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-   -   Boxy vs aerodynamic design (http://www.jeepforum.com/forum/f118/boxy-vs-aerodynamic-design-1495958/)

Rob K 03-19-2013 04:21 PM

Boxy vs aerodynamic design
 
2 Attachment(s)
I hear it stated often that a boxy vehicle does not have good fuel economy compared to a more aerodynamic vehicle. This is often the reason given when we talk about the demise of the suv and why new vehicles are all looking like aerodynamic crossovers. I found some evidence that does not support this reasoning.

Compare the 2013 Jeep Compass and the 2013 Jeep Patriot. They both have the same drive train. The difference is that one is boxy and the the other is more aerodynamic. Interestingly they both get the same gas mileage. Obviously there's not enough difference in the body style to have an affect on fuel economy. Here's the specs on fuel economy.
http://www.fueleconomy.gov/feg/Find....32842&id=32841

Apparently it takes a major difference in body style to affect fuel economy. The changes we see in body styles may have more to do with market trends than actual fuel savings. The case is stated. What are your thoughts on this? Keep it civil.

dmill89 03-19-2013 05:08 PM

I agree completely. The main determinates of fuel economy are vehicle weight (which has been steadily increasing for the last 15-20 years due to safety regulations, and additional "features") and the efficiency of the drive-train. Aerodynamics has some effect (mainly at high speeds) but it is negligible compared to the above factors.

Another example is the "brick like" Camaro SS and the base Corvette which is much more aerodynamic, they both have the same basic drive-train (LS3 & 6-speed) The Camaro is rated at 15/24 mpg, the Corvette 15/25 mpg and Camaro weighs 500 lbs more than the Corvette which is likely the main factor in the 1mpg hwy advantage the Corvette has.

I personally hate "jelly-bean" cars and think SUVs should have right angles, though I realize that not everyone has the same opinion. Not to mention the fact that I would gladly give up fuel-economy for performance, reliability, and style.

A little off topic but really I can't stand all the fuel economy "garbage" that they put on engines these days such as MDS/cylinder deactivation (if I wanted a 4cyl. I would have bought one rather than a V8), Turbos/"eco-boost" (negligible fuel economy gains with a massive increase in maintenance costs and decrease in reliability/longevity), etc.

XJ2Timer 03-20-2013 07:15 AM

Both the Chrysler 300 and the Ram 1500 'look' boxy and not aerodynamic. But in fact both are aerodynamic. There is no technical reason why the upcoming KL Cherokee couldn't have looked more like a Jeep.

jay-h 03-27-2013 01:24 PM

That goofy little Scion is pure box, but gets pretty good mileage. Efficiency is often in the details.

georgejeri 04-04-2013 01:33 PM

I like the looks of our 09 Liberty. It looks stout, rugged, "manly." To me most other SUVs look more like soccer mom vehicles. I traded a 96 Honda Passport in for our Jeep. The passport gave me the same impression. Not quite as "boxy" as the Liberty but......

Butchy_Boy 04-04-2013 04:05 PM

This begs the question as to whether the boxy look could have been used in the Cherokee, and why then they chose to ignore it.

Rob K 04-04-2013 06:37 PM

Quote:

Originally Posted by Butchy_Boy (Post 15247382)
This begs the question as to whether the boxy look could have been used in the Cherokee, and why then they chose to ignore it.

From my point of view they are just following everyone else on the body style. The only thing that really sets Jeep apart from the crowd now is the Wrangler.

XJ2Timer 04-05-2013 07:10 AM

Quote:

Originally Posted by Rob K (Post 15248100)
From my point of view they are just following everyone else on the body style. The only thing that really sets Jeep apart from the crowd now is the Wrangler.

The side and rear of the new Cherokee is so bland and blends in with every other CUV out there. Then they went kind of over the top on the front end trying too hard to make it look something like a Jeep.

It is an example of too little on 3/4 of the vehicle and way too much on the other 1/4.

Like many other vehicles today it looks like it was designed by committee. Each team responsible for one part of the design but none of the teams talked to each other.

gunshw301 04-07-2013 09:38 AM

Quote:

Originally Posted by Rob K
I hear it stated often that a boxy vehicle does not have good fuel economy compared to a more aerodynamic vehicle. This is often the reason given when we talk about the demise of the suv and why new vehicles are all looking like aerodynamic crossovers. I found some evidence that does not support this reasoning.

Compare the 2013 Jeep Compass and the 2013 Jeep Patriot. They both have the same drive train. The difference is that one is boxy and the the other is more aerodynamic. Interestingly they both get the same gas mileage. Obviously there's not enough difference in the body style to have an affect on fuel economy. Here's the specs on fuel economy.
http://www.fueleconomy.gov/feg/Find....32842&id=32841

Apparently it takes a major difference in body style to affect fuel economy. The changes we see in body styles may have more to do with market trends than actual fuel savings. The case is stated. What are your thoughts on this? Keep it civil.

Very true, ugly does not have anything to do with aerodynamics.....apparently the new Chrysler designers have not figured this out yet.

Wavedatya 04-10-2013 06:01 AM

As long as the wrangler doesn't change ill be happy.

The haven't changed for decades and I don't see them changing any time soon though. Vehicles evolve but don't change too much. Look at the Porsche. You see the front and immediately know what it is.

Even if they change the jeep line and wrangler I'm sure in 20 years they'll bring the model back as a retro. Challenger, charger, dart, cuda etc...

starscream 04-11-2013 10:58 AM

Quote:

Originally Posted by Rob K (Post 15159840)
Compare the 2013 Jeep Compass and the 2013 Jeep Patriot. They both have the same drive train. The difference is that one is boxy and the the other is more aerodynamic. Interestingly they both get the same gas mileage. Obviously there's not enough difference in the body style to have an affect on fuel economy. Here's the specs on fuel economy.
http://www.fueleconomy.gov/feg/Find....32842&id=32841

Apparently it takes a major difference in body style to affect fuel economy. The changes we see in body styles may have more to do with market trends than actual fuel savings. The case is stated. What are your thoughts on this? Keep it civil.

My thoughts are, your logic is completely flawed. Factory computed MPG is calculated indoors on a dynometer where the vehicle is not moving, so there is no wind resistence being factored in. That is why the Patriot and Compass have the same estimated MPG. This has been a criticism from the EPA for a long time, that no real world driving is used to make these estimates. And by calling them estimates, the manufacturer is taking away any libality from the fact that your real MPG will vary from what is advertised.

Rob K 04-11-2013 09:46 PM

Quote:

Originally Posted by starscream (Post 15281091)
My thoughts are, your logic is completely flawed. Factory computed MPG is calculated indoors on a dynometer where the vehicle is not moving, so there is no wind resistence being factored in. That is why the Patriot and Compass have the same estimated MPG. This has been a criticism from the EPA for a long time, that no real world driving is used to make these estimates. And by calling them estimates, the manufacturer is taking away any libality from the fact that your real MPG will vary from what is advertised.

I thought the estimates were and average taken from real world test drives. Am I wrong?

Just got the answer to my question. The EPA tests and certifies mpg using a series of tests that are done on a dynometer in the lab. Here's the long winded article I read.
http://www.caranddriver.com/features...-mpg-estimates

So where do we go to find real world mpg for these vehicles? Or is this something we will not be able to find and can only speculate? Someone must have done real world tests to verify that the manufacturer and EPA numbers are legit.

jay-h 04-12-2013 08:22 AM

What a bunch of idiocy at taxpayers expense.

Emoto 04-12-2013 08:24 AM

Quote:

Originally Posted by jay-h (Post 15285409)
What a bunch of idiocy at taxpayers expense.

This.

slickrocksteve 04-12-2013 08:41 AM

And WHAT do we expect from the feds?

More beauacratic gobbldygook? YEP!


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