning Brakes
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St. Jude Donor '08
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This type of response to value forum members is just uncalled for. 
I’ve sat back and have stayed out of these mount discussions since last year with the hope, as jjvet comment suggest, someone would; “step up to the plate” and ether correct it or be upfront and tell people this will GREATLY affect the vibration levels into the chassis. I won’t go into here but to point out this is a bad thing to allow this increase in vibration into body areas that are not designed for it.
Any mount will have an as installed resonate point. A lot of work goes into their design to put the maximum amount of damping at this resonate point. Your repeated answer that it is made out of aluminum and has no moving parts is misleading and clouds the true issue. This mount that jjvet and other are install lacks damping and more important lacks it in the right frequency range. That is why people are complaining. Not to mention being treated as if they are stupid.
To suggest that the problem is everything but your mount is laughable. Feedbacks from members of this forum are supplying the bulk of information to show what the problem is. Typically mounts are designed to have a resonate point ether above or below the primary forcing function, like an engine. From Cassidy’ post he pointed out that the vibration is worse between 2300 and 2800 rpm. This puts this replacement mount resonate point at about 170Hz with next to no damping. The stock diff mount is set right around 58Hz. This puts its resonant point at about 870 engine rpm. The main difference in the stock mount compared to this aluminum replacement is the stock mount has maximum damping at the 58Hz resonant point and makes it a non issue.
On an engine that produces power from 8 pulses every 720° of crankshaft rotation, no amount of balancing will stop this short of a 200 pound engine flywheel. I would be willing to bet that the folks that are complaining the most have lower inertia flywheels. Telling them to fix this because your mount has no moving parts is just plain wrong.
I’ve sat back and have stayed out of these mount discussions since last year with the hope, as jjvet comment suggest, someone would; “step up to the plate” and ether correct it or be upfront and tell people this will GREATLY affect the vibration levels into the chassis. I won’t go into here but to point out this is a bad thing to allow this increase in vibration into body areas that are not designed for it.Any mount will have an as installed resonate point. A lot of work goes into their design to put the maximum amount of damping at this resonate point. Your repeated answer that it is made out of aluminum and has no moving parts is misleading and clouds the true issue. This mount that jjvet and other are install lacks damping and more important lacks it in the right frequency range. That is why people are complaining. Not to mention being treated as if they are stupid.
To suggest that the problem is everything but your mount is laughable. Feedbacks from members of this forum are supplying the bulk of information to show what the problem is. Typically mounts are designed to have a resonate point ether above or below the primary forcing function, like an engine. From Cassidy’ post he pointed out that the vibration is worse between 2300 and 2800 rpm. This puts this replacement mount resonate point at about 170Hz with next to no damping. The stock diff mount is set right around 58Hz. This puts its resonant point at about 870 engine rpm. The main difference in the stock mount compared to this aluminum replacement is the stock mount has maximum damping at the 58Hz resonant point and makes it a non issue.
On an engine that produces power from 8 pulses every 720° of crankshaft rotation, no amount of balancing will stop this short of a 200 pound engine flywheel. I would be willing to bet that the folks that are complaining the most have lower inertia flywheels. Telling them to fix this because your mount has no moving parts is just plain wrong.
1. This part works great for the majority of users
2. No one is forcing anyone to keep this part on their car.
3. If a customer called up and said "this part just does not work on my car, I get too much vibration", Pfadt would work with the customer to make it right.
4. We are not having problems with firing pulse frequency and resonance here, we are having problems with unbalanced rotational parts. If it were firing frequency every car should have it.
To imply that this thread is representative of customers with our powertrain mounts is laughable. Our reputation for our parts and customer service is unmatched. If something does not work for a customer we make it right. Are you unhappy with one of our parts Eric? We'll be happy to work with you.
Oh and insinuation about parts being unsafe/causing damage is untrue and uncalled for. That type of fear mongering is very lowbrow.
Sincerely,
Aaron Pfadt
10-01-2009, 03:43 PM
#62
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St. Jude Donor '09-'10-'11
I spent some time today reading through this thread. It is important to understand that there are no moving parts within our mount assembly thus no possible way it could create a vibration. The factory mounts are softer by design than our mount but they offer poor performance and a lot of potential for breakage in terms of parts twisting.
Last edited by Eric D; 10-01-2009 at 07:54 PM.
10-01-2009, 07:55 PM
#63
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Sometimes reading posts on this forum can make you want to slit your wrist. You install a part from Pfadt racing hence the word racing and complain it causes resonance or vibrating maybe you should sit in a race car then you can feel resonance and vibration. This is the same crap when guys double the horsepower and say oh these trannys and rears stink they don't hold up. If GM would have balanced and had zero tolerances on these cars they wouldn't be 40,000 50,000 dollars new so they use rubber mounts and mask these issues. Heres a idea don't touch your car and you will have none of the issues.Also since the day Pfadt introduced these mounts some people were complaining about the issues and you still purchased them and now its beat up on Pfadt time.
10-01-2009, 09:56 PM
#64
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St. Jude Donor '08
Damn it I was composing a long post and lost it in damn computer
It,s late but Iwant to get on board and ask Pfadt to quit acting like a politician and step up to the plate on this
To me it does not matter if GM did,nt have there act together on this
Most of us bought this product to correct a problem we did,nt sign on for another one .I am not an engineer but I am not stupid ,this is a resonance problem and Pfadt needs to man up and help us instead of all the BS stop telling us that we all have problems with our cars.Mine is a z06 and it prob. worst than most.I don,t want to take it out but that is prob.what I will have to do if they refuse to help us.Can you imagine a forum where we could offer a group repurchase
I,ll will tell you what I think might help I am planning to put a piece of rubber under the center support and carrier and maybe I want have to have a new flywheel clutch pressure plate throwout bearing drive shaft out shaft etc etc .Hey I am older tham most does any one rember the Lockeed Electra? nuff said
It,s late but Iwant to get on board and ask Pfadt to quit acting like a politician and step up to the plate on this
To me it does not matter if GM did,nt have there act together on this
Most of us bought this product to correct a problem we did,nt sign on for another one .I am not an engineer but I am not stupid ,this is a resonance problem and Pfadt needs to man up and help us instead of all the BS stop telling us that we all have problems with our cars.Mine is a z06 and it prob. worst than most.I don,t want to take it out but that is prob.what I will have to do if they refuse to help us.Can you imagine a forum where we could offer a group repurchase
I,ll will tell you what I think might help I am planning to put a piece of rubber under the center support and carrier and maybe I want have to have a new flywheel clutch pressure plate throwout bearing drive shaft out shaft etc etc .Hey I am older tham most does any one rember the Lockeed Electra? nuff said
I think they are a standup company willing to help any customer.
Its just unrealistic to think that it is Pfadt's fault when a vibration is expose on cars with a lots of aftermarket parts.
10-02-2009, 01:37 AM
#65
Burning Brakes
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brace
Well lets see
1 of coarse when we talk about resonance we know there are no moving parts but I know I did,nt have a problem with it until brace
2 I keep hearing we are nuts and nothing about brace will cause these problems so why do they have a softer ? mount in the center available and now there are softer ? pads, I almost burned up belt sander trying to shave a little off as per your last suggestion ,also was told to keep pads a little off carrier
3 I have tried every thing Pfdat has suggested I even put half of damper back in
4 Yes pfdat is a raceing co. I did,nt see or hear them not wanting to sell to us that were searching for some thing to help the original GM prob.
5 Some dude even suggested we should stop whining [ like my brace ] and never change anything so I guess I should not have bought as an example
the rocker rails or maybe screen to keep trash out of radiator ,these products did not cause any other issues
6 I don,t want to dog on Pfdat I want them to make my car livable again or this is offical .THIS PART IS NOT WORKING FOR ME, THIS PART JUST DOES NOT WORK ON MY CAR I GET TO MUCH NOISE
1 of coarse when we talk about resonance we know there are no moving parts but I know I did,nt have a problem with it until brace
2 I keep hearing we are nuts and nothing about brace will cause these problems so why do they have a softer ? mount in the center available and now there are softer ? pads, I almost burned up belt sander trying to shave a little off as per your last suggestion ,also was told to keep pads a little off carrier
3 I have tried every thing Pfdat has suggested I even put half of damper back in
4 Yes pfdat is a raceing co. I did,nt see or hear them not wanting to sell to us that were searching for some thing to help the original GM prob.
5 Some dude even suggested we should stop whining [ like my brace ] and never change anything so I guess I should not have bought as an example
the rocker rails or maybe screen to keep trash out of radiator ,these products did not cause any other issues
6 I don,t want to dog on Pfdat I want them to make my car livable again or this is offical .THIS PART IS NOT WORKING FOR ME, THIS PART JUST DOES NOT WORK ON MY CAR I GET TO MUCH NOISE
10-02-2009, 09:52 AM
#66
Team Owner
I don't understand how you can expect to remove the soft factory bushing and replace it with a "dual" larger surface area, harder poly bushing set up and not expect some more vibration through the drive train. I'm not sure Pfadt is being completely realistic with some of their statements either.
10-02-2009, 11:12 AM
#67
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St. Jude Donor '09-'10-'11
I don't understand how you can expect to remove the soft factory bushing and replace it with a "dual" larger surface area, harder poly bushing set up and not expect some more vibration through the drive train. I'm not sure Pfadt is being completely realistic with some of their statements either.
Well, most likely from what they have read. If you talk about what people expect from a product from a “racing supplier” the supplier’s verbiage is what a large number of people use to make their decision on what to purchase or not. Statements like “The soft stock mounts allow power-robbing movement that shakes the car and can break parts.” From their website.
This could easily be interpreted to mean, "If I don’t change to this part I could break something".
Then add “Our mounts reduce the massive powertrain shake.” Would not one expect a reduction in “powertrain shake” vibration?
If you take the stance commonly used here, that it is only aluminum and polyurethane with no moving parts so how can it cause vibration, and turn around and claim that it reduces massive powertrain shake? No moving parts so how can it do this? You can’t have it both ways.
If it were possible to eliminate every imbalance and every engine order forced response we wouldn’t need any isolation. At least to date, that hasn’t been done.
Anyway, it is good that we have choices and I choose to leave this thread and wish you all the best!
10-02-2009, 11:32 AM
#68
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After reading about 2 pages of this I had to throw my two cents in. Before I had the Pfadt Trans brace my car was ridiculously twisting and I only have 400rwhp with 4:10's and I felt like my car was going to twist in half. I installed this brace and it was the best mod ever. It made everything so tight and I really felt that the power was getting to the ground so much better. The vibration you are feeling it the trans brace fighting the twist in the drive train. This is what it is designed to do. Its a race engineered product of course it is going to make the car louder and ride harder thats the idea behind it! I love the brace. The install PITA to the extreme. I had to widen the holes in my rear cradle to make it fit. What a pain! Anyway though, if you cant stand the vibration take it off, some people cant stand their corvettes being loud I mean I dont know why anyone would ever want a quiet car but thats just me!
10-02-2009, 11:39 AM
#69
Burning Brakes
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St. Jude Donor '08
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jjvet,
I'm sorry if this has gotten a little contentious. I know that we have talked personally, and this is not a blame situation. I think that your car is unique when it comes to this mount. The few people that have had vibration that they considered unacceptable have been able to correct it with some of the small tweaks that you and I have discussed. We have outrigger pads in a softer durometer (which I believe that you have) that lower the frequency (to Eric D's point) and have helped some problem cars.
Because you still have this resonance/vibration, I would suggest removing the part. There is something in or on your car that makes it unique and a problem with this mount. I do not have any other suggestions to fix the vibration by changing our mount. Give us a call and we should work out a solution that is mutually acceptable.
-Aaron
I'm sorry if this has gotten a little contentious. I know that we have talked personally, and this is not a blame situation. I think that your car is unique when it comes to this mount. The few people that have had vibration that they considered unacceptable have been able to correct it with some of the small tweaks that you and I have discussed. We have outrigger pads in a softer durometer (which I believe that you have) that lower the frequency (to Eric D's point) and have helped some problem cars.
Because you still have this resonance/vibration, I would suggest removing the part. There is something in or on your car that makes it unique and a problem with this mount. I do not have any other suggestions to fix the vibration by changing our mount. Give us a call and we should work out a solution that is mutually acceptable.
-Aaron
10-02-2009, 12:09 PM
#70
Team Owner
jjvet,
I'm sorry if this has gotten a little contentious. I know that we have talked personally, and this is not a blame situation. I think that your car is unique when it comes to this mount. The few people that have had vibration that they considered unacceptable have been able to correct it with some of the small tweaks that you and I have discussed. We have outrigger pads in a softer durometer (which I believe that you have) that lower the frequency (to Eric D's point) and have helped some problem cars.
Because you still have this resonance/vibration, I would suggest removing the part. There is something in or on your car that makes it unique and a problem with this mount. I do not have any other suggestions to fix the vibration by changing our mount. Give us a call and we should work out a solution that is mutually acceptable.
-Aaron
I'm sorry if this has gotten a little contentious. I know that we have talked personally, and this is not a blame situation. I think that your car is unique when it comes to this mount. The few people that have had vibration that they considered unacceptable have been able to correct it with some of the small tweaks that you and I have discussed. We have outrigger pads in a softer durometer (which I believe that you have) that lower the frequency (to Eric D's point) and have helped some problem cars.
Because you still have this resonance/vibration, I would suggest removing the part. There is something in or on your car that makes it unique and a problem with this mount. I do not have any other suggestions to fix the vibration by changing our mount. Give us a call and we should work out a solution that is mutually acceptable.
-Aaron
Wow, you cant ask for more than that. Pfadt seems like really caring, stand up place.
Kudos!!
Also, for whatever reason, I think a lot of people have an unrealistic expectation of this part on a daily driver.
10-02-2009, 01:45 PM
#71
Burning Brakes
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brace
Just got off the phone with AAron Pfdat {35 min] ,I told him at out set that I would post our talk in a positive way even if he could offer no more solutions than what I,ve triedI told him that I could not rule out a problem with my car but I had no noise before install .But something could have gone wrong after no real way to tell unless you take out brace.
There is the problem if I take it out and noise goes away problem solved and that still does not prove the brace is bad maybe just not good for my car ,GM does,nt make all the same . If noise does,nt go away then I would have to correct what might be wrong and I would have to put brace back to keep car from hopping.It did not hop that much but once is too much.
I would also like to saythat to me my problem is more a whine but people tend to describe the same thing differently so who knows
I told him I wanted to try something between the mount bracket and carrier he suggested cuttin a mudflap I will try that and let him know
Look it,s still almost a free country and youy have a right to post here but I think no matter which side you are on here unless you have a dog in this fight it would be nice if you did,nt fan the flames
We who seem to have a problem need solutions not stupid comments like we should have known there would be issues if we installed this part
If you drive once a week to church or drive the sheet out of it every minute Aaron does nt want you to be dissatisied.
Sorry for long post Aaron and I are cool and I will not post on this again unless I can have something to say that helps
Now I,m going for a Blue Moon
10-02-2009, 02:00 PM
#72
Team Owner
Well, let me know how it works out. I have been interested in one of these mounts to help w/ wheel hop. If you still have issues, remove the mount and send it to me. I'll try it on my car. I'll validate the noise/no noise issue and if I end with no noise I will buy it from you.
My car's drivetrain is 100% stock so it is a great test. I only have LG streets and Z06 exhaust.
My car's drivetrain is 100% stock so it is a great test. I only have LG streets and Z06 exhaust.
10-02-2009, 02:38 PM
#73
Just got off the phone with AAron Pfdat {35 min] ,I told him at out set that I would post our talk in a positive way even if he could offer no more solutions than what I,ve triedI told him that I could not rule out a problem with my car but I had no noise before install .But something could have gone wrong after no real way to tell unless you take out brace.
There is the problem if I take it out and noise goes away problem solved and that still does not prove the brace is bad maybe just not good for my car ,GM does,nt make all the same . If noise does,nt go away then I would have to correct what might be wrong and I would have to put brace back to keep car from hopping.It did not hop that much but once is too much.
I would also like to saythat to me my problem is more a whine but people tend to describe the same thing differently so who knows
I told him I wanted to try something between the mount bracket and carrier he suggested cuttin a mudflap I will try that and let him know
Look it,s still almost a free country and youy have a right to post here but I think no matter which side you are on here unless you have a dog in this fight it would be nice if you did,nt fan the flames
We who seem to have a problem need solutions not stupid comments like we should have known there would be issues if we installed this part
If you drive once a week to church or drive the sheet out of it every minute Aaron does nt want you to be dissatisied.
Sorry for long post Aaron and I are cool and I will not post on this again unless I can have something to say that helps
Now I,m going for a Blue Moon
Let me know if you sell your PFADT Trans Brace...
Christian
10-02-2009, 10:34 PM
#74
Burning Brakes
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Well, let me know how it works out. I have been interested in one of these mounts to help w/ wheel hop. If you still have issues, remove the mount and send it to me. I'll try it on my car. I'll validate the noise/no noise issue and if I end with no noise I will buy it from you.
My car's drivetrain is 100% stock so it is a great test. I only have LG streets and Z06 exhaust.
My car's drivetrain is 100% stock so it is a great test. I only have LG streets and Z06 exhaust.
I have extended warranty but I can,t go to my friendly GM dealer with this thing on my car
If it was not such a PITA to put in or take out I would already know what to do
10-02-2009, 10:37 PM
#76
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Eric, it's fun to see you back in this game.
Corvettejoe98, about your car feeling like it was about to twist in half before the Pfadt brace, realize that the C5 puts next to no engine torque load through the chassis. Could this be a case of "prettier looking girls are better in bed"?
Eric D happens to be a powertrain and vibration expert, and an engineer by trade. Probably worth listening to.
Last edited by Warp Factor; 10-03-2009 at 08:57 AM.
10-03-2009, 04:15 PM
#77
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Eric, it's fun to see you back in this game.
Corvettejoe98, about your car feeling like it was about to twist in half before the Pfadt brace, realize that the C5 puts next to no engine torque load through the chassis. Could this be a case of "prettier looking girls are better in bed"?
Eric D happens to be a powertrain and vibration expert, and an engineer by trade. Probably worth listening to.
Corvettejoe98, about your car feeling like it was about to twist in half before the Pfadt brace, realize that the C5 puts next to no engine torque load through the chassis. Could this be a case of "prettier looking girls are better in bed"?
Eric D happens to be a powertrain and vibration expert, and an engineer by trade. Probably worth listening to.
as i pull away from a light and the whole damn car feels like its going to shake its self apart. Ohh no its ok its just this ...... blah blah blah i bolted on.
11-23-2009, 10:06 PM
#78
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I installed the trans mount about 6 months ago on my 02Z. I did not read the instructions and used all the shims supplied-big mistake. My car had a huge vibration but only at a certain rpm. I raised the car back up on my lift and pulled 2 shims out of each side-test drove. Vibration was gone and the pads were still resting on the cross member-just not nearly as tight. I then purchased PFADT motor mounts for my car and I still have no vibrations at all. They make a great product when they are installed right.
