BIG car - Page 2 - Fuelly Forums

Click here to see important news regarding the aCar App

Reply
 
Thread Tools Display Modes
 
Old 09-27-2007, 10:13 PM   #11
Team GasMisers5!
 
landspeed's Avatar
 
Join Date: Nov 2006
Posts: 440
Country: United States
If the engine is coming out, how about increasing the compression ratio a little bit? I think that would give more fuel economy, and maybe even more power (if you can avoid knock at maximum load).
__________________

__________________

Team GasMisers5 - #1 for first three rounds of the original GS Fuel Economy Challenge
Miles displaced by e-bike since 1 Jan 2008: 62.6 (0 kWh used)
Hypomiler
landspeed is offline   Reply With Quote
Old 09-27-2007, 10:32 PM   #12
Registered Member
 
theclencher's Avatar
 
Join Date: Aug 2006
Posts: 542
Country: United States
I applaud his decision to use a sedan to move the 5 big folks instead of the more usual "need" to get a Subdivision or Explosion.

I also understand that since this car practically fell in your lap, that's what you're going to use. Just to mention, though, if you come across a GM full-size fwd with the 3.8 (think Le Sabre, Bonneville, etc.) from the late '80's on, they should give an honest 30 mpg hwy properly driven, stock. For some reason that 3.8 is a decent fe package in those larger cars, equalling or besting the fuel efficiency of the same model with a smaller engine! I wonder how they would perform with a 5-speed stick and removal of all those power-robbing accessories?

IMHO, the four-valve head's main strength lies in high rpm applications, OR, if equipped with a variable valve control system of some sort, low and high rpm applications. Since it is unlikely you'll transplant a variable valve control system (and I don't know if it was ever offered on that engine series???) AND since low rpm operations are our fe friend, my instinct is to stay with the 2-valve head. You may want to research fe ratings for different versions of that engine in as consistant a drivetrain package as possible to see what is really going on out there.

If the 6 speed offers a taller OD than the 4 speed it MAY help. If cruise rpm is too high for best fe, higher rear end gears and/or taller tires could help too without being as big an effort or expense.

Even with these mods I have my doubts about getting 30. It's just such a tall order for a V8 especially in a full-size package. Seems the odds get much better with a 6 cyl.
__________________

__________________
Tempo/Topaz:
Old EPA 23/33/27
New EPA 21/30/24

F150:
New EPA12/14/17

theclencher is offline   Reply With Quote
Old 09-29-2007, 02:34 AM   #13
Registered Member
 
Join Date: Sep 2007
Posts: 22
Country: United States
rearend

I didn't see mention of changing out the rear gears for lower cruising rpms yet.
sipnciv is offline   Reply With Quote
Old 09-29-2007, 02:55 AM   #14
Registered Member
 
Join Date: Sep 2007
Posts: 22
Country: United States
Yep, it's there.
sipnciv is offline   Reply With Quote
Old 09-29-2007, 03:15 AM   #15
Registered Member
 
s1120's Avatar
 
Join Date: Sep 2007
Posts: 64
Country: United States
Well a gear swap may not work. Whats in there now? It is a big car, and those Mod motors like some rev's so if you go to too tall a ratio, you could drop the motor out of its power band, and make the millage worse.
__________________
Paul B

s1120 is offline   Reply With Quote
Old 09-29-2007, 11:31 AM   #16
Registered Member
 
omgwtfbyobbq's Avatar
 
Join Date: Jul 2006
Posts: 1,516
Country: United States
The power band does not usually equate to efficiency at a cruise.
__________________
Quote:
Originally Posted by FormulaTwo
I think if i could get that type of FE i would have no problem driving a dildo shaped car.
omgwtfbyobbq is offline   Reply With Quote
Old 09-29-2007, 01:52 PM   #17
Registered Member
 
theclencher's Avatar
 
Join Date: Aug 2006
Posts: 542
Country: United States
i know from my f150 that it's possible to gear too high. it falls "off the cam" and without retuning (cam, intake, exhaust) for the lower rpm ops the fe gains just weren't there for me.
__________________
Tempo/Topaz:
Old EPA 23/33/27
New EPA 21/30/24

F150:
New EPA12/14/17

theclencher is offline   Reply With Quote
Old 09-29-2007, 03:10 PM   #18
Registered Member
 
omgwtfbyobbq's Avatar
 
Join Date: Jul 2006
Posts: 1,516
Country: United States
How do you know it's a problem with the intake/exhaust profile and not the TCC?
__________________
Quote:
Originally Posted by FormulaTwo
I think if i could get that type of FE i would have no problem driving a dildo shaped car.
omgwtfbyobbq is offline   Reply With Quote
Old 09-29-2007, 04:25 PM   #19
Registered Member
 
Join Date: Sep 2007
Posts: 27
Country: United States
Quote:
Originally Posted by omgwtfbyobbq View Post
The power band does not usually equate to efficiency at a cruise.
peak torque = max efficiency....

engine is most efficient, when it is at the rpm where its making the most peak power.
Pyrorocketeer is offline   Reply With Quote
Old 09-29-2007, 04:36 PM   #20
Registered Member
 
omgwtfbyobbq's Avatar
 
Join Date: Jul 2006
Posts: 1,516
Country: United States
I got a few BSFC maps that disagree with that. Not to say that it's impossible for peak torque and minimum BSFC to coincide, just that it generally doesn't happen IME.
__________________

__________________
Quote:
Originally Posted by FormulaTwo
I think if i could get that type of FE i would have no problem driving a dildo shaped car.
omgwtfbyobbq is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Fuelly badge not updating for about 2 - 3 weeks Need Fuelly Web Support and Community News 18 07-01-2012 02:01 PM
Fuelly Android App - eehokie Fuelly Web Support and Community News 2 07-14-2010 08:59 PM
VW Jetta fast riser coolbreeze General Fuel Topics 5 07-21-2009 11:25 PM
DIY: Wire Tuck!!! SVOboy Experiments, Modifications and DIY 11 09-21-2006 04:17 AM
Condensator orevgym General Fuel Topics 0 07-23-2006 10:25 AM

» Fuelly iOS Apps
Powered by vBadvanced CMPS v3.2.3


All times are GMT -8. The time now is 02:50 PM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2024, vBulletin Solutions, Inc.