|
Re: Cylinder Heads and Horsepower
[Re: 440Jim]
#550897
12/13/09 09:30 AM
12/13/09 09:30 AM
|
Joined: Jan 2003
Posts: 2,939
A shed in England
Tig
master
|
master
Joined: Jan 2003
Posts: 2,939
A shed in England
|
Here's Mine
Indy 572-13's 380 @ .700
9.57 @ 142.5 3850lb.
'74 Challenger..9.46 @ 145.9 1/4, 6.001 @ 118 1/8 so far. 4023lb !!! # N/A, Marsh performance 655ci, Indy Maxx, T/R, Indy 600-13 X's, Street legal, pump gas, full interior, Cal-Tracs, mufflers, 3:73's and real 10.5 radials.
9.51 @ 142.4 1/4, 6.003 @ 114 1/8 with our old mule KB, 572-13, 580 wedge.
RHD '68 Barracuda Fastback 323ci street/strip. Best ET 13.88 @ 99.03
|
|
|
Re: Cylinder Heads and Horsepower
[Re: S/ST 3040]
#550902
12/13/09 09:44 AM
12/13/09 09:44 AM
|
Joined: Aug 2003
Posts: 1,314
Charlotte, NC
LSP
pro stock
|
pro stock
Joined: Aug 2003
Posts: 1,314
Charlotte, NC
|
Quote:
Jim, I have your's at 2.11 HP per CFM
That's figured from .600" lift or max valve lift x 87%
The smaller engines don't seem to utilize the air flow available
with as much efficiency.
I would think compression needs to be considered as well. If you can't get anymore in, squeeze what's in there more.
|
|
|
Re: Cylinder Heads and Horsepower
[Re: S/ST 3040]
#550903
12/13/09 10:00 AM
12/13/09 10:00 AM
|
Joined: Jan 2003
Posts: 2,939
A shed in England
Tig
master
|
master
Joined: Jan 2003
Posts: 2,939
A shed in England
|
Quote:
Quote:
Here's Mine
Indy 572-13's 380 @ .700
9.57 @ 142.5 3850lb.
860 HP
2.26 HP per CFM
Wow  Maybe my head guys rig reads low?
He always says "never pay much attention to it any way", "they're better for a before and after comparison".
They will flow a tickle over 390 @.800 (on his bench) however but my cam is .737 gross lift. With .030 lash and any geometry issues I figured .700 best where they flowed 380.
Hope I haven't thrown a spanner in the works here 
Thanks for the info 
'74 Challenger..9.46 @ 145.9 1/4, 6.001 @ 118 1/8 so far. 4023lb !!! # N/A, Marsh performance 655ci, Indy Maxx, T/R, Indy 600-13 X's, Street legal, pump gas, full interior, Cal-Tracs, mufflers, 3:73's and real 10.5 radials.
9.51 @ 142.4 1/4, 6.003 @ 114 1/8 with our old mule KB, 572-13, 580 wedge.
RHD '68 Barracuda Fastback 323ci street/strip. Best ET 13.88 @ 99.03
|
|
|
Re: Cylinder Heads and Horsepower
[Re: S/ST 3040]
#550904
12/13/09 10:17 AM
12/13/09 10:17 AM
|
Joined: Feb 2005
Posts: 4,324
Prospect, PA
BSB67
master
|
master
Joined: Feb 2005
Posts: 4,324
Prospect, PA
|
Vic,
Cool thread. I've been thinking about how my data would apply, or if it should be used. I think the simple answer is that it would/should not.
I think that the premis is: what kind of power might be possible based upon head flow. Correct?, If so this would presume that the induction system and exhaust system are also designed to support the potential of the head. In my case the mild cam, and restrictive exhaust robs the head of its potential, and would be a nonrepresentative data point in your data set and would skew the results. Correct?
Also, would'nt you need the DA as well to adjust the actual hp numbers from the calculator to standard conditions?
If I'm mistaken, let me know, I'll throw in my data.
|
|
|
Re: Cylinder Heads and Horsepower
[Re: S/ST 3040]
#550906
12/13/09 10:56 AM
12/13/09 10:56 AM
|
Joined: Jan 2003
Posts: 16,934
NC
440Jim
I Live Here
|
I Live Here
Joined: Jan 2003
Posts: 16,934
NC
|
Quote:
Jim, I have your's at 2.11 HP per CFM
That's figured from .600" lift or max valve lift x 87%
The smaller engines don't seem to utilize the air flow available
with as much efficiency.
I like the way you are doing something to account for cam lift when using the head flow number. 85% or 100% of max cam lift, I don't know, but I like the idea of not using the .800" flow number when the engine has a .600" lift cam.
As mentioned, there are lots of variables, but as long as you state what you are doing, I think it makes a useful comparison for us "typical" racers.
|
|
|
Re: Cylinder Heads and Horsepower
[Re: S/ST 3040]
#550909
12/13/09 11:25 AM
12/13/09 11:25 AM
|
Joined: Jun 2003
Posts: 52,972
Romeo MI
MR_P_BODY
Master
|
Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
|
Quote:
Jim, I have your's at 2.11 HP per CFM
That's figured from .600" lift or max valve lift x 87%
The smaller engines don't seem to utilize the air flow available
with as much efficiency.
This could be due to the pressure differential, a
big cylinder can hold the pressure differential for
a greater period of time over a smaller cylinder
(just thinking out loud)
I know that I dont use my heads to their max ability
but I didnt want to change springs all the time,
but after running mine for a few years now I see
that I can get away with more cam and still not
have a spring issue
|
|
|
Re: Cylinder Heads and Horsepower
[Re: S/ST 3040]
#550910
12/13/09 11:34 AM
12/13/09 11:34 AM
|
Joined: Feb 2003
Posts: 1,646
Ontario,Canada
firefighter3931
top fuel
|
top fuel
Joined: Feb 2003
Posts: 1,646
Ontario,Canada
|
Quote:
I'm really curious about this one. (NO, not because it's a BB!)
I sent Dwayne one of my heads to flow and our benches are actually
pretty close.
Can you give all the flow numbers and cam specs?
What did it MPH and race weight?
No track times as of yet...this engine just came off the dyno a few weeks ago. It's a Heavy street car (4100 race weight) with 4.10's and 727 trans.
I don't have the flow sheet from Dwayne yet but they did peak right at 360cfm.
Cam is a .660lift roller with 266/272@.050 & 110 LSA. Installed @ 106* ICL
Ron
|
|
|
Re: Cylinder Heads and Horsepower
[Re: S/ST 3040]
#550912
12/13/09 11:38 AM
12/13/09 11:38 AM
|
Joined: Jan 2005
Posts: 3,635
Oakland, MI
dizuster
master
|
master
Joined: Jan 2005
Posts: 3,635
Oakland, MI
|
I think it all just proves the point that flow doesn't mean squat. Ask the best head porters in the country and they will tell you the same thing. Port cross section and shape, are much more important then whatever flow comes as a byproduct. Just cause the head flows a lot of air doesn't mean the motor will make big HP. Just like the heads with the right port cross section and shape, may make power above their "CFM potential". It's all about having the right size/shape port, for the CID/RPM you need to run. Here is a very good thread (VERY LONG) that has a lot of good info. There is a great example on the 2nd page. It used the same SBC short block on back to back dyno tests. Same casting # heads, same CFM on the same flow bench, same exact port volume.... But head "B" made 117HP more then head "A"!!!! Like I said. Flow doesn't mean squat! http://speedtalk.com/forum/viewtopic.php?t=15709&highlight=csa
|
|
|
|
|
