Go Back   EcoModder Forum > EcoModding > EcoModding Central
Register Now
 Register Now
 

Reply  Post New Thread
 
Submit Tools LinkBack Thread Tools
Old 03-12-2017, 10:27 AM   #1 (permalink)
Cyborg ECU
 
California98Civic's Avatar
 
Join Date: Mar 2011
Location: Coastal Southern California
Posts: 3,920

Black and Green - '98 Honda Civic DX Coupe
Team Honda
90 day: 59.76 mpg (US)

Black and Red - '00 Nashbar eBike custom built
90 day: 3671.43 mpg (US)
Thanks: 1,399
Thanked 1,083 Times in 721 Posts
What's better, lean burn or tall gearing?

Which is better? It depends on how your car is engineered and how you are going to drive it, but I thought this screenshot I just bumped into in my notes might be a useful. It is a reminder about how the original VX was designed. I assume that they are using some approximation of the EPA test cycle for these estimates. Notice that gearing is credited with 21% of the FE gain of the 1992 VX over the 1991 DX at the time, while lean burn is credited with just 5-10%. In fact, all the vtec-e stuff amounts to less impact on FE than gearing.


Attached Thumbnails
Click image for larger version

Name:	VX FE improvement technologies over DX.png
Views:	118
Size:	84.4 KB
ID:	21367  
__________________


See my my car's mod thread and my electric bicycle's thread for ongoing projects. I will rebuild Black and Green over decades as parts die, until it becomes a different car of roughly the same shape. My fuel economy goal is 55+ mpg while averaging posted speed limits. See my Honda manual transmission specs post too.

  Reply With Quote
The Following 4 Users Say Thank You to California98Civic For This Useful Post:
BabyDiesel (03-15-2017), Daschicken (03-12-2017), Gasoline Fumes (03-12-2017), Joggernot (03-13-2017)
Alt Today
Popular topics

Other popular topics in this forum...

   
Old 03-12-2017, 03:37 PM   #2 (permalink)
Custom User Title
 
Gasoline Fumes's Avatar
 
Join Date: Oct 2009
Location: New York State
Posts: 950

Nut Wagon - '91 Honda Civic Wagon DX
Team Honda
Wagons
90 day: 53.2 mpg (US)

CRXFi - '88 Honda CRX XFi
Thanks: 378
Thanked 387 Times in 221 Posts
I'm borrowing a 2001 Insight and lean burn seems to double the instantaneous cruising MPG. Maybe the test cycle doesn't let Hondas enter lean burn much? The best tank in the Wagon with the original trans (shorter FD than '91 DX hatchback) was 70 MPG. Best tank after installing the CRX HF trans (taller than '92 VX) was 82. So the gearing increase more or less matches what I saw.
__________________
Best tank with the Honda so far is 81 MPG.
  Reply With Quote
Old 03-12-2017, 06:42 PM   #3 (permalink)
Cyborg ECU
 
California98Civic's Avatar
 
Join Date: Mar 2011
Location: Coastal Southern California
Posts: 3,920

Black and Green - '98 Honda Civic DX Coupe
Team Honda
90 day: 59.76 mpg (US)

Black and Red - '00 Nashbar eBike custom built
90 day: 3671.43 mpg (US)
Thanks: 1,399
Thanked 1,083 Times in 721 Posts
Quote:
Originally Posted by Gasoline Fumes View Post
... Maybe the test cycle doesn't let Hondas enter lean burn much?...
I bet that's right. Certainly an ecomodder worth his salt can get mch more out of thre car's engineering. But that's also true of skilled driving with taller gearing. The Insight prolly has more advanced LB parameters than the VX. I know the 6th gen HX Civic did. And the first Insight, of course, came after the HX.
__________________


See my my car's mod thread and my electric bicycle's thread for ongoing projects. I will rebuild Black and Green over decades as parts die, until it becomes a different car of roughly the same shape. My fuel economy goal is 55+ mpg while averaging posted speed limits. See my Honda manual transmission specs post too.

  Reply With Quote
The Following User Says Thank You to California98Civic For This Useful Post:
Gasoline Fumes (03-12-2017)
Old 03-12-2017, 07:46 PM   #4 (permalink)
V8 guy
 
oil pan 4's Avatar
 
Join Date: Jul 2011
Location: NewMexico (USA)
Posts: 4,379

Sub - '84 Chevy Diesel Suburban C10
SUV
90 day: 19.5 mpg (US)

camaro - '85 Chevy Camaro Z28

Riot - '03 Kia Rio POS
Team Hyundai
90 day: 30.21 mpg (US)

Bug - '01 VW Beetle GLSturbo
90 day: 26.43 mpg (US)

Sub2500 - '86 GMC Suburban C2500
90 day: 11.95 mpg (US)
Thanks: 97
Thanked 965 Times in 706 Posts
Lean burn was good for another +20% for me.
I would expect up to +20% from a fairly radical gear change from 4.11 to 3.21, what I have in store for the suburban or from 3.73 to 3:1 or 3.25 to 1 for the firebird.
__________________
1984 chevy suburban, custom made 6.5L diesel turbocharged with a Garrett T76 and Holset HE351VE, 22:1 compression 13psi of intercooled boost.
1989 firebird mostly stock. Aside from the 6-speed manual trans, corvette gen 5 front brakes, 4th Gen disc brake fbody rear end.
  Reply With Quote
Old 03-12-2017, 07:49 PM   #5 (permalink)
Aero Deshi
 
ChazInMT's Avatar
 
Join Date: Jan 2010
Location: Vero Beach, FL
Posts: 1,021

MagMetalCivic - '04 Honda Civic Sedan EX
90 day: 34.37 mpg (US)
Thanks: 420
Thanked 612 Times in 332 Posts
I just replaced my 2004 Civic EX manual transmission with an LX letting my 75mph RPM drop to 3050 from 3800. I drove from FL to OH but did not see great gains in efficiency. I will be driving to Arizona then back to Tennessee in the next 6 weeks so I should have a better idea. I did remove an upper grill block that I didn't replace when I changed the gearbox out, and didn't put it back in. I also did not drive as well as I could have. It does make highway speeds much quieter not going as far up in the RPM range, a nice bonus.
  Reply With Quote
Old 03-12-2017, 07:57 PM   #6 (permalink)
Cyborg ECU
 
California98Civic's Avatar
 
Join Date: Mar 2011
Location: Coastal Southern California
Posts: 3,920

Black and Green - '98 Honda Civic DX Coupe
Team Honda
90 day: 59.76 mpg (US)

Black and Red - '00 Nashbar eBike custom built
90 day: 3671.43 mpg (US)
Thanks: 1,399
Thanked 1,083 Times in 721 Posts
Quote:
Originally Posted by ChazInMT View Post
I just replaced my 2004 Civic EX manual transmission with an LX letting my 75mph RPM drop to 3050 from 3800. I drove from FL to OH but did not see great gains in efficiency. I will be driving to Arizona then back to Tennessee in the next 6 weeks so I should have a better idea. I did remove an upper grill block that I didn't replace when I changed the gearbox out, and didn't put it back in. I also did not drive as well as I could have. It does make highway speeds much quieter not going as far up in the RPM range, a nice bonus.
Well, I'd say if you delted two things that are well-known to give you better FE (grill block and hypermiling) and still go the same FE as before the swap, then that suggests the swap might have saved you.
__________________


See my my car's mod thread and my electric bicycle's thread for ongoing projects. I will rebuild Black and Green over decades as parts die, until it becomes a different car of roughly the same shape. My fuel economy goal is 55+ mpg while averaging posted speed limits. See my Honda manual transmission specs post too.

  Reply With Quote
The Following 2 Users Say Thank You to California98Civic For This Useful Post:
ChazInMT (03-13-2017), MobilOne (03-13-2017)
Old 03-13-2017, 07:05 PM   #7 (permalink)
EcoModding Lurker
 
Join Date: Jul 2015
Location: Louisiana
Posts: 31
Thanks: 0
Thanked 10 Times in 10 Posts
I've always liked gearing that allows low RPMs while cruising on the road. No only is it generally good for economy through less piston speed and related friction, but it's more relaxing for the driver not having to listen to a screaming engine for hours on end. I also believe it's good for engine longevity due to less wear and tear provided, of course, the engine is not being lugged.

My 2015 2.0L Mazda3 with the six-speed automatic is an example of my preference. At 60 mph, it's turning over at a leisurely, diesel-like 1700 RPM, and at 70 mph it's just reaching 2000, all the while developing about 85% of its maximum torque. I do like those long legs.

I believe this is part of the reason I've been able to record an overall 43.4 mpg during the 23,000 miles I've driven it so far. I don't hypermile per se, but I have driven it almost exclusively on the highway with essentially no short-trips in between. Another help is the 13.0:1 compression ratio, which Mazda has managed to employ while allowing the use of cheap ole RUG. My overall fuel cost is at 4.5 cents per mile so far, not bad for a car I got out the door for $20K brand new.

My data does not answer the OP's question about lean burn, but it does support the use of tall gearing, for sure.

__________________
  Reply With Quote
The Following User Says Thank You to MeteorGray For This Useful Post:
MobilOne (03-14-2017)
Reply  Post New Thread


Thread Tools




Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Content Relevant URLs by vBSEO 3.5.2
All content copyright EcoModder.com