AFR heads available soon!
10-20-2003, 09:50 AM
#41
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Re: AFR heads available soon! Beast96Z, hmm interesting. I guess I was looking at LS1/LS6 5.7l heads. I didn't realize the 5.3s came with such small ports from the factory. VERY INTERSTING!!!
10-20-2003, 10:21 AM
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Re: AFR heads available soon! Here's my post from one of those threads...
"$2800 is a no-go for me for the CNC heads.
Given the differences in flow benches, my admittedly uninformed opinion would be that they aren't demonstrating a significant advantage over the Patriot LS6 style heads... which are $1000 less.
Get them under $2000 for the CNC ported 205's and you might have something there, but at this point I honestly can't see why I would get worked up about them given what else is currently available.
Would some experts chime in and tell me where I have this wrong? "
Now, I guess they are $2450 for the ported version, but one thing that has not been clarified is whether or not the versions in the information posted are the CNC ported or the "as-cast" 205's.
If "as cast" they flow the numbers shown (which are very comparable to a relatively weak S2 CNC head), then we can expect a considerable jump for the CNC head.
If the CNC AFR head is running neck and neck with the S2 head chosen (which ain't the best S2 head out there for flow), then I fail to see the advantage, especially in light of the price.
BTW: I priced other AFR heads out of a magazine this morning. $1200 for LT1's (if memory serves). Now, relative to economy of scale, the LS1 has is all over the LT1 since it is shared with the truck family, so the market is much bigger. There is no good reason in the world for the as-cast head to be more expensive than an LT1 head.
Cripes almighty. Given an AFR CNC head that significantly out-flows the S2 heads out there (the real ones) at $1800, AFR would own the LS1 world. At $2000, they would still own the world given a better head.
Instead, we're quoted ~$2450 - which is right in line with the BBC heads, which have a TON more material in them and would therefore require more machining time.
Straighten the pricing out gentlemen or make a solid case for a $600 premium over the benchmark cost/performance head out there.... please. If the CNC head can't show a significant advantage over the better S2 heads out there available at less than $2200, you're in deep kimchee.
"$2800 is a no-go for me for the CNC heads.
Given the differences in flow benches, my admittedly uninformed opinion would be that they aren't demonstrating a significant advantage over the Patriot LS6 style heads... which are $1000 less.
Get them under $2000 for the CNC ported 205's and you might have something there, but at this point I honestly can't see why I would get worked up about them given what else is currently available.
Would some experts chime in and tell me where I have this wrong? "
Now, I guess they are $2450 for the ported version, but one thing that has not been clarified is whether or not the versions in the information posted are the CNC ported or the "as-cast" 205's.
If "as cast" they flow the numbers shown (which are very comparable to a relatively weak S2 CNC head), then we can expect a considerable jump for the CNC head.
If the CNC AFR head is running neck and neck with the S2 head chosen (which ain't the best S2 head out there for flow), then I fail to see the advantage, especially in light of the price.
BTW: I priced other AFR heads out of a magazine this morning. $1200 for LT1's (if memory serves). Now, relative to economy of scale, the LS1 has is all over the LT1 since it is shared with the truck family, so the market is much bigger. There is no good reason in the world for the as-cast head to be more expensive than an LT1 head.
Cripes almighty. Given an AFR CNC head that significantly out-flows the S2 heads out there (the real ones) at $1800, AFR would own the LS1 world. At $2000, they would still own the world given a better head.
Instead, we're quoted ~$2450 - which is right in line with the BBC heads, which have a TON more material in them and would therefore require more machining time.
Straighten the pricing out gentlemen or make a solid case for a $600 premium over the benchmark cost/performance head out there.... please. If the CNC head can't show a significant advantage over the better S2 heads out there available at less than $2200, you're in deep kimchee.
10-21-2003, 01:20 AM
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Re: AFR heads available soon! PacerX-although your username is a nightmare reminder, I do agree with the no need for a LS1 Premium, what helps is the LS6 crowd, easy to overcharge parts for guys that pay excessive amounts for a vette! NEWay, between the name, AFR, premium and ours LSx it is hard to accept. BUT, I called AFR and spoke with a tech, I was told that the CNC ported version still holds quite a bit of material for hand finishing, or more porting which would mean the heads can still WAY outflow anything we currently have, sans the C5R, unsure about those flows numbers.
Once the track testing is done, and compared to other heads and the potential is there, then we can celebrate, til then stay skeptical.
Once the track testing is done, and compared to other heads and the potential is there, then we can celebrate, til then stay skeptical.
10-21-2003, 02:25 AM
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Re: AFR heads available soon! If these heads really can flow more/have more velocity than a good s2 ported head then I would probably be interested in a set especially since they can be ported themselves. We definetly need to see these in action though before making a firm decision.
10-21-2003, 08:22 AM
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Re: AFR heads available soon! We can speculate, but I think we are going to have to wait until these heads are on the market, and have been installed by a few brave, wealthy,
enthusiasists to come to any real conclusion. The budget minded enthusiasts will have to chew on this for a while.
enthusiasists to come to any real conclusion. The budget minded enthusiasts will have to chew on this for a while.
10-21-2003, 08:41 AM
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Re: AFR heads available soon! the as cast versions are 200cc, cnc ported are 205cc (the 300cfm ones) and the 225's are for bigger motors and flow numbers werent released for them from what ive been reading about the afr stuff on this board.
10-21-2003, 10:24 AM
#47
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Re: AFR heads available soon! The most common mistake racers make when selecting cylinder heads is to choose ports that are too big for the engine displacement. Racers have a tendency to believe "bigger is better," but that is usually not true when it comes to runner volumes. If you are debating between heads with different port sizes, my advice is to choose the smaller runners. During a typical gear change, the engine speed drops 1500 to 2000 rpm in less than .05 seconds. This rapid change in engine speed can disturb the entire intact tract, so it is essential to keep the velocity of the intake charge as high as possible during these transitions. That's why I advocate a conservative approach when choosing cylinder heads, intake manifolds, and carburetors. Smaller is often faster. Oversized ports can make an engine sluggish and unresponsive, and that's not what you want when you're trying to judge both your opponent and the finish line. If you're a heads-up racer, you need an engine that's sharp when it comes off the throttle stop. Having the right cylinder heads is as crucial for consistency as using the right converter and carburetor. Used wisely, a flow bench can be a useful tool in engine development, just like a timing light or a dynamometer. Unfortunately, some racers believe that a flow bench is the ultimate answer machine. When the subject is cylinder heads, the four words I dread to hear are, "What do they flow?" Novice racers and magazine writers share a fixation about airflow. The mistaken belief that "more is better" is often the false assumption that produces an underperforming engine. A flow bench measures air movement in a very rudimentary way - steady-state flow at a constant depression (vacuum). Obviously the conditions that exist inside a running engine are quite different. The flow bench can't simulate the effects of the pistons going up and down, the reversion pulses as the valves open and close, the sonic waves that resonate inside the runners, the inertia of the fuel droplets, and all of the other phenomena that influence engine performance in the real world. When you flow test a cylinder head, you are simply measuring how far you can move the liquid in a manometer. The bigger you make a port, the more it flows. That's hardly shocking news. Bolt a sewer pipe onto a flow bench and it will generate terrific flow numbers. So should we use ports as big as sewer pipes on our race cars? The flow bench says we should - the time slip says something completely different. If airflow were everything, we would all use the longest duration camshafts we could find - after all, more duration means more flow. In fact we know that there is a finite limit to how long the valves can be open before performance suffers. That is because the valve events have to be in harmony with the rest of the engine. The same principle applies to cylinder heads. Simple airflow capacity should never be the first consideration in evaluating cylinder heads. Characteristics that are far more important include air speed, port cross section, port volume and shape, and the relationship between the size of the throat and the valve seat. If these attributes are wrong, you can work forever on the flow bench and not overcome the fundamental flaws. Here is a do-it-yourself example: Turn on a garden hose and the water will dribble out a couple of feet. Now put a nozzle on the hose and the water will spray across your backyard. The water pressure and volume haven't changed, but the velocity has increased dramatically. Now think about the air and fuel going into your engine's cylinders. Which would you prefer: slow and lazy or fast and responsive? An engineer will tell you that an engine requires a prescribed amount of air and fuel to produce "X" horsepower. In a perfect world, that may be true - but we race with imperfect engines. The shape and cross-sectional area of the runners are absolutely critical to performance. am not against flow benches. What I am against is over reliance on flow numbers as the primary measurement of a cylinder head's performance. A flow bench is a valuable tool that can help a racer fine tune a combination - but it is not the ultimate authority.
10-21-2003, 10:36 AM
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Re: AFR heads available soon!
"HELLO AFR? Anybody listening? A head that flows +300 cfm at .600 lift is available right now for $1800 with no core charge."
may i ask which head is this. i'm not saing that i dont belive but i am just intereasted in who offers these heads.
may i ask which head is this. i'm not saing that i dont belive but i am just intereasted in who offers these heads.
The heads that are on my car. Patriot LS6 style.
I'm anxious for these new heads to come out and see if they live up to the high expectations.
10-21-2003, 06:56 PM
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Re: AFR heads available soon!
The most common mistake racers make when selecting cylinder heads is to choose ports that are too big for the engine displacement. Racers have a tendency to believe "bigger is better," but that is usually not true when it comes to runner volumes. If you are debating between heads with different port sizes, my advice is to choose the smaller runners. During a typical gear change, the engine speed drops 1500 to 2000 rpm in less than .05 seconds. This rapid change in engine speed can disturb the entire intact tract, so it is essential to keep the velocity of the intake charge as high as possible during these transitions. That's why I advocate a conservative approach when choosing cylinder heads, intake manifolds, and carburetors. Smaller is often faster. Oversized ports can make an engine sluggish and unresponsive, and that's not what you want when you're trying to judge both your opponent and the finish line. If you're a heads-up racer, you need an engine that's sharp when it comes off the throttle stop. Having the right cylinder heads is as crucial for consistency as using the right converter and carburetor. Used wisely, a flow bench can be a useful tool in engine development, just like a timing light or a dynamometer. Unfortunately, some racers believe that a flow bench is the ultimate answer machine. When the subject is cylinder heads, the four words I dread to hear are, "What do they flow?" Novice racers and magazine writers share a fixation about airflow. The mistaken belief that "more is better" is often the false assumption that produces an underperforming engine. A flow bench measures air movement in a very rudimentary way - steady-state flow at a constant depression (vacuum). Obviously the conditions that exist inside a running engine are quite different. The flow bench can't simulate the effects of the pistons going up and down, the reversion pulses as the valves open and close, the sonic waves that resonate inside the runners, the inertia of the fuel droplets, and all of the other phenomena that influence engine performance in the real world. When you flow test a cylinder head, you are simply measuring how far you can move the liquid in a manometer. The bigger you make a port, the more it flows. That's hardly shocking news. Bolt a sewer pipe onto a flow bench and it will generate terrific flow numbers. So should we use ports as big as sewer pipes on our race cars? The flow bench says we should - the time slip says something completely different. If airflow were everything, we would all use the longest duration camshafts we could find - after all, more duration means more flow. In fact we know that there is a finite limit to how long the valves can be open before performance suffers. That is because the valve events have to be in harmony with the rest of the engine. The same principle applies to cylinder heads. Simple airflow capacity should never be the first consideration in evaluating cylinder heads. Characteristics that are far more important include air speed, port cross section, port volume and shape, and the relationship between the size of the throat and the valve seat. If these attributes are wrong, you can work forever on the flow bench and not overcome the fundamental flaws. Here is a do-it-yourself example: Turn on a garden hose and the water will dribble out a couple of feet. Now put a nozzle on the hose and the water will spray across your backyard. The water pressure and volume haven't changed, but the velocity has increased dramatically. Now think about the air and fuel going into your engine's cylinders. Which would you prefer: slow and lazy or fast and responsive? An engineer will tell you that an engine requires a prescribed amount of air and fuel to produce "X" horsepower. In a perfect world, that may be true - but we race with imperfect engines. The shape and cross-sectional area of the runners are absolutely critical to performance. am not against flow benches. What I am against is over reliance on flow numbers as the primary measurement of a cylinder head's performance. A flow bench is a valuable tool that can help a racer fine tune a combination - but it is not the ultimate authority.
10-21-2003, 09:15 PM
#50
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Re: AFR heads available soon! "Here is a do-it-yourself example: Turn on a garden hose and the water will dribble out a couple of feet. Now put a nozzle on the hose and the water will spray across your backyard. The water pressure and volume haven't changed, but the velocity has increased dramatically."
Wrong.
Volume drops.
There is no such thing as a free lunch in fluid dynamics. You get the added velocity by increasing effective pressure through introducing a restriction.
Wrong.
Volume drops.
There is no such thing as a free lunch in fluid dynamics. You get the added velocity by increasing effective pressure through introducing a restriction.
10-21-2003, 10:13 PM
#51
Re: AFR heads available soon! Pacerx, be ready to back that up...sure pressure is built, but then becomes static and once the pressure is built to "x" the volume increases to its origional "drip" volume. Not trying to be an expert, and this may not be true in all cases, but it is in some, depending on what is supplying the pressure and if it can be held back by the restriction. Sometimes the restriction it takes to increase velocity is not enough to effectively slow the volume for a sustained period of time. I have NO idea which would take place inside a LS1.
Either way, I'll be ..as some stated above, both a knucklehead and an "idiot"...not because its necessarily a wise decision, but because I want to. Why? The same motivation that keeps me in this wacky world of LS1 overpriced modding. I know, that at any day, I can change my mind, accept my losses, ditch the stuff, and buy a cabbage patch kid or whatever turns me on at the time.
The only logical reason I have placed a pre-order (CNC 205's thru EDC) is I hope to see 15-25lbs boost and the deck thickness sounds good. The rest is based in hope. Yes I gamble.
As always, in the world of cars, and especially LS1's, I reseve the right to change my mind at any given moment....until the money order is sent.
J-
Either way, I'll be ..as some stated above, both a knucklehead and an "idiot"...not because its necessarily a wise decision, but because I want to. Why? The same motivation that keeps me in this wacky world of LS1 overpriced modding. I know, that at any day, I can change my mind, accept my losses, ditch the stuff, and buy a cabbage patch kid or whatever turns me on at the time.
The only logical reason I have placed a pre-order (CNC 205's thru EDC) is I hope to see 15-25lbs boost and the deck thickness sounds good. The rest is based in hope. Yes I gamble.
As always, in the world of cars, and especially LS1's, I reseve the right to change my mind at any given moment....until the money order is sent.
J-
10-21-2003, 10:56 PM
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Re: AFR heads available soon!
Pacerx, be ready to back that up...sure pressure is built, but then becomes static and once the pressure is built to "x" the volume increase to its origional "drip" volume. Not trying to be an expert, and this may not be true in all cases, but it is in some, depending on what is supplying the pressure and if it can be held back by the restriction....
erh, but I'm guessing no one really cares that much about the "finger over the hose" analogy.
as I stated before, I think its silly to buy something that hasn't come out yet. But hey, someone has to be the guinea pig! might as well not be me! heh. jk. I have alot of faith in AFR, but until there are some actual numbers out there I'm keeping my credit card in my wallet.
I can't wait to see some independent flow tests of the AFR heads back to back with some of the other stageII heads out there. I think the next few months are going to be VERY interesting with the advent of the LSX intake, and the AFR heads.
10-22-2003, 12:56 AM
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Re: AFR heads available soon!
I think the next few months are going to be VERY interesting with the advent of the LSX intake, and the AFR heads.
. The longer I wait more new and better hardware keeps being released. At this rate I'll never touch the engine! 
Understanding basic engineering principals is great but theory is only going to get you so far. I want to see results!! Track times, dyno numbers on modified and stock cars is what I am personally waiting for.
10-22-2003, 01:31 AM
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Re: AFR heads available soon! And heres a real kick in the jimmy:
It seems that what works well on your car and combo, may not be so hot on mine even when we have the same cams, etc.... Look at all the different combos, why so many? Not because I want to be different, but your "X" didnt work for me, then of course is brand loyalty etc... These heads will no doubt match the performance of MTI, currently the money grabber heads right now. So, they may work well on your X cammed etc...but not so on mine, or maybe more so...As long as they dont fall on their faces, which i tend to doubt highly coming from AFR, they will be bought in mass just like everything else hear. Look at Patriot, sooo many people doubted these heads, their price, the quality etc...hell the heads are good, yep had a little problem with retainers and stuff.....BUT I believe all the problems were fixed more than satisfactorily.
It seems that what works well on your car and combo, may not be so hot on mine even when we have the same cams, etc.... Look at all the different combos, why so many? Not because I want to be different, but your "X" didnt work for me, then of course is brand loyalty etc... These heads will no doubt match the performance of MTI, currently the money grabber heads right now. So, they may work well on your X cammed etc...but not so on mine, or maybe more so...As long as they dont fall on their faces, which i tend to doubt highly coming from AFR, they will be bought in mass just like everything else hear. Look at Patriot, sooo many people doubted these heads, their price, the quality etc...hell the heads are good, yep had a little problem with retainers and stuff.....BUT I believe all the problems were fixed more than satisfactorily.
10-23-2003, 12:20 AM
#55
Re: AFR heads available soon! We are now taking orders to provide you with one of the first sets that become available.
Tom
BTW the LT1 stuff starts at $1900 and goes up to around $2600 so we are in the same ball park here.
Bret
10-23-2003, 02:11 AM
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Re: AFR heads available soon! SStrokerAce
On corvetteforum.com the onwer of AFR posted about the initial release date not being feasible. He corrected TByrne but was unable to inform him before he posted.
On corvetteforum.com the onwer of AFR posted about the initial release date not being feasible. He corrected TByrne but was unable to inform him before he posted.
10-28-2003, 02:00 PM
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Just like you were going to be the first company to have the NXL kits right
Vendors ended up getting 1 or 2 instead of large shipments. The LS1 AFR heads should be out around the 1st of the year but as with all new products, that could change. I'm working on getting some flow numbers to compare the two versions.
Tom
