News on AFR heads
09-29-2003, 09:44 AM
#21
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Re: News on AFR heads From Tony:
All numbers posted are taken off an SF600 Superflow, as well as a flowbench I built myself, which I know to be accurate and spits out numbers to the CFM compared to the 600. All figures I quote are taken @ 28" of water, which I feel is a better standard than 25". Also, all my exhaust figures are recorded utilizing a 1.875 "flowtube" which is about 8-9" in total length. It bolts to the exhaust port much like a header and immediatly hooks down and back, closely resembling any primary tube you might find from the various manufacturers....after the turn, the pipe has about a 3-4" section of straight pipe. If you have ever seen an Amduri flow tube, it is basically very similar. All my exhaust ports are optimized and designed that way from their inception so as to try and simulate real world operating conditions when ultimately the heads are sitting between your framerails with a nice long-tube header attached to them.
As far as the flow figures based on a 3.910 bore versus a 3.900 bore....the difference between the two would be just about unrecognizable on the flowbench, assuming you could even locate the heads the exact same for both tests. The additional "shrouding" of the smaller bore is always only half the difference in diameter, so where talking about .005 here....not much more than the thickness of a sheet of average paper. Even a dramatic change 20 times that amount (3.910-4.125) only had an effect no greater than 7 cfm at one particular liftpoint in the curve. I attribute part of that to the fact I designed the chamber around the smaller stock 346 CID bore, assuming thats where most of the 205's would find a home. Our larger 225 will be offered in both small bore and large bore combustion chamber configurations, allowing the end user to choose accordingly based on his application. (The low-lift flow will be significantly better with the larger chamber program).
One more quick point....As it's a known fact that Flowbench's and Dyno's are barometers at best, trying to get accurate, comparable numbers from one to another is almost impossible. The main reason this is so is simply all the variables that come into play during a test session with either. You could have every conceivable variable covered and one dyno might show higher than another because the owner of that dyno took more time in setting up his room and it has better evacuation of spent gases with a very isolated fresh air "hat". Anyway, you get my point....lots of variables come into play flowtesting as well...so lets talk about something more concrete....Net gains (or losses for that matter)
With the same bench and test equipment, AFR recorded that a stock LS1 port flowed 230-235 CFM....the LS6 head flowed 260 CFM (@.550 where it peaked and then went turbulent and lost over 10 cfm @ .600), the new AFR 205 went 308 CFM @ .600, a 70 plus and 40 plus gain respectfully as I had mentioned in a previous post. All of these comparisons were taken on the larger bore by the way, hence the higher recorded number from the AFR 205. Also, I might add I tested a GM CNC ported LS6 head (LPE stamped in casting), which flowed only 288 CFM at 243 cc's....20 CFM less with almost a 40 cc advantage over the smaller AFR!
I will try and provide more flow comparisons utilizing the exact same flow equipment to be reported over the following weeks and months as the oppurtunities present themselves....I might even try and start a separate post with all the facts and figures.
All numbers posted are taken off an SF600 Superflow, as well as a flowbench I built myself, which I know to be accurate and spits out numbers to the CFM compared to the 600. All figures I quote are taken @ 28" of water, which I feel is a better standard than 25". Also, all my exhaust figures are recorded utilizing a 1.875 "flowtube" which is about 8-9" in total length. It bolts to the exhaust port much like a header and immediatly hooks down and back, closely resembling any primary tube you might find from the various manufacturers....after the turn, the pipe has about a 3-4" section of straight pipe. If you have ever seen an Amduri flow tube, it is basically very similar. All my exhaust ports are optimized and designed that way from their inception so as to try and simulate real world operating conditions when ultimately the heads are sitting between your framerails with a nice long-tube header attached to them.
As far as the flow figures based on a 3.910 bore versus a 3.900 bore....the difference between the two would be just about unrecognizable on the flowbench, assuming you could even locate the heads the exact same for both tests. The additional "shrouding" of the smaller bore is always only half the difference in diameter, so where talking about .005 here....not much more than the thickness of a sheet of average paper. Even a dramatic change 20 times that amount (3.910-4.125) only had an effect no greater than 7 cfm at one particular liftpoint in the curve. I attribute part of that to the fact I designed the chamber around the smaller stock 346 CID bore, assuming thats where most of the 205's would find a home. Our larger 225 will be offered in both small bore and large bore combustion chamber configurations, allowing the end user to choose accordingly based on his application. (The low-lift flow will be significantly better with the larger chamber program).
One more quick point....As it's a known fact that Flowbench's and Dyno's are barometers at best, trying to get accurate, comparable numbers from one to another is almost impossible. The main reason this is so is simply all the variables that come into play during a test session with either. You could have every conceivable variable covered and one dyno might show higher than another because the owner of that dyno took more time in setting up his room and it has better evacuation of spent gases with a very isolated fresh air "hat". Anyway, you get my point....lots of variables come into play flowtesting as well...so lets talk about something more concrete....Net gains (or losses for that matter)
With the same bench and test equipment, AFR recorded that a stock LS1 port flowed 230-235 CFM....the LS6 head flowed 260 CFM (@.550 where it peaked and then went turbulent and lost over 10 cfm @ .600), the new AFR 205 went 308 CFM @ .600, a 70 plus and 40 plus gain respectfully as I had mentioned in a previous post. All of these comparisons were taken on the larger bore by the way, hence the higher recorded number from the AFR 205. Also, I might add I tested a GM CNC ported LS6 head (LPE stamped in casting), which flowed only 288 CFM at 243 cc's....20 CFM less with almost a 40 cc advantage over the smaller AFR!
I will try and provide more flow comparisons utilizing the exact same flow equipment to be reported over the following weeks and months as the oppurtunities present themselves....I might even try and start a separate post with all the facts and figures.
09-29-2003, 10:30 AM
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Re: News on AFR heads ...OK you guys could garner a HUGE portion of the market share for after-market heads...but only if the price is really competitive ...say $1,200-$1,500...
Your estimated selling price seem too high, however???
Your estimated selling price seem too high, however???
09-29-2003, 10:46 AM
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Re: News on AFR heads If these heads are the quality that they appear to be I dont see a problem with the price. And this is coming from someone who is broke trying to rebuild his motor.
09-29-2003, 10:50 AM
#25
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Re: News on AFR heads Wow, 20cfm over the LPE ls6 head is quite impressive. I'd like to see how they stack up against MTI, TEA, AS, and GTP. It might be pretty interesting. What type of gasket are you going to recommend for these heads?
I'd test out a set if you'd like. We'd be able to see how they stack up against TEA S2 5.3's.
I bet we may just see a 500rwhp H/C car by next summer if these heads perform as well as Tony says along with the LSx intake
Keep us posted please,
Matt Vello
mvello@vt.edu
I'd test out a set if you'd like. We'd be able to see how they stack up against TEA S2 5.3's.
I bet we may just see a 500rwhp H/C car by next summer if these heads perform as well as Tony says along with the LSx intake
Keep us posted please,
Matt Vello
mvello@vt.edu
09-29-2003, 04:10 PM
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Re: News on AFR heads Maybe I thick-headed.
I don't understand why I can buy a ported set of AFR heads for a LT1 car or Gen 2 engine for way less than a grand. Why should the aftermarket heads for a LS1/LS6 cost over $2K????
Same deal with stroker crankshafts ....I can buy a Gen 2 crank for under a grand but for a Gen 3 it is almost $2K...
What gives here?
I don't understand why I can buy a ported set of AFR heads for a LT1 car or Gen 2 engine for way less than a grand. Why should the aftermarket heads for a LS1/LS6 cost over $2K????
Same deal with stroker crankshafts ....I can buy a Gen 2 crank for under a grand but for a Gen 3 it is almost $2K...
What gives here?
09-29-2003, 04:15 PM
#27
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Re: News on AFR heads Supply and demand...
Look, it doesn't cost any more to cast the cheapest heads as it does to cast the most expensive one, say a bottom of the line 23^ heads vs an 18^ degree race head. But look at the price delta....
Look, it doesn't cost any more to cast the cheapest heads as it does to cast the most expensive one, say a bottom of the line 23^ heads vs an 18^ degree race head. But look at the price delta....
09-29-2003, 05:45 PM
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Re: News on AFR heads As J-Rod said, it's all about what the market will bear. If no one was willing to pay $2k+ for a set of assembled, ported factory heads, it wouldn't cost that much to get the work done.
10-06-2003, 01:57 PM
#30
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Re: News on AFR heads More from Tony:
I will say with a fair amount of confidence, that if you had the opportunity to flow-test our new 225's versus your current heavily ported stock castings on the same flowbench, you would see that at all the lift-points that really matter (.200-.600), the AFR head would comfortably outflow the modified LS6 head. But even better than that is the fact that the AFR 225 is probably at least 20 cc's smaller than your re-worked stocker, so not only does the motor have the capability to generate more peak HP numbers (lets say 20-30 conservatively if your stock heads were really killer), but the entire power and torque curve BELOW peak power would be up considerably. This is directly a result of the increased “efficiency” of the AFR head. (My definition of “increased efficiency” stemming from much higher port velocity thru the cylinder head, better overall port shapes and contours, superior valve-job “design”, and a new heart shaped combustion chamber design with a double “quench pad” to tie it all in).
Keep in mind guys, the only way to get more airflow thru a smaller hole is to have a much more efficient shaped port that can generate increased port velocity and higher terminal airspeed. (The best situation in the world is to have a port the size of your index finger that flows 600 CFM or so....It's impossible, at least measured @ 28" of water, and I am of course joking, but I'm just trying to emphasize the point I was trying to make).
************************************************** **************
Another BIG point to make here concerning AFR versus LS1/LS6 ported heads...If my hands were tied as a designer/headporter that I could only REMOVE material from a factory casting to try and get more airflow out of it (which is the case of any shop that is offering aftermarket ported castings), there is no way AFR could have ever offered you a cylinder head that is as efficient as the new 205/225 design. It would have been simply impossible....a head porter is only as good as what he has to work with. The factory castings, in my opinion, leave a lot to be desired in terms of there shape, roof height, short turn, etc. that all play into what you can ultimately end up with after spending days or weeks with a grinder. As I have stated in a previous post, I spent more time adding material (in the right places) to dramatically change the port shape and increase the ports ultimate airflow potential…..with the huge secondary benefit resulting in a port that was actually smaller and flowed more air. When placed on a running engine, that’s the “have your cake and it it too” scenario. Generate big bottom end power with the small efficient runner volume and generate big top end power with ultimate airflow potential the new design provides. This kind of situation just can't happen if you start out with the limitations of the OEM ports and combustion chamber design...your final results are ultimately dictated and limited by the shape of the original castings. (Unless of course you start epoxying or welding to add material in the right places which produces questionable results and reliability issues.)
************************************************** **************
Getting back to the original question, hopefully soon we will have actual real-world dyno figures, but what I would expect you to see is a 20-50 HP increase in peak power for normally aspirated applications, and significantly higher numbers from there when you start talking about forced induction or NOS applications (Depending on how good or how bad your factory ported castings flow versus their volume). I would also expect you to see a significant boost over the entire power curve, such that your "average" HP and Torque showed an increase higher than just your "peak" gains. It is this reason why the car will likely perform better at the track (or you favorite stretch of road) than just your peak HP increases might lead you to believe.
The really good news (in my opinion) is the ultimate increased drivability the higher flowing smaller ports will create. It will seem your engine just woke up one morning with another 1/4 inch of stroke to it. Throttle response, higher gear "roll on" grunt, not to mention the ability to knock down better gas mileage if you can bear keeping your foot out of the throttle, will all be available to you with the more efficient smaller port design. This, of course, is only all the fringe benefits....bury the throttle and let all the additional airflow and port velocity work for you, and you will see the "Mr Hyde" part of this equation come to life!!
Bolting on a high flowing head with a small cross-sectional area is one of the few modifications you can do that will have no "downsides" whatsoever to overall engine performance. (the only "downside" might be the lightening of your wallet....but you wont even think about that after your first ride...) The only other engine modification I could think of and say the same about is simply building a larger displacement motor....increasing compression would also generate only "upside" results, however fuel costs play into that with the higher price of the better fuel required with the higher compression ratio.
Alright...this post certainly got a bit out of hand and I apologize for it being so “lengthy”, but I did touch on some important considerations when trying to compare a factory ported head with the new AFR design...and don't forget our crazy overkill build quality!!
Regards to all,
Tony Mamo
PS The gains I have been referencing are considering the airflow and power producing potential of most of the LS6 ported heads. You should see even higher gains if you compare the new AFR heads to ported LS1 or obviously any un-ported LS1/LS6 cylinder head.
------------
Leave it to Erik to ask the good qustions:
RACER7088
Senior Member
83 posts [100%]
Houston Tx
Re: AFR New "LS" Cylinder heads..... (John's vette) 12:05 AM 10/2/2003
Tony,
I don't know about the stock LS6 heads leaving a lot to be desired in port shape or short turn but the the castings when ported extensively become just too weak and eggshell thin to be very long term reliable especially with roller springs. If nothing else the added beef of the AFR castings will help everybody trying to move out with these cars. They can move tremendous air with tiny valves and they make great power.
We've made over 700 hp with the ported stockers so wait until you dyno the AFR stuff before you get too crazy! I'm sure that they will rock as the AFR Ford heads seem to be great and I've used three sets and had exceptional results. We looked at trying to pick up your Windsor 205s but they mapped out at very small and almost right on the money for their size vs their flow. Basically the only way we could make them move more air was to make them bigger so I left them alone except for some very small clean up work. They are definitely very efficient nice street or race heads. We've also had good luck with your AFR 215 RRs and AFR 227 comp ready Chevy heads with just bolting each on and having great results.
No offense but generally people that can't make heads flow are the ones saying it doesn't matter but the truth is that air flow is VERY important especially if you aren't engine speed limited but rather flow limited as most of these street deals are. It also goes without saying that I mean a good port that flows more air not just a bigger port. This isn't particularly directed at AFR but just the head guys that always seem to say that. We've had LSx stuff go over 350 cfm with only 2.080 valves and a 45 degree seat but the price is a fairly thin head left that can barely hold any spring pressure at all without developing cracks etc. If you needed the 350 cfm however you will make more power (bigger inches and/or rpm) but if not it's just a bigger lower velocity head which won't really do anything good.
--------------------------
More from Tony:
OK...OK....Fairly good departure from the current chamber design....Kinda looks like a figure eight in the chamber now....similar to a Yates head. This creates a double quench pad which is always a winner for atomization and making power. The intake port on the 205 has a MUCH higher short turn than stock LS6, with a real straight approach to the back of the valve due to its height. I've also lowered the roof as well....It was taller than it needed to be. Might pull it back a hair on the finished 225, but not much. Between the raised short turn and the lower roof height you would be amazed how small the cross-sectional area is right in front of the short turn....looks much smaller than the factory LS6 and you wouldn't think for a minute the head was capable of 300+ CFM, especially after looking at the stock LS6 port and knowing it was only capable of around 260CFM.
I seriously can't wait to get a set of these bolted on an engine...should be interesting....Want to see airflow theory turn into real world power!!
Regards,
Tony
I will say with a fair amount of confidence, that if you had the opportunity to flow-test our new 225's versus your current heavily ported stock castings on the same flowbench, you would see that at all the lift-points that really matter (.200-.600), the AFR head would comfortably outflow the modified LS6 head. But even better than that is the fact that the AFR 225 is probably at least 20 cc's smaller than your re-worked stocker, so not only does the motor have the capability to generate more peak HP numbers (lets say 20-30 conservatively if your stock heads were really killer), but the entire power and torque curve BELOW peak power would be up considerably. This is directly a result of the increased “efficiency” of the AFR head. (My definition of “increased efficiency” stemming from much higher port velocity thru the cylinder head, better overall port shapes and contours, superior valve-job “design”, and a new heart shaped combustion chamber design with a double “quench pad” to tie it all in).
Keep in mind guys, the only way to get more airflow thru a smaller hole is to have a much more efficient shaped port that can generate increased port velocity and higher terminal airspeed. (The best situation in the world is to have a port the size of your index finger that flows 600 CFM or so....It's impossible, at least measured @ 28" of water, and I am of course joking, but I'm just trying to emphasize the point I was trying to make).
************************************************** **************
Another BIG point to make here concerning AFR versus LS1/LS6 ported heads...If my hands were tied as a designer/headporter that I could only REMOVE material from a factory casting to try and get more airflow out of it (which is the case of any shop that is offering aftermarket ported castings), there is no way AFR could have ever offered you a cylinder head that is as efficient as the new 205/225 design. It would have been simply impossible....a head porter is only as good as what he has to work with. The factory castings, in my opinion, leave a lot to be desired in terms of there shape, roof height, short turn, etc. that all play into what you can ultimately end up with after spending days or weeks with a grinder. As I have stated in a previous post, I spent more time adding material (in the right places) to dramatically change the port shape and increase the ports ultimate airflow potential…..with the huge secondary benefit resulting in a port that was actually smaller and flowed more air. When placed on a running engine, that’s the “have your cake and it it too” scenario. Generate big bottom end power with the small efficient runner volume and generate big top end power with ultimate airflow potential the new design provides. This kind of situation just can't happen if you start out with the limitations of the OEM ports and combustion chamber design...your final results are ultimately dictated and limited by the shape of the original castings. (Unless of course you start epoxying or welding to add material in the right places which produces questionable results and reliability issues.)
************************************************** **************
Getting back to the original question, hopefully soon we will have actual real-world dyno figures, but what I would expect you to see is a 20-50 HP increase in peak power for normally aspirated applications, and significantly higher numbers from there when you start talking about forced induction or NOS applications (Depending on how good or how bad your factory ported castings flow versus their volume). I would also expect you to see a significant boost over the entire power curve, such that your "average" HP and Torque showed an increase higher than just your "peak" gains. It is this reason why the car will likely perform better at the track (or you favorite stretch of road) than just your peak HP increases might lead you to believe.
The really good news (in my opinion) is the ultimate increased drivability the higher flowing smaller ports will create. It will seem your engine just woke up one morning with another 1/4 inch of stroke to it. Throttle response, higher gear "roll on" grunt, not to mention the ability to knock down better gas mileage if you can bear keeping your foot out of the throttle, will all be available to you with the more efficient smaller port design. This, of course, is only all the fringe benefits....bury the throttle and let all the additional airflow and port velocity work for you, and you will see the "Mr Hyde" part of this equation come to life!!
Bolting on a high flowing head with a small cross-sectional area is one of the few modifications you can do that will have no "downsides" whatsoever to overall engine performance. (the only "downside" might be the lightening of your wallet....but you wont even think about that after your first ride...) The only other engine modification I could think of and say the same about is simply building a larger displacement motor....increasing compression would also generate only "upside" results, however fuel costs play into that with the higher price of the better fuel required with the higher compression ratio.
Alright...this post certainly got a bit out of hand and I apologize for it being so “lengthy”, but I did touch on some important considerations when trying to compare a factory ported head with the new AFR design...and don't forget our crazy overkill build quality!!
Regards to all,
Tony Mamo
PS The gains I have been referencing are considering the airflow and power producing potential of most of the LS6 ported heads. You should see even higher gains if you compare the new AFR heads to ported LS1 or obviously any un-ported LS1/LS6 cylinder head.
------------
Leave it to Erik to ask the good qustions:
RACER7088
Senior Member
83 posts [100%]
Houston Tx
Re: AFR New "LS" Cylinder heads..... (John's vette) 12:05 AM 10/2/2003
Tony,
I don't know about the stock LS6 heads leaving a lot to be desired in port shape or short turn but the the castings when ported extensively become just too weak and eggshell thin to be very long term reliable especially with roller springs. If nothing else the added beef of the AFR castings will help everybody trying to move out with these cars. They can move tremendous air with tiny valves and they make great power.
We've made over 700 hp with the ported stockers so wait until you dyno the AFR stuff before you get too crazy! I'm sure that they will rock as the AFR Ford heads seem to be great and I've used three sets and had exceptional results. We looked at trying to pick up your Windsor 205s but they mapped out at very small and almost right on the money for their size vs their flow. Basically the only way we could make them move more air was to make them bigger so I left them alone except for some very small clean up work. They are definitely very efficient nice street or race heads. We've also had good luck with your AFR 215 RRs and AFR 227 comp ready Chevy heads with just bolting each on and having great results.
No offense but generally people that can't make heads flow are the ones saying it doesn't matter but the truth is that air flow is VERY important especially if you aren't engine speed limited but rather flow limited as most of these street deals are. It also goes without saying that I mean a good port that flows more air not just a bigger port. This isn't particularly directed at AFR but just the head guys that always seem to say that. We've had LSx stuff go over 350 cfm with only 2.080 valves and a 45 degree seat but the price is a fairly thin head left that can barely hold any spring pressure at all without developing cracks etc. If you needed the 350 cfm however you will make more power (bigger inches and/or rpm) but if not it's just a bigger lower velocity head which won't really do anything good.
--------------------------
More from Tony:
OK...OK....Fairly good departure from the current chamber design....Kinda looks like a figure eight in the chamber now....similar to a Yates head. This creates a double quench pad which is always a winner for atomization and making power. The intake port on the 205 has a MUCH higher short turn than stock LS6, with a real straight approach to the back of the valve due to its height. I've also lowered the roof as well....It was taller than it needed to be. Might pull it back a hair on the finished 225, but not much. Between the raised short turn and the lower roof height you would be amazed how small the cross-sectional area is right in front of the short turn....looks much smaller than the factory LS6 and you wouldn't think for a minute the head was capable of 300+ CFM, especially after looking at the stock LS6 port and knowing it was only capable of around 260CFM.
I seriously can't wait to get a set of these bolted on an engine...should be interesting....Want to see airflow theory turn into real world power!!
Regards,
Tony
10-06-2003, 11:39 PM
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Re: News on AFR heads Heres another update sorry had to beat ya to it J-ROD
-Rod....Hello
I certainly appreciate you forwarding my information to the LS1 Tech board....and to be honest with you I had anticipated and hoped someone would do that. I have also been following that board and knew at some point I would probably hop on and post a thing or two. To be very honest, it gets to be very time consuming and someone like myself that has a true passion for airflow, engine building, engine theory, POWER...lol....it's very easy to get "sucked in" and half your evening or weekend goes by in front of the computer screen. I figured anyone on the other boards following this information that had pressing questions, concerns, etc., would probably email me or contact me directly @ AFR.
Anyway, thanks again for "spreading the word" so to speak....I was going to post my thoughts on some other issues brought up recently so I guess now is as good a time as any. I had mentioned in a previous post that I thought the factory port design "left alot to be desired"....I feel that statement is a fairly accurate one for the following reasons. With almost identical port volumes, exact same entrance and exit locations and shapes, the new AFR head goes 75 CFM better than an LS1 casting, and 45 CFM better than an LS6 casting (with an even smaller runner!). Certainly the LS6 is a big improvement over the LS1, but anyone that has spent a fair amount of time with a grinder and a flowbench will tell you that those kinds of gains are impressive even if you had increased the volume of the port significantly. Look at the GM/LPE CNC head....287 CFM (on my equipment @ .600) and a whopping 243 cc's. My point is with the new AFR port shape and chamber design showing those kind of gains with virtually the same runner volume, factory location and entrance shape as the stock head, just how efficient are the factory castings?? Certainly you see where I'm coming from...
Now what I did not mean to insinuate is that ALL of the aftermarket "ported" factory castings leave alot to be desired...there are some good flowing heads out there....however, certainly I feel that had the same headporter/tuner started with the new AFR castings, even better results in headflow and ultimately horsepower would have more than likely been achieved. As I have also stated in a previous post, a head porter can only be as good as what he has to work with and in my opinion, working with the factory castings will undoubtedly "tie your hands" to some extent.
Also, I will "stick my neck out" and say that if the current "bar" for a big inch normally aspirated "LS" engine with ported factory heads is around 700 HP for arguments sake, than I do feel the more efficient AFR piece will raise that bar with some significance....Once again, keep an eye out for the "average" power and torque gains across the board...not just the potential increase in peak power. (Jeeez, I hope I'm right or there will be a Corvette "lynch mob" coming after me....lol)
Have more to add, but need to get back to work....J-Rod, if you will kindly pass this along to the LS1 Tech board, I would appreciate it, and if any of you have any questions or something to share, feel free to contact me by telephone or email here at AFR....
My email address is tony@airflowresearch.com Hopefully shortly, I will get signed up on the other board and say hello as well....till then feel free to contact me at AFR....thanks
Regards to all,
Tony Mamo
-Rod....Hello
I certainly appreciate you forwarding my information to the LS1 Tech board....and to be honest with you I had anticipated and hoped someone would do that. I have also been following that board and knew at some point I would probably hop on and post a thing or two. To be very honest, it gets to be very time consuming and someone like myself that has a true passion for airflow, engine building, engine theory, POWER...lol....it's very easy to get "sucked in" and half your evening or weekend goes by in front of the computer screen. I figured anyone on the other boards following this information that had pressing questions, concerns, etc., would probably email me or contact me directly @ AFR.
Anyway, thanks again for "spreading the word" so to speak....I was going to post my thoughts on some other issues brought up recently so I guess now is as good a time as any. I had mentioned in a previous post that I thought the factory port design "left alot to be desired"....I feel that statement is a fairly accurate one for the following reasons. With almost identical port volumes, exact same entrance and exit locations and shapes, the new AFR head goes 75 CFM better than an LS1 casting, and 45 CFM better than an LS6 casting (with an even smaller runner!). Certainly the LS6 is a big improvement over the LS1, but anyone that has spent a fair amount of time with a grinder and a flowbench will tell you that those kinds of gains are impressive even if you had increased the volume of the port significantly. Look at the GM/LPE CNC head....287 CFM (on my equipment @ .600) and a whopping 243 cc's. My point is with the new AFR port shape and chamber design showing those kind of gains with virtually the same runner volume, factory location and entrance shape as the stock head, just how efficient are the factory castings?? Certainly you see where I'm coming from...
Now what I did not mean to insinuate is that ALL of the aftermarket "ported" factory castings leave alot to be desired...there are some good flowing heads out there....however, certainly I feel that had the same headporter/tuner started with the new AFR castings, even better results in headflow and ultimately horsepower would have more than likely been achieved. As I have also stated in a previous post, a head porter can only be as good as what he has to work with and in my opinion, working with the factory castings will undoubtedly "tie your hands" to some extent.
Also, I will "stick my neck out" and say that if the current "bar" for a big inch normally aspirated "LS" engine with ported factory heads is around 700 HP for arguments sake, than I do feel the more efficient AFR piece will raise that bar with some significance....Once again, keep an eye out for the "average" power and torque gains across the board...not just the potential increase in peak power. (Jeeez, I hope I'm right or there will be a Corvette "lynch mob" coming after me....lol)
Have more to add, but need to get back to work....J-Rod, if you will kindly pass this along to the LS1 Tech board, I would appreciate it, and if any of you have any questions or something to share, feel free to contact me by telephone or email here at AFR....
My email address is tony@airflowresearch.com Hopefully shortly, I will get signed up on the other board and say hello as well....till then feel free to contact me at AFR....thanks
Regards to all,
Tony Mamo
10-07-2003, 02:06 AM
#33
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Join Date: Mar 2003
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Re: News on AFR heads J-Rod and Madboost, thanks for the explanation on what AFR is doing. Since you've clearly discovered the same thing we have, I don't mind backing uo what you're saying (cat's out of the bag now). We certainly have seen that the addition of material to certain areas has produced a greater change than simply "hogging-out" the ports. In fact, we've gotten approx 25 ft/lbs from "simply" messing with the area nearer the valves. We're seeing 330 CFM/223 CFM from the LQ9/LS6 heads, and we aren't done.
Can't wait to see the AFR heads. as I am totally with you on the state of the stock castings, puhleeeeze! Thanks for shrouding the #@$&! out of the valves on these heads, Mr. Goodwrench. Have you guys (AFR) done anything in this area?
Can't wait to see the AFR heads. as I am totally with you on the state of the stock castings, puhleeeeze! Thanks for shrouding the #@$&! out of the valves on these heads, Mr. Goodwrench. Have you guys (AFR) done anything in this area?
10-08-2003, 03:14 AM
#36
11 Second Club
Re: News on AFR heads i dont know it would seem like a bit of a waist to slap a beautiful flowing set of heads like this on a stock cam...i would bump up your cam to exploit these heads
10-08-2003, 09:18 AM
#38
6600 rpm clutch dump of death Administrator
Thread Starter
Re: News on AFR heads If it were me, I would consider a cam upgrade, or at least an '02 cam. Here is why.
'01 cam
204/211 .525/.525
vs
'02 cam
204/218 .551/.547
With the 1.85s on the '01 cam you end up with.
206/213 .582/.582
with the '02 cam and 1.85's you end up with
206/220 .599/.595
The lobes aren't as agressive on the 01 and '02 cams as they are on say an XE-R comp lobe. For example, here is a 2002 cam up against a very similar Comp cam with the same VE's but using XE and XE-R lobes.
Quick and Dirty Cam Calculator Spreadsheet
0.006 0.050 0.200
Intake Duration - ID 261 208 128 XE lobe 3707
Exhaust Duration - ED 269 220 143 XE-R lobe 3720
Lobe Center Angle - LCA (also known as LSA) 117 117 117
Intake Centerline - ICL 117.4 118.9 118
Intake Valve opens - IVO 13.1 -14.9 -54 BTDC (- indicates ATDC)
Intake Valve closes - IVC 67.9 42.9 2 ABDC
Exhaust Valve Opens - EVO 71.1 45.1 7.5 BBDC
Exhaust Valve Closes - EVC 17.9 -5.1 -44.5 ATDC (- indicates BTDC)
Exhaust Centerline - ECL 116.6 115.1 116
Overlap 31 -20 -98.5 degrees
0.006 0.050 0.200
Intake Duration - ID 270 204 166.6
Exhaust Duration - ED 275 218 178
Lobe Center Angle - LCA (also known as LSA) 117 117 117
Intake Centerline - ICL 117.4 118.9 118
Intake Valve opens - IVO 17.6 -16.9 -34.7 BTDC (- indicates ATDC)
Intake Valve closes - IVC 72.4 40.9 21.3 ABDC
Exhaust Valve Opens - EVO 74.1 44.1 25 BBDC
Exhaust Valve Closes - EVC 20.9 -6.1 -27 ATDC (- indicates BTDC)
Exhaust Centerline - ECL 116.6 115.1 116
Overlap 38.5 -23 -61.7 degrees
0.006 0.050 0.200
IVO delta -4.5 2 -19.3
IVC delta -4.5 2 -19.3
EVO delta -3 1 -17.5
EVC delta -3 1 -17.5
ECL delta 0 0 0
Overlap -7.5 3 -36.8
So, you get a cam that opens later, but has 3 degrees more overlap. That is not to say the stock cam isn't good, and the stock computer works well with it, but a cam change isn't a bad idea. But, if I was going to swap the heads and throw on a set of 1.85s I'd think about the 2002 cam. The 2001 isn't bad, as you end up with around .580 lift which is nice and safe with a Comp 918 spring, but even with .600 on the intake side, the lobe isn't as agressive, but you'd need to make sure the springs are up to the task. I'd think the 918 would be ok...
But as for HP numbers, that would be a swag, but looking at the numbers AFR is throwing around, I think that should be an achievable goal with bolts ons and headers.
Anyhow....
'01 cam
204/211 .525/.525
vs
'02 cam
204/218 .551/.547
With the 1.85s on the '01 cam you end up with.
206/213 .582/.582
with the '02 cam and 1.85's you end up with
206/220 .599/.595
The lobes aren't as agressive on the 01 and '02 cams as they are on say an XE-R comp lobe. For example, here is a 2002 cam up against a very similar Comp cam with the same VE's but using XE and XE-R lobes.
Quick and Dirty Cam Calculator Spreadsheet
0.006 0.050 0.200
Intake Duration - ID 261 208 128 XE lobe 3707
Exhaust Duration - ED 269 220 143 XE-R lobe 3720
Lobe Center Angle - LCA (also known as LSA) 117 117 117
Intake Centerline - ICL 117.4 118.9 118
Intake Valve opens - IVO 13.1 -14.9 -54 BTDC (- indicates ATDC)
Intake Valve closes - IVC 67.9 42.9 2 ABDC
Exhaust Valve Opens - EVO 71.1 45.1 7.5 BBDC
Exhaust Valve Closes - EVC 17.9 -5.1 -44.5 ATDC (- indicates BTDC)
Exhaust Centerline - ECL 116.6 115.1 116
Overlap 31 -20 -98.5 degrees
0.006 0.050 0.200
Intake Duration - ID 270 204 166.6
Exhaust Duration - ED 275 218 178
Lobe Center Angle - LCA (also known as LSA) 117 117 117
Intake Centerline - ICL 117.4 118.9 118
Intake Valve opens - IVO 17.6 -16.9 -34.7 BTDC (- indicates ATDC)
Intake Valve closes - IVC 72.4 40.9 21.3 ABDC
Exhaust Valve Opens - EVO 74.1 44.1 25 BBDC
Exhaust Valve Closes - EVC 20.9 -6.1 -27 ATDC (- indicates BTDC)
Exhaust Centerline - ECL 116.6 115.1 116
Overlap 38.5 -23 -61.7 degrees
0.006 0.050 0.200
IVO delta -4.5 2 -19.3
IVC delta -4.5 2 -19.3
EVO delta -3 1 -17.5
EVC delta -3 1 -17.5
ECL delta 0 0 0
Overlap -7.5 3 -36.8
So, you get a cam that opens later, but has 3 degrees more overlap. That is not to say the stock cam isn't good, and the stock computer works well with it, but a cam change isn't a bad idea. But, if I was going to swap the heads and throw on a set of 1.85s I'd think about the 2002 cam. The 2001 isn't bad, as you end up with around .580 lift which is nice and safe with a Comp 918 spring, but even with .600 on the intake side, the lobe isn't as agressive, but you'd need to make sure the springs are up to the task. I'd think the 918 would be ok...
But as for HP numbers, that would be a swag, but looking at the numbers AFR is throwing around, I think that should be an achievable goal with bolts ons and headers.
Anyhow....
10-11-2003, 08:46 PM
#39
6600 rpm clutch dump of death Administrator
Thread Starter
Re: News on AFR heads From WA2FAST:
I'm getting my info from the new Corvette Fever magazine, so take it FWIW.
I'm sure the posted flow figures below are from AFR's testing and not an independent source. However, I can say from experience that AFR seems fair when doing their testing, and their products are, quite honestly, second-to-none.
The new head is due out around Jan. '04. Price for the CNC-ported LS205 head (they will also have a 225 head which is designed for big-inch strokers/blower/turbo motors) will be in the $2800 range. However, there won't be a core charge necessary since these are NOT ported LS1/LS6 castings, but rather a completely new head.
A more affordable "as cast" (no CNC porting) will also be offered.
Combustion chamber volume will be either 66cc or 76cc.
The current LS6 head has a chamber of 64.45cc and the LS1 head is 66.6cc. So, to keep compression very close to the current setup, you'd want the 66cc chamber. The 76cc head would be good for a blower/turbo car not wanting to swap out pistons to get lower CR. My educated guess is that this head will lower CR to ~9.7:1. Not really low, but more manageable than bolting on a blower/turbo to a 10.5:1 CR motor.
*My hope is that the deck of these heads is thicker than the stock LS1/LS6 casting. I've learned that our heads do not have really thick decks and this can certainly contribute to lifting head gaskets under severe conditions (cylinder pressure).*
Another great thing is that while the AFR intake runner is only 205cc (smaller than the LS6's 211cc and a CNC ported LS6 head which is ~243cc) it will flow MORE than either of these AND since it can do it through a smaller port...guess what? Air velocity goes UP! Hello low, mid-range TQ! So this will be the best of both worlds. Better low-end TQ and more top-end HP.
Here are the flow #s:
INTAKE
Lift LS1 LS6 CNC LS6 AFR 205
.200 136 137 142 144
,300 196 188 209 208
.400 217 233 257 255
.500 224 260 283 287
.550 227 245 286 296
.600 230 245 287 302
.650 233 245 289 304
EXHAUST
Lift LS1 LS6 CNC LS6 AFR 205
.200 108 116 118 116
.300 145 153 156 170
.400 170 175 189 206
.500 186 193 220 221
.550 192 199 227 227
.600 198 200 231 232
.650 200 202 233 236
Again, looking at the figures (and this is the smaller 205 head), even if the #s are just = that of ported heads, remember that since they are flowing this well through a smaller port... efficiency is better and velocity is higher which = more power.
I am going to get in touch with AFR as soon as I can. I talked with Tony (the guy who develops/designs their heads) about 2 months ago and he has a C5 and was working on the R&D at the time.
I'm getting my info from the new Corvette Fever magazine, so take it FWIW.
I'm sure the posted flow figures below are from AFR's testing and not an independent source. However, I can say from experience that AFR seems fair when doing their testing, and their products are, quite honestly, second-to-none.
The new head is due out around Jan. '04. Price for the CNC-ported LS205 head (they will also have a 225 head which is designed for big-inch strokers/blower/turbo motors) will be in the $2800 range. However, there won't be a core charge necessary since these are NOT ported LS1/LS6 castings, but rather a completely new head.
A more affordable "as cast" (no CNC porting) will also be offered.
Combustion chamber volume will be either 66cc or 76cc.
The current LS6 head has a chamber of 64.45cc and the LS1 head is 66.6cc. So, to keep compression very close to the current setup, you'd want the 66cc chamber. The 76cc head would be good for a blower/turbo car not wanting to swap out pistons to get lower CR. My educated guess is that this head will lower CR to ~9.7:1. Not really low, but more manageable than bolting on a blower/turbo to a 10.5:1 CR motor.
*My hope is that the deck of these heads is thicker than the stock LS1/LS6 casting. I've learned that our heads do not have really thick decks and this can certainly contribute to lifting head gaskets under severe conditions (cylinder pressure).*
Another great thing is that while the AFR intake runner is only 205cc (smaller than the LS6's 211cc and a CNC ported LS6 head which is ~243cc) it will flow MORE than either of these AND since it can do it through a smaller port...guess what? Air velocity goes UP! Hello low, mid-range TQ! So this will be the best of both worlds. Better low-end TQ and more top-end HP.
Here are the flow #s:
INTAKE
Lift LS1 LS6 CNC LS6 AFR 205
.200 136 137 142 144
,300 196 188 209 208
.400 217 233 257 255
.500 224 260 283 287
.550 227 245 286 296
.600 230 245 287 302
.650 233 245 289 304
EXHAUST
Lift LS1 LS6 CNC LS6 AFR 205
.200 108 116 118 116
.300 145 153 156 170
.400 170 175 189 206
.500 186 193 220 221
.550 192 199 227 227
.600 198 200 231 232
.650 200 202 233 236
Again, looking at the figures (and this is the smaller 205 head), even if the #s are just = that of ported heads, remember that since they are flowing this well through a smaller port... efficiency is better and velocity is higher which = more power.
I am going to get in touch with AFR as soon as I can. I talked with Tony (the guy who develops/designs their heads) about 2 months ago and he has a C5 and was working on the R&D at the time.
