NVH Solutions

[Michael2]

From the following web site :


https://www.expeditionexchange.com/defender/

some ideas on reducing driveline vibration.


Land Rover Genuine Parts Rubberized Spring Isolator (ANR2938) $14
The Rubberized Spring Isolator is factory fitted to the tops of the rear springs of several Land Rover vehicles and is designed to minimize the transmission of road, suspension, and drivetrain vibration and noise to the vehicle's cabin. D90's, of course, didn't come with these fitted. This isolator can also be used as a spring shim to level out a listing vehicle, or even to raise a vehicle. Unlike the Old Man Emu 10mm Trim Packer (which can be mounted safely only to the tops of the rear springs), this isolator can be fitted front or rear, top or bottom. You can even mount eight different isolators to all four of your springs for additional lift and/or additional vibration and noise attenuation.

Land Rover Genuine Parts Rubberized Shock Tower Securing Ring (RBC100111) $29

Replace your sheetmetal shock tower retaining ring with this rubberized version that is factory fitted to Disco2's, but is conspicuously absent from your Defender. The bolt pattern and diameter are identical, and this unit will fit the Defender without modification to the vehicle. The entire unit is covered in rubber and attenuates the transmission of road, suspension, and drivetrain vibration and noise to the Defender's cabin. Mounting hardware included. (Shown with Old Man Emu Heavy-Duty Spring which is sold separately.)

[dullbird]

i thought they just reduced road noise

[Outlaw]

nice idea

[discowhite]

got the d2 ones for the front have to get the rears. these one wont fit the rears of 110's they have a larger coil.
there isnt much point putting them on the bottom, they go on the top to isolate the springs ei road noise from the chassi.

cheers phil

[JDNSW]

got the d2 ones for the front have to get the rears. these one wont fit the rears of 110's they have a larger coil.
there isnt much point putting them on the bottom, they go on the top to isolate the springs ei road noise from the chassi.

cheers phil

I do not think it would make much difference if they were top or bottom - if you isolate the spring from road noise, it is not going to pick it up between there and the top of the spring. But obviously no point (except a bit of lift) to having them top AND bottom.

John

[Michael2]

got the d2 ones for the front have to get the rears. these one wont fit the rears of 110's they have a larger coil.
there isnt much point putting them on the bottom, they go on the top to isolate the springs ei road noise from the chassi.

cheers phil

aaaargh... I just ordered 3 pairs of cones for the back of (3) 110 Defenders.

I should have them on Thursday, so I'll see how they line up anyway.

[Michael2]

i thought they just reduced road noise

sorry, by vibration I meant resonance / noise, not mechanically induced vibrations. I should have better chosen my words.

[Offender90]

sorry, by vibration I meant resonance / noise, not mechanically induced vibrations. I should have better chosen my words.

It's supposed to dampen out high frequency vibration, which is regenerated by the body panels to cause some of the high speed "hum" noise. In discos, (which are better insulated from noise), I'm guessing this is a significant component of overall cabin noise, and therefore worth eliminating.

Unfortunately, it doesn't do much on the defenders (that one I know). The defender rear tub is made from very thin aluminium panel which has very poor transmission loss characteristics. Defender in-cab noise is dominated by tyre/road interaction transmitting through the floor, so eliminating vibration regenerated noise will make no difference in overall internal levels.

Vibration and Harshness are both due to lower frequency vibration from the wheels and the engine / drivetrain, which go straight through the rubberised ring "isolator" so once again, don't expect much.

To cut a long story short, the ruberised ring is great as a 10mm spacer in a Defender, but don't expect any improvement in NVH (I should know, I have them in my 90). If you're serious about noise insulation there is a thread on it here. Keep in mind it is practically difficult to achieve, given the defender's bolt on construction. Ultimately, if you want a quiet(er) 4WD, buy a disco or a rangie.

As an aside, next time you drive your defender, have a listen to what's causing the noise. At low speeds, it should be the diesel clacking away, while at higher speeds, especially > 70 km/h (less if you have muddies), the noise should be dominated by the road/tyre interaction "hum". In order to cut it out, follow the link above before you worry about fitting a ruberised spacer.

If you have an Isuzu county, forget all of the above, there is just no hope. Just get rid of it, buy a disco!...




... Sell your county to me!