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.