DavidNJ

Tony or someone who knows...why the drop off above .6"? An aggressive roller would end up there just to get more lift lower. Why the loss?

Thanks,

David

JS

iTrader: (4)

These 225's out of the box must be awesome on a 346 and the right cam,LSX and 90TB..
Very impressive...

Big-DEN

A couple of CFM - who cares.

Tony Mamo @ AFR

iTrader: (13)

Ive already stated this publically a few times, but just to reiterate....During the design and development of the 225 cylinder heads, I focused all of my efforts on crushing low and midlift numbers while still trying to maintain a good peak figure at .600 lift....I spent 100's of hours back and forth to the flowbench as part of this process (NO JOKE) and during this "process" I made some decisions on port shape, chamber shape, and ultimately valvejob design that cost me peak flow but in my opinion added enough to the "area under the curve" to make it a smart decision. We designed a head to make power, not to look good in advertisements or internet posts....although I confess it always bothered me to make a decision that I knew was costing me some "bragging rights" regarding peak flow numbers.

Guys...unless your running a .700 + solid roller, numbers above .600 lift mean JACK. Most applications are running right at or slightly above .600 lift and I focused my efforts on designing a cylinder head that was going to work WELL in 99% of all the applications. Even a .660 lift solid roller by the time you take out valve lash and deflection of the valvetrain, pushrods, etc. barely lifts the valve to a net of .625 and its spends all of 10 crank degrees there. You know where it spends about 100 crank degrees...between .550 and .600 lift...on the way to peak lift and on the way past peak lift. Not to mention the killer low and midlift flow the 225 heads provide adding to the cylinder fill both on the way up and on the way down as well.

In the 18 months since I started this project I havent flowed a single head (LS1) that comes close to the figures the 225's develop from the crack of the valve to .550 lift....two other heads (much larger in volume) tied it at .600 and one head covered the 225 by 5 CFM there but it was almost 20 cc's larger and had a 2.100 valve (but had very dissappointing low and midlift numbers and a weaker exhaust port everywhere).

Two tuners (LG Motorsports and Mikey at Rapid) have already set new records with combinations built around the 225 heads, and more records are getting ready to be broken as we speak. Very shortly my personal ride will be coming apart and I plan on having THE stoutest 346 on the planet that still displays decent street manners with the addition of the 225's and a slightly larger camshaft in the next month or two (waiting on the 62 cc heads myself)....and I will accomplish that knowing I left a little power under the table by not putting a larger camshaft in the engine to help maintain decent street manners.

Thats it for now....

Thanks guys,
Tony M.

SPIV

I cannot wait to see the result of the 225's/larger cam combo so that I can replicate it in my street/strip ride.

Awesome...!!!

Bo White

iTrader: (59)

Average cfm per cc of runner you cannot beat the AFRs casting. I have spoken with Tony many times and will always respect his work and ethics at making better products for more power for the performance community. Looking forward in seeing more outcome of the new LS1 products we are being "blessed" with here lately because like gomer and I were talkin the other night, its just begun on whats capable of being done with the LS1/2/6/7- especially with dropping F-body prices.

2001CamaroGuy

iTrader: (6)

are these as cast or ported?

DavidNJ

Tony, maybe I should have worded my question more carefully. Cast Iron Bowties, very common in Saturday night oval racing, also have a fall off over .6. However, it is very slight...a few percent.

The way mikey, the 553rwhp 402 guy, started this thread it sounded much more severe than that. Mike Norris also chimed in with some numbers. However, neither mikey or Mike Norris gave any numbers above .6".

Some of the cams I've looked at--and admittedly haven't run--spend 50-80 deg above .6 (isn't .020 flex a little high for Jesel or T&D rockers?). Even that many deg is not that much, especially if the loss is small.

So, how much is the drop off up there?

LSonederfull

I would add here to consider flow test with the intake you will run because, flow drop off at .600" and up lift will lessen when overall flow drops from intake manifold influence. Example if 320 cfm port flows 290 with intake on for testing, drop from .600" to say .650" will usually be less than when testing w/out intake. The lower actual flow thru port will allow higher lift before dropping off. I havent tested AFR but i have seen this enough to safely say it should be considered. Hope this helps.

Tony Mamo @ AFR

iTrader: (13)

Thank you...

That is exactly right and I was going to touch on it in my response to "DavidNJ", but I will add the following as well...

ALL "LS" style cylinder heads go into "port stall", and usually quite abruptly, no matter how big the cross sectional area is.....even the 240+ cc runners, but they will usually get closer to .650 or just beyond before they back up in flow.
It is inherent in the design of the intake port and is a fact of life. The "curtain area" of the valve is very open with a 15' valve angle and once that curtain area can pull more air than the port can provide, the intake port will stall and flow will immediatly back up. Your cast iron bowties (David) have a 23' valve angle and a completely different chamber design where the valve stays alot more shrouded for a much longer period of time....comparing them is the whole apples and oranges thing and the new LS heads will smoke all but the best 23' heads and really show an advantage in area under the curve due to the better chamber design and flatter valve angle.

Another thing to consider is that a flowbench, while a great tool in developing a cylinder head, does not completely mimic airflow thru the engine. An engine will never see peak lift numbers for more than a fraction of a second and if I quickly go past .600 (to say .640 or so) on my bench with my opening fixture and back to .600....simiulating what a valve will actually be doing on an operating engine, the 225 head will not stall and airflow hangs right around the low 320's....this doesnt even take into account that the manifold restriction will make it less likely to stall as we already touched on above.

David, my advice to you (and everyone else) is to run a camshaft in the mid .600 lift range (solid roller grind) which will give you stellar performance and compliment the 225's flow curve perfectly while also adding reliability to your engine by not having to lift the valve as high and still be able to put down huge numbers at the track or your local chassis dyno. I would rather have a head that put up big numbers from the crack of the valve to .600 lift, than a head that had a larger runner and only showed an improvement on the flowbench at say .650 (mainly due to its physically larger port). If you dont subscribe to that theory, feel free to take a pass on the 225's, but as more and more results from this head hit the market, if my theory proves to be true, you might be sorry you made that decision.

Guys...we have been doing this a long time (manufacturing performance cylinder heads) and its the ONLY thing we do. There is alot of things to consider when designing and building and aftermarket head and you guys (the LS1 crowd) are getting the oppurtunity to sample our latest and greatest efforts at producing an "out of the box" killer piece....hopefully, the results will continue to speak for themselves and I can spend far less time typing on these boards....AMEN

Regards to all,
Tony M.

JZ'sTA

iTrader: (23)

Tony you just need to learn how to copy and save real well.
J/K
I believe you have made yourself quite a few extra sell's by coming on the boards and explaining what your are offering.
Some of the best C/S on this web site.
Thanks

DavidNJ

The CI Bowties are a rule thing, and I if I was starting from scratch I think I would build a W-2 Mopar.

Ok, everything makes sense. However, what solid roller are you are recommending? 'Street' grinds seem milder than a Comp XE-R, and most of the rest have way to much lobe lift for a big ratio rocker.

Thanks,

David

P.S.
"Tony Mamo @ AFR", you really didn't need to but my handle in quotes!