Generation IV External Engine LS2 | LS3 | LS7 | L92 | Bolt-Ons | Intakes | Exhaust | Ignition | Accessories
Sponsored by:
Sponsored by:

lightened internals= better mpg?

Thread Tools
 
Search this Thread
 
Old Feb 3, 2012 | 03:18 PM
  #1  
bp944's Avatar
Thread Starter
Launching!
iTrader: (4)
 
Joined: May 2010
Posts: 245
Likes: 1
Default lightened internals= better mpg?

I was looking at the components to do a engine buildup and I realized that if you do it right you can take a lot of weight out of the engine. This is all rough math but a callies crank can be 5-15lbs lighter, a set of rods can be 1-2 pounds, pistons can be 1 pound. Along with a 5-10 pound lighter flywheel. Its almost conceivable to pull off 20 lbs on the moving internals. How much does that result in mpgs? I'd be doing this for power but if you had a stock internals and forged but were the same specs what would be the difference in mpg?
Reply
Old Feb 3, 2012 | 07:40 PM
  #2  
S10xGN's Avatar
TECH Junkie
iTrader: (11)
 
Joined: Jul 2005
Posts: 3,782
Likes: 7
From: Port Neches, TX
Default

I wouldn't think it would help anything at a "steady state" cruise, a lighter rotating mass mainly aids in acceleration...
Reply
Old Feb 3, 2012 | 08:04 PM
  #3  
redtan's Avatar
TECH Junkie
iTrader: (5)
 
Joined: May 2008
Posts: 3,764
Likes: 17
From: Belmont, MA
Default

I wouldn't think it would help anything at a "steady state" cruise, a lighter rotating mass mainly aids in acceleration...
Why not? Any increase in efficiency and power will result in less throttle needed to keep the car going at a steady rate, thus increasing MPGs.
Reply
Old Feb 3, 2012 | 08:25 PM
  #4  
wadd's Avatar
Staging Lane
 
Joined: Jan 2006
Posts: 69
Likes: 0
From: New York
Default

might give better mileage around town due to lower rotating inertial but the effects will likely be very small. No difference in steady state driving since loses are due to friction (bearings, rings/bore). It's possible there might be a slight reduction in piston side loading, but again, likely wouldn't show up in improved mileage.
Reply
Old Feb 3, 2012 | 10:17 PM
  #5  
3rdCoastPowerSports's Avatar
TECH Fanatic
iTrader: (5)
 
Joined: Jun 2011
Posts: 1,154
Likes: 6
From: Loony Bin
Default

i wouldn't think you would really see any better MPG
Reply
Old Feb 4, 2012 | 04:44 AM
  #6  
LS1MCSS's Avatar
TECH Junkie
iTrader: (18)
 
Joined: Jan 2006
Posts: 3,831
Likes: 8
From: Dover, Arkansas
Default

One thing you most likely will see is less durability.
Reply
Old Feb 4, 2012 | 05:23 AM
  #7  
HioSSilver's Avatar
10 Second Club
20 Year Member
Liked
Loved
Community Favorite
iTrader: (8)
 
Joined: Aug 2002
Posts: 6,128
Likes: 645
From: Winchester, VA
Default

I have taken about 42lb off my rotating mass, no diff in mpg.
Reply
Old Feb 4, 2012 | 06:17 AM
  #8  
davidws6's Avatar
TECH Enthusiast
iTrader: (36)
 
Joined: Oct 2004
Posts: 747
Likes: 5
From: Kansas
Default

I think it would help, but the results would probably be minimal.

One thing that helps for mileage is optimizing your timing tables.
I've seen many timing tables below 40 > 50 kpa flat to WOT. Yet there can be a few degrees added in the cruise regions without any detonation. Then after optimizing your timing table, you'll probably have to take out a little fuel as the fuel trims go positive cause the engine is more efficient.
Reply
LS1 Tech Stories

The Best V8 Stories One Small Block at Time

story-0

Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin

 Verdad Gallardo
story-1

6 Common C5 Corvette Failures and What's Involved In Repairing Them

 Pouria Savadkouei
story-2

Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph

 Verdad Gallardo
story-3

Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked

 Pouria Savadkouei
story-4

Top 10 Most Powerful Chevy Trucks Ever Made!

 
story-5

Hennessey's New Supercharged Silverado ZR2 Has 700 HP

 Verdad Gallardo
story-6

Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes

 Verdad Gallardo
story-7

Awesome K5 Blazer Restomod Comes With C7 Corvette Power

 Verdad Gallardo
story-8

10 Camaros You Should Never Buy

 
story-9

10 LS Engine Myths That Refuse to Die

 Verdad Gallardo
Old Feb 4, 2012 | 03:17 PM
  #9  
john kilgore's Avatar
TECH Regular
 
Joined: Feb 2004
Posts: 439
Likes: 1
From: burbank ca
Default

learn to drive with a vaccuum guage
Reply
Old Feb 4, 2012 | 09:37 PM
  #10  
S10xGN's Avatar
TECH Junkie
iTrader: (11)
 
Joined: Jul 2005
Posts: 3,782
Likes: 7
From: Port Neches, TX
Default

Originally Posted by redtan
Why not? Any increase in efficiency and power will result in less throttle needed to keep the car going at a steady rate, thus increasing MPGs.
Just to clear it up, a steady state cruise requires a certain amount of HP (disregarding incidentals like wind, elevation changes, etc) to maintain a given speed. Messing with the rotating assembly will have zero effect on that required HP number. Hence, no change in the engine's HP output.
Reply




All times are GMT -5. The time now is 02:08 PM.

story-0
Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin

Slideshow: This heavily modified 1971 Camaro mixes classic muscle car styling with a fifth-generation Camaro interior and modern LS3 power.

By Verdad Gallardo | 2026-05-12 18:06:42


VIEW MORE
story-1
6 Common C5 Corvette Failures and What's Involved In Repairing Them

Slideshow: From wobbling harmonic balancers to failed EBCMs, these are the issues that define long-term C5 ownership and what repairs typically involve.

By Pouria Savadkouei | 2026-05-07 18:44:57


VIEW MORE
story-2
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph

Slideshow: A modern Camaro transformed into a retro icon, this limited-run "Bandit" build blends nostalgia with brute force in a way few revivals manage.

By Verdad Gallardo | 2026-04-21 13:57:02


VIEW MORE
story-3
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked

Slideshow: Cadillac didn't just crash the high-performance luxury vehicle party, it showed up loud, supercharged, and occasionally a little unhinged...

By Pouria Savadkouei | 2026-04-16 10:05:15


VIEW MORE
story-4
Top 10 Most Powerful Chevy Trucks Ever Made!

Slideshow: Top ten most powerful Chevy trucks ever made

By | 2026-03-25 09:22:26


VIEW MORE
story-5
Hennessey's New Supercharged Silverado ZR2 Has 700 HP

Slideshow: Hennessey has turned the Silverado ZR2 into a 700-hp off-road monster with supercharged V8 power and a limited production run.

By Verdad Gallardo | 2026-03-24 18:57:52


VIEW MORE
story-6
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes

Slideshow: A one-off sports car that looks like a vintage Italian exotic-but hides a C6 Corvette underneath-just sold for the price of a new mid-engine Corvette.

By Verdad Gallardo | 2026-03-23 18:53:41


VIEW MORE
story-7
Awesome K5 Blazer Restomod Comes With C7 Corvette Power

Slideshow: A heavily reworked 1972 K5 Blazer swaps its off-road roots for a low-slung street-focused build with modern V8 power.

By Verdad Gallardo | 2026-03-09 18:08:45


VIEW MORE
story-8
10 Camaros You Should Never Buy

Slideshow: There are thousands of used Camaros on the market but we think you should avoid these 10

By | 2026-02-17 17:09:30


VIEW MORE
story-9
10 LS Engine Myths That Refuse to Die

Slideshows: Which one of these myths do you believe?

By Verdad Gallardo | 2026-01-28 18:10:11


VIEW MORE