A&Q about Lotus
Q:
I've had an Elise for about a month and have been on a campaign to quiet down the interior. I bought a Sport Elise and it was totally raw as far as sound deadening went. Even the demo car I drove with a touring option was kind of droney. When I bought the car, the noise didn't bother me initially but getting out after a 50 mile drive left my ears pretty tweeked.
I know ear plugs are an option but not what I want to deal with
In case anyone's interested, here's what I did:
1. I put a layer of this stuff on the floor pan and under the seats. I used the thicker "Pro" version. Basically , it's Dynomat without the stupid logo stamped all over the aluminum layer for you to look at.
This reduced lots of road noise. From what I could tell this is pretty much what you get with the touring option.
2. Pulled the plastic cover behind the seats. I added some strips of the damping mat to the firewall and the back of the plastic cover. After putting the car back together the car had a HUGE increase of engine noise and MORE drone than before. I found that if the plastic cover touched the firewall, the noise transmitted right through into the cabin. I carefully cut away areas of the mat to keep the parts from touching and this brought it back to about the same level as before. Maybe a little quieter but the drone persisted.
3. I pulled the rear cover back off and drove around with it removed. I noticed a big reduction in the overall drone in the 3-4k RPM range. Looking at way that the car is constructed, I found two hollow cavities behind the "B" pillar. The cavities are from the body as it flares out over the rear wheels. They make perfect resonant boxes when the rear cover is installed.
I put a ball of polyester quilt batting in the cavity and that reduced the drone by a bunch. It also makes the howel from the intake cam advancing much better.
The additional weight gain was ~5lbs from the rubber mat. The polyester batting was neglegable. Seeing as how I could make it up by cutting back on the sweets to lose the 5 lbs gained seems worth it for a little hearing protection.
A:
Sounds great! Nice going!
Pictures?
A:
Post pictures if you get a chance
Cool deal...
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Sorry no. I guess I should have. I didn't even think about posting this until today. I think if you pull the rear cover off you'll see what I mean from my description.
It takes about 20 minutes to pull the top and seats out to get access to the body where you'll see the cavities. Pretty simple. The trick is removing the tube that was installed in my car for the 5 point harness. Not a problem on most Elises just the Exiges.
A:
Hi Jeff,
Nice going! I'd like to see how you filled the two hollow cavities behind the "B" pillar. Let me know when you drive it in to work & I'll come take a look.
I second the suggestion of posting photos.
Thanks,
Joe
A:
With the touring pack those two cavities are filled with foam. It's all one piece of foam that goes across the whole firewall and at each end is a large molded section which fits into those cavities. You can probably go to a dealer and order that piece of foam as a replacement part and fit it into place.
A:
I bought a touring pack car which has some sound deadening material and carpet. I removed it all - IMO the less weight the better. "To each their own I guess."
A:
Originally Posted by rwarden
I bought a touring pack car which has some sound deadening material and carpet. I removed it all - IMO the less weight the better. "To each their own I guess."
Did you notice a difference in cabin noise?
A:
To me, the most annoying sound is the wooshing wind noise coming from the corners of the softop to windshield area. I don't mind the tire noise or engine noise on long trips, but that wind noise bugs me.
A:
Originally Posted by rwarden
I bought a touring pack car which has some sound deadening material and carpet. I removed it all - IMO the less weight the better. "To each their own I guess."
Absotively posolutely!
A:
Well, it looks like I may have reinvented the wheel but at least it confirms what I found.
About the added weight - can anyone out there honestly say that they can feel the difference in the way the car handles when you have a delta of a gallon of gas in the tank? It's about the same as some foam and carpet squares.
A:
Originally Posted by Randy Chase
To me, the most annoying sound is the wooshing wind noise coming from the corners of the softop to windshield area. I don't mind the tire noise or engine noise on long trips, but that wind noise bugs me.
You just need to turn up your stereo !
A:
Originally Posted by J honeyman
Well, it looks like I may have reinvented the wheel but at least it confirms what I found.
About the added weight - can anyone out there honestly say that they can feel the difference in the way the car handles when you have a delta of a gallon of gas in the tank? It's about the same as some foam and carpet squares.
When holding the entire foam part in my hands, this piece that fills those voids and covers the firewall, I can't even notice a different in my arms and hands. It's light enough that I don't notice i'm holding it. Honestly, I don't see how this item could affect (or effect??) the power or perf of the car. Your hearing is worth a lot, and this foam piece weighs nothing - I'd say don't take it out. Besides; reverberating tire noise (which is what I heard when I removed this foam while working on a stereo install) just covers up the wonderful exhaust note IMHO and doesn't add anything.
A:
I read somewhere that the stock rear foam piece weighs 4.5 lbs.
BTW.. cheap source for polyester quilt batting:
(6 oz per square yard, 0.67 oz per square foot)
A:
Originally Posted by mikester
You just need to turn up your stereo !
Ha, if I turn up my stereo on the interstate, I just get to replace wind noise with the sounds of a vibrating, buzzing set of speakers. Not any better, IMO.