I just got the flow numbers for my AFR 210s Race ready heads...

These where flowed by TEA... they are a bit odd on the exhaust port

Lift... Intake / Exhaust
100.. 67.3 / 47.1
200.. 131.4 / 107.1
300.. 189.6 / 162.3
400.. 237.0 / 214.1
500.. 269.8 / 248.0
550.. 278.3 / 256.3
600.. 280.9 / 262.6
700.. 282.9 / 274.4

Those exhaust flows look like INTAKE FLOW from 500 up!!!

There must be something wrong there... if there is nothing wrong then I guess that I should hcange the cam to a 224/230 instead of a 224/236 cam...

Heads are pretty maxed out over 600 which was why I chose 620 lift cam intake... 3192/3196 lobes... Let me know what you guys think.

 

TEA uses a pipe on the exhaust.

 

What do you mean a pipe?

 

yup, those are piped numbers.

They use a "mock header" when they flow them

 

Ok... then... translation???

Will they flow 230s in the exhaust "non piped"

Are they good numbers???

Oppinions...

I expected a bit more, but... 5cfm shy of what they claim is not bad.

 

AFR exhaust flow numbers are generally so good the use of a single pattern cam is often recomended. Which is good, you'll have more torque than with dual pattern cam.

You should give them a call with your specific application.

 

[QUOTE]Originally posted by The Highlander
[B]I just got the flow numbers for my AFR 210s Race ready heads...

These where flowed by TEA... they are a bit odd on the exhaust port


How big was the bore they used to flow the heads?
AFR uses 4.150" which usually makes them flow less when using 4.030" bore.

Arnold

 

Good question.. i'll go ask

 

4.048"

 

TEA always has very high flow numbers on the exhaust, it's their bench not the heads. Anyone who has ever tested heads on their bench then on another bench see the same thing. On the intake side I have seen within 2cfm , but the exhaust even with a pipe can be WAY OFF. I would presume the numbers listed by AFR are much closer.

Bret

 

I swear I'm not just ragging on you today, I promise.....


The choice of single vs. dual pattern has more to do with the whole system rather than just the flow numbers or E/I ratio. The more TQ on a single pattern vs a dual pattern is also bogus, intake duration and closing point has much more of an effect on the TQ curve than the dual vs. single pattern has to do with it.

Bret

 

Why? There seems to be some kind of urban legend around cam lift surpassing peak head flow numbers. If it was my car i'd go as high as spring control for my max rpm would allow.

-brent

 

quote:
--------------------------------------------------------------------------------
Originally posted by The Highlander

Heads are pretty maxed out over 600 which was why I chose 620 lift cam intake...
--------------------------------------------------------------------------------

Why? There seems to be some kind of urban legend around cam lift surpassing peak head flow numbers. If it was my car i'd go as high as spring control for my max rpm would allow.

-brent
==========================================

Brent.......
it seems no one remembers or has had any experience with NHRA SuperStock engines "before" NHRA allowed cylinder heads to be ported .

"before porting" SuperStock Chevy heads flow numbers
stopped flowing or took a dive above .450" Intake Lift,
but SS engine builders used and went much faster with .660" to .720" lift cams with 1.940 valves

the extra lift above .450 increased the dwell time above .450"
even though flow stopped or fell off ...everyone went faster

so instead of accessing flow at .450" Lift for only a few crank degrees....you would access same flow with .700" lift cam for 60 to 110 degrees of crank rotation

200 cfm Flow for 5 degrees -VS- 200 cfm flow for 60 to 110 degrees of crank rotation

the only drawback is you have to be careful of lifting intake valve too far as you will slow air velocity too much in the curtain area
usually anything less than 240 fps is too slow
or .41 times valve diameter is max lift possible
.37 times int valve diameter works almost 100 percent
in all out racing (.37 to .41 times intake valve diameter)

the only other reason for less lift is for greater valvetrain life !!
and move engine rpm range lower

at .25 times valve diameter the curtain area = valve area
at .25 times valve diameter the valve is controlling all the flow

above .25 the port shape starts influencing flow

you get to .37 to .41 ...and flow gains are just about over

from other previous Post;
Lift... Intake / Exhaust
100.. 67.3 / 47.1
200.. 131.4 / 107.1
300.. 189.6 / 162.3
400.. 237.0 / 214.1
500.. 269.8 / 248.0
550.. 278.3 / 256.3
600.. 280.9 / 262.6
700.. 282.9 / 274.4

2.080 * .25 = .520 lift
look at flow rate increase from .100 to .500 ...pretty good ?

then look at .500 to .700..the rate is slowing quickly

2.080 * .37 = .770 lift
and if port is correctly ported..flow will still be gaining till .770 lift to .41 * 2.080 = .853 lift

but above .37...flow in curtain area is usually too slow and point of diminishing returns unless its Comp or ProStock technology
curtain area velocity will be OK till .41 x VD before diminishing returns


you use valve lift to keep valve open as long as possible above
.25 x diameter to increase flow dwell time

.25 x int valve diameter should be minimum recommended
Street/Strip cam in order to realize healthy Torque/HP gains from good cylinder heads

.37 x intake valve diameter would be for best all out HP
with older style heads

.41 x intake valve diameter would be for current state of art Comp and ProStock technology

 

Goods post and explaination of that Larry. I always wonmdered where that old wives tale of you only want to lift the valve as high as the point where flow levels off. Your example shows where the real limit is on valve lift for a given port. It definately supports what I have seen, all though I don't do any work on SS motors, but that does show the stock head LS1 and LT1 guys that there is no real limit on valve lift for them.

There are a lot of odd things like that out there, like the pressure over the nose theory. Well doesn't anyone ever account for the rocker arm? Nope they just take the spring pressure at the max lift and use that. Well a 1.5:1 rocker vs. a 2.0:1 rocker is going to effect the pressure the lifter sees over the nose. LS1 guys also have some mysterous limit of max lift at the valve you can do on a stock block. They might want to think where that max lift limit actually is.

Bret

 

Bret ...here is another real-world example =>

i know its a small block Chrysler 360 but its relevant and the closest flow sheet within reach at the moment ;

Original Flow Sheet for #596 castings with 1.880int/1.600exh
Lift------Int-------Exh
.200---109.6---106.7
.300---163.6---132.3
.400---195.1---141.7
.450---201.1
.500---195.1----146.0
.550---194.0----
.600---193.2-----148.5
.650---193.2----
.700---193.2-----148.5
.750---194.0-----
.800----194.7----149.4

Comp Cams 308-8/312-8 .440/.440 Lobes 1.60/1.55 ratios
.704 intake lift
.682 exhaust lift

360 +.060 engine 9.46:1 CR Carter ThermoQuad carb
3530 Lbs Dodge Aspen

flow hit a brick wall at .450"

but the best DragStrip and Dyno cam had .704/.682 Lift

this was "before" you could port NHRA SuperStock heads

engine was by Alan Patterson and Kip Martin at that time