Boxter vibration problem and exhaust noise

[Jeff396]

Hey all,

I purchased a 2002 Boxter S about 1 1/2 years ago and just love it. I am having two problems that have been there since I bought it. I hope someone can help me with these as a search didn't find anything similar.

The first problem is a vibration that comes on around 70 or 75 mph. It's hard to tell if it's in the seat or the wheel. It really feels like it's in both places. I had the tires balanced by a tire place and the improvement was very slight. They said they were pretty close to begin with. Someone told me that the Porsche's are really particular about wheel balance and I needed to take them to someone who does a more thorough job of balancing going as far as tire shaving. I saw some other issues concerning vibration in my search but none seem to match my poroblem. Any opinions on this would be helpful.

The second issue I have, that I did not search on yet as I just rememebered it is a strange fluttering noise coming from the exhaust. To my untrained ears it sounds like it's an air cooled motor instead of water cooled. Kinda like an exhaust leak. This car came with a Borla exhaust on it so I don't have any point of reference of what the stock exhaust sounded like. Any thoughts on this issue?

Any help would be really appreciated!!!

Jeff

[BYprodriver]

I would refine the info you have been given to say tire balance gets sensitive only if you exceed factory air pressure specs especially on the front 29psi. That being said I always get the tire shop to "balance" my bare wheels first to see how far from perfect the wheels are before mounting a tire on it. (do not add balance weights until after tire is mounted then balance wheel & tire assembly)

I would check/replace the front engine mount if tire pressures are correct. If you do a search for motor mount you will see all the strange things that go on when the mount wears & its not to hard to change.

[Zeke]

The stock exhaust is rather quiet. You will hear a lot more induction noise inside and even thru the outside intake on the driver's side.

Getting a tire balanced perfectly is an art indeed. Only one guy around here can do it every time. I had mine done with a Hunter Road Force last time and it's pretty good, but not as good as the guy that lightly shaves them and balances them on the machine and then on the car with a strobe.

[BYprodriver]

Originally Posted by milt

The stock exhaust is rather quiet. You will hear a lot more induction noise inside and even thru the outside intake on the driver's side.

Getting a tire balanced perfectly is an art indeed. Only one guy around here can do it every time. I had mine done with a Hunter Road Force last time and it's pretty good, but not as good as the guy that lightly shaves them and balances them on the machine and then on the car with a strobe.

Can you tell me who does the on the car tire balance?

[Zeke]

Nate Jones in Signal Hill.

[BYprodriver]

I have used him several times, became more & more difficult to work with. Paid him to diagnose a vibration problem where I thought it was a rear wheel bearing. He said it was probably the tires since they were low on tread. I was right as the bearing was on the verge of coming apart. I was hoping you had a more professional alternative. Thanks anyway.

[Zeke]

He doesn't make that many mistakes. Yes, he's as bull headed as they come, but his credentials are pretty good to call him less than professional. If you thought you had a bearing problem, why did you go to a tire shop?

I know, I know, you just wanted to rule out the tires. He may not be that interested in that kind of work. He has too many Bonneville racers to service. Does a lot of old Ferraris with wire wheels as well. Too bad you couldn't word with him.

BTW, I've thought many times over the years of buying the same equipment and doing what he does. The thing is, I understand the theory, but I don't have the 40+ years of experience.

Nate used to have a partner named Mel Hamer. Mel has pased, but in his day he had 2 patents that dealt with balancing. Mel was one of the first to drill vent holes in drum brakes, He did this for his 50's Bonneville car. Soon, he was doing this for a lot of racers and pioneered drilling rotors as well. All while keeping an eye on the balance of the rotating mass.

Nate must know something.

BTW, they split up before Mel died. The reason, I think, is because Nate is messy and Mel was a neatnik. And then there's the personality thing. I never knew for sure, but the was a big age difference between the two, I wonder if Nate's dad was a factor. I've never heard a word spoken about a Nate Jones Sr. or any other Jones related to Nate.

I should write a book about Long Beach and the old hot rodders like Mickey Thompson (whom I worked for), Bill Stroppe and Lion's Drag Strip.

[BYprodriver]

I went BACK to Nates shop off of Spring because I had used him many times to balance wheels & tires on new cars prior to high speed testing for magazine articles. (Porsches included) Starting with the shop on Redondo. During these visits I noticed the sign on the wall that advertised vibration troubleshooting. I knew he had the ability to detect the source of my problem without pulling the axles & I assumed he knew that tire tread depth has nothing to do with balance/roundness of the tire. I believe he did not want to spend much time on my car because he said the tires were "worn out" & couldnot do anything more until I replaced the tires. Since the tires were all evenly worn with 2-3 32nds tread remaining & 2 yrs. old they were in the prime of their life for traction & ride quality & not leaving my car until I got the benifit of 2yrs. of grooming to get them to that state. The polished Mickey Thompson wheels on the car were most likely to blame for any vibration problem since they were made around 1968 but Nate was undoubtablly aware of this & did have time to take my money once he made his pronouncement of the problem. Within a week I removed my right rear brake drum & found the axle had about 1/4" freeplay side to side movement & worn enough to require replacement. That was over 8 years ago & I have not been back.

[Jeff396]

Thanks for the replies!

I'll check the front motor mount. I did read a lot of posts where they thought that had caused some problems. I'll also check the front tire pressure.

On the tire balancing, where would I begin to look for a place that does the really in depth tire balancing?

My wife and I took the Boxter to the mountains a couple weeks ago. I've decided that I gotta get rid of that Borla exhaust. The constant droning drove me crazy after a bit. Any suggestions for an exhaust somewhere between the Borla and stock as far as exhaust note goes?

Jeff

[BYprodriver]

First step in resolving any ride disturbance problem is to set all tires to factory psi spec's. Next drive car on the smoothest road you can go 75mph (your problem speed), if the steering wheel shimmys side to side at a specific speed more than likely you have a balance problem with 1 or both of the front wheel&tire assemblys. Since you have balanced them twice already I suspect a bent wheel which can be verified by spinning the bare wheel on the balance machine as if you where balancing a tire & watch the wheel for movement up & down or side to side & look to see how much weight is required to balance the bare wheel. 1oz. is common for a acceptable wheel. If there is no shimmy in the steering wheel & your car does not already have the improved Cayman front motor mount I would put one on, mine is arriving today from Pelican. This step will prevent all sorts of mysterys & improve shifting. From reading several Forums the past 5 yrs. it seems to me all nonstock mufflers have objectional noises at varying rpm's, I love the sound of my original S muffler with headers & Dansk sport Cat midpipes. If I knew where you are I might suggest balancing shops but the easiest way is to make sure all your tires are less than 5 yrs. old & have the word "Michelin" on the side.

[RNajarian]

I had an unusual vibration coming from the driver's rear wheel which would begin at 68 mph and end at 74 mph. It was loud enough to concern me. I feared it was a wheel bearing BUT fortunately I figured it out before the expensive repair.

The rear FLOOR COVER TRIM-BLA OEM-9865043940001C (translation- "mud flap"/wheel trim in front of the wheel well) was missing. At speed the plastic liner in the wheel well must have been flapping around causing the noise.

I replaced it and the sound is gone.

[Wayne 962]

Originally Posted by Jeff396

Thanks for the replies!

I'll check the front motor mount. I did read a lot of posts where they thought that had caused some problems. I'll also check the front tire pressure.

On the tire balancing, where would I begin to look for a place that does the really in depth tire balancing?

My wife and I took the Boxter to the mountains a couple weeks ago. I've decided that I gotta get rid of that Borla exhaust. The constant droning drove me crazy after a bit. Any suggestions for an exhaust somewhere between the Borla and stock as far as exhaust note goes?

Jeff

The DANSK sport muffler is nice too, much less drone than the Borla. I ran that on my Boxster for a short while, and I liked it. Not as much as the FabSpeed one that is on there right now, but it was really nice.

-Wayne

[Wayne 962]

As for vibration problems, I would start with the following:

- Rotate the tires. Even if they are directional, you should be able to drive with the tread running the opposite way for a short distance just for testing. See if that makes a difference.

- Try driving with the top down and the top up as well. The harmonics of the car change with the change in the top - sometimes odd vibrations can be amplified or dampened with the change. It's not going to solve your problem, but you might be able to better isolate the noise.

I would start there.

-Wayne