KGSloan

thanks for the great info.

i know you have a lot of time invested in tested all of those heads.

i already wanted a set of 205's and you're not making it any easier on me to hold off.

Bo White

iTrader: (59)

No doubt on the 205s, they average 251.8cfm with a 205cc intake port so thats 1.2284cfm per cc of port volume . The only thing even close to that is the 225 and again

9T9BlueTA

iTrader: (2)

This is AWESOME info, Thanks Tony

BTW I love my AFR 205's, finally a head on my car that I know flows the numbers given to me .

MUSTANGEATER

iTrader: (10)

So you're comparing ported stock castings to ported aftermarket if I'm reading this correct?

jwastedx

iTrader: (5)

Wow! Bo's heads have production valves with a smaller bore fixture and still in the running with the rest of them if they were flowed on the same bore fixture. He even has a new port design that I will be running on my car soon If his old bore design was flowed on the same bore fixture he whould flow closer to 290.

Brian Tooley Racing

iTrader: (13)

Tony,

I would like to throw something in the mix. If a head is flowed with a paticular entry, lets say a radius plastic or something of the like, and you remove that and flow it with clay and it flows more air which one is correct?

Now lets say you flow it with this plastic entry and it flows to .600" lift, and then you install the clay entry and it flows more air but then stalls sooner, which one is more correct?

Thanks in advance for the reply

nassau joe

that's what im talking about! sick em boys, i think we got em' treed!!!!!!

nassau joe

here's an interesting challenge: i have a 99 6 speed vette witha 422 iron block stroker, best internals, billet rods, diamond, etc, with TEA 6.0 heads. before moving to the northern parts of the universe, I had TEA replace a head gasket and freshen up the heads, as i live in memphis and the drive is going to be more than just a whim to run up to bowling green. while up at their shop, i had them install kooks 1/7/8, x ipie, etc, as i already had them put the fast 90 etc on. car dynoed at 526 rwhp, forot torgue, 50something. if we were to put a set of the 225 heads on this car, is what i am seeing true that it would be faster? i am asking? if this were to be the case, im up for a test bed and see if there is any "improvement". not intending to flame tony or brian. just opening up the possibilities of real back to back comparison. if they in fact pick it up, ill gladly flop down the coin. anyone that has dealt with me knows i can back up my offer. joe in memphis

Tony Mamo @ AFR

iTrader: (13)

Mmmmmm….sounds like which ever buzzer I press I will be leaving the show with some “nice parting gifts”….LOL

Seriously, there isn’t a right answer or a wrong answer to your question. The real right answer is to flow every head thru a manifold with a radiused entry in front of the throttle body and an injector positioned in the intake (oooops….now which intake do we use??) Are we doing port development work or just flowing a set of heads to see how they stack up? The reality is that flowing with intake, TB, etc., would be a very time consuming process if you were having to flow test a significant number of cylinder heads and few shops would want to go thru all that trouble if you were looking to just have somewhat comparative data.

The bottom line is that we try to eliminate as many variables as possible when designing ports or simply flow testing and evaluating a cylinder head. A fixed radiused entry does exactly that…it’s contours are exact and consistent around the entire perimeter. It would be impossible to get consistent results over and over again by using a clay radius. Take it off, place it on another head that has a slightly different inlet shape…start massaging it to fit etc…..too many variables. And again, impossible to get a consistent radius that helps guide the air into the port. Perhaps an inconsistent radius would alter the way the air enters the port causing the head to flow more, or maybe it causes the head to flow less. No right answer there…just an observation of would could or could not happen.

Again…We feel the less variables in flow testing the better….A fixed perfectly radiused entry is just another tool that helps give us consistency so we are testing cylinder heads…no need to add variables with how the air enters the port into the mix. All of the testing I have referenced in my first post was on the same equipment using the exact same fixtures I test the AFR stuff on every day. That might have helped some heads or hurt some heads, but none the less, it puts all the cylinder heads in the test on an even playing field.

Tony M.

BrentB@TEA

so you used a fixed pefectly radiused inlet on all the heads you tested? No problems with the port matching up from several different vendors?
I would think the playing field isn't even if it was radiused and sized to your own CNC ports.
Just a thought..no ball busting intended.

Tony Mamo @ AFR

iTrader: (13)

Just to clarify....the inlet we use is slightly larger than our port...slightly. No clay at the transition (between head and radius plate) is necessary. If I flow a head that is significantly smaller than ours (rare), I would use a thin smear of clay where the radius would transition into the slight forward lip the smaller entrance created. Some of the larger heads were opened up slightly at the entrance and our radius plate on those heads makes for a "net" fit or is slightly smaller, but with the radius plate positioned right in the center, there has never been a step (going the right way) of any significance. Whats interesting to note is that heads that are low 200 cc's compared to heads that might be mid 240's don't have a much different sized entrance....the primary reason being it would take a heavily massaged intake manifold to fit, not to mention the available cross section of the entrance is really enough to get the job done anyway.

Keep in mind that all the info recorded over the last 18 months or so was not being gathered to post up on LS1 tech one day...It was for internal use to see how we compare to the cross section of heads on the market. We would have only been kidding ourselves by not properly flowing all of the heads in question.

Richard@WCCH

iTrader: (3)

Interesting discussion here everyone.......... Just another thought to add to the mix about the radiused inlet. Is it relevant to flow with a rectangular inlet as opposed the the "Cathedral" shaped inlet? Peak flow will sometimes suffer between the two shapes. One shape is the real world and one shape is the bench world...........which has more relevance and why? On one hand an intake manifold runner would better represent the intake tract as a whole much the way most engines are configured. And on the other hand we're trying to compare port to port flow differences and we shouldn't care what's upstream from the port.
Nice thread. Thanks for your input.

Richard

disco192

This is not the reason why mid lift numbers are important at all. They could get hit 12 times for all I care... the fact is, on an agressive cam, the amount of time spent under 200 lift is very small compared to the time spent over it. The steeper the lobes, the less mid lift matters. This is a pet peeve of mine that has carried over from the days of flat tappet cams and non-agressive lobes.

This is interesting data because I see alot of companies claiming AFR inflates their numbers, but I guess EVERYONE inflates their numbers... who knows. I would like to see it on a 3.9 bore because thats what alot of people are using.

2c5s

iTrader: (11)

A pet peeve of yours in what, your whole 20 years of experiance.(credibilty out the window) Funny, I have had some aggresive LS1 cams in my cars, and the duration under the curve is actualy fat. Maybe you should look at a cam again. And maybe you should check their website, I think the 3.9 numbers are there. I would stack their 3.9 numbers against the numbers of the other heads on the big bore fixture.

70 TA

I had my AFR 205's delivered on Wednesday.

Had em flowed by Agostino Racing on Thursday and they were in fact pretty much bang on with the advertised #s, actually beating the advertised numbers by a few CFM across the board.

They look damn pretty too if that counts for anything

One of the things that hasn't been mentioned here in this thread I dont think is the valve size in all these heads. Most of those stage 3 heads would likely have much larger 2.08 or maybe even 2.10 valves and yet the the smaller port AFR 205 with the smaller 2.02 valves dont really give up much till the higher lifts where realistically the valve doesnt spend much time at all.

Bo White

iTrader: (59)

True, all of the heads in Tonys list probably have 2.02/1.57 or larger valves. I also understand what Brian is talking about and the entry will have an effect on the total air flow in a given head but its time consumming to flow the ports with all of the different types of inlet fixtures/radiuses. Use the one thats most commonly used and go with it is how I feel about it.

Tony Mamo @ AFR

iTrader: (13)

Guys...

Trust me when I tell you the radiused entrance we used did not have an ill effect on any of the heads we tested. Whether a certain shaped clay entrance would have helped or hurt the numbers of some of the heads is certainly debatable, as is whether flowing it with a "cathedral" shaped entrance is ideal or less than ideal which Richard pointed out, but the bottom line is that is what is typically done in the industry and how most, if not all shops will advertise their numbers. Consistency and lack of variables is the key if we are trying to keep the test results as authentic as possible. Port develpment work is a whole different topic and there are other tools I use which better simulate an actual running engine....that kind of info I'm not at liberty to discuss.

I spent a bunch of time this weekend flowing some heads....I have four more Stg 3 results to add to the list. One of them broke the "volume" record coming in at 254 cc's on the intake and 91 cc's on the exhaust. I can't update any of this info till I get back to the office....I have jury duty this week ......hopefully they will throw me out of the courthouse.

I will update the "list" as well as the avg. flow numbers and volumes when I have some time.

Thanks for all your input....

Tony

PS....Most heads in this group have 2.080 valves and there are a few 2.100 heads in there as well. Flowing these type's of cylinder heads on a small bore will provide less than stellar results and most of the manufacturers and suppliers will tell you staight up that they are more aimed at a 4" bore and larger application. Some of these heads get KILLED on a 3.900 bore, but keep in mind they were never meant to be placed on one.

Bo White

iTrader: (59)

Maybe mine will make "the list" this time around since my new intake ports are bigger and should move more air than before
254cc intake ports in a ls6 GM casting is huge, there are probably some thin spots here and there in the casting to make the ports that big. That also brings up durability of a given head when ports get that big. Thats over 40cc of material removed
I also agree about the idea of putting some of these heads on a 3.900 fixture killing the flow on some of the heads. Some probably get real turbulent up past .500 or sooner on a 3.900.

2c5s

iTrader: (11)

Tony,

Does the owner of the "254" port get a prize for breaking a record???

Remember: GO BIG OR GO HOME

disco192

Honestly, I dont have years and years of experience, but I do know more than your average Joe on this board. I am a student in Aerospace engineering and have taken more fluid dynamics/mechanics classes than most people on here, so I think I have some credibility to speak on cylinder head flow. If you dont believe me, why dont you read this article by David Reher (a professional engine builder).

http://www.rehermorrison.com/techTalk/16.htm