Go Back   EcoModder Forum > EcoModding > EcoModding Central
Register Now
 Register Now
 

Reply  Post New Thread
 
Submit Tools LinkBack Thread Tools
Old 10-01-2016, 11:45 PM   #1 (permalink)
'07 Toyota Matrix - 36MPG
 
Join Date: Oct 2016
Location: Southern California
Posts: 28

Small Red - '07 Toyota Matrix
90 day: 37.49 mpg (US)
Thanks: 11
Thanked 4 Times in 4 Posts
Matrix too noisy w/ rear seats out

Hi all,

I tried going "full hypermiler" a few years ago with my 2007 Toyota Matrix (base) and removed the rear seats and cargo area floor and spare tire a few years back. After a short while I put them all back. It was LOUD in my car, and I had problems using the cargo area w/o my shiz flying forwards.

Now, I'm trying round two. I have the spare tire, tire changing tools, and rear seats out, along with a bunch of other misc items, for 113.5 lbs of weight loss. I know from experience that my car will be louder w/ the rear seats out. I thought I might add a few pounds of Dynamat or other sound deadening material, but after removing the seats earlier this evening, I realized that there was some factory sound deadening material installed (see attached). Would adding some Dynamat on top of that help at all??...

A friend (non-hypermiler) said it sounded like I was trying to have my cake and eat it too. He suggested maybe Dynamatting the wheel wells..




Attached Thumbnails
Click image for larger version

Name:	Rear_driversside_seat.jpg
Views:	171
Size:	181.0 KB
ID:	20625   Click image for larger version

Name:	Rear_passengersside_seat.jpg
Views:	169
Size:	177.6 KB
ID:	20626  

Last edited by MPGee; 10-01-2016 at 11:46 PM.. Reason: Added car model
  Reply With Quote
Alt Today
Popular topics

Other popular topics in this forum...

   
Old 10-03-2016, 01:13 PM   #2 (permalink)
Master EcoModder
 
freebeard's Avatar
 
Join Date: Aug 2012
Location: northwest of normal
Posts: 27,562
Thanks: 7,738
Thanked 8,554 Times in 7,041 Posts
I've never used Dynamat myself, but my understanding is that it is most effective in the center of flat panels that would otherwise act as a drum-head.

And I've seen people putting Dynamat on top of Dynamat, so it probably could go over the factory stuff. At least it easier than putting it underneath.
  Reply With Quote
Old 10-03-2016, 01:24 PM   #3 (permalink)
Master EcoModder
 
Join Date: Jan 2015
Location: Atlanta area
Posts: 410
Thanks: 966
Thanked 74 Times in 63 Posts
A long time ago, maybe 30+ years, I used Dynamat in some car I owned and was pleased with the result. IIRC, I used a Canadian made substitute that was available at the time.
  Reply With Quote
Old 10-03-2016, 02:13 PM   #4 (permalink)
...beats walking...
 
Join Date: Jul 2009
Location: .
Posts: 6,190
Thanks: 179
Thanked 1,525 Times in 1,126 Posts
*IF* you never plan on re-installing the seats, have you thought about filling the area with expanding insulation foam (use the low-density stuff) underneath a thin sheet of plywood?
  Reply With Quote
Old 10-03-2016, 06:14 PM   #5 (permalink)
'07 Toyota Matrix - 36MPG
 
Join Date: Oct 2016
Location: Southern California
Posts: 28

Small Red - '07 Toyota Matrix
90 day: 37.49 mpg (US)
Thanks: 11
Thanked 4 Times in 4 Posts
Quote:
Originally Posted by Old Tele man View Post
*IF* you never plan on re-installing the seats, have you thought about filling the area with expanding insulation foam (use the low-density stuff) underneath a thin sheet of plywood?
Thanks all, for your input.

So far, everything I've done to my car is reversible, should I decide to sell the car. I'm not 100% certain I want to keep the rear seats out, as my needs may change.

Old Tele Man, I've seen some pics of builds where people built a straight plywood platform, to have a level load floor. That might be OK, but I'm concerned about weight. I'm trying to lighten things - not add them back!

After a few day's contemplation, I'm trying out making the pictured area where the rear seats were as my primary cargo area; e.g., I fill that area first, when loading the car. That way (hopefully), the mass of my items helps absorb some of the sound energy. A possible issue is items sliding off the front of the seats, down to the floor, during harder stops. If this proves to be a good plan, I might cut a thin strip of plywood out as a ledge and bolt it on using the existing seat bolts & holes, and maybe even get some matching fabric to make it and the bare seat area a little more presentable.

I primarily listen to podcasts & talk radio, and it's frustrating to not be able to understand what they are saying because of road noise (and I value my hearing enough that I don't like the workaround of cranking up the volume).
  Reply With Quote
Old 10-03-2016, 06:42 PM   #6 (permalink)
Master EcoModder
 
Ecky's Avatar
 
Join Date: Dec 2011
Location: New Zealand
Posts: 5,005

ND Miata - '15 Mazda MX-5 Special Package
90 day: 42.54 mpg (US)
Thanks: 2,866
Thanked 2,501 Times in 1,547 Posts
If your driving is not primarily stop and go, the weight reductions will net close to zero improvement in economy. My Insight gets basically the same economy when cruising on the highway when it's completely empty as it does with 5-800lbs of cargo - which is like 33-50% additional mass, given how light the car is to begin with.
  Reply With Quote
Old 10-03-2016, 09:19 PM   #7 (permalink)
'07 Toyota Matrix - 36MPG
 
Join Date: Oct 2016
Location: Southern California
Posts: 28

Small Red - '07 Toyota Matrix
90 day: 37.49 mpg (US)
Thanks: 11
Thanked 4 Times in 4 Posts
Quote:
Originally Posted by Ecky View Post
If your driving is not primarily stop and go, the weight reductions will net close to zero improvement in economy. My Insight gets basically the same economy when cruising on the highway when it's completely empty as it does with 5-800lbs of cargo - which is like 33-50% additional mass, given how light the car is to begin with.
I do, perhaps, 40% stop/go city driving. I understand it'll be a marginal gain, at best. But I'll take what I can get.
  Reply With Quote
Old 10-06-2016, 11:01 PM   #8 (permalink)
'07 Toyota Matrix - 36MPG
 
Join Date: Oct 2016
Location: Southern California
Posts: 28

Small Red - '07 Toyota Matrix
90 day: 37.49 mpg (US)
Thanks: 11
Thanked 4 Times in 4 Posts
OK... I discovered one source of noise intrusion when my car was backlit by the setting sun, parked in the garage. See attached photo. See that brightly lit hole? That's where one of the seat belt harnesses was bolted in. It goes clear through the bottom of the car... I'll need to plug that with something...
Attached Thumbnails
Click image for larger version

Name:	AGPR-636113805596050000.jpg
Views:	37
Size:	46.5 KB
ID:	20653  
  Reply With Quote
Old 10-07-2016, 12:13 AM   #9 (permalink)
EcoModding Apprentice
 
LittleBlackDuck's Avatar
 
Join Date: Jul 2016
Location: The Land Downunder
Posts: 229

CT - '11 Lexus CT200h Luxury
Thanks: 26
Thanked 80 Times in 61 Posts
Quote:
Originally Posted by MPGee View Post
Thanks all, for your input.

So far, everything I've done to my car is reversible, should I decide to sell the car. I'm not 100% certain I want to keep the rear seats out, as my needs may change.

Old Tele Man, I've seen some pics of builds where people built a straight plywood platform, to have a level load floor. That might be OK, but I'm concerned about weight. I'm trying to lighten things - not add them back!

After a few day's contemplation, I'm trying out making the pictured area where the rear seats were as my primary cargo area; e.g., I fill that area first, when loading the car. That way (hopefully), the mass of my items helps absorb some of the sound energy. A possible issue is items sliding off the front of the seats, down to the floor, during harder stops. If this proves to be a good plan, I might cut a thin strip of plywood out as a ledge and bolt it on using the existing seat bolts & holes, and maybe even get some matching fabric to make it and the bare seat area a little more presentable.

I primarily listen to podcasts & talk radio, and it's frustrating to not be able to understand what they are saying because of road noise (and I value my hearing enough that I don't like the workaround of cranking up the volume).
How about putting a layer of plastic film over the floor to protect it, then place a plywood false floor and fill the space between them with expanding foam. The plastic will give a more robust outer surface and make it release cleanly from the floor whilst still bonding to the ply. Once cured it can be trimmed up and made more presentable. Be wary of the foam leaking out the sides and filling holes in the body. A variation on this (filling a plastic bag with the foam and sitting in it) is how I made custom fitted seat inserts to minimise body movement in my go kart.

Simon
  Reply With Quote
The Following User Says Thank You to LittleBlackDuck For This Useful Post:
MPGee (10-07-2016)
Old 10-07-2016, 03:19 AM   #10 (permalink)
Master EcoModder
 
Join Date: Jan 2009
Location: USA
Posts: 263

Winsight - '06 Honda Insight
Gen-1 Insights
90 day: 72.19 mpg (US)
Thanks: 244
Thanked 86 Times in 61 Posts
Quote:
Originally Posted by MPGee View Post
OK... I discovered one source of noise intrusion when my car was backlit by the setting sun, parked in the garage. See attached photo. See that brightly lit hole? That's where one of the seat belt harnesses was bolted in. It goes clear through the bottom of the car... I'll need to plug that with something...
Foam ear plugs, just roll them up and put them in. A great seal and easily removable.


Have you installed a belly pan or anything in the rear wheel wells to seal them up as well? That should keep some noise out. What about installing a partition between the front and rear? That would help with things flying forward too.

It's popular to seal up all the access holes in the inner panels. I think that will help out with your noise now without adding too much weight. Aluminum flashing cut to size/shape, butyl rubber to seal it and some screws to keep it in place.

__________________
  Reply With Quote
The Following User Says Thank You to fusion210 For This Useful Post:
MPGee (10-07-2016)
Reply  Post New Thread


Thread Tools




Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Content Relevant URLs by vBSEO 3.5.2
All content copyright EcoModder.com