PONTIAC ZONE TECH FORUMS
 

Go Back   PONTIAC ZONE TECH FORUMS >
Engine Tech
> ECM Heads up / Comedy Section
User Name
Password

ECM Heads up / Comedy Section Home of the fastest Heads up Pontiac's in the country "Caution may cause cases of BUTT HURT"

Reply
 
Thread Tools
Old 11-13-17, 03:29PM   #1
SikGoat
ECMTTFMF'S
 
SikGoat's Avatar
 
Join Date: Nov 2008
Location: East Coast Biotch!
Posts: 2,383
Default Flow bench # nut's step inside

Quote:
How Much Does it Flow?

This has been the standard question for evaluating a cylinder head for years. Today, it is only one factor in the port design process. Big ports that flow a lot of air frequently do not run well. I often tell racers that all good running ports flow good, but not all good flowing ports run good.

The flowbench has been a valuable tool. When we were working with poorly designed ports, we made airflow gains that made the port more efficient. These gains made more power and we all got flowbench crazy. Eventually, we started to realize that the flowbench does not accurately simulate a running engine and to make ports better, we had to look at other factors.

A flowbench has only one dynamic action, the steady state airflow at a specified depression (usually 28 inches H2O). A running engine has multiple dynamic actions occurring simultaneously like piston movement, valve movement, intake flow, exhaust flow and pulse waves from multiple cylinders. This complicates the port design which needs to be tuned to the engine size, rpm range, and intended use of the application.

When evaluating cylinder heads for modern racing engines, airflow should be low on the list of important factors because as a professionally prepared port, they should all flow well. I recommend working with a cylinder head designer that has knowledge with the head requirements for your engine design and racing application.

Dave Visner
And this would be why we don't race flow bench's
__________________
"The quickest way to double your money is to fold it and put it back into your pocket."
ECM Member# 0016
7.22 @ 194 @ 3700lbs
4.70 @ 157mph @ 3700lbs
SikGoat is online now   Reply With Quote
Old 11-13-17, 04:14PM   #2
turbo louie
Registered User
 
turbo louie's Avatar
 
Join Date: Dec 2008
Location: mastic ny
Posts: 1,964
Default

So I guess this is where BES, Marcella , Wilcox and the others come in to figure for what actual port to use for whatever you're doing...
__________________
If it's gona be it's up to me!
turbo louie is online now   Reply With Quote
Old 11-13-17, 08:19PM   #3
Gach
Administrator
 
Gach's Avatar
 
Join Date: May 2003
Location: ....
Posts: 17,717
Default

Itís so true, and it weeds out the poorly designed heads. These opinions are the only ones that matter, cause these guys have the history of making real power. Not someone fresh out of porting classes. Or some painter turn head Porter

Many may not know this but Vinser involvement with Pontiacís goes back to Marty Palbykin days, they knew each other well.
__________________
The things they hide, the way they spin things, the excuses that they make and the things they omit.
Gach is offline   Reply With Quote
Old 11-13-17, 09:19PM   #4
JSPONT
Registered User
 
JSPONT's Avatar
 
Join Date: Feb 2014
Posts: 1,318
Default

Quote:
Originally Posted by SikGoat View Post
And this would be why we don't race flow bench's
So is that why you need that big supercharger on that car, to make up for crappy heads?? LMFAO! JK Billy
JSPONT is offline   Reply With Quote
Old 11-13-17, 09:30PM   #5
SikGoat
ECMTTFMF'S
 
SikGoat's Avatar
 
Join Date: Nov 2008
Location: East Coast Biotch!
Posts: 2,383
Default

Quote:
Originally Posted by JSPONT View Post
So is that why you need that big supercharger on that car, to make up for crappy heads?? LMFAO! JK Billy
LOL Look Phucker we all like to get blown!
__________________
"The quickest way to double your money is to fold it and put it back into your pocket."
ECM Member# 0016
7.22 @ 194 @ 3700lbs
4.70 @ 157mph @ 3700lbs
SikGoat is online now   Reply With Quote
Old 11-13-17, 10:21PM   #6
JSPONT
Registered User
 
JSPONT's Avatar
 
Join Date: Feb 2014
Posts: 1,318
Default

LMAO! True! That photo of your car wheels up you posted is great, tires wrinkled like crazy!!!!!!!!!! Looks sick.
JSPONT is offline   Reply With Quote
Old 11-14-17, 12:03AM   #7
Steve C
Verified User
 
Join Date: Dec 2002
Location: .
Posts: 970
Default

Related ?

"This is what we like to refer to as ďarea under the curveĒ when itís related to cylinder head airflow figures. Once again AFR port and combustion chamber designs excel in this area (as well as peak flow) and this is a key often overlooked in design element for performance cylinder heads. Everyone is always discussing peak flow but here is a wakeup call for you. Look at the low lift numbers more closely when comparing heads. Also, contrary to popular belief, a head with strong low and mid lift flow doesnít mean it will have stronger power in the lower and middle part of the horsepower curve (although it will make more there), it means it will make more power everywhere due to the fact that every time an intake and exhaust valve opens and closes it will be able to move more air in total than a head with similar peak numbers and a much softer area under the curve. In fact if anything, an efficient head with better low and mid-lift flow numbers usually shows its stuff up top allowing the torque curve to hang on a little longer producing a higher peak HP figure and carry much better past peak as well (not roll over as quickly). Thatís because at the higher RPMís, when there is much less time to fill and evacuate the cylinder, airflow demand of the engine is at a premium and any little extra you cram in there (and remove) will pay you big dividends."

http://www.airflowresearch.com/excep...mid-lift-flow/


.
Steve C is offline   Reply With Quote
Old 11-14-17, 12:07AM   #8
Steve C
Verified User
 
Join Date: Dec 2002
Location: .
Posts: 970
Default

More if interested.....


"Huge flow numbers may be impressive, but optimizing airflow at mid-valve lift is key to power. If airflow though a valve port is plotted on a graph for the entire valve cycle (from opening to peak lift and back to close), the area under the curve is total airflow, which corresponds to total power. So if you can fatten the curve on both sides of peak lift in the low to mid-range area rather than just raising the maximum peak, you end up with more total area under the curve and more usable power."

More here: http://www.enginebuildermag.com/2013...-head-porting/


.
Steve C is offline   Reply With Quote
Old 11-14-17, 09:42PM   #9
Mb125
Registered User
 
Mb125's Avatar
 
Join Date: Mar 2005
Location: AZ
Posts: 3,986
Default

Look at what power has been made with SBC vortec heads with small valves.
__________________
Open the door sit in the seat turn the key and go
Mb125 is offline   Reply With Quote
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

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

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
SLP's 1800 cfm flow bench for sale Zedo Grape Vine - General Discussion 0 12-30-14 05:16PM
interesting head porting comment Zedo Grape Vine - General Discussion 68 12-27-14 02:31PM
Flow bench variations gtofreek Engine Tech Discussion - Street or Strip 42 11-26-08 01:02AM
FLOW BENCH FALACIES....By David Reher JMackPontiac Engine Tech Discussion - Street or Strip 5 06-18-08 12:20AM
flow bench comparison- Superflow vs. custom entire flow path- CV1 heads get thumbs up Zedo Grape Vine - General Discussion 11 02-26-08 10:48PM


All times are GMT -3. The time now is 08:25AM.

Featured Ads
Ken's Speed & Machine
Mayhem Turbocharging

Carter Cryogenics.  What can we freeze for you?

Pacific Performance Racing

Central Virginia Machine Service.  Home of the Injun Engine!

All Pontiac Engine Kits

Larry's Auto Machine.  Full serivce auto, marine machine shop, domestic and foreign.

Powered by vBulletin® Version 3.6.8
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.
2001 - 2007 PontiacZone.com
Page generated in 0.07210 seconds with 12 queries