Go Back   EcoModder Forum > EcoModding > Hypermiling / EcoDriver's Ed
Register Now
 Register Now
 

Reply  Post New Thread
 
Submit Tools LinkBack Thread Tools
Old 04-02-2008, 09:38 PM   #21 (permalink)
ECO-Evolution
 
Lazarus's Avatar
 
Join Date: Nov 2007
Location: Central Texas
Posts: 1,482

Iron Horse (retired) - '97 Iron horse Intrepid

Ninja - '08 Kawasaki 250R
90 day: 76.23 mpg (US)
Thanks: 17
Thanked 43 Times in 32 Posts
I think the discussing needs to be quantified between standard and automatic transmission.

__________________
"Judge a person by their questions rather than their answers."

  Reply With Quote
Alt Today
Popular topics

Other popular topics in this forum...

   
Old 04-02-2008, 10:22 PM   #22 (permalink)
Who
UnderModded
 
Join Date: Dec 2007
Location: San Jose
Posts: 319

Pablo - '07 Hyundai Santa Fe AWD
90 day: 23.62 mpg (US)
Thanks: 0
Thanked 1 Time in 1 Post
Mileage sucks until you're in top gear. There is an optimal acceleration rate and it might be surprisingly quick on some vehicles for what the owners might actually think it is.

I still haven't tested this. A accelerate at a LOD of 50 or so, although I'm using LPH instead but it really gets impacted by the cold. I need more than 1!
__________________
  Reply With Quote
Old 04-16-2008, 09:28 AM   #23 (permalink)
EcoModding Lurker
 
Join Date: Apr 2008
Location: Ireland
Posts: 33

Baz - '93 Peugeot 106
90 day: 62.39 mpg (US)
Thanks: 0
Thanked 0 Times in 0 Posts
In terms of simple physics, one would assume that the extra energy needed to propel at a higher velocity, within a short time frame would be exceptionally costly, but maybe I'm incorrect.
__________________


Goal: 3L/100KM
  Reply With Quote
Old 04-16-2008, 03:39 PM   #24 (permalink)
Depends on the Day
 
RH77's Avatar
 
Join Date: Nov 2007
Location: Kansas City Area
Posts: 1,761

Teggy - '98 Acura Integra LS
Sports Cars
90 day: 32.74 mpg (US)

IMA - '10 Honda Insight EX
Team Honda
90 day: 34.76 mpg (US)

Tessie - '06 Acura TSX Base
90 day: 28.2 mpg (US)
Thanks: 31
Thanked 41 Times in 35 Posts
Quote:
Originally Posted by Lazarus View Post
I think the discussing needs to be quantified between standard and automatic transmission.
I agree -- without full control in an automatic, one would expect to get to the desired speed at a high load / lowest RPM possible -- or relatively quickly. Depending on the engine. I'd need to see the BSFC, but mine is about half of where max torque is made (5200/2 = 2600) 2500-3000 seems to be the best operating range.

Of course tests are required to confirm.

So how about a slap-shift auto? On the TSX I can force upshifts in the 2300 RPM range and keep the accelerator mashed (not fully, but 75% or so). I almost always drive with the manu-matic -- prevents the unexpected downshift until it computes that it absolutely has to based on speed.

RH77
__________________
“If we knew what we were doing, it wouldn't be called research” ― Albert Einstein

_
_
  Reply With Quote
Old 04-17-2008, 10:10 AM   #25 (permalink)
EcoMudder
 
Harpo's Avatar
 
Join Date: Mar 2008
Location: Gainesville, FL
Posts: 79

Harpo's Honda - '05 Honda Civic VP
90 day: 42.64 mpg (US)
Thanks: 0
Thanked 2 Times in 2 Posts
Quote:
Originally Posted by Lazarus View Post
I think the discussing needs to be quantified between standard and automatic transmission.
http://forum.ecomodder.com/em-fuel-log.php?vehicleid=16

Dang .. you've got that thing tweaked!
__________________
  Reply With Quote
Old 04-17-2008, 12:43 PM   #26 (permalink)
ECO-Evolution
 
Lazarus's Avatar
 
Join Date: Nov 2007
Location: Central Texas
Posts: 1,482

Iron Horse (retired) - '97 Iron horse Intrepid

Ninja - '08 Kawasaki 250R
90 day: 76.23 mpg (US)
Thanks: 17
Thanked 43 Times in 32 Posts
Quote:
Originally Posted by Harpo View Post
http://forum.ecomodder.com/em-fuel-log.php?vehicleid=16

Dang .. you've got that thing tweaked!
I guess I will change the name on that. It's a bike not a car

Done.
__________________
"Judge a person by their questions rather than their answers."

  Reply With Quote
Old 04-25-2008, 04:52 PM   #27 (permalink)
EcoModding Lurker
 
Join Date: Apr 2008
Posts: 21

Focus - '05 Ford Focus ZX3 SE
90 day: 30.86 mpg (US)
Thanks: 0
Thanked 1 Time in 1 Post
Here is what I learned from my last car, which I got quite a bit into both mileage and performance enhancement, was an AWD Turbo, this should pertain quite a bit to you:

Open-loop = horrible, horrible for mileage. I got anywhere from 2-6 mpg in open loop at WOT (wide-open-throttle). Turbocharged cars, especially older ones can go very very rich (8:1 was possible) under open loop, which kills mileage in a hurry. This is the easiest way to save (and also waste) fuel.

Somewhat counter-intuitively, low throttle position = bad for mileage. The throttle plate is a restriction to the engine. The pistons have to work hard to suck air through a closed throttle plate, which leads to large parasitic losses. This is a big reason why diesels get better mileage than gasoline engines - no throttle plate. The less resistance to movement you can get on the engine, the better. This includes things like a more open intake and exhaust to get rid of the pumping losses, windage trays in the oil pan to get rid of oil slinging around the crank, using good oil, etc. The easier it is for the engine to turn, the more efficient it is. This is difficult to do, because usually open throttle = open-loop, which ends up being less mileage overall, see above.

The trick is finding a balance between open-throttle and closed-loop. If you can use external methods to force both of these conditions, that's optimal for mileage, but can come with problems of its own (turbocharged cars run rich under wot for a reason, to protect the engine from knock).

The turbocharger also improves efficiency (theoretically). You are scavenging otherwise-wasted energy from the exhaust gas. The problem is, as stated above, that when the turbo spools up under WOT, the car runs rich to keep everything safe, which takes any efficiencies the turbo gives you and throws them on the ground angrily.

What I was just starting to get into on my last car before it broke was a way to have the throttle fully open, the turbo fully spooled, but yet running extremely lean so I didn't keep accelerating. It was technically open-loop, but I was manually keeping an eye on the EGT, the knock, the temps etc, and running way leaner than 14:1 (which is where closed-loop keeps you). Didn't have time to get much into it before an unrelated event broke my car and I decided I was sick of it.

My 3 cents.

-Jesse

  Reply With Quote
Reply  Post New Thread


Thread Tools




Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2020, vBulletin Solutions Inc.
Content Relevant URLs by vBSEO 3.5.2
All content copyright EcoModder.com