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Fuel economy, why has it not improved more? #4516815
09/15/17 08:05 AM
09/15/17 08:05 AM
Joined: Dec 2002
Posts: 1,568
North Carolina
Rat407 Offline OP
Rat407  Offline OP
Joined: Dec 2002
Posts: 1,568
North Carolina
Food for thought but with today's technology one would thing we would be a lot farther along with fuel economy than we are. Case in point. My 2002 Silverado with a 5.3 4x4 extended cab gets on average 16mpg, If I want I can get 19 but that is keeping it at 55mph and taking it easy. Spring forward to todays new GM vehicles with direct injection and 8sp transmissions and they are only getting 20mpg. To me that isn't much of an advancement in economy. Come to think of it, my dad's 1977 Chevy 1500 stepside with a three on the tree and a 350ci engine got 15mpg. Funny, a three speed and a carborated engine getting what modern tech is getting today.

Another point was when I had my 91 VW Jetta diesel, I was getting 50mpg out of it as well as when I had my parents old 1979 Rabbit diesel it got 50mpg. Granted I know that emissions have a major play in what diesels get now but seems to me one would thing we would be getting the same mileage on an average mpg on new diesels more so than not. My Cruze diesel gets consistent 45mpg but I have been able to get 50mpg if I really hyper-mile.

Just seems odd that we are no farther along than we are when it comes to economy.


2002 Silverado 5.3 0w-20 AMSOIL
Re: Fuel economy, why has it not improved more? [Re: Rat407] #4516817
09/15/17 08:10 AM
09/15/17 08:10 AM
Joined: Jul 2005
Posts: 30,439
NY
demarpaint Offline
demarpaint  Offline
Joined: Jul 2005
Posts: 30,439
NY
I said the same thing when my 00 Century would log mid to high 30 mpg numbers when we'd run it to Fort Lee VA from NY. There are a lot of new 4 cylinder engines that can't do it, and lets keep in mind the size of an 00 Century.


God Bless Our Troops

Re: Fuel economy, why has it not improved more? [Re: Rat407] #4516819
09/15/17 08:11 AM
09/15/17 08:11 AM
Joined: Oct 2009
Posts: 3,222
Wet side WA
JohnnyJohnson Offline
JohnnyJohnson  Offline
Joined: Oct 2009
Posts: 3,222
Wet side WA
Good question why didn't VW build their prototype diesel they built in the 80's that delivered over 200 MPG? I guess it would have never sold.


2004 Corolla 124805
Out: VML 5w-30 TG4967 OCI 5007 Miles
In: EDGE EP 5W-30 Bosch 3311 122537 7-18-18
2006 Duramax 74277
Out: T6 5W-40 M1-303
In: T6 5W-40 XG9100 74705 4-22-18
Re: Fuel economy, why has it not improved more? [Re: Rat407] #4516826
09/15/17 08:20 AM
09/15/17 08:20 AM
Joined: Jun 2003
Posts: 10,430
Illinois
javacontour Offline
javacontour  Offline
Joined: Jun 2003
Posts: 10,430
Illinois
Competing regulatory demands.

As I understand it, and I reserve the right to be wrong...

1. We've regulated NOx levels such that you cannot use a lean burn technology.

2. Safety demands, we've set up standards such that you need more safety equipment, multiple air bags, ABS, Traction Control, higher belt lines to help pedestrians, and who knows what else. This drives up the weight in cars.

3. More standard equipment. Back in the 70's and 80's, A/C, power windows and door locks and so on were optional. You could really build a 2000# car. Today, it's hard to find a car that is less than 3000#

4. Even more equipment invented. More power/heated/cooled seats, satnav/infotainment, and who knows what else. That also drives up weight. Add on the bigger wheels and tires that are fashionable today. Try to find an econobox with 13" wheels. Other than maybe that tiny Mitsubishi offering, I don't think there is much new on the market that might even have such small wheels and tires.

All of the above conspires to keep fuel economy from rising.

One other thing to consider is the testing today is more accurate compared to the numbers we saw in the 70s, 80s and 90s. The EPA has revised their methodology a few times. So it isn't even and apples to apples comparison to compare older EPA numbers with the numbers we see today.


network down, IP packets delivered via UPS -BOFH
Re: Fuel economy, why has it not improved more? [Re: Rat407] #4516827
09/15/17 08:22 AM
09/15/17 08:22 AM
Joined: Apr 2008
Posts: 12,863
Onondaga County
Miller88 Offline
Miller88  Offline
Joined: Apr 2008
Posts: 12,863
Onondaga County
That pretty much sums it up. Cars are so much heavier than they used to be - even a compact car has gained over 1000 pounds in the last 20 years. And the EPA doesn't like lean running engines ... gotta keep those cats glowing!


18 Forester 2.5I 6M
00 Jeep Cherokee
01 Ford F-350 XL 4x4 5M
Re: Fuel economy, why has it not improved more? [Re: Rat407] #4516832
09/15/17 08:24 AM
09/15/17 08:24 AM
Joined: Jun 2002
Posts: 18,223
Elizabethtown, Pa
Al Offline
Al  Offline
Joined: Jun 2002
Posts: 18,223
Elizabethtown, Pa
laws of thermodynamics. The Otto Cycle gas efficiency has limits. There is the more efficient Diesel Cycle. Those are the only practical power cycles for cars.

Efficiency has come a long way. Equivalent engine efficiencies have risen 1/3 since the 70s

Last edited by Al; 09/15/17 08:26 AM.

Re: Fuel economy, why has it not improved more? [Re: Rat407] #4516834
09/15/17 08:26 AM
09/15/17 08:26 AM
Joined: Apr 2010
Posts: 4,398
Storrs, Connecticut
jeepman3071 Offline
jeepman3071  Offline
Joined: Apr 2010
Posts: 4,398
Storrs, Connecticut
Weight.


2000 Jeep Cherokee 4.0L (180k) - Pennzoil 10w30, Napa Gold 1516, Magnefine trans filter
2009 BMW 328i (33k) - Castrol Edge Euro 0w40, MANN HU816X
Re: Fuel economy, why has it not improved more? [Re: Rat407] #4516835
09/15/17 08:28 AM
09/15/17 08:28 AM
Joined: Jan 2013
Posts: 1,351
America's Dairyland
LotI Offline
LotI  Offline
Joined: Jan 2013
Posts: 1,351
America's Dairyland
Size, weight, higher speed limits, congestion, and impatience are a few that come to mind.

A speeding Prius isn't efficient. Honda Civic is now a midsize car. Etc...


03 Honda Interceptor
11 Kawasaki KLR 650
12 Ford E450
17 VW GTI
[IMG]http://badges.fuelly.com/images/sig-us/803455.png[/IMG]
Re: Fuel economy, why has it not improved more? [Re: Rat407] #4516841
09/15/17 08:36 AM
09/15/17 08:36 AM
Joined: Oct 2010
Posts: 1,781
.
Danh Offline
Danh  Offline
Joined: Oct 2010
Posts: 1,781
.
Guess my experience is different. Compared to their 1999 and 2005 sedan/SUV equivalent predecessors my current vehicles are at least 20-25% more fuel efficient. Plus they're quieter, handle better, accelerate at least as well, have tons more safety features and technology, etc. They also have more fuel dilution, though...

Re: Fuel economy, why has it not improved more? [Re: Rat407] #4516851
09/15/17 08:45 AM
09/15/17 08:45 AM
Joined: Dec 2009
Posts: 748
Battle Creek, MI
SVTCobra Offline
SVTCobra  Offline
Joined: Dec 2009
Posts: 748
Battle Creek, MI
Something we are forgetting though is power output. Yes it's getting similar fuel mileage, but the power has doubled in some cases. My old 7.3 Powerstroke gets 16-17 mpg and my brothers 6.7 Powerstroke is slightly less (mainly due to how he drives it), but makes double the horsepower, more than double the torque.


If marriage was outlawed only outlaws would have in-laws.
Re: Fuel economy, why has it not improved more? [Re: Rat407] #4516853
09/15/17 08:45 AM
09/15/17 08:45 AM
Joined: Jan 2008
Posts: 3,972
Guilford, CT
exranger06 Offline
exranger06  Offline
Joined: Jan 2008
Posts: 3,972
Guilford, CT
Americans want power and speed. The old cars you mentioned take roughly 20 seconds to get to 60 mph, and 65-70 mph is about their top speed. The modern vehicles you mentioned can accelerate at least twice as fast and have about 3 times the power while STILL getting better mileage. AND they weigh significantly more due to all the safety features. If people were willing to live with underpowered, slow vehicles, then sure, maybe they'd get significantly better mileage. But the automakers will only build what people will buy, and nobody would buy a car like that.


2006 Ford Ranger Sport
1992 Honda Accord EX
2004 Honda CR-V LX
1994 Ford Bronco XLT (project)
2011 Cadillac Escalade ESV (wife's)
Re: Fuel economy, why has it not improved more? [Re: Rat407] #4516854
09/15/17 08:46 AM
09/15/17 08:46 AM
Joined: May 2009
Posts: 12,192
N.H, U.S.A.
ARCOgraphite Offline
ARCOgraphite  Offline
Joined: May 2009
Posts: 12,192
N.H, U.S.A.
Java has it covered. My Wifes old 198? carbureted Dodge Colt 3dr hatch she had when we got married in 1991 weighed under 1 ton had a wide RATIO 4 speed manual and averaged 37MPG. I'm sure HP was under or around 80 MAX.
CATS require soich or richer A/F NO LEAN BURN for NOx limits.

Sub and Compact cars weigh at least 500- 800 lbs More than in the 80s given added safety requirements of 10 air bags and improved unibody structure and then them dooh daads.

Large diameter wheels suck gas and slow the car during acceleration

Much wider tire footprints suck gas. IIRC the colt had 155-70r-13 or close to that.

Finally Much higher specific engine output with torque produced at higher rpm.

Todays 2L 140 HP eco car could RARELY be had, and then only in limited. special H.O. variants

My lowly 4 cyl Nissan Rogue makes more TRUE HP than my mid 80s Mustang 5.0!


2014 Nissan Rogue S CVT, OC#9 41392mi-QSUD10W30 + M110A CHAMP Filter; 2017 Subaru Crosstrek CVT OC#2 ?? mi-SOA/Idemitsu 0w20 + SOA Filter
Re: Fuel economy, why has it not improved more? [Re: Rat407] #4516855
09/15/17 08:46 AM
09/15/17 08:46 AM
Joined: Apr 2016
Posts: 1,185
Campbellsville, KY
Alex_V Offline
Alex_V  Offline
Joined: Apr 2016
Posts: 1,185
Campbellsville, KY
Not the whole reason, but food for thought:
"Emissions" isn't always conducive to max fuel economy.
Neither is a thing called *amenities*. How were those old VW diesels equipped, and how much did they weigh? The gas Cruze weighs something around 3,300 lbs. empty, not to count the weight of the diesel engine when equipped - within 150 lbs. of what an early, 4 cyl. XJ Cherokee (let's say, in the same segment as an Equinox today) weighs. Traverse weighs 4,800 lbs. where my '67 Suburban with the biggest optional engine, heavy arse, iron 4-speed transmission, and HD suspension, etc. weighs 4,600.
Air bags, entertainment systems, air conditioning, power windows, extra mufflers/resonators, sound deadening material, etc. - they all weigh something. Add them up, along with the increased heft of the structural components to meet safety standards or have the best tow rating in its class, and it makes a difference.

If the 1.4T in my Cruze can get 37 (easy) to 40 (near perfect conditions) pushing its 3,300 pound shell with a high hoodline for "pedestrian crash" safety down the road, what could that same drivetrain do in the shell of an equivalent car of, say, 30 years ago? (Corsica, Citation, Jetta/Passat, Accord?) Food for thought.


I like Chevy and Valvoline.

'13 Cruze, 1.4T, 113K
'85 GMC C3500, 454, 130K
'82 Mercedes 300CD, OM617 turbo, 169K
'67 Suburban, 350, 331K
Re: Fuel economy, why has it not improved more? [Re: Rat407] #4516860
09/15/17 08:52 AM
09/15/17 08:52 AM
Joined: May 2009
Posts: 12,192
N.H, U.S.A.
ARCOgraphite Offline
ARCOgraphite  Offline
Joined: May 2009
Posts: 12,192
N.H, U.S.A.
I will say in the Compact SUV segment Subaru has found the secret formula - My wife could EASILY get over 33 MPG AVE in a "largish" Forester with a 6 speed stick and AWD. That is an achievement.

The last Subaru EJ253 used intake tumble valves and a "VTEC-like" variant that mainly used only 1 intake valve at light throttle and low-mid rpm. BUT the Engine still made 175 HP at high RPM when the aggressive cam profile came into play. Brilliant.


2014 Nissan Rogue S CVT, OC#9 41392mi-QSUD10W30 + M110A CHAMP Filter; 2017 Subaru Crosstrek CVT OC#2 ?? mi-SOA/Idemitsu 0w20 + SOA Filter
Re: Fuel economy, why has it not improved more? [Re: Rat407] #4516870
09/15/17 08:58 AM
09/15/17 08:58 AM
Joined: Mar 2016
Posts: 949
PA,US
HemiHawk Offline
HemiHawk  Offline
Joined: Mar 2016
Posts: 949
PA,US
I think weight is a huge factor. I had a 2003 Cavalier 5-speed. The only option was air conditioning. I think it was rated for 31ish highway. I could easily pull over 40 highway. That car had just about zero fuel saving technologies like cars today have. Of course I would much rather be in an accident in a modern car than that tin can.


2016 Nissan Frontier Pro4x
2017 VW GTI sport
1995 Mustang GTS
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