Piston Slap: A Dual-Mass Shift In the Right Direction?

Sajeev Mehta
by Sajeev Mehta

David writes:

This is a quote from Nissan’s specs for the current Sentra SE-R Spec V: “6-speed close-ratio manual transmission with dual-mass flywheel.” Ok, so I am interested in buying one of these top dollar Sentras, but would like to know what a “dual mass” flywheel is. The Spec V is the only Sentra with it. Thanks!

Sajeev Replies:

One of the biggest advantages to a dual-mass flywheel is the ability to lower the engine’s NVH (noise, vibration, harshness) levels inside the cabin. You can read far more detailed information here, if so inclined. For applications that need it, the technology is sound and proven after decades of use.

Back to the Sentra: considering the Spec V revs like a mother (6600 revs to make peak power) with those 200 horses, having a dual-mass unit ain’t a bad idea for a chubby street car that’s a far cry from it’s sport compact origins dating back to the early 1990s. Then again, what modern car isn’t bigger than its britches?

Bonus! A Piston Slap Nugget of Wisdom:

Sticking with the SE-R Ain’t What It Used To Be theme: it’s ironic that the only manual cog swappers in the lineup are the super-strippo Sentra, or the top dollar SE-R Spec V. Everything in between has the fun-sucking CVT. Even the SE-R, albeit with paddle shifters that must help with…something!

Perhaps Nissan should take a page from their marketing tagline, do us all a favor and “Shift The Way They Move?”

(Send your queries to mehta@ttac.com)

Sajeev Mehta
Sajeev Mehta

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  • Brian P Brian P on Jan 25, 2010

    VW TDI diesels have dual-mass flywheels. Usually that (and the clutch that goes with it) is the first thing that needs to be chucked out and replaced with a conventional flywheel and clutch when you hot-rod them, and a few unfortunates have had the DMF mechanism let go on a stock vehicle. I haven't had a hint of trouble with mine, though.

  • Findude Findude on Jan 25, 2010

    The first generation MINI Cooper S has a dual mass flywheel. Ours failed three times in less than 30,000 miles. It's a very common, and expensive, failure in MINIs with the 6-speed transmission. If it's a sound and proven technology, please head over to MINI and tell them where to source the sound and proven ones.

  • Rcdickey Rcdickey on Jan 25, 2010

    Been there done that. Ford used a dual mass flywheel on their diesel light trucks (F250 up). Replaced many because of vibrations. Upon taking them out you would find the springs inside were broken. They were similar to dual spring valve springs. Also, each time one of the manuals needed a clutch I would find the DM flywheel had broken springs and needed replacing as well. I haven't worked in repair since the mid 90s (work for a manufacturer now) so there may be some improvement. But knowing how those old ones were built I don't have confidence in them. the problem was the springs were not sealed and dust from the clutch got in them and with the vibration would wear the springs down till they broke. Just my 02.

  • Another_pleb Another_pleb on Jan 26, 2010

    Honest John, (the Sajeev Mehta of the Daily Telegraph's motoring section) is not a fan of DMFs by any stretch of the imagination.

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