Piston Slap: The Ear of The Beholder

Sajeev Mehta
by Sajeev Mehta
piston slap the ear of the beholder
TTAC Commentator Seminole95 writes:Dear TTAC, I enjoy this page every day. Thanks for your great work. I especially enjoy the business news and analysis. I will be shopping for a new car in the next year or so and would like a car with low NVH. Do you know of a publication that tests cars for this extensively? I have been unable to find one on the web.I am looking for a low NVH car with a stick. I am guessing the Lexus IS 250 might work but I haven’t driven one yet. I like to listen to podcasts and music in isolation from the daily grind of a commute but still want to enjoy the pleasure of controlling the car via a stick shift. I am a long time Honda buyer but don’t think I’ll buy another for this very reason. I drove a 09 Accord V6 stick Coupe the other week. Nice looking car and sweet power train but man was it loud. Thanks a lot.Sajeev Answers:Not that you’re doing it intentionally, but the phrase “barking up the wrong tree” comes to mind. NVH is a matter of personal taste and scientific analysis. No matter how many decibels are measured by a machine, you could beg to differ. Humans (obviously) come to different conclusions than machines. More to the point, we bicker amongst ourselves because our tastes (and eardrums?) are subjectively different.Nobody in their right mind thinks a Corolla is as NVH-perfect as a Lexus LS460, but you made the mistake of driving basic transportation (Accord) against its upscale (Acura) sibling. Luxury cars usually earn the title for a reason, so compare cars in the same class. Just don’t expect NVH calculations to bear fruit: it’s in the “ear of the beholder.”I thought I was clever for coming up with that phrase all by myself, until I googled it. Thanks a lot for raining on my parade, Dr. Pranab Saha. And while the good doctor’s twenty-something years in the NVH biz isn’t fully utilized in the snippet-link above, it’s safe to say that others agree with my belief. If self-shifting NVH is your primary measuring “stick”, I suspect the Acura TL or Lexus IS250 manuals are your best choices. Test drive ‘em both.Bonus! A Piston Slap Nugget of Wisdom:Sometimes NVH problems are cured via the automotive aftermarket. Strategically placed Dynamat, Fat Mat or any other kind of “mat” out there is good for door panels (inner and outer skins), quarter panels, pillars and even the roof. Especially the roof, it’s often the most neglected body part. Case in point: last weekend I installed Fat Mat’s foil-backed insulation + hood mat on the roof of my brother’s 1991 Mustang notchback. Not that I wanted to, but the headliner-to-roof insulation crumbled in my hands after removing the 19-year-old headliner assembly. And once I started, I couldn’t stop. The difference is stunning: the Mustang’s roof makes a firm thud while Lexus’ products make a tinny bang with the same effort. I wouldn’t be surprised if this Fox coupe has the quietest thunderstorm cabin short of a CL-Mercedes. And all it took was 5-7lbs of product, an afternoon’s work, and about $100. Moral of the story? Buy whatever you like, make it perfect later. Send your queries to mehta@ttac.com. Spare no details and ask for a speedy resolution if you’re in a hurry.
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  • Seminole 95 Seminole 95 on Oct 27, 2010

    Thanks to everyone for the posts. I look forward to this column and it is pretty cool to see mine answered.

  • Mach Mach on Oct 28, 2010

    What about a 2010 VW Jetta TDI? I recently got one and am frankly impressed with the interior quietness, and also disappointed with the engine loudness. The turbo, diesel particulate filter, catalytic converter, and muffler really chop the exhaust note off at the knees, but it still has plenty of power and gets outstanding fuel economy. I also listen to podcasts, streaming radio, etc and the car works great for that. Just personally wishing that I could hear the engine a little more when I put the hammer down.

  • MRF 95 T-Bird In 1986 the Yugo was listed as $3990, which was the lowest priced car in America at the time. The base Hyundai Excel was listed at $1k more at $4995. I knew someone at the time who purchased a base Excel hatchback in red with a four speed. I think he added an aftermarket stereo. He was trading in a Renault Alliance that he purchased a few years earlier for about $5k.
  • SCE to AUX Good summary.I still think autonomous driving should be banned until some brave mfr claims Level 5 capability, and other distractions like games and videos should only be available for stationary vehicles.As for the A/C, I just turn a knob in my Hyundai EV.
  • MrIcky My bet is flood.
  • Lou_BC "A Stellantis employee recommended the change after they had a near-miss with an emergency vehicle they couldn’t hear."I was at a traffic light and the car next to me had the stereo cranked. My whole truck was vibrating. A firetruck was approaching lights and sirens. They should have seen it since it was approaching from their side. Light changed and they went. It was almost a full on broad-side. People are stupid. A green light at an intersection does not mean it is safe to go. You still have to look especially at a "fresh" green. Idiots run the light, an emergency vehicle is coming, or it's icy and vehicles can't stop.
  • Lou_BC My kids drove around in a 2 wheel drive Chevy Colorado crew cab I bought off a neighbour when they were moving to Alberta. We kept it 4 years but sold it recently due to various engine codes popping up and the engine sounding more tired. It was one of the inline 5's known to have soft valve seats. All I had to repair was new front brakes and rotors, a wheel bearing and a battery. Both kids wrecked a tire clipping a curb. My oldest backed into it with his pickup which required a grill and headlight replacement. We bought a 2008 Corolla as a replacement for my 19 year old. It came with 4 new summers and a set of decent winter tires on rims. We'll run that until it looks like it will implode/explode. My oldest currently has 3 Cherokees (2 for parts), an F150 "Jelly bean", and a Mercury Grand Marquis. Insurance is very expensive for young drivers. That's why beaters can save some money. I haven't put them on my new truck's insurance since that would add around 90 per month in costs. I'll add my oldest to it temporarily so he can use it to get his "full" driver's license.