Annoying Rattling Noise When Car is Warm

[Gilach]

Does anyone know what kind of clutch type is on the Emira, ie sprung or unsprung/non dampaned? Also, i'm assuming the manual has a single mass flywheel. Wondering if these components may contribute to the gear chatter.

 

[VL3X]

Does anyone know what kind of clutch type is on the Emira, ie sprung or unsprung/non dampaned? Also, i'm assuming the manual has a single mass flywheel. Wondering if these components may contribute to the gear chatter.

It's a sprung type clutch and lightweight flywheel made by AP (or was it ACT?)... Pretty sure a Lotus tech told me it was AP (same as our calipers). @Porter may be able to confirm...

 

[Gilach]

Not sure if this is helpful:

Gear Rattle

Gear Rattle Increased gear rattle noise may occur when changing to an aftermarket performance clutch and/or flywheel, including ACT’s products. The most common gear rattle noise occurs whe

www.advancedclutch.com

 

[Porter]

Generally speaking I think a lot of the driveline noise that people experience on these cars is a result of it being a relatively sporty clutch combined with a lightweight flywheel. The sounds that the Emira makes are not dissimilar from other cars I've had (or worked on) that had lightweight flywheels.

The solution in my own Emira is to simply drive it in a higher RPM band than I would normally use in a standard vehicle, because the noise disappears above about 1500rpm.

I generally don't ever let the RPMs drop below 1500, and I accelerate for a longer period in each gear even when driving slowly, to keep the revs up after they drop on the gear change.

To editorialize slightly... I suspect that automatic transmissions in normal daily-driver cars have given many of us an "auditory memory" for shifting that's much lower in the rev band than appropriate for this car, so we have to un-learn it to have a good experience with this car when driving at sedate speeds.

Now if you're doing this, and still experiencing a rattling noise that's unaffected by the change, then something else is going on and you should have the dealer investigate.

 

[Gilach]

i think in some cases, the chattering noise if from the lightweight flywheel. If you do a generic search for lightweigh flywheels pros/cons chattering noise is at the top of the list.

 

[Blackthought_]

I think what youre describing is normal for lotus cars. On the Evora GT I had it sounded like marbles in a tin can when I accelerated slowly. I hear it I common for the Toyota transmission that is used in these cars

 

[flyingbear]

I went from a 22lb flywheel to a 8lb flywheel in my S2000. Love the performance but got intermittent drivetrain chatter upon deceleration. It sounds a lot like the noise my Emira makes while “lugging” the engine.

How much does the Emira flywheel weigh?

Hard to tell how quickly it revs with drive by wire and various driving modes :/