Aftermarket spring maker Eibach now advertising MPG savings of lowering kits

[Big Dave]

The test was definitely questionable, but the idea has merit.

I lowered my truck 4 inches and 6" in the back and gained a solid 1.0 MPG.

[EVDRVR]

It might have taken so much time to repeat the test in order to do it enough times to finally find a run with a good set of numbers.

Show us the numbers @ 45-50-55 & 60. Nobody does 70 all the time.

Get the Firefly too low and you won't get very good mpg, just all hung up on a speed bump or lost in a pothole.

[ShadeTreeMech]

Originally Posted by lunarhighway

Cd from 0.37 to 0.31 ...

if it where that easy gm would have dropped it a bit themselves i should think...

Isn't that a very VERY big assumption? Namely believing GM would do something to a car that would increase costs but give a marginal increase in economy?

GM (and Ford, Dodge, etc.) care about making money. That is all they care about. Trusting a car firm is like trusting a lawyer.....not always advisable.

[lunarhighway]

Isn't that a very VERY big assumption? Namely believing GM would do something to a car that would increase costs but give a marginal increase in economy?

perhaps....i don't have much sympathy for any big company and i know their final products especially a car like that, are more the result of marketing studies than science. On the other hand i do think they have people working there developing cars that know their stuff and a 13% gain should be very marketable in these times.

Also lowering a car really doesn't cost much to a car company. A sping that's an inch shorter cost just as much to make and install in the factory that the long one.
In fact car companies do sometimes lower their special "eco" models to get better FE but along with other mods we all know about this usually on gives a 0.01 improvement in Cd.

The only, and perhaps main, reason i see for them not to lower to much is that they have a minimum ride height that suited for everyday traffic so you can drive about without worying about airdams and oil pans being torn off.
(models solled in china are usually raised a bit due to the bad road conditions in some areas for example)

anyway, the basic point i wanted to make was that even GM isn't so stupid not to see such low haning aero fruite and 13% is likely bs. The people calling the shots at GM might be idiots, designs like the ev1 and opel calibra show they have people working for them that know all there is to know about car aerodynamics, and they have come out with a few cars that i think where small aerodynamic milestones.

[Frank Lee]

Originally Posted by ShadeTreeMech

Namely believing GM would do something to a car that would increase costs but give a marginal increase in economy?

Increased cost to build the car = 0.

Increased costs in warranties and repairs and volume of customer complaints due to bottoming out damage = substantial.

I wouldn't sell a lowered car to the public either unless I could get them to sign a damage waiver.

Believe me, GM knows EXACTLY how much lowering/rake it takes to improve aero... waaaay more than Eibach does.

[Fr3AkAzOiD]

If they said 2.5% - 5% I would have believed it but 13% is BS.

I plan on lowering my car a little when I get some spare money (like there is even such a thing) but I would be shocked at more then a 2.0 mpg increase and more likely then not expect to only get between 1.0 - 1.5 mpg more.

Figuring if I get 1 mpg increase and use 400 gallons of gas a year and average 50 mpg thats less then $25 a year saved. I would never make back the cost of the parts and install over the life of my car.

[Piwoslaw]

Maybe they repaired a dragging brake while installing the new suspension?

[brucey]

Do the new camaro's sit as high as an SUV?

5% sounds realistic to me, but at least they did testing and showed their methods. Has anyone here done A/B/A testing on lowering?

[Frank Lee]

Truck Trends did fe "testing" too...

[jamesqf]

The problem with the "why don't the car companies build them lower" is that through the SUV marketing and so on, they've got a large share of the public convinced that it wants to "sit up high". Look at the smaller, supposedly build for fuel economy models: they stick up like over-filled muffins. Compare for instance Honda CRX with Smart Fortwo.