Slava

I have about 6,000 miles on my exactly 2 months old automatic TL and just saw something weird for the first time today.
Normally I drive without too much traffic and get about 26-27-28 MPG if my speed is about 75 to 80 MPH. I thought that was pretty good considering 28 MPG is max as stated on the sticker

Well, today after the fillup at the gas station that was right next to the freeway I reset the trip computer right as I got on the freeway. There was some traffic there so I was going about 55-60MPH. When I checked my Trip Computer after about 15 miles of such driving it said 33 MPG
As traffic eased up and I went to my normal 80MPH the MPG slowly but surely went down all the way to 28

On the one hand it's great that my car is capable of such mileage, but on the other hand NO WAY will I be driving this slow to attain it.

So I was wondering what is the highest mileage anyone ever gotten and at what speed? Of course I am talking about highest gear so 5th for Auto and 6th for Manual.

Road Rage

Surprisingly, i have actually studied this in a number of vehicles, driven by my sick need to know things.

There are 3 principles at work here:
1) Drivetrain efficiency (engine/tranny/differential/tire rolling resistance, etc))
2) Aerodynamics (body drag, tire drag)
3) Ambient air temperature

Too slow, and one is not getting optimal #1 - too fast, and #2 raises its ugly head, and the power to offset aero effects rises as the square of the delta. That is why it can take over 500 wheel HP to go over 200 mph! And I found that about 68 - 70 degrees Fahrenheit yield the best fuel economy - too cold and the fuel system has to enrich - too hot, and air density suffers, and the ECU retards the spark timing when things heat up as well.

My studies found that somewhere between 45 mph and 50 mph is optimal for fuel economy. So if you ever were in a desert, low on fuel, that is the speed to drive. Until the buzzards catch up to you and come in through the moonroof.

Chet03TL-S

Optimal speed for high MPG is about 55-65MPH.

THe best I got on my 2nd Gen TL-S is 36MPG. I think I had a tail wind helping me. Otherwise, in several occassions I got 32-34MPG, all freeway cruising at 70-75MPH for 12-14gal burned.

Salut

Damn I get 18-20 mpg if i'm lucky...

But again I push my car, all the time, and hard (just like my women- hehe)

I don't expect to see the MPG you guys are seeing and that's good...

That is why I got the 6MT... to drive it baby...

Gas - Shmas


Salut

TheOne305

i got 34 but i also shift to "N" when coasting down hill or when coasting is possible it helps and i tried driving this way in the city and got my MPG to 27 which i probably not do again since im not a granny driver.i just figured ill see what happens.My avg. is 22 MPG

Casper42

Salut, you fucking rule. Your gonna have to come join us for a Eastern Ventura County meet since your so close. I cant wait to meet you. I'm on the far east side of Simi so we only live like 5 min from each other on the 118.

mastertl

Umm...there was a thread back a while ago of someone (sorry i forgot) who tested driving speeds with respect to how many miles they got. the optimum for the TL was 55 mph for the best mpg. lemme find the thread

mastertl

http://acura-tl.com/forums/showthrea...ghlight=55+mph

if you are too lazy (btw the post was made by Jtruman)

I now have 9000 miles on my car, and on my 6 hour road trip yesterday, I did another calibration of the MPG vs. MPH.

Cruise control at various speed, drive for about 5 miles to let the MID settle

6MT, at 6th gear

55MPH = 38MPG
65MPH = 34MPG
75MPH = 31MPG
85MPH = 27MPG
95MPH = 24MPG
105MPH = 21MPG

It was a bit difficult to keep the speed at 105 for 5 miles, kept coming up to other slow cars.

So for the rest of the way, I set the cruise control at 80MPH, and after 300 miles, it indicated 29MPG.

Going 55MPH would have been great for my wallet, but I would absolutely go crazy driving 4 hours at 55MPH. Come to think of it, if someone has the patience to drive 55MPH for the entire trip, you can get over 600 miles to a tank!


I know it is 6sp, but im not sure how much that would differ from at

lindros2

I've found 55-65 is definitely the best for higher MPG.

However, the Turanza EL42's provided better mileage (by 1-4MPG) over the Michelin Pilot Sport A/S on now.

TBone2004

good info - I agree cause I normally do 80mph in my commute and I am getting 27-28 MPG for the past 4 months.

55 would be maddening! but so was my $225 gas bill last month tho too....

92NSX

I have been getting 21mpg while also averaging a whopping 23 mph !!!

Road Rage

I do not see where anyone measured at my 45-50 mph. Hmmmm?

rets

I also got the best MPG around my driveline vibration spots, between 50-55 MPH at 5th gear/1500 RPM. It will go up to 32~34+ MPH more, but I barely can stand at that zone too long. So bad.


I'd say so because a few months ago I drove almost 510 mile in a single tank, almost 16 gallons (Miles to Empty had shown "0" for miles), I was staying between 55 MPH and 85 MPH. My 5AT is GREAT, too.



Sidenote: My 5AT has averaged 14~18 MPG in NYC.







RR: what's your final figure there???

Salut

Cool bud...
Let me know...

VTEC=Happiness is also a local 118 boy...

You know what I've been wanting to do, is post (sorry ) here for all SoCal TL'ers to meet up and cruise or just meet up somewhere...

PM me with a couple days notice when you and yours are ready to saddle up and ride again...

Regards
Salut

Slava

Unba-freaking-believable!!!

There is just something wrong with this picture. Does anyone have a power distribution chart (what horsepower is generated at what rpm) for the TL?

You'd think that a car that can generate a maximum horsepower 270 would have the most optimal mileage at little higher speed than a car that can generate only 100 horsepower.

On my father's '97 Mazda Protege (with a wopping 95 horsepower) the most optimal speed is about 70mph (according to him) and his RPM is about 2,800

So why is it that on my car I have to go slower, with less rpm, in order to get my optimal mileage out of the car? It looks like the TL engine was diesigned to do 270mph BUT only at a cost of being very ineffient. The optimal mileage-per-gallon on the TL looks to be at about 55MPH where the car may generate only a measily 100 horsepower (ballpark figure of course), roughly the same horsepower my father's car generates

So I guess I answered my own next question:
Why the sticker on car shows 21 city - 28 highway when it can do a lot more than that?

Well, would YOU buy a car that was designed more be driven at 55mph at 38mpg
or
would YOU buy a car that was designed to be driven 105mph at 21mpg?

It all comes down to marketing..... ... it always does!!

Ken1997TL

The fuel economy numbers are derived from the EPA. Their tests are SIMULATIONS done in a lab using math formulas and leave out a LOT of important factors such as air conditioning and the fact that most people drive faster than 55 on the highway.


As for your "theory" on powerband usage to get fuel economy... that is really umm "interesting" (trying to hold my tongue here).

Basically you want to keep the revs low (2000 rpms or so) without bogging the engine in the process to get the best MPG returns. It has NOTHING to do with peak horsepower.

If that were the case, I'm going to buy an S2000 right now and keep it spinning at 8500 rpm's all day...

jtruman

One follow up, I was on a regular expressway the other night, I put the car in 6th gear and drove around 45MPH... the fuel efficiency was above 40MPG.

As for why they post 28MPG (5AT) / 30MPG (6MT) for fuel efficiency on freeway when the car is capable of much higher, it's because they have a certain routine (drive xMPH for y miles, change speed to zMPH and drive for ... etc) to calculate the metrics. Exactly what I am not sure.

ITL

I'd have to guess that weight, size, and aerodynamics play a big role. The Protege is not exactly a big car.

carcar

Our brand new (2 day old) TL has 270 some miles on it (drove it up from Chicago where the dealer was) and going 80, on this BRAND NEW not even broken in car I got 24 mpg. The average speed, unusually, is 35 mph, which we can't figure out! Oh well, just thought I'd add.

carcar

Slava

I understand what you are saying about keeping RPMs low to get best MPG results. But for me it's just a little dissappointing that 3 different engines (with 5,500 and 6,800 and 8,500 RPM readlines) all have their most optmal MPG values at below 2,000 rpm. I'd think that the "sweet" spot was proportional to the highest RPMs that could be achieved.

But I guess it isn't so. There is NO difference for most efficient fuel economy between Mazda Protege, Honda S2000, or Acura TL...

1FasTL

Best fuel economy for ANY car is highest gear, at lowest RPM's (without lugging). Plain and simple.

Listen to RR if you want to be more technical. Aerodynamics play the biggest part at speeds over 50 MPH (to quote RR: the power to offset aero effects rises as the square of the delta) True!

Road Rage

Slava, you did not sleep through physics class did ya? Aerodynamics play a much bigger role than the power curve beyond certain speed, including the ones we are discussing here (highway). Increases in speed cause increases in power demand that are squared functions - it swamps the effects of the power curve. It was item #2 in my post.

If you double your speed, you will increase the power needed by far more than double. A vehicle that requires 20 horsepower at 50 mph might require 100 horsepower at 100 mph. As I said, this why a Ford GT needs 550 HP to go 205 mph.

I also mentioned air density, which has to be optimum for power in the engine, and minimized density for the car to plow through.

The issue is fairly complex, and simplistic answer will not feed the bulldog.

road load power = av + bv2 + cv3

"The letter v represents the velocity of the car, and the letters a, b and c represent three different constants:

The a component comes mostly from the rolling resistance of the tires, and friction in the car's components, like drag from the brake pads, or friction in the wheel bearings.
The b component also comes from friction in components, and from the rolling resistance in the tires. But it also comes from the power used by the various pumps in the car.
The c component comes mostly from things that affect aerodynamic drag like the frontal area, drag coefficient and density of the air. "

To get the full impact of how a small increment in speed requires huge factors of power increase, read the full link in:
http://auto.howstuffworks.com/question477.htm

Road Rage

To build on 1fastTL's statement, getting up to speed with the highest efficiency has actually shifted since the days of the carburetor.

In the carb days, fuel metering was imprecise compared to today's FI cars - and the accelerator valve dumped a lot fo fuel. So in those days, the very slow movement up to speed was best - the proverbial "egg between your foot and the gas pedal" recommendation.

With today's modern fuel-injected precision metering, this is no longer true. Actually, moderately brisk accleration up to the desired terminal speed is best. That does not mean flooring it, of course.

Road Rage

I have seen as high as 35 in the 50 mph zone or slightly below, as I predicted, but like you, I cannot stand it too long. I crusie in the 68 mph range and get about 31-32 with the 5AT - it is amazing. I wonder if the system is accurate?

Ken1997TL

^^ That sounds about right.

Did a 750 mile roadtrip in an '03 TL (nearly the same gear ratios as the '04 auto)

I got 33 mpg on regular gas going about 70 mph the whole way.

Road Rage

I get much better fuel economy in the TL than my S2000. It is not even close.

Ken1997TL

I assume its because the TL is revving far lower in 6th gear than an S2000 in 6th gear.

Road Rage

That would be the major reason, certainly.

Brokedoc

You may get better MPG by shifiting in/out of neutral but you're going to kill you clutch plate (MT) or need an early AT overhaul from all the extra wear.

Brokedoc

Here's a variation on this MPG question:

Assuming the same vehicle speed on the highway, do you get better mileage with
A - the A/C on and the windows up (improved aerodynamics) or
B - the A/C off and the windows down (worse aerodynymics)

Care to venture a guess, RR?

Road Rage

I usually do not guess, but make informed speculations: given the efficiency of modern compressors and cyclic programming, I would say that one would get worse mileage at highway speeds with all the windows down than with the A/C on. A window cracked of course would reverse my opinion. Bypassing Auto mode will also improve mileage, as higher fan speeds provide better A/C efficiency.

How did I do, Prof?

Brokedoc

Are you related to John Kerry? Your "scientific reasoning" seems to support both choices. If I am interpreting your political stance properly, I think you are favoring choice A as having better mileage...correct?

I think we need to have some experiments to settle this one.

ddehorn

I drove from the Bay area (Danville, CA) to LA (Long Beach, CA) over the Labor day weekend. I was following my wife in her Oddessy. She was driving about 75 mph. I was not using cruise control as it is really hard to use cruise control on I-5 during such a high traffic weekend. I got 32 mpg and was doing about 75 mph consistantly until I got into the Pasadena area, where I hit bumper to bumper traffice for about 45 minutes. I think I could have gotten 33 mph without the slow down in Pasadena. On my way up to the Bay area, I went about 400 miles. However It took me two hours to go the first 60 miles leaving LA on a Friday afternoon. I still got 28 mpg for the total trip up to the Bay area and I was on my own driving about 85 mph after the first slow two hours. Very fun over the Grapevine.

04 TL 5at

Fun!

Tedanddenise

Years ago, back in the early 70's, there was a NATIONAL SPEED LIMIT imposed and limited everyone (theoretically) to a 55 mph speed limit to save gasoline. Truckers wildly protested since they had to slow down from their 75 mph in some states. Anyway, to me, air resistance is the biggest factor affecting mileage - there are little things that can also help, like the A/C off, etc, but, air resistance is the biggest factor which is why the TL is pretty good. I notice a tremendous variation in my motorcycle depending on speed alone. If I average 80 mph (I recently came back from a trip to the west coast), my mileage drops to around 40 mpg - if I average 60 mph, the mileage increases to a little over 50 mpg. The only variable other than temperature and altitude is the speed.

Road Rage

I hate Kerry, and I have no idea what you are tallking about The question said the windows down - without knowing how far down, I could not answer B without qualification, which you seem to think it waffling like the Waffle King (he looks like Muldoon (fred Gwynn) on the Car 54 re-runs).

The answer is: with all the windows down, one would get better mileage on the highway if one rolled them up, and turned on the air, especially if one bypassed AUTO mode and ran higher fan speeds. BTW, I do believe this has been studied.

I hope that makes my position clearer - so what is the answer, Brokedoc? Or was your Q a teaser?

Road Rage

http://money.cnn.com/2003/09/25/pf/autos/save_gas/

Note that this was not reported by Dan Rather.

fuque

That's nothing - I've gotten MPG so high it's off the scale (the MID just says "> 50"). One time I took a snap of the MID with my shitty camera phone. It's hard to read, but the MPG is 48 at an average speed of 72 MPH.

Brokedoc

It was a genuine question that I didn't know the answer to.

As always, thank you for your insight, RR.

Road Rage

You're welcome - now fuque, when are you going to admit you were decending Mount Everest to get those numbers? R U actually claiming that on a flat surface, you can get 48 MPG at 72 MPH? That is a bit of a stretch - got photoshop? It defies the physical laws stated in the formula, and common sense. Were you in a wormhole?

Brokedoc

I like the wormhole theory. A couple of light-years on one gallon of gas. But then you're travelling faster than the speed of light and when you come out of the other end, you're driving your brand new 04TL and everyone else will be driving their 2025 Acura Shuttlepod TLs.