10sec_rx7

yep how well with that go over when they dont flow what they are claimed to flow?

spuewing i didnt send the brand new set of V2 230's i had sitting on the floor before xmas to the same bench for a flow..

TransAmcoupe98

iTrader: (10)

AFTER they were sent to someone else to be worked over...

TransAmcoupe98

iTrader: (10)

Just cut the BS and pleasantries. 10sec Rx7 is saying that AFR's heads dont flow what they say they flow. There get it out of the way.

KnightEngines

Not to be a *****, but even Tony stated that they backed up at .600" lift on his bench, AFR's advertised figures don't show that........

Now, if a head backs up hard at .600" lift at 28" depression on a steady state flow bench what do you think it'll do when you bolt it on a running engine that'll pull quite a lot more than 28" depression?

Answer - it'll back up even earlier, in fact if it backs up at .600" & 28" depression it'll back up in the lift range of a mild street hyd roller on a running engine.
A good head should not back up for AT LEAST .100" past the lift to be used, preferably it shouldn't back up at all untill the valve is out the head, but that's asking a bit much from a cathedral port head.
That's why you see good head porters flowing heads well past the lift to be used - they are not looking for inflated figures, they are looking for a head that does not back up with higher airflow volumes.

butler

One thing I do know in my 55 years experience is that it is not always the cylinder heads fault why an engine does not perform how it is thought it should perform. Too many variables. I am sure no one has done a head flow comparison on afr heads. Your porter demands numbers. Have him take another set of 225's and check it out. Take afr to court and see how it pans out. Then maybe your head porter's work can be checked out to see if his numbers are correct. If it is advertised in a certain way it should flow like that. But it does not mean the motor will pick up a ton of horsepower. You sound like a child.

butler

I would suggest you design your own head and put afr out of business. I am not a big afr fan but do know they put out a decent product.

KnightEngines

We know why it wasn't performing right - the seats were up the sh\t, most of the exhausts were getting close to burning, concentricity was all over the shop, none of them sealed properly.
They came off to have all that fixed & a touch up of the porting, I did SFA work to start with as being AFR heads I expected them to be pretty good & just need the rough seats fixed up. I was somewhat taken aback when they flowed so much less than AFR's figures & backed up so early, I wasn't expecting it.
So now instead of just tidying them up I have to port them properly to fix issues that I didn't expect to find.

Just grabbing another set of 225's is a little difficult seeing as we are on the other side of the world & these heads have been out of production for a while.

Have a read of what I posted, I'm not mindlessly bashing AFR's stuff, my critisisms are legit & are clearly explained, if you cannot understand what I'm saying them do us all the courtesy of witholding comment on something you clearly know nothing about & are not prepared to learn.

butler

You are a funny man. I have owned a set of afr 225 heads. No they didn't look like the set you posted up. Maybe the valve job had something to do with it. I was saying the op did the bashing. Read my posts. And please spell correctly.

KnightEngines

Wots rong wiv my speeling?

Have a read & learn a bit dude, focus on what causes a head to back up in flow when the curtain area is actually increasing & the port is big enough to support the curtain.
Heads backing up is bad karma & is the biggest reason why so many cathedral port LS heads do not back up their flow #'s on the track, yeah, they flow great in the lift range to be used at 28" depression, but on the engine they fall flat.

10sec_rx7

your dribble means nothing... Just a typical load of trash...

So does anyone actually have flow figures?

soop

Yet the heads performed the same after the rework as they did before. Strange that.

Tony Mamo @ AFR

iTrader: (13)

News flash.....

Most LS heads back up early....I don't care who's name is on the endpad or whether we are discussing OEM ported heads for that matter either. Even large port runners with healthy cross sections dont muster much more than .650 lift before they fall flat or back up a little.....most peak closer to .600 or so. Ive flowed more Gen III heads than I can shake a stick at and I'm well versed on this topic. Check my sticky at the top of this page (the "flowthread') and that's just scratching the surface, not to mention is years old.

Knight Engines I respect that everyone has their opinions but I just happen to completely disagree about yours concerning a port backing up. A port that backs up a little is not necessarily a bad thing. Application, RPM, and the rest of the flow curve are more important IMO.

Heads that are designed to flow a big peak number generally flow softer in the lower/middle part of the curve. I will take a head that backs up at .600 all day long if I was running close to a 600 lift cam and the numbers themselves to .600 looked strong. IMO a head that flowed less to the same number and more at a liftpoint the engine would not see (say over .600 in this example) would NOT make more power and in fact make less power.

What most forget that adhere to this line of thinking (that a port backing up is always bad) is a valve is never stuck at a certain liftpoint like it is sitting on top of a flowbench. In the real world on a real running engine the valve is lifting and falling so quickly from peak lift the air never has a chance to change direction or back up and the usable flow curve is KING. A flowbench is a tool.....its not an engine and it doesn't operate like an engine. You have to think more intuitively about how an engine is actually working/operating. Valves are opening and closing 50 times a second at only 6000 RPM!

Knight, next time your on the flowbench with any head that backs up, try quickly depressing the valve past the point it back ups and quickly releasing it letting it snap back to the point it doesn't (basically quickly open and close the valve). The air wont change dynamics or back up.....it doesn't have time. The flow manometer will pretty much stay at it highest peak value prior to backing up and trust me an engine snaps that valve open and closed 10X faster than you will be able to by hand on the flowbench.

Steady state flow on a bench is not very representative of a running engine....only representative of the type of flow available at various lift points that matter and once you know that its somewhat easy to determine the type of power that particular cylinder head can support. "X" amount of air is capable of roughly "X" amount of HP in an ideal situation.

Real world example to prove a point...my 383 had a set of 225's that were milled aggressively to get the CR I wanted.....at the end of the day peak flow was "only" around 314 CFM (after the mill knocked it down a bit) and it backed up pretty hard at .580 lift where its peak flow was observed (but had strong numbers from the crack of the valve to that liftpoint however). I ran a solid roller cam in that engine with .660 lift (well above the point the heads backed up) and only modest duration figures. I was disappointed the head didnt hang on longer but it was a great test of my theory and I was headed to the dyno in less than two weeks regardless. I also thought about the fact my goal was 600 or more at the crank and that 314 CFM should be able to support a little more than that.

With only 11.25 compression (a bit soft by some of todays standards), that engine was one of the most powerful 383 street combo's I have seen to date producing mid 500's to the wheels, 620 flywheel, and trapping 130 MPH in so so air (1500 positive D/A). I built that engine in 2005....given some of the better parts available today I could make 20 more RWHP easily with the same general specs on paper and the exact same cylinder heads. Kind of debunks the whole "cant make power if the port backs up theory".....at least if you have an open mind to real world results that might just lend some credence to a different way of thinking.

Folks.....there are lots of opinions on what works and why....my own opinions falling under the same category (the category of opinions are like you know what )....some opinions of course have merit, some of course do not (and others fall in a gray area).

To that I say welcome to the Internet.....and enjoy the show

-Tony

lemons12

iTrader: (71)

You know this... I love your replies. To say they are detailed is a gross understatement.

To many, thats not true because thats not how it works. You tell WHY it is not true and how to get the answer along with the answer and 5 other wrong answers! LOL

butler

Without theory we would not have the internal combustion engine. But people overdose on theory. My 383 with afr 225 heads ran 131 mph n/a. Not too bad. And in reality it was too much head. I am not a headporter but if the cathedral heads are so bad why is the ls motor right out of the box so strong compared to other motors? Some of this stuff is conjecture.

10sec_rx7

so no inderpendent person has flow figures yet?? still no 4in bore flow figures from MR AFR him self? just another load of spin??

Tony Mamo @ AFR

iTrader: (13)

"Spin" ?? Some might consider what I presented as informative.

I already discussed what happens on a 4" bore in a previous post.

Lower/midlift flow is off a little (3-6 CFM's typically)....peak flow is similar and it usually occurs at a later lift point. Also there is a tendency for the port to hang on longer and sometimes even flow more at the higher lifts.

Now if we are discussing a 3.900 bore versus a 4.125 bore you can see slightly greater losses. Here is information straight from AFR's website comparing the two (figures reflect the new 230 heads).





The older 225's would have shown similar losses if we were discussing a 3.900 versus a 4.125 or 4.155 bore......a 4" bore would be somewhere in the middle as the valve is obviously not as shrouded.

There is no smoke and mirrors here....take any other manufacturer's head and flow it on various size bores and the same trend will also take place. The numbers are obviously effected (more so on the really small bore) but the peak flow is actually somewhat close. What the chart above doesn't show is the small bore head continues to climb in flow as it approaches .650 lift matching or even exceeding the peak number of the larger bore but requiring more lift to get there.

-Mr. AFR

TurboS10

iTrader: (12)

The valve job is huge on how the heads work.

The fact that you were too lazy or cheap to get them flowed independent of your porter says something also.
It's not uncommon for shop's to put down various out of the box heads to make their work look better. Most shops will put down other's work for some reason or another. Simple marketing strategy...

If AFR's flowed like you claim then all the AFR headed combo's would be getting put on the trailer by Patriot or PRC combo's.....and it would be posted all over here that it was happening. You would be able to find plenty of post's saying don't waste your money on AFR's, just order some Patriot's and be done with it. I've yet to see a post from someone who swapped from ported stock castings to AFR's that regretted it.

Example- When the Holley 950HP carb's came out. Within 1 1/2 years it was out on the boards that they only flowed about 830cfm- from flow bench testing-. Some netizens called BS and others posted the demensions of the various part's used on a 950 and noted the same part demensions were used on the 830 rated nascar carb's etc...

While your heads may not flow what they should and they weren't stock btw, making the blanket statement that AFR's flow substanially less than advertised and then asking others to validate your claim for you is simply you trying to make yourself feel better about the cash you wasted.
It simply can't be your fault. It must be the parts you bought being sub par and everyone else that touched them does unquestionable work.

Learn from your mistakes and move on.

KnightEngines

Tony, we're going to have to agree to disagree on heads backing up being a bad thing, many very well known porters agree with me & I've seen the results of fixing a head that backs up on the dyno, so I'm not going to be convinced otherwise.

You CAN stop an LS cathedral port from backing up without hurting the mid lift flow & it definately does make a difference on a running engine, don't know if you saw this, but these are the figures off a set of ported factory 243 castings I did, 2.08" valve flowed on a 4" bore, these are the only 243 castings I've ever ported, a bit more tme with them & I could do better:

.1 - 73.4
.2 - 145.7
.3 - 212.6
.4 - 265.2
.5 - 303.3
.6 - 327.8
.65 - 334.5
.7 - 338.6

As you can see, they do not back up, wish I'd recorded flow at .750" & .800", at the time I didn't see the need, but they did not back up all the way to .800" lift (only gained a couple of CFM, but did not back up or go turbulent).
No, they are not as strong through the mid range as the figures for your 230's, but they are factory castings, not performance aftermarket castings.

Dale has performance & dyno figures for the 225's before the valve job was screwed up, we'll be able to compare how they perform after I've fixed them, should open a few eyes.

hymey

No attack on anyone here mainly a question to mr mamo. Why are head porters still supplying flow figures at 28 inches of depression, the 28 inch value came from Smokey Yunick in his testing of the internal combustion engine which was typical of the efficiency of a race cylinder head of his day. Todays 15 deg head is light years ahead of the heads in those days. Real tests have shown that the real running depression in an engine through a modern head peaks much less then that. In fact pro stock head developers test at 5 inches as this is a real world number. A good cylinder head will flow the same hp at 10 inches as it does 28. And a bad cyl head will infact go turbulent at the same lift regardless weather its 10 inches or 28 inches, So why are these 28 numbers still advertised? Tony Mamo I'm sure you are not the type of guy that lays all his cards out on a public forum but just goes to show how much influence some guys have on the industry.

hymey

Ie there is much less friction through a modern port so therefore the resultant depression is much less then old school theories.