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

Critique my Flow numbers please

Thread Tools
 
Search this Thread
 
Old Sep 29, 2005 | 03:43 PM
  #1  
JRick212's Avatar
Thread Starter
On The Tree
iTrader: (6)
 
Joined: Apr 2005
Posts: 148
Likes: 0
From: The Berlin Turnpike
Default Critique my Flow numbers please

These are a set of Ls6 heads that had been worked by Xtreme performance that I just bought off another member on here. I must say I am more than slightly dissappointed with my purchase.
Attached Thumbnails Critique my Flow numbers please-flow-sheet-ls6.jpg  

Last edited by JRick212; Sep 29, 2005 at 04:31 PM.
Reply
Old Sep 29, 2005 | 04:11 PM
  #2  
xfactor_pitbulls's Avatar
TECH Addict
iTrader: (16)
 
Joined: Jul 2004
Posts: 2,218
Likes: 0
From: Nevada, TX
Default

Originally Posted by JRick212
These are a set of Ls6 heads that had been worked by Xtreme performance that I just bought off another member on here.
It would be nice if the intake was flowed at 28" instead of 24". Thats kinda queer. Engines pull with more pressure than 28" to start with, 28" is just the standard. When you start looking at issues with turbulence, something lower than a standard pressure is misleading. Exhaust isnt super, but its pretty good for an N/A.

Brandon
Reply
Old Sep 29, 2005 | 04:23 PM
  #3  
JRick212's Avatar
Thread Starter
On The Tree
iTrader: (6)
 
Joined: Apr 2005
Posts: 148
Likes: 0
From: The Berlin Turnpike
Default

I asked him about the 24" and he said something about when the heads start flowing more volume it has to be bumped down to 24" to compensate but the numbers there are adjusted for 28"
Reply
Old Sep 29, 2005 | 04:40 PM
  #4  
LedFut's Avatar
14 Second Truck Club
 
Joined: Apr 2002
Posts: 89
Likes: 0
From: PA/CT
Default

For what he advertised, those flow numbers are crap.
Reply
Old Sep 29, 2005 | 04:47 PM
  #5  
JRick212's Avatar
Thread Starter
On The Tree
iTrader: (6)
 
Joined: Apr 2005
Posts: 148
Likes: 0
From: The Berlin Turnpike
Default

This is what I was told they flowed

Lift: Intake: Exhaust:
.200 119 101
.400 246 187
.650 330 234

and I completely understand all the different variables from bench to bench but this is not even close
Reply
Old Sep 29, 2005 | 05:31 PM
  #6  
52172's Avatar
TECH Junkie
20 Year Member
Photogenic
Photoriffic
Shutterbug
iTrader: (2)
 
Joined: Jul 2003
Posts: 3,489
Likes: 1
From: Buellton Ca
Default

Similar thing happened to me I bought a set of cnc heads from a memeber that is now banned ls1powerhouse and he stated they flow 310 cfm@ .600 and they did not even flow 300 cfm @ .650! I ended up having them reworked, but I was pissed off and tried getting some money back and that never happened.
Reply
Old Sep 29, 2005 | 06:54 PM
  #7  
Ben R's Avatar
TECH Junkie
 
Joined: Aug 2002
Posts: 3,726
Likes: 0
From: Fort Collins, CO
Default

Originally Posted by JRick212
I asked him about the 24" and he said something about when the heads start flowing more volume it has to be bumped down to 24" to compensate but the numbers there are adjusted for 28"
You can convert flow @ 24" to flow @ 28". Here is what they flow at 28":

.100 - 69
.150 - 108
.200 - 140
.250 - 171
.300 - 200
.350 - 228
.400 - 250
.450 - 263
.500 - 274
.550 - 287
.600 - 294

That does reflect laminar flow, not turbulent. You need to have the heads re-flowed @ 28" to verify that they don't go turbulent.
Reply
Old Sep 29, 2005 | 08:16 PM
  #8  
52172's Avatar
TECH Junkie
20 Year Member
Photogenic
Photoriffic
Shutterbug
iTrader: (2)
 
Joined: Jul 2003
Posts: 3,489
Likes: 1
From: Buellton Ca
Default

now all of a sudden they look a lot better!
Reply
LS1 Tech Stories

The Best V8 Stories One Small Block at Time

story-0

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

 Brett Foote
story-1

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

 Pouria Savadkouei
story-2

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

 Verdad Gallardo
story-3

7 Most Reliable High-Performance Engines GM Has Ever Built

 Verdad Gallardo
story-4

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

 Verdad Gallardo
story-5

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

 Pouria Savadkouei
story-6

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

 Verdad Gallardo
story-7

Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked

 Pouria Savadkouei
story-8

Top 10 Most Powerful Chevy Trucks Ever Made!

 
story-9

Hennessey's New Supercharged Silverado ZR2 Has 700 HP

 Verdad Gallardo
Old Sep 30, 2005 | 06:18 AM
  #9  
JRick212's Avatar
Thread Starter
On The Tree
iTrader: (6)
 
Joined: Apr 2005
Posts: 148
Likes: 0
From: The Berlin Turnpike
Default

My guy is telling me that those numbers you are seeing are already converted to 28" for the intake even though it says 24" and how did you go about calculating those numbers?

Last edited by JRick212; Sep 30, 2005 at 06:23 AM.
Reply
Old Sep 30, 2005 | 08:56 AM
  #10  
Ben R's Avatar
TECH Junkie
 
Joined: Aug 2002
Posts: 3,726
Likes: 0
From: Fort Collins, CO
Default

Square Root of (New Pressure / Old Pressure) x Old Flow = New Flow
Reply
Old Sep 30, 2005 | 10:22 AM
  #11  
Tony Mamo @ AFR's Avatar
Flow Wizard
20 Year Member
iTrader: (13)
 
Joined: Feb 2004
Posts: 2,197
Likes: 7
Default

You would multiply by exactly 1.08 to convert CFM at 24" to 28" figures (Benji's math was correct....I'm just saving you the time). I also question why the heads were only flowed at 24"....more than likely the bench used didn't have enough capacity to flow at 28". I would take those heads to another facility to back up those numbers. If the numbers you posted were already converted and they are reasonably backed up by another independent bench, there are alot of other head choices out there that would have obviously make a bunch more power. I wouldn't just bolt them on and hope for the best....do more investigating so you have all the facts and can make an informed decision on which direction to go.

If they do prove to be well off the mark (of what you expected), perhaps you have some recourse with the company you purchased them from....Good luck

Tony M.
Reply
Old Sep 30, 2005 | 04:35 PM
  #12  
JRick212's Avatar
Thread Starter
On The Tree
iTrader: (6)
 
Joined: Apr 2005
Posts: 148
Likes: 0
From: The Berlin Turnpike
Default

I purchased them from a private party and I guess the old story goes....you get what you pay for. I am not sure of any other benches in my area so I will have to do some more reasearch.

But in the condition they are in I would never just put them on the car and hope for the best. It would be a waste of head gaskets and my time.
Reply
Old Sep 30, 2005 | 10:00 PM
  #13  
silverTA2002's Avatar
12 Second Club
iTrader: (1)
 
Joined: May 2005
Posts: 684
Likes: 0
From: Bradenton, FL
Default

Originally Posted by JRick212
I purchased them from a private party and I guess the old story goes....you get what you pay for. I am not sure of any other benches in my area so I will have to do some more reasearch.

But in the condition they are in I would never just put them on the car and hope for the best. It would be a waste of head gaskets and my time.
Maybe you could send them to TEA to get them reworked?

Depending on which cam you choose, the flow numbers might be sufficient though.

You could have heads flowing 500 cfm, but if the rest of your engine doesn't match, it won't make a difference.
Reply




All times are GMT -5. The time now is 10:42 AM.

story-0
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 | 2026-06-04 18:13:20


VIEW MORE
story-1
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 | 2026-05-28 11:05:11


VIEW MORE
story-2
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-3
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-4
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-5
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-6
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-7
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-8
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-9
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