Ideas? - noisy interior
#16
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My car has been pretty noisy since I bought it. Being my 3rd 911 I know they aren't Lexus but it seemed excessive. I used a handy decibel meter and the interior averaged 105db! According to C&D I'm way over full throttle measurements.
http://www.caranddriver.com/var/ezfl...4df852475f.pdf
My Michelins look like they have a great deal of life left. It's most noticeable at cruising highway speeds. It doesn't sound mechanical unless it's bearings.
Any ideas? Anyone else have the same experience?
http://www.caranddriver.com/var/ezfl...4df852475f.pdf
My Michelins look like they have a great deal of life left. It's most noticeable at cruising highway speeds. It doesn't sound mechanical unless it's bearings.
Any ideas? Anyone else have the same experience?
1. Go check that reading again.
2. Don't drive for long without ear protection.
If you got that reading right, your car is way too loud. I wonder if people are noticing the number you quote. Anything over 100 decibels is in the range of an unmuffled race car engine. Are you running a modified muffler system?
Gary
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I have 18's on my '05 C2, and it's way noisier than my previous '06 Cayman S. Sounds a bit like a rattle box along with louder engine noises. Tires have a good amount left. I call it my beater. It's wierd because the Cayman's engine was right behind my shoulders. Maybe the larger cabin captures it all and amplifies it.
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I'm riding on 19s on the same Houston roads, but I haven't noticed the road noise being too loud. I don't have any trouble holding a conversation with a passenger or over bluetooth either.
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Gary
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Makes no sense to me unless things have changed with 997.2 My Cab is fine, fine, fine noise wise and I have driven it through those nasty Dallas roads and bounced around California concrete and over Oregon tar strips.
I don't find it too noisy at all. Maybe that's the counter-intuitive trick - get a cab!
I don't find it too noisy at all. Maybe that's the counter-intuitive trick - get a cab!
#22
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We're talking road roar here, not engine noise or rattles. Worse on concrete and coarse road surfaces. it was awful on my Cayman S with Bridgestone 19s and improved but still irksome in my C2S with Michelin 19s. The Michelins are quieter (and better) than the Bridgestones so the cheapest fix is to swap tyres. The new Pirellis may be quieter still but they will wear faster. What you gain on the swings you lose on the roundabouts. Switching to 18s will improve comfort and noise but that is a more expensive fix.
In the end, it's all part of the Porsche experience. I've stopped worrying about it.
In the end, it's all part of the Porsche experience. I've stopped worrying about it.
#24
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When I sit at a light the db level is 72. Steady cruising in town is 92 db.
I remeasured the noise at cruising on concrete freeways and the noise level is 96db so it seems to be normal. The peak was still 105 but that could be indicative of road bumps or some imperfection but it's still way louder than the C&D measurements in the link. It's probably due to new tires in their instrumented test. The only modifications I have are the EVO intake and PSE so I don't think it's those contributing too much. I think, as everyone mentioned, the larger rear tires than the ones on 993s.
I remeasured the noise at cruising on concrete freeways and the noise level is 96db so it seems to be normal. The peak was still 105 but that could be indicative of road bumps or some imperfection but it's still way louder than the C&D measurements in the link. It's probably due to new tires in their instrumented test. The only modifications I have are the EVO intake and PSE so I don't think it's those contributing too much. I think, as everyone mentioned, the larger rear tires than the ones on 993s.
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I'll get you some numbers today, but 105 db is just not in the cards with a properly operating street car. One thing it sounds like. You need to have the meter set for averaging to take this sort of reading.
Gary, with no time
Gary, with no time
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The PS2s on my car were noisy as hell at zero miles, and are absolute howlers now that I'm close to the wear markers. These tires give a rock hard ride, no grip in the wet, and wear down like they're made of chalk. Their only quality is dry grip, and it's comparable to tires with much better treadwear and wet traction. Plus, $488 per rear tire! ![grr](https://rennlist.com/forums/graemlins/cussing.gif)
Damned French tires make me miserable. Once I've burned 'em off I'm going back to Bridgestones and never looking back.
M.
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Damned French tires make me miserable. Once I've burned 'em off I'm going back to Bridgestones and never looking back.
M.
#27
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Thanks for all the feedback. I'm glad to know I'm not alone.
number9ine - I'm with you. Costco now sells Bridgestones so I'm getting those next too.
number9ine - I'm with you. Costco now sells Bridgestones so I'm getting those next too.
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When I sit at a light the db level is 72. Steady cruising in town is 92 db.
I remeasured the noise at cruising on concrete freeways and the noise level is 96db so it seems to be normal. The peak was still 105 but that could be indicative of road bumps or some imperfection but it's still way louder than the C&D measurements in the link. It's probably due to new tires in their instrumented test. The only modifications I have are the EVO intake and PSE so I don't think it's those contributing too much. I think, as everyone mentioned, the larger rear tires than the ones on 993s.
I remeasured the noise at cruising on concrete freeways and the noise level is 96db so it seems to be normal. The peak was still 105 but that could be indicative of road bumps or some imperfection but it's still way louder than the C&D measurements in the link. It's probably due to new tires in their instrumented test. The only modifications I have are the EVO intake and PSE so I don't think it's those contributing too much. I think, as everyone mentioned, the larger rear tires than the ones on 993s.
Measured in a 997.2S with PASM in regular mode (touring?). 19" Carrera II wheels, with Michelin PS2 well worn. Not by any means to the wear bars, but worn enough I've been thinking ahead to their replacement in the near future.
70-72 dB Idling
80-85 dB cruising at sixty on somewhat porous asphalt that should have been repaved last year, if not earlier.
88-90 dB cruising at 73 mph on concrete freeway. Clearly affected by the surface condition, but never getting above the 92 I saw crossing a section starting to wear badly and prematurely compared to the rest.
94-96 dB at 85 mph on a stretch of asphalt road being disputed between county and city maintenance departments and therefore well overdue for re-paving or even ordinary "throw in a shovel full of asphalt" repairs.
96-100 dB at 100 mph on that same road. Obviously the stretches getting rough
generated the jumps to 100 dB.
102 dB was the highest I managed. I went to another stretch under bureaucratic dispute quite heavily traveled nonetheless. I set the cruise control for the highest I could manage without attracting LE attention, 63 mph, and then swerved back and forth seeking the stretches actually starting to break up. I constrained myself only to avoid visible chunks that might fly into the bodywork. I was able to sustain 100 dB in the 'ruts' of this segment, but only got 102 dB at a half repaired broken up section adjacent to the dirt. Part of the shoulder technically.
Since I'm getting numbers so low with the same tires as you, 19" Michelin PS2, I think your problem lies elsewhere. Either your measurement procedure or a problem with the car.
Oh yes, as several people said, this noise level is almost completely attributable to the road noise. Those reading dropped only a couple of dB when I coasted, and full throttle acceleration never exceeded 94 dB. I think. Kinda tough to check a meter while asking an S for full throttle. But my ear agreed. The engine and exhaust never contributed enough to match that broken-up road section or the 100 mph cruise on rough asphalt.
The Carrera isn't a Lexus, but it sure doesn't cruise at 105 dB or I'd never have bought one.
Gary
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Gary. Cheers for your empirical feedback. What instrument are you using to measure? I'm not sure how accurate my iPhone app is but I am going to ask my brother to drive my car so I can really observe the results.
At least the idling db levels are on par with yours.
At least the idling db levels are on par with yours.
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I used the Radio Shack Sound Level Meter, catalog number 33-2050. It is the one recommended by stereophile magazines for adjusting an amplifier to fit your specific room. Very repeatable results and easy to use, and those sources assert it is quite accurate, though I haven't bothered to find a place to calibrate my own. Can't remember the price, I've had it for years, but it wasn't expensive. Probably thirty dollars.
A new one is mentioned to me every day. I'm waiting for an iPhone app that removes your gall bladder.
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Check that app to see if it has an averaging function and how it deals with the A/C weighting distinction. For future reference, since we'll have this discussion in the archives, I set the meter for C weighting and fast response on the averaging. For better accuracy, the Radio Shack unit is a classic meter with ranges provided. The needle indicates dB above or below the center value for the range. After stepping down from the high values like 120dB, I settled on 90 dB for those results I reported, until I found a condition that threatened to peg the needle on the high side. Then I shifted to the 100 dB range.
Obviously, the figures for idling and low speed cruise required use of the quieter ranges. The 70 dB one I believe it was, although I was really just providing a baseline there since we were concerned about the loud events, not the quiet ones.
Gary
Last edited by simsgw; 04-03-2010 at 04:46 AM. Reason: Correct typo in numeric value