Author Topic: Stock Head Flow #'s  (Read 2779 times)

0 Members and 1 Guest are viewing this topic.

Offline good2win22

  • Turbo Street Outlaw
  • *******
  • Posts: 2019
  • PSI: 0
  • No man lives happily lest he remove the boredom
    • View Profile
Stock Head Flow #'s
« on: May 30 2014, 12:02:38 PM »
Does anyone have or can anyone point me in the direction of a chart with stock intake and exhaust CFM numbers?  I am sitting here at work pondering the gains of the a particular aluminum head.  I have a copy of it's flow numbers at varying stages of lift but I can't locate anything on a stock head.  Wouldn't it  be nice to have my own flow bench.....
Jason

1966 Ford Ranch Wagon
1982 Jeep Wagoneer Limited
1986 Grand National BLK PHNX
1987 Turbo Regal Limited
2018 Ram 2500 Cummins

Offline TexasT

  • Legend in my own mind
  • Turbo Street Outlaw
  • *******
  • Posts: 2170
  • PSI: 1
  • So, This black car is fast?
    • View Profile
Re: Stock Head Flow #'s
« Reply #1 on: May 30 2014, 01:40:39 PM »
The aluminum provides much more than just additional flow. You are able to use higher compression ratio and additional timing to gain power with an aluminum head and its detonation resistance.
Rich

"Goals without actions are just dreams."

Offline motorhead

  • Turbo Street Outlaw
  • *******
  • Posts: 2265
  • PSI: 4
  • look at my balls... look at them!!!
    • View Profile
Re: Stock Head Flow #'s
« Reply #2 on: May 30 2014, 02:58:57 PM »
cfm isn't everything, a better designed/modified port will lend itself to velocity over cfm; a better designed naturally aspirated air pump will effectively respond better to boost conditions.

But, here you go (a little down the page): http://users.erols.com/srweiss/tablehdc.htm#Buick

And yes, those are some of the shittiest production flow numbers in history.  I recently drove a stock N/A 3.8L Buick V6 (because I own it) and it was the worst motoring experience of my life.  I will always maintain what a crappy engine these are without a turbocharged band-aid...
>>>Das Instagram<<<
'80 LeMans Wagon|'87 Monte Carlo SS|'92 Camaro Z28|'07 TrailBlazer SS|'15 Colorado Z71|'19 Hellcat Widebooty M6

Offline good2win22

  • Turbo Street Outlaw
  • *******
  • Posts: 2019
  • PSI: 0
  • No man lives happily lest he remove the boredom
    • View Profile
Re: Stock Head Flow #'s
« Reply #3 on: May 30 2014, 04:04:58 PM »
That's exactly what I was hoping to find!  Thanks motorhead!  BTW, was looking at a wagon about a month ago and it was sold before I could make an offer.  Always enjoy reading your build.
Jason

1966 Ford Ranch Wagon
1982 Jeep Wagoneer Limited
1986 Grand National BLK PHNX
1987 Turbo Regal Limited
2018 Ram 2500 Cummins

Offline Steve Wood

  • Turbo Street Outlaw
  • *******
  • Posts: 9898
  • PSI: 34
    • View Profile
    • http://www.vortexbuicks-etc.com/
Re: Stock Head Flow #'s
« Reply #4 on: May 30 2014, 04:11:04 PM »
The aluminum provides much more than just additional flow. You are able to use higher compression ratio and additional timing to gain power with an aluminum head and its detonation resistance.

Not so....:)

All things being equal, the aluminum head will produce less power than the cast iron head due to its poor thermal efficiency when it comes to the combustion process.

The real benefit of aluminum is lightweight and ease of repair.  Of course, as we cannot buy an iron head with the port size of an aftermarket aluminum head, that breaks the "all things being equal" :)
Steve Wood

http://www.vortexbuicks-etc.com

A lot of broken parts does not make you a racer; it makes you a slow learner.

Offline TexasT

  • Legend in my own mind
  • Turbo Street Outlaw
  • *******
  • Posts: 2170
  • PSI: 1
  • So, This black car is fast?
    • View Profile
Re: Stock Head Flow #'s
« Reply #5 on: May 30 2014, 09:08:44 PM »
Iron might have thermal efficiency, but I still say the aluminum has more detonation resistance allowing additional compression and timing. Then there's that weight savings thing you mentioned.
The decision becomes are you going fast or are you going long?
Rich

"Goals without actions are just dreams."

Offline Steve Wood

  • Turbo Street Outlaw
  • *******
  • Posts: 9898
  • PSI: 34
    • View Profile
    • http://www.vortexbuicks-etc.com/
Re: Stock Head Flow #'s
« Reply #6 on: May 30 2014, 09:44:56 PM »
Once you raise the compression to make up for the lost heat, then you lose any perceived detonation resistance.  The old rule of thumb that one raises the CR one point to make up for the power lsot from using aluminum works pretty well.

Now if you play with cam timing in order to affect dynamic cylinder pressure, you add another variable.

Modern heads may use swirl and chamber design to allow even more compression but that has nothing to do with the material.

Detonation is the auto-ignition of the end gasses in the chamber as opposed to ignition caused by the flame front started by the plug firing.  It is affected by mixture distribution and temperature as well as fuel resistance to auto-ignition. 

Aluminum retains less heat in the chamber and thus makes less power unless compensated for by timing, compression, or boost.

yes, one can run more compression but only to the point that one gets back to the heat retained by a cast iron chamber-  being able to increase compression does not allow us to exceed that of the iron unless we change other variables as some modern engines do :)

I have learned to believe in science as I got older
Steve Wood

http://www.vortexbuicks-etc.com

A lot of broken parts does not make you a racer; it makes you a slow learner.

Offline earlbrown

  • Turbo Street Eliminator
  • ******
  • Posts: 1571
  • PSI: 6
    • View Profile
Re: Stock Head Flow #'s
« Reply #7 on: May 31 2014, 01:30:11 AM »
Having to increase compression to get back to even also increases the parasitic pumping losses too.



Plus aluminum conducts more combustion heat into the waterjacket... .     and we all know you have to have a $10,000 custom radiator to start with.  :D
'87 GN - 4.2L SFI Turbocharged innercooled V6 - Chrome valve covers - supra pump - 14" K&N - 52mm throttlebody - rocker shaft supports -  1/2 intake spacer - TB coolant bypass - 3" ATR exhaust tip - Alum intake pipe - NOS timing cover - chip - relocated charcoal canister - CR42's - stock

 

SimplePortal 2.3.7 © 2008-2024, SimplePortal