Recent Topics
Buzzing rumble after new pads rotors.
by JustinH
08/29/14 06:54 AM
Kia Sorento 2.5 CRDi.
by Silk
08/29/14 05:55 AM
Mann - Corolla - Paper and foam !!! (see photo)
by NGRhodes
08/29/14 04:59 AM
SAAB 340 and de-icing boots
by crinkles
08/29/14 04:46 AM
Traction Control Warning Light Stays On
by bobbob
08/29/14 02:34 AM
AAP ships ATF but not Oil
by Apollo14
08/28/14 11:25 PM
Good Morning Vietnam/USO Supporters
by GumbyJarvis
08/28/14 11:10 PM
Just bought an NB Miata! What oil?
by Klutch9
08/28/14 11:06 PM
New-to-me '99 Miata - fluids?
by Klutch9
08/28/14 11:03 PM
Pick my tow vehicle
by Nick1994
08/28/14 11:00 PM
What are the plastic tanks on a radiator made of?
by joegreen
08/28/14 10:47 PM
eeking every last mile out of an AC compressor....
by gregk24
08/28/14 10:20 PM
Newest Members
kbaba7, hpb, johnny69, Katy, docsavage
51129 Registered Users
Who's Online
51 registered (97f150, aquariuscsm, 2009Edge, Apollo14, 77GrandPrix, 6 invisible), 987 Guests and 177 Spiders online.
Key: Admin, Global Mod, Mod
Forum Stats
51129 Members
64 Forums
218451 Topics
3444626 Posts

Max Online: 2862 @ 07/07/14 03:10 PM
Donate to BITOG

Page 1 of 2 1 2 >
Topic Options
#3319259 - 03/21/14 06:35 PM Better gas mileage with stiffer suspension.
Nayov Offline


Registered: 08/01/09
Posts: 703
Loc: ME
Well, why not? Shock absorbers (struts) soak up energy and turn it into heat which is wasted energy. When a car bobs up and down while going down the road, it cost energy to lift the car. Anyone who's ridden a dual suspension bicycle knows that it saps energy from the rider.

So taking this to the absurd level, would a car with no suspension render better fuel mileage? I know it would be undriveable, so it's for illustrative purposes only.

I got to thinking about this after I replaced all 4 struts on my car. It now rides dramatically harder and I'm wondering if I will see better fuel mileage.

Top
#3319262 - 03/21/14 06:40 PM Re: Better gas mileage with stiffer suspension. [Re: Nayov]
zzyzzx Offline


Registered: 05/18/12
Posts: 1612
Loc: Baltimore, Maryland, USA
This seems unlikely to me.

Top
#3319263 - 03/21/14 06:43 PM Re: Better gas mileage with stiffer suspension. [Re: Nayov]
yonyon Offline


Registered: 03/06/12
Posts: 3492
Loc: NJ, USA
It seems to me that a softer suspension would be the way to go (less energy lost compressing the suspension) for fuel economy over bumps but realistically it isn't going to add up to much. It really isn't all that much energy wasted.

For the suspension to provide a real-world benefit to fuel economy you want a setup that reduces or eliminates the need to brake before cornering. That will save you a lot more wasted energy than gliding over bumps.

Top
#3319266 - 03/21/14 06:47 PM Re: Better gas mileage with stiffer suspension. [Re: Nayov]
PandaBear Offline


Registered: 08/05/02
Posts: 12328
Loc: Silicon Valley
Compare to aerodynamics and rolling resistance, suspension loss is nothing.

A stiffer suspension means your car will bump higher and then bonce a bit stiffer than softer suspension, just how long will those "bonce around" turns into heat, but they all turns into heat eventually.

The only way I see it is a harder suspension reduce comfort, and force the driver to slow down to be more comfortable. It is like saying speed bump reduce speed and make your drive more fuel efficient.
_________________________
"You keep asking questions PandaBear and you'll end up a vegetarian like my wife" - Camu Mahubah

Top
#3319273 - 03/21/14 06:57 PM Re: Better gas mileage with stiffer suspension. [Re: Nayov]
yonyon Offline


Registered: 03/06/12
Posts: 3492
Loc: NJ, USA
This discussion has me wondering if those BMW control arm bushings that always break might be designed to do that. The front wheels, when hitting a bump while the bushings are broken, get shoved rearward and accelerate upwards more slowly so as to change less forward motion to upwards motion, then they snap up over the ridge of the bump. UFO

Top
#3319278 - 03/21/14 07:05 PM Re: Better gas mileage with stiffer suspension. [Re: Nayov]
Trajan Offline


Registered: 07/16/05
Posts: 3314
Loc: SE PA
Originally Posted By: Nayov
Well, why not? Shock absorbers (struts) soak up energy and turn it into heat which is wasted energy. When a car bobs up and down while going down the road, it cost energy to lift the car. Anyone who's ridden a dual suspension bicycle knows that it saps energy from the rider.

So taking this to the absurd level, would a car with no suspension render better fuel mileage? I know it would be undriveable, so it's for illustrative purposes only.

I got to thinking about this after I replaced all 4 struts on my car. It now rides dramatically harder and I'm wondering if I will see better fuel mileage.


A shock absorber is a mechanical device designed to smooth out or damp shock impulse, and dissipate kinetic energy.

Nothing more. Nothing less.
_________________________

Lack of harm does not mean proof of benefit.

Top
#3319286 - 03/21/14 07:14 PM Re: Better gas mileage with stiffer suspension. [Re: Trajan]
Nayov Offline


Registered: 08/01/09
Posts: 703
Loc: ME
Originally Posted By: Trajan

A shock absorber is a mechanical device designed to smooth out or damp shock impulse, and dissipate kinetic energy.

Nothing more. Nothing less.


Yes, but I would add that dissipated energy (heat) is wasted and it costs fuel, but I do concede that the amount is in all probability immeasurable.

Top
#3319289 - 03/21/14 07:16 PM Re: Better gas mileage with stiffer suspension. [Re: Nayov]
Burt Offline


Registered: 01/08/09
Posts: 1028
Loc: texas
I have a hard time seeing how vertical motion/energy is converted into horizontal motion/energy by a stiffer suspension.

Kind of like hitting a hammer up or down on your car and expecting it to move forward.
_________________________
2011 RX350 22k miles
1998 Windstar 201k miles and runs like new, well sort of.
Original owner, tranny and head gasket.

Top
#3319299 - 03/21/14 07:28 PM Re: Better gas mileage with stiffer suspension. [Re: Nayov]
Trav Offline


Registered: 11/20/06
Posts: 9491
Loc: MA, Mittelfranken.de
Originally Posted By: Nayov
I got to thinking about this after I replaced all 4 struts on my car. It now rides dramatically harder and I'm wondering if I will see better fuel mileage.

Go a step further and remove the shocks totally. Use the bouncing motion of the springs to run a generator to charge the batteries in a hybrid system. LOL

No. Stiffer struts wont improve fuel economy unless its a Nissan Maxima then it might get 20% more.
_________________________
ASE L1, Master. Deutsch Meisterbrief.

Top
#3319314 - 03/21/14 07:42 PM Re: Better gas mileage with stiffer suspension. [Re: Nayov]
spasm3 Offline


Registered: 05/30/10
Posts: 3573
Loc: north carolina
If you have to slow down more to corner and turn due to the body roll with no or really soft shocks, you will consume more energy getting back up to speed. Verses coasting at a faster rate around corners/s turns and using less fuel to accelerate from a higher exit speed due to better suspension.
_________________________
13 elantra 27k penplat5w30
03 chevy avalanche63k m1 0-30
02 saturnsc1 55k pennultra
01 saturnsc1 160k nextgenhm
93 ciera 63k 5w30 nexgenhm
gz250 hdeo15w40

Top
#3319345 - 03/21/14 08:07 PM Re: Better gas mileage with stiffer suspension. [Re: Trav]
Nayov Offline


Registered: 08/01/09
Posts: 703
Loc: ME
Originally Posted By: Trav
Originally Posted By: Nayov
I got to thinking about this after I replaced all 4 struts on my car. It now rides dramatically harder and I'm wondering if I will see better fuel mileage.

Go a step further and remove the shocks totally. Use the bouncing motion of the springs to run a generator to charge the batteries in a hybrid system. LOL



It's been done! Well, a car powered road generator.

"The Road Surface Generator device is a revolutionary new device that incorporates current technology by utilizing the motion and weight of vehicles to produce clean, economical and ecologically sound electrical current. The Road Surface generator relies on kinetic energy produced by moving vehicles then transferred via a simple device located on surfaces that connect to a turbine generator to produce energy."

http://www.google.com/patents/US20080106103

Top
#3319353 - 03/21/14 08:20 PM Re: Better gas mileage with stiffer suspension. [Re: Nayov]
JHZR2 Offline



Registered: 12/14/02
Posts: 33510
Loc: New Jersey
You're assuming that you're converting potential energy of fuel to potential energy of ride height.

Perhaps a bouncy car has a worse aerodynamic profile, but I doubt it is much.

I can see savings from taking curves faster, as forward momentum can be wasted and is valuable.

Top
#3319369 - 03/21/14 08:38 PM Re: Better gas mileage with stiffer suspension. [Re: Nayov]
Trajan Offline


Registered: 07/16/05
Posts: 3314
Loc: SE PA
Originally Posted By: Nayov
Originally Posted By: Trajan

A shock absorber is a mechanical device designed to smooth out or damp shock impulse, and dissipate kinetic energy.

Nothing more. Nothing less.


Yes, but I would add that dissipated energy (heat) is wasted and it costs fuel, but I do concede that the amount is in all probability immeasurable.


How is it wasted? Shock absorbers do not power or draw power from the engine.
_________________________

Lack of harm does not mean proof of benefit.

Top
#3319382 - 03/21/14 09:01 PM Re: Better gas mileage with stiffer suspension. [Re: Nayov]
Merkava_4 Online   content


Registered: 01/30/07
Posts: 9079
Loc: Clovis, CA
The more you keep the car in a straight line, the better the fuel mileage will be.

A car getting tossed around from stiff suspension is going to affect its straight line.

Top
#3319401 - 03/21/14 09:28 PM Re: Better gas mileage with stiffer suspension. [Re: Nayov]
Donald Offline


Registered: 03/21/04
Posts: 13323
Loc: Upstate NY
It the suspension makes a difference at all, the wind and how much coffee the driver has had probably make double the difference as suspension.

Its pretty hard to accurately measure MPG unless you use a flow meter like Consumer Reports does.
_________________________
2001 Jeep Grand Cherokee Laredo 4.0 - PP & M1
1999 Dodge Ram 2500 w/Cummins - Rotella T6 & M1
Amsoil ATF in both vehicles & Magnefine filter.

Top
#3319449 - 03/21/14 10:30 PM Re: Better gas mileage with stiffer suspension. [Re: Nayov]
eljefino Offline


Registered: 06/15/03
Posts: 23761
Loc: ME
The tire theory of setting to not-too-high a PSI is the tire pushes back against the road after it goes over a pebble. Stiffening the tire interferes with that. It stands to reason that stiff shocks might too.

Top
#3319597 - 03/22/14 09:01 AM Re: Better gas mileage with stiffer suspension. [Re: Nayov]
whip Offline


Registered: 03/03/05
Posts: 1518
Loc: ohio
Originally Posted By: Nayov
Originally Posted By: Trajan

A shock absorber is a mechanical device designed to smooth out or damp shock impulse, and dissipate kinetic energy.

Nothing more. Nothing less.


Yes, but I would add that dissipated energy (heat) is wasted and it costs fuel, but I do concede that the amount is in all probability immeasurable.

Until you can convert the energy from the bump into a way to propel the vehicle, it has zero effect on the fuel economy. Buying a lighter car would help more than anything.

Top
#3320122 - 03/22/14 07:13 PM Re: Better gas mileage with stiffer suspension. [Re: eljefino]
Nayov Offline


Registered: 08/01/09
Posts: 703
Loc: ME
Originally Posted By: eljefino
The tire theory of setting to not-too-high a PSI is the tire pushes back against the road after it goes over a pebble. Stiffening the tire interferes with that. It stands to reason that stiff shocks might too.


Fascinating. I always thought the harder the tire the better for MPG, but, this makes sense. He's to hoping my gas mileage won't be plummeting with my sporty stiff struts. whistle

Top
#3320138 - 03/22/14 07:26 PM Re: Better gas mileage with stiffer suspension. [Re: Nayov]
Eddie Offline


Registered: 12/07/03
Posts: 6652
Loc: Florida, Cape Coral
If you make force vs distance diagram you'd see that what you gain is easly lost in the noise. Ed
_________________________
CX5 Touring 2.5L :-)

Top
#3320221 - 03/22/14 08:42 PM Re: Better gas mileage with stiffer suspension. [Re: Nayov]
jeepman3071 Offline


Registered: 04/15/10
Posts: 1663
Loc: Storrs, Connecticut
The money you save in gas with stiffer shocks will probably not be enough to cover your doctor bills from back problems down the road.
_________________________
2000 Jeep Cherokee Sport 4.0L (146k) - PYB 10w40, Wix 51085, Magnefine trans filter

Top
#3329346 - 03/31/14 04:22 PM Re: Better gas mileage with stiffer suspension. [Re: Merkava_4]
Trajan Offline


Registered: 07/16/05
Posts: 3314
Loc: SE PA
Originally Posted By: Merkava_4
The more you keep the car in a straight line, the better the fuel mileage will be.

A car getting tossed around from stiff suspension is going to affect its straight line.


Shocks and springs are not powered by the engine, nor is any energy from them used to move forward.
_________________________

Lack of harm does not mean proof of benefit.

Top
Page 1 of 2 1 2 >