Fuel Economy, Hypermiling, EcoModding News and Forum - EcoModder.com - View Single Post - I'd like to add sound deadening material to my car. How adversely will it affect MPG?

NoD~ · 08-13-2016, 05:55 PM

Depends. 30lbs on a 1500lb car is a lot of weight (2%)! But 30lbs on a 4000lb car is very little (0.75%). This is especially true for your 0-60 times (or just daily driving acceleration).

For MPG sake, it depends on your routes and how you drive. The more you use your brakes, the more weight effects you. Hence, why weight makes little/no difference on the highway. But, the above applies and you really need to look at it in percentages.

Could you tell a good difference in sound when you added it? I'm guessing it was subtle difference. That's been my experience, at least, mostly dulling the noise, but not ridding of it (a lot of drone/low-mid frequency still about as loud). As mentioned in a prior post, 2-leaf system using foam and MLV is far more effective, but also, adds a lot of weight.

08-13-2016, 05:55 PM	#39 (permalink)
NoD~ Master EcoModder Join Date: Sep 2011 Location: USA Posts: 469 Frogger - '00 Honda Insight Gas Only (unHybrid) 90 day: 68.51 mpg (US) Thanks: 13 Thanked 247 Times in 133 Posts	Depends. 30lbs on a 1500lb car is a lot of weight (2%)! But 30lbs on a 4000lb car is very little (0.75%). This is especially true for your 0-60 times (or just daily driving acceleration). For MPG sake, it depends on your routes and how you drive. The more you use your brakes, the more weight effects you. Hence, why weight makes little/no difference on the highway. But, the above applies and you really need to look at it in percentages. Could you tell a good difference in sound when you added it? I'm guessing it was subtle difference. That's been my experience, at least, mostly dulling the noise, but not ridding of it (a lot of drone/low-mid frequency still about as loud). As mentioned in a prior post, 2-leaf system using foam and MLV is far more effective, but also, adds a lot of weight.