Generation III Internal Engine 1997-2006 LS1 | LS6
Sponsored by:
Sponsored by:

Help with compression calculator!

Thread Tools
 
Search this Thread
 
Old Sep 20, 2011 | 06:45 PM
  #1  
Blownz28man's Avatar
Thread Starter
TECH Regular
iTrader: (2)
 
Joined: Nov 2007
Posts: 434
Likes: 0
From: OK,Elk City
Default Help with compression calculator!

Ok guys, I'm sure I feel stupid but I've been trying diff compression calculators and all of them give me different answers.. anyone have links to accurate one or just the good ol formula. Heres what I got..

5.3L Not 0 decked standard deck is 9.240 0-deck at 9.236
-11cc Wiseco Pistons for 3.903 bore
stock crank 3.62"
Stock head gaskets .052 crushed
317 heads 70CC's

I think thats about it.. Thanks a million. Need to see how much to shave heads to try to get to my target.
Reply
Old Sep 20, 2011 | 07:09 PM
  #2  
chrisfrost's Avatar
TECH Fanatic
15 Year Member
iTrader: (8)
 
Joined: Nov 2009
Posts: 1,112
Likes: 16
From: phx the cactus patch
Default

Stock stroke is 3.622" and I would recommend using thinner head gaskets to bring You closer to You're goal/target scr . Do You know how far the pistons come out of the cylinder at TDC ? I've seen compression calc's that did'nt ask this and some that do . I've seen comp calc's that ask how far down the piston the first comp ring is so You just have to look at a bunch of them to find the more accurate 1's . and make sure You're figures are accurate .
Reply
Old Sep 20, 2011 | 07:10 PM
  #3  
Whiteaw57's Avatar
TECH Resident
iTrader: (2)
 
Joined: Sep 2010
Posts: 909
Likes: 0
From: Salisbury, NC
Default

Im getting 8.9:1
Reply
Old Sep 20, 2011 | 07:46 PM
  #4  
Blownz28man's Avatar
Thread Starter
TECH Regular
iTrader: (2)
 
Joined: Nov 2007
Posts: 434
Likes: 0
From: OK,Elk City
Default

Care to share?? LOL. I know i'm overlooking something. zero deck they say is 9.236 with a 6.125 rod. i shouldn't have to zero deck the block so it should be 9.240. So it should be .004 in hole right??
Reply
Old Sep 20, 2011 | 08:49 PM
  #5  
Whiteaw57's Avatar
TECH Resident
iTrader: (2)
 
Joined: Sep 2010
Posts: 909
Likes: 0
From: Salisbury, NC
Default

well what are you trying to achive. I calculated .0012 out of the hole. But i thought you had a 6 inch rod
Reply
Old Sep 20, 2011 | 09:12 PM
  #6  
Blownz28man's Avatar
Thread Starter
TECH Regular
iTrader: (2)
 
Joined: Nov 2007
Posts: 434
Likes: 0
From: OK,Elk City
Default

Well its a street drivin boosted application. I'm trying to get 9.0-9.2. It shouldnt be outta hole any. If anything in hole right?? Based of the measurements the piston manufacture gave for 0-deck ?
Reply
Old Sep 20, 2011 | 09:16 PM
  #7  
Whiteaw57's Avatar
TECH Resident
iTrader: (2)
 
Joined: Sep 2010
Posts: 909
Likes: 0
From: Salisbury, NC
Default

pretty sure stock ls1s come out of the hole .008 what is your rod length and compression height. ill just do all the math on that. 3.622 crank right
Reply
Old Sep 20, 2011 | 09:57 PM
  #8  
Blownz28man's Avatar
Thread Starter
TECH Regular
iTrader: (2)
 
Joined: Nov 2007
Posts: 434
Likes: 0
From: OK,Elk City
Default

Yea I'm sorry. From what I've read is the stock piston did come out of hole. its a 3.622 stroke, 6.125 rod, -11cc pistons.
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 Sep 21, 2011 | 06:47 PM
  #9  
Blownz28man's Avatar
Thread Starter
TECH Regular
iTrader: (2)
 
Joined: Nov 2007
Posts: 434
Likes: 0
From: OK,Elk City
Default

Anyone??
Reply
Old Sep 21, 2011 | 07:09 PM
  #10  
chrisfrost's Avatar
TECH Fanatic
15 Year Member
iTrader: (8)
 
Joined: Nov 2009
Posts: 1,112
Likes: 16
From: phx the cactus patch
Default

I've read guys whos pistons come out .015 . I've got a 5.3 n mine were the same .015"+ stock stroke, stock 6.098 rods with Speed-Pro flat-tops .
Reply
Old Sep 21, 2011 | 10:28 PM
  #11  
Blownz28man's Avatar
Thread Starter
TECH Regular
iTrader: (2)
 
Joined: Nov 2007
Posts: 434
Likes: 0
From: OK,Elk City
Default

Man every damn calculator I use..different answer. What do you guys use?? As I understand from Weisco's website is the piston is sticking out .004. HELP! Need an answer or pointed in the right direction
Reply
Old Sep 21, 2011 | 11:15 PM
  #12  
Whiteaw57's Avatar
TECH Resident
iTrader: (2)
 
Joined: Sep 2010
Posts: 909
Likes: 0
From: Salisbury, NC
Default

Im getting 8.97:1 Tell me your compression height of the piston and Ill show you all of the math to it
Reply
Old Sep 22, 2011 | 12:26 AM
  #13  
Beaflag VonRathburg's Avatar
OWN3D BY MY PROF!
iTrader: (176)
 
Joined: Feb 2006
Posts: 9,146
Likes: 3
From: Jax Beach, Florida
Default

^ Agreed. This isn't rocket science.

In / Out of the hole = (compression height + half of stroke + rod length) - deck height

Those values are variable with some basic algebra. I use this compression ratio calculator: http://www.csgnetwork.com/compcalc.html
Reply
Old Sep 22, 2011 | 12:29 PM
  #14  
Blownz28man's Avatar
Thread Starter
TECH Regular
iTrader: (2)
 
Joined: Nov 2007
Posts: 434
Likes: 0
From: OK,Elk City
Default

Whiteaw57- Hey thanks man for all your help. I was just curious why the compression calculators I was using were way off from each other. Heres the specs. School Me.
Wiseco -11cc
Compression Height 1.300
Rod-6.125
0 Deck- 9.236
Std Deck-9.240
Head Gasket-.052 compresed
Bore-3.903

Beaflag- Agreed its not rocket science. But when you have several compression calculators giving different numbers you want answers. I do not have the equation in front of me and was asking for assistance.
Reply
Old Sep 22, 2011 | 12:32 PM
  #15  
Blownz28man's Avatar
Thread Starter
TECH Regular
iTrader: (2)
 
Joined: Nov 2007
Posts: 434
Likes: 0
From: OK,Elk City
Default

Allright.. Now I'm connectiong the dots. Its 6.236 (light bulb). So stock is 9.240 deck height. So these ARE in hole .004. Right??
Reply
Old Sep 22, 2011 | 03:45 PM
  #16  
Beaflag VonRathburg's Avatar
OWN3D BY MY PROF!
iTrader: (176)
 
Joined: Feb 2006
Posts: 9,146
Likes: 3
From: Jax Beach, Florida
Default

(1.300 + 6.125 + 1.811) - 9.240 = -.004 (in the hole).

You'll need to have the block surfaced if it is used as well as production variances on the rods / pistons. I would say a safe estimate is .010. Use .006 out of the hole.

I am getting 8.81:1 with the calculator I am using. All the number variances that are showing up in this thread are about .1-.2 of a point of comrpession. If you are getting varied numbers google the original formula and do the math yourself. Either way you are about .2-.4 low on your goal. Get the bottom end assembled, measure the distance the piston is in / out of the hole, and mill your heads as needed.
Reply
Old Sep 22, 2011 | 09:38 PM
  #17  
chrisfrost's Avatar
TECH Fanatic
15 Year Member
iTrader: (8)
 
Joined: Nov 2009
Posts: 1,112
Likes: 16
From: phx the cactus patch
Default

From what I've seen with some of the different comp calc's is many of them are asking for different specs or #'s for You to plug in and that's why most are different from 1 another . Take a look at a few of them and see if they are asking for the exact same things n I'll bet You'll notice alot of them are asking for 1 or 2 different things than other 1's . The 1's that are gonna be most accurate are the 1's that are asking for the most #'s to plug in .
Reply




All times are GMT -5. The time now is 01:27 AM.

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