YODAONE

Acquired quantity 5 of DEI 12.5" X 24" X 4mm Boom Matt vibration dampening panels for application to floor pan, Seat base crossmembers and interior rocker frame rail.

http://designengineering.com

see:

https://www.clublexus.com/forums/ls-1st-and-2nd-gen-1990-2000/825403-sound-dampening-ls400-door-panels.html


This project requires removal of the front seats, rear seat, console, glove box, passenger and drivers side dash footwell undercovers, door sill trim, gas pedal and carpeting.

My 1999 LS400 incorporated selective floor panel dampening materials, with meaningful NVH reduction, however discernible NVH at rocker panel area...

Rather than needlessly slathering dampening material (and weight) over the entire floor pan, I determined to complement existing dampening by filling in the gaps amd areas lacking.

After removing above interior items, I assemled necessary tools; paper grocery bags for templates, Sharpie, scissors and box cutter

Images of the project...driver's and passenger side:



Front passemger side floor panel...and crossmember which seat mounts. Door sill side rail, crossmember and floor pan areas not covered with dampening material is very tin can sounding.


Paper is your friend for templates...


Interior side of rocker panel (at door sill) covered with Boom Mat and paper template fitted for floor pan to be covered...


Work around with the OEM sound deadening material...


Image of front drivers side interior side frame rail. The two squares represent the factory attempt at NVH reduction. This area will respond well to apllication of Boom Mat.


After application of Boom mat material. More than adequate room under carpet.

timmy0tool

iTrader: (7)

impressions on the NVH afterwards?

Yamae

It would be nicer with the comparison data of before and after.

YODAONE

At the momemt there is no comparison data to provide....

From a before and after comparison perspective, there is no test equipment employed....

The greatest (perceived) NVH reduction was achieved by treating the door panels...with the added benefit of improved (door) speaker performance.

https://www.clublexus.com/forums/ls-1st-and-2nd-gen-1990-2000/825403-sound-dampening-ls400-door-panels.html

The next biggest NVH reduction was achieved by treating rear quarter panels...the drumming sound spread from the rear and up through the roof is significantly reduced.

https://www.clublexus.com/forums/ls-1st-and-2nd-gen-1990-2000/879838-rear-quarter-panels-eliminating-drumming.html

To a lesser degree, the treatment described in this post makes a discenible difference...

What would really provide a hiuge reduction in NVH is to inject two-part automotive grade closed-cell polyurethane foam into the hollow subframe rails and crossmembers......BIG project however...

Investigating removing and injecting foam into the hollows of the rear subframe tubing....always best to isolate NVH closest to the source... mufflers are hung from there.