AudioCircle
Community => Non-audio hobbies and interests => Cars and Bikes => Topic started by: Kenneth Patchen on 30 Jul 2015, 02:29 pm
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With today's cars I no longer question how things work. Why bother trying to understand something that will require a mechanic and a computer to fix?
Anyway, here are two questions. (It's not that I'm lazy. I've searched the internet but haven't found the answers. Perhaps something here could help.)
Does AWD create a noisier riding experience than FWD? If so, is the ride slightly noisier or significantly so?
Are 19" tires noisier than 17"?
There must be a standard measurement for car noise but none of the car reviews ever mention it and only talk about car noise in vague terms such as "very noisy", "very quiet", etc? Why don't they provide actual numbers?
My thanks for your time.
KP
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Should we assume your overall goal is to have a quieter ride? What is the make / model of your car?
I think tire noise is more dependent on tire design and materials more so than tire size, but perhaps some others here have more insight.
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There are very few mechanical things in AWD or FWD that create any real noise. Most measurable noise in cars comes from tire contact with pavement, wind, engine and exhaust.
Insulation and dampening compounds cost money and add weight. They are usually more prevalent on higher trim levels and vary according to brand. Newer cars are however getting better all the time in that regard.
The tires are the only option most of us have to affect noise in our ride. Tread design (think 35" truck knobby mud tires as a worst case) and rubber formulation play a huge dividend in road noise.
There are other things like suspension bushings (soft or stiff) that affect tire noise too. just like audio, dampening makes things quiet.
Go drive a new AWD Buick and you will get an idea of what is possible with modern dampening and insulation. Then to experience the other end of the spectrum go drive a 1985 4x4 Toyota pickup with 32" muders.
I would imagine you can find a model and trim package that is a good compromise between capability and comfort. There has never been a time like this where such performance and selection were available in the automotive world. :thumb:
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I have nothing to add, but agree with everything that's been said so far. :thumb:
"Back in the day", magazine reviews used to publish interior noise dB numbers at certain speeds.
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AWD vs FWD is a non-issue wrt noise, AWD is a performance feature than some find valuable and others do not. Personally, I hate how fwd cars drive and would rather have rwd, but I own a Subaru WRX which is AWD.
Tire sidewall height (aspect ratio) will make a massive difference in NVH (noise, vibration and harshness) as will the type of tire selected. A 17" vs 19" rim with the same tire diameter will have very different feel to them, as well as very different prices when you need to change them. This is really a personal choice and you should test drive both options if possible.
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I own FWD and AWD. AWD has more moving parts, so is bound to be noisier.
And I agree with Dave that sidewall height affects NVH, but tread design is the only substantial factor here. Gripper, off road tread designs are noisy. I suppose tire compound (harder/softer) could also affect road noise.
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Not precisely related but I just upgrade my Jeep's wheels from 33" Duratracs (not mudders, more of a hybrid aggressive all terain) to 35" Nitto Mud Grapplers. The difference in noise is significant! In my case it adds to cool factor. Before I had the Jeep my dad had BFG hybrids and they were a lot noisey (and worse performing) than the Duratracs. So tread pattern I would say it very significant.
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Audi Quattro - and never look back.....
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Well...Ok, now I'll chime in...
AWD is only FWD unless front wheel slippage is detected, then the rear wheels kick in. So yea, while AWD does technically have more moving parts, half of them aren't doing anything under the vast majority of driving conditions.
As far as tire noise goes, there will be no difference between sizes. Doesn't matter if it's a 15" or a 22". Given the fact the tire brand, speed rating, and tread design is the same. Now, when you hit a pothole, a tire with more sidewall will take that hit with less pomp and circumstance than a lower sidewall.
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Yes, a quiet ride is at the top of my list of 'must haves'.
My Ford Fusion Hybrid is now in the auto graveyard after being T-boned in NC. Very quiet car, good mpg. I'm looking at 2016 vehicles, mostly SUVs. I have dogs, plural, and a camping trailer, singular. I drove a Honda CRV for a few years, several changes in tires, sound dampening added, still, highway noise so loud I feared for my hearing. Crap mpg. Never again.
I've read dozens of reviews. Not one mentioned NVH specifically or an NVH rating, if there is one. Cars are described as "noisy" or "quiet" or something along those lines. Why isn't there a Marcel Marceau reference scale of sound measurement, this car rates an acceptable 12 but this car is a menacing 42 on the MM scale. Yes, I too remember when the car mag reviews included decibel ratings. No longer.
I'm driving a Mazda CR5 today, reviewed as 'quiet', better than average mpg. But how quiet is quiet?
Waiting for zee bus ... (that's a Marcel Marceau reference kids).
Thanks all.
KP
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Well...Ok, now I'll chime in...
AWD is only FWD unless front wheel slippage is detected, then the rear wheels kick in. So yea, while AWD does technically have more moving parts, half of them aren't doing anything under the vast majority of driving conditions.
As far as tire noise goes, there will be no difference between sizes. Doesn't matter if it's a 15" or a 22". Given the fact the tire brand, speed rating, and tread design is the same. Now, when you hit a pothole, a tire with more sidewall will take that hit with less pomp and circumstance than a lower sidewall.
There are all sorts of different AWD systems, some are like you say others like in my WRX split the power 50/50 using a viscous coupling. The STi has a computer controlled center differential but is usually 40/60 when cruising around, but it can be locked or limited by the driver. Other Subarus with automatic transmissions are 90% FWD until it slips, then more power is transferred.
I agree tire noise depends on tread but aspect ratio makes a huge difference in handling, vibration, etc...
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KP,
I can't say anything to the FWD vs AWD nor can I say anything about the 17" vs 19" as these are out of my experience. However, I can speak to noise damping in vehicles.
My son and I removed the seats, carpets, center consoles, door liners, etc. from my '07 Access cab Tacoma a few years ago. We cleaned the metal before laying down a patchwork of Dynamat Xtreme (not a solid layer - more a checkerboard coverage) onto the metal floor, rear wall, side walls, and fire wall. Then, we lay down a full coverage 'carpet' of Raammat Ensolite peel & stick damping material over the checkerboard Dynamat. We then replaced all the carpeting, console, seats, etc.
Neither the Dynamat nor the Raammat is particularly heavy. We may have added 15 lbs to my pickup. When folks complain about how heavy damping material is, they must be talking about Mass Loaded Vinyl (MLV), which is very heavy.
I have an exceptionally quiet pickup thanks to all the damping material in my cab.
http://www.raamaudio.com/ensolite-iuo-peel-and-stick-14-sq-ft-per-running-yard-3-per-pack-of-bxt-ii-recommended-absolutely-the-best-foam-on-the-market/
Michael
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Retired English teacher's note: I did not use 'dampening' materials to 'damp' the noise levels in my pickup. I do not dampen my audio equipment in an effort to damp noise. Do people use spray bottles or just dump a gallon of water on their equipment?
to dampen = to moisten
to damp = to make quieter
Honestly, I promise to refrain from further grammar corrections. This grammar lesson has been percolating inside my mind for months because I've read dozens of posts about the SQ improvement realized after moistening audio equipment. These testimonials come from average Joes, but also from industry manufacturers who ought to know better than to recommend moistening audio gear. It boggles the mind.
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KP,
][/i] material over the checkerboard Dynamat. We then replaced all the carpeting, console, seats, etc.
I have an exceptionally quiet pickup thanks to all the damping material in my cab.
http://www.raamaudio.com/ensolite-iuo-peel-and-stick-14-sq-ft-per-running-yard-3-per-pack-of-bxt-ii-recommended-absolutely-the-best-foam-on-the-market/
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Retired English teacher's note: I did not use 'dampening' materials to 'damp' the noise levels in my pickup. I do not dampen my audio equipment in an effort to damp noise. Do people use spray bottles or just dump a gallon of water on their equipment?
to dampen = to moisten
to damp = to make quieter
Honestly, I promise to refrain from further grammar corrections.
Michael,
No problem with the grammar lesson, appreciate it. I went to a military high school taught by fierce benedictine monks. I had a tendency to drift off during the exciting bits so I missed some things. I remember the punishment but can't remember if it was corporal or corporeal.
Can I blame that dampening error on auto-correct? My IPAD is acting possessed today.
I added Dynamat to the CRV, didn't do much.
Thanks all, your answers have been very helpful.
Take care,
KP
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Just for grins, I checked Car&Driver to see if they published cound level specs on a new car.
Since I work for Volvo, I checked an XC60. Here's the interior sound decibel level under various circumstances.
Check the table on the left side, bottom page:
http://media.caranddriver.com/files/2015-volvo-xc60-t6-drive-e-test-review-car-and-driver2015-volvo-xc60-t6-drive-e.pdf
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Well, a CRV is not a high-end vehicle, nor are typical Toyotas, Mazdas, Nissans, Fords, etc. That's not to say there aren't exceptions in this auto sector with regard to refinement, but.......
Where you'll pretty much always find quieter and more refined vehicles are the luxury brands, like Acura, Lexus, Mercedes, BMW, Audi, Cadillac, etc....
Costs to damp (thanks mresseguie!) these more expensive vehicles are less scrutinized by the bean counters and is a point of differentiaton between, for example, a Camry and an Lexus GS.
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Tirerack.com runs user surveys on all the tires it sells. Tires are rated on many aspects, including ride and noise. Check that out.
Me ---I would not do without my AWD Audi S6 Avant, especially on Minnesota snowy roads. With winter tires it is unstoppable on nasty roads. It is quiet and comfortable, not much noise unless all 350HP are opened up. No, it is not a FWD with rear drive kicking in when needed. Power is split front and rear as needed, but mostly RWD.
Frank
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The Goodyear Wrangler® SilentArmor® has a DuPont™ Kevlar layer that really works. They are the quietest tires I have ever had on my '77 Jeep Wagoneer, plus they are very grabby off road, paved streets, and in the rain.
https://www.goodyear.com/en-US/tires/wrangler-silentarmor (https://www.goodyear.com/en-US/tires/wrangler-silentarmor)
(https://www.goodyear.com/images/tireImages/goodyear/primaryImage/Wrangler_Silent_Armor_366.jpg)
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+1 for TireRack.com to do your research.
Unfortunately they don't sell/cover every brand, but the only popular brand that they don't handle that I was interested in were Cooper.
I've had very good experiences with Goodyear Assurance Comfort Treads and Goodyear Assurance Triple Treads, racking up over 400,000+ miles on them. Not inexpensive, but they last the rated 80,000 miles and are very good in rain and snow. On my Outback I've never failed to make it through any sane amounts of snow.
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Are 19" tires noisier than 17"?
I have seen sport cars with big wheels and low tire noise.
What increases tire noise is the design of the riding band proper for land.
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Just for grins, I checked Car&Driver to see if they published cound level specs on a new car.
Since I work for Volvo, I checked an XC60. Here's the interior sound decibel level under various circumstances.
Check the table on the left side, bottom page:
http://media.caranddriver.com/files/2015-volvo-xc60-t6-drive-e-test-review-car-and-driver2015-volvo-xc60-t6-drive-e.pdf
Thanks muchly, Bob, that's exactly what I was looking for but didn't find. I'll check for others . I visited the Mazda dealer today and none of the salesmen could give me exact figures on noise levels. Evidently, I'm the first person to ask for them. Ever. I did like driving the CX5 Grand Touring. Quiet on side streets and highway.
The salesman did tell me that 19" wheels were quieter than 18" and a leather interior absorbed more extraneous noise than cloth interiors and I said hmmmm.
Thanks to everyone for tire recommendations. Frank, thanks for the tip about the Audi.
Cheers,
KP
Frank,
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The 19 may be quieter than the 18 because the manufacture changed the tire brand/model/performance rating between the two???
But if he can't get hard statistics, then it's probably just his opinion and not based on information given my the manufacturer.
Also, the car with the trim and/or performance package that comes with the 19 might be stuffed with more sound absorption than the 18?
I'm speculating here, just based on past experience. I do not know specifically of what Mazda is doing.
But leather absorbs more noise than cloth?
Well, acoustics aren't my forte, but I'm thinking that (again), a cloth interior car is a base model than has less interior sound absorption than a leather clad interior.
Seems the masses demand leather and cloth is for the poors. For some reason. It's hard to find a high end car or trim level that contains a cloth interior, so if you want cloth, then you must have less money to spend on a car, therefore it won't be as quiet as a "richer" car (within the same model line).
So yea, I can see why he would say that, or at least how he came up with his opinion.
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I'm with you Bob, prefer cloth to leather upholstery. The salesman is problem inventing reasons to sell an upgrade, but I suppose there is a slight chance that the leather option has more padding and so slightly lower noise levels. Remember a secretary at work put towels on her leather seats in the summer. Her husband had won the car (the last Buick Reatta built, British racing green with tan interior).
This whole discussion is a bit ironic to me. 30 years ago was shopping for a new car and test drove an Acura Integra with manual tranny. Darn engine was so quiet and smooth I ground the starter not realizing it was already running and then had to use the tach to shift as I couldn't hear the engine rev. That and a crummy trade-in offer soured me on the deal.
Actually like the growl of my Subaru boxer engine so I can monitor the engine without looking at the tach. My 4 cylinder Camry is quiet and can hardly hear the engine.
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I wouldn't buy 19" wheels simply for the reason that it's an odd size, and tires for it tend to be ridiculously expensive. 17s (or 20s, for that matter) are a lot cheaper.
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Frank, if take you any more test drives be sure to get the car over 55 or 65 MPH. I rented a 2007 Subaru Legacy FWD and it was fine around town even up to 35MPH, but once I got it up to highway speeds on the interstate it was very NOISY. Transmitted noise and vibration were unacceptable. I rented a Toyota Corolla in 2008 that was amazingly quiet, my wife and I just looked at one another in disbelief, it was as quiet as much more expensive cars.
Scotty
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Frank, if take you any more test drives be sure to get the car over 55 or 65 MPH. I rented a 2007 Subaru Legacy FWD and it was fine around town even up to 35MPH, but once I got it up to highway speeds on the interstate it was very NOISY. Transmitted noise and vibration were unacceptable. I rented a Toyota Corolla in 2008 that was amazingly quiet, my wife and I just looked at one another in disbelief, it was as quiet as much more expensive cars.
Scotty
Subaru has never made a FWD Legacy. They are all mechanical, full time AWD.
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Well...Ok, now I'll chime in...
AWD is only FWD unless front wheel slippage is detected, then the rear wheels kick in. So yea, while AWD does technically have more moving parts, half of them aren't doing anything under the vast majority of driving conditions.
That's not entirely true. Audi, Porsche, and Subaru all use full time, mechanical AWD.
There may be others, but relatively speaking, it is rare. Even Lamborghini uses Haldex.
I suspect the idea leather interior is quieter, may be due to it being part of a higher trim package, which by default may also include more insulation.
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They mechanically run all four wheels all the time? Like a 30 year old 4x4 truck? :scratch:
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Frank, if take you any more test drives be sure to get the car over 55 or 65 MPH. I rented a 2007 Subaru Legacy FWD and it was fine around town even up to 35MPH, but once I got it up to highway speeds on the interstate it was very NOISY. Transmitted noise and vibration were unacceptable. I rented a Toyota Corolla in 2008 that was amazingly quiet, my wife and I just looked at one another in disbelief, it was as quiet as much more expensive cars.
Scotty
Huh. I own a 2009 Subaru Outback (currently with 133k miles on it) it seems to be noisier at lower speeds where I can hear the boxer engine "growl". Note that it has a 4 speed automatic. Also owned a 2009 Toyota Corolla eventually with 153k miles on it, also with a 4 cylinder & 4 speed automatic, that was quieter but more underpowered. Just replaced both rear wheel bearings on the Outback that I could hear at 40 - 60 mph, wonder if that was what you experienced? Both are/were good cars, but the Subaru requires more maintenance (and at much higher prices via the dealership). The Subaru feels more substantial, my Toyotas (now have my 3rd Camry) have more of a precision feel and also get better mileage.
Yes, except for the BRZ, all recent Subarus use full time, symmetrical all wheel drive.
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Yes, except for the BRZ, all recent Subarus use full time, symmetrical all wheel drive.
Yup....and I'm pretty sure they've been this way a long time. I would go as far as to say that Subaru's AWD system is their main point of market differentiation. Without it, they're basically just another auto maker.
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I stand corrected on the AWD thing. :oops: I would have never imagined they'd do that.
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They mechanically run all four wheels all the time? Like a 30 year old 4x4 truck? :scratch:
Actually, what you describe is "full wheel drive." For a long time I didn't know the difference either, until a friend explained it to me. Here's a good, short, explanation.
http://www.digitaltrends.com/cars/whats-the-difference-between-four-wheel-drive-and-all-wheel-drive/
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Yes. That's what Mike said in used in some modern cars on post #25.
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Saw that, but your question is post #26, so it made me think maybe Mike didn't provide enough detail in his explanation for ya. :thumb:
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Yes, except for the BRZ, all recent Subarus use full time, symmetrical all wheel drive.
True, but there are big differences between models. The "symmetrical" thing is marketing bs. The auto-trans cars are 90% fwd until they slip, then a computer controlled system transfers torque. On manual trans cars there is a viscous coupling, which is fully mechanical and has a 50/50 split... with the exception of the STi, which features a computer-controlled center diff whose torque-split is driver-adjustable.
The STi is only car that is truly "symmetrical" though as it's the only car Subaru offers with front and rear limited slip differentials. The other cars have traction control, which avoids wheelspin through applying the brakes, but that's more of a band-aid than having real limited slip differentials. The STi's drivetrain and brakes are very impressive but unless you're taking it to the track it's overkill vs the WRX, which offers very similar performance in most circumstances.
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Saw that, but your question is post #26, so it made me think maybe Mike didn't provide enough detail in his explanation for ya. :thumb:
Yea, I've given up. I'm good. :lol:
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Actually, what you describe is "full wheel drive." For a long time I didn't know the difference either, until a friend explained it to me. Here's a good, short, explanation.
http://www.digitaltrends.com/cars/whats-the-difference-between-four-wheel-drive-and-all-wheel-drive/ (http://www.digitaltrends.com/cars/whats-the-difference-between-four-wheel-drive-and-all-wheel-drive/)
I know that's probably not written for car people, but it's somewhat too-overly-simplified in that it equates normal 4WD systems to a locking differential.
The difference is not small:
https://www.youtube.com/watch?v=mkSiJ3UZlso (https://www.youtube.com/watch?v=mkSiJ3UZlso)
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My AWB rig is 60/40. On all the time. Because the rear is slight lighter than the front, it allows the rear to act slightly like a rear wheel drive when corning. If you know what I mean. The rear will come out slightly when corning, but not out so far it gets out of control or spins around, like a rear wheel drive.
The tires probably produce the most amount of road noise. it seems that I have noticed differing amounts of road noise with different brands. Michelin being the quietest of all brands bought.
The fact that my rig was built on a truck platform does not help road noise, I guess, I know the 2006's were built on a newer lighter frame and are lighter/faster and overall a much quiter rig, basically a completely different rig. My 2005 is heavier, and I think that produces more noise, because of the fact that a heavier rig produces more friction, where the rubber meets the road. (IMHO).
Good luck,
V...
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I know that's probably not written for car people, but it's somewhat too-overly-simplified in that it equates normal 4WD systems to a locking differential.
The difference is not small:
https://www.youtube.com/watch?v=mkSiJ3UZlso (https://www.youtube.com/watch?v=mkSiJ3UZlso)
True. It is a very much a layman's explanation. I posted it for that reason, as not all of us are major "car guys" perhaps including the OP. Sometimes getting too technical can be confusing when only a basic understanding is all that is required for the topic of vehicle noise (mechanical, wind, road, etc).
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AWD vs 4WD is super simple. 4WD uses a transfer case that transfers 50% of the power to the front and 50% to the rear all of the time. AWD uses a differential between the front and rear axles and is capable of slip and transfer of power front to rear, which can be accomplished mechanically (torsen or viscous coupling usually) or with a computer controlled differential. Some AWD systems have a locking mechanism for the center diff, converting the car to 4WD which is effective in low traction situations or if the car is stuck.
Lockers or limited slip differentials on the front or rear differentials are a totally different topic and can be used by vehicles with awd or 4wd systems.
If you want specific info about what cars use what system, and how they work in detail... here you go:
http://www.awdwiki.com/en/home/