Forced Induction Superchargers | Turbochargers | Intercoolers

Compression ratio for max effenciancy

Thread Tools
 
Search this Thread
 
Old May 3, 2008 | 07:19 PM
  #1  
blackangel327's Avatar
Thread Starter
On The Tree
iTrader: (3)
 
Joined: Sep 2007
Posts: 150
Likes: 0
From: arkansas
Default Compression ratio for max effenciancy

I did a search, but couldn't come up with anything. I got to wondering what would be more efficient, if you use a High CC head with a flat top or Dome piston to achieve your desired Compression Ratio or Low CC head with a flat top or Dished piston to achieve your target Compression ratio?
Reply
Old May 4, 2008 | 08:17 AM
  #2  
BigJls1's Avatar
Launching!
 
Joined: Feb 2007
Posts: 297
Likes: 0
From: Tucson
Default

no one has enough money or time here to answer that, there is so many variables. I am not very helpful in you question but I'll get u a bump.
Reply
Old May 4, 2008 | 09:49 AM
  #3  
veee8's Avatar
8 Second Club
iTrader: (40)
 
Joined: Aug 2005
Posts: 1,861
Likes: 0
From: Raleigh,North Carolina
Default

I went with large cc chambers on my heads, so I could run a flat top piston. So I could have a little bit more meat on the crown, being FI.
Reply
Old May 4, 2008 | 10:42 AM
  #4  
blackangel327's Avatar
Thread Starter
On The Tree
iTrader: (3)
 
Joined: Sep 2007
Posts: 150
Likes: 0
From: arkansas
Default

thats kind of what i was thinking as well, i mean if you dish your piston it seams to me that its not going to atomize as well but thats why i asked because I would like to know before making an assumption and making a wrong desision
Reply
Old May 4, 2008 | 11:35 AM
  #5  
MY99TAWS6's Avatar
TECH Veteran
iTrader: (3)
 
Joined: Apr 2002
Posts: 4,719
Likes: 3
From: Kelowna,BC
Default

Don't think it matters much at all. More important is what compression you wind up with and there is big debate on that as well. I have seen guys with low compression 8 or 8.5 to 1 say they didn't notice any doggyness off boost and guys say that you should go with 9.0 or 9.5 for off boost. I do see factory using low compression in lots of their turbo cars. And we even saw low compression in 70s down to like 7.6 in my 400 trans am. Yet the car still seemed to do not too bad with that low compression.

Lower compression is useful as you can run more boost and boost makes more power than compression. I went with 9.5 to 1 on my build. With 72cc afr heads and custom wisecos. It seemed fairly reasonable compression ratio and I have no desire to run boost likley much past 12 or maybe 15 tops on my setup. I do plan on running alc/meth injection full time.
Reply
Old May 4, 2008 | 11:48 AM
  #6  
blackangel327's Avatar
Thread Starter
On The Tree
iTrader: (3)
 
Joined: Sep 2007
Posts: 150
Likes: 0
From: arkansas
Default

this isn't about power though its about atomization of the fuel to prevent detonation. I know what compression ratio I'm going with with what amount of boost, I just would like to know which is more efficient.
Reply
Old May 5, 2008 | 08:06 AM
  #7  
ls1290's Avatar
Dumb Ass Vette Moderator
20 Year Member
Photogenic
Photoriffic
Shutterbug
iTrader: (20)
 
Joined: Jun 2002
Posts: 4,281
Likes: 2
From: Colorado
Default

If at all possible you want to avoid using dome pistons as they affect the burn and travel characterists of the flame as it comsumes the air/fuel charge. The best solution is the choose the heads you want for your application and then size the pistons to reach your desired compression level. If the heads you want to use will result in a lower compression level that what you want with flat top pistons, then mill the heads to create your target compression level.

Keith
Reply
Old May 5, 2008 | 08:30 AM
  #8  
Websy21's Avatar
TECH Addict
iTrader: (34)
 
Joined: Jun 2007
Posts: 2,346
Likes: 1
From: Alberta, Canada
Default

I wouldn't mill heads in a boosted application, that means less deck which means less clamping strength.
Reply
LS1 Tech Stories

The Best V8 Stories One Small Block at Time

story-0

10 Reasons Daily Driving a Swap Project SUCKS! (& 1 Reason to Do It Anyway)

 Michael S. Palmer
story-1

6 Gifts Neither Your Dad Nor Grad Will Shove Into the 'Trinket Drawer'

 Brett Foote
story-2

Topdon ONE vs. Artidiag 800 BT2: Which is the Diagnostic Tablet For You?

 Pouria Savadkouei
story-3

Gas Monkey Built a 6-Wheel Ferrari Testarossa With a Corvette LT4 Engine

 Verdad Gallardo
story-4

7 Most Reliable High-Performance Engines GM Has Ever Built

 Verdad Gallardo
story-5

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

 Verdad Gallardo
story-6

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

 Pouria Savadkouei
story-7

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

 Verdad Gallardo
story-8

Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked

 Pouria Savadkouei
story-9

Top 10 Most Powerful Chevy Trucks Ever Made!

 
Old May 5, 2008 | 06:03 PM
  #9  
blackangel327's Avatar
Thread Starter
On The Tree
iTrader: (3)
 
Joined: Sep 2007
Posts: 150
Likes: 0
From: arkansas
Default

well they are 70cc heads, and I'm looking at right around 9.5 Compression. just wondering what would be more effiecient, just wanted to see what everyone else thought
Reply




All times are GMT -5. The time now is 11:28 PM.

story-0
10 Reasons Daily Driving a Swap Project SUCKS! (& 1 Reason to Do It Anyway)

Slideshow: 10 reasons daily-driving a swap project might not be for you. Or is it?

By Michael S. Palmer | 2026-06-17 09:39:05


VIEW MORE
story-1
6 Gifts Neither Your Dad Nor Grad Will Shove Into the 'Trinket Drawer'

Don't get dad new socks or a grill brush this year.

By Brett Foote | 2026-06-09 14:55:56


VIEW MORE
story-2
Topdon ONE vs. Artidiag 800 BT2: Which is the Diagnostic Tablet For You?

Slideshow: We take a close look at the ONE and Artidiag 800BT2 diagnostic tools from Topdon and the reasons to buy one over the other.

By Pouria Savadkouei | 2026-06-18 10:26:23


VIEW MORE
story-3
Gas Monkey Built a 6-Wheel Ferrari Testarossa With a Corvette LT4 Engine

Slideshow: The controversial Ferrari F6 swaps its original flat-12 for a Corvette Z06-derived LT4 V8 and sends power to four rear wheels through a custom-built drivetrain.

By Verdad Gallardo | 2026-05-26 18:23:54


VIEW MORE
story-4
7 Most Reliable High-Performance Engines GM Has Ever Built

Slideshow:These GM engines didn't just make huge power, they survived abuse, boost, track days, and six-digit mileage with a reputation for refusing to quit.

By Verdad Gallardo | 2026-05-21 16:45:27


VIEW MORE
story-5
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-6
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-7
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-8
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-9
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