Head comp. Ported AFR 225's vs. stock 205's.
07-26-2007, 04:55 PM
#1
Head comp. Ported AFR 225's vs. stock 205's. This post is informational only. It is not made to say one is better than the other. It is simply to see which will make more power and explore some theories.
I have two sets of AFR heads right now. One is an unported 59cc AFR 205. The other is a set of 55cc AFR small bore 225's that have been ported to 252cc by a supporting Vendor that will remain nameless. I was kind of shocked at the results in flow numbers.
Both heads were flowed on the same day with the same radius inlet and no exhaust flow tube. They were flowed on a 4.155 bore with a 6.0l head gasket. Here are the flow results.
AFR 59cc 205cc runner, 2.02 intake, 1.60 exh
int.----------------exh.
.100----76.7------.100----69.5
.200---144.4------.200---120
.300---202--------.300---161
.400---252--------.400---194.3
.500---284--------.500---214.8
.600---304--------.600---224
.650---295--------.650---227
AFR 55cc 252cc runner, 2.08 intake, 1.60 exh.
int.----------------exh.
.100----76.7------.100----66.3
.200---146--------.200---113.7
.300---203.5------.300---156.4
.400---259.6------.400---195.5
.500---306.3------.500---216.4
.600---328.5------.600---229.1
.650---330.7------.650---233.8
I have a 12.0:1 compression fully forged 383 with every bolt on except an EWP. The cam I am running is a comp 239/244 .651//612 112+2. Which head do you all think will make more power and be faster. I will have dyno and track numbers in the next week or so.
Brett
I have two sets of AFR heads right now. One is an unported 59cc AFR 205. The other is a set of 55cc AFR small bore 225's that have been ported to 252cc by a supporting Vendor that will remain nameless. I was kind of shocked at the results in flow numbers.
Both heads were flowed on the same day with the same radius inlet and no exhaust flow tube. They were flowed on a 4.155 bore with a 6.0l head gasket. Here are the flow results.
AFR 59cc 205cc runner, 2.02 intake, 1.60 exh
int.----------------exh.
.100----76.7------.100----69.5
.200---144.4------.200---120
.300---202--------.300---161
.400---252--------.400---194.3
.500---284--------.500---214.8
.600---304--------.600---224
.650---295--------.650---227
AFR 55cc 252cc runner, 2.08 intake, 1.60 exh.
int.----------------exh.
.100----76.7------.100----66.3
.200---146--------.200---113.7
.300---203.5------.300---156.4
.400---259.6------.400---195.5
.500---306.3------.500---216.4
.600---328.5------.600---229.1
.650---330.7------.650---233.8
I have a 12.0:1 compression fully forged 383 with every bolt on except an EWP. The cam I am running is a comp 239/244 .651//612 112+2. Which head do you all think will make more power and be faster. I will have dyno and track numbers in the next week or so.
Brett
Last edited by Pray; 07-26-2007 at 05:22 PM.
07-26-2007, 05:32 PM
#4
IMO, those large valved 225s with a chamber that small opening up on a 3.905" bore are going to be shrouded pretty bad in the low and mid-lifts. They may actually flow worse on a 3.900" bore fixture than the 205s do. Since the hogged out 225s do not flow better until .500", I would expect that the 205s with the smaller intake valves would make at least the same power, if not more...all with better throttle response. Airspeed means a lot in this application.
We picked up power by going to smaller intake valves and better mid-lift flow by swapping from the large valved 225s.
We picked up power by going to smaller intake valves and better mid-lift flow by swapping from the large valved 225s.
__________________
2013 Corvette Grand Sport A6 LME forged 416, Greg Good ported TFS 255 LS3 heads, 222/242 .629"/.604" 121LSA Pat G blower cam, ARH 1 7/8" headers, ESC Novi 1500 Supercharger w/8 rib direct drive conversion, 747rwhp/709rwtq on 93 octane, 801rwhp/735rwtq on race fuel, 10.1 @ 147.25mph 1/4 mile, 174.7mph Half Mile.
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2023 Corvette 3LT Z51 soon to be modified.
Custom LSX tuning in person or via email press here.
2013 Corvette Grand Sport A6 LME forged 416, Greg Good ported TFS 255 LS3 heads, 222/242 .629"/.604" 121LSA Pat G blower cam, ARH 1 7/8" headers, ESC Novi 1500 Supercharger w/8 rib direct drive conversion, 747rwhp/709rwtq on 93 octane, 801rwhp/735rwtq on race fuel, 10.1 @ 147.25mph 1/4 mile, 174.7mph Half Mile.
2016 Corvette Z51 M7 Magnuson Heartbeat 2300 supercharger, TSP LT headers, Pat G tuned, 667rwhp, 662rwtq, 191mph TX Mile.
2009.5 Pontiac G8 GT 6.0L, A6, AFR 230v2 heads. 506rwhp/442rwtq. 11.413 @ 121.29mph 1/4 mile, 168.7mph TX Mile
2000 Pewter Ram Air Trans Am M6 heads/cam 508 rwhp/445 rwtq SAE, 183.092 TX Mile
2022 Cadillac Escalade 6.2L A10 S&B CAI, Corsa catback.
2023 Corvette 3LT Z51 soon to be modified.
Custom LSX tuning in person or via email press here.
07-26-2007, 05:42 PM
#5
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why flow on the fixture?
The flow number are kinda useless for a 383 motor with a 3.905 bore. Unless you have like a 4.100 all bore stock stroke setup.
I would use the 205's myself.
The flow number are kinda useless for a 383 motor with a 3.905 bore. Unless you have like a 4.100 all bore stock stroke setup.
I would use the 205's myself.
07-26-2007, 06:20 PM
#7
The flow information (comparison) should have been done on the correct bore size as others touched on. While the flow numbers from the large runner (when tested utilizing the large bore fixture) certainly look strong, their meaningless for an application that has a quarter inch smaller bore. What you will see is the larger head get hurt more when they are both tested on the same (very small) 3.900 bore. The larger valve will be much more crowded and the .125 lip from bore to chamber wont help either (small mismatch is OK....thats getting significant). How much will the larger head be hurt is anybody's guess. It wont be a fixed number....some lifts will be more effected than others.
Also, unless a very good flowing manifold is placed in front of the big head, alot of the larger airflow gains wont be realized with the similar net airflow moving more slowly thru a much larger cross section....that is not a situation thats condusive to power.
Im not saying the larger head wont make more power....just stating these are some of the things to be concerned with. I would have liked to have tested that head against something similar I did for Patrick....a small port with huge low and midlift numbers when tested on the appropriate 3.900 bore. That would have been interesting.
Im certainly looking foward to the results....should be very interesting. If this were a larger displacement engine with at least a 4" bore I think the bigger head in this test would have been a shoe in, but the 3.900 bore 383 cube makes this test very interesting.
I'll be subscribing...
Regards,
Tony
Also, unless a very good flowing manifold is placed in front of the big head, alot of the larger airflow gains wont be realized with the similar net airflow moving more slowly thru a much larger cross section....that is not a situation thats condusive to power.
Im not saying the larger head wont make more power....just stating these are some of the things to be concerned with. I would have liked to have tested that head against something similar I did for Patrick....a small port with huge low and midlift numbers when tested on the appropriate 3.900 bore. That would have been interesting.
Im certainly looking foward to the results....should be very interesting. If this were a larger displacement engine with at least a 4" bore I think the bigger head in this test would have been a shoe in, but the 3.900 bore 383 cube makes this test very interesting.
I'll be subscribing...
Regards,
Tony
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07-26-2007, 07:17 PM
#8
Thanks for the input guys. I know the big heads made 550rwhp on a 347 before I got them. They were ported for a 3.90 bore. They are the small bore 225's and I don't think the chamber has been opened up. The chamber still fits all with in my head gasket. The guy that flowed them pointed out the restriction on the exhaust and said if I opened up the chamber I would gain alot. He flowed the heads on the smallest fixture he had so I can't do any thing about that. We did use a 6.0L gasket to try to shrink the bore some. He also did not have a flow tube for the exhaust. I was told that the exhaust was ported for a tube and would pick up substantialy with one. But I think both heads would pick up substantialy with a flow tube. I tried to keep the test as fair and impartial as possible. Both heads were flowed exactly the same on the same day.
The plan is to run these heads on a 427-440 engine in the future. I am trying to build my top end for that upcomming larger motor. I am just stuck with a 383 for right now. They were also basicly free. I got a ported 90/90 from a friend in trade for some work so the intake is taken care of. The only bolt on I am missing is an EWP. I have an awsome set of headers now thanks to Tony, so this thing will only be limited by the heads. I was making around 480/455rw with the 205's and LS6 intake.
To tell the truth I was dissapointed in the big heads flow numbers. I was especially dissapointed when I saw the size of the intake runner. I didn't even bother ccing the exhaust. It has alot of porting done there as well. But the flow numbers are almost exactly the same as the 205's.
I was told by the porter and the engine builder that originaly had them ported that flow numbers aren't everything. We will see. Like I said I will have these heads on the car this weekend and get it street tuned with my WB and EFI live. I will try to hit a dyno next weekend for some tangible results. Then to the track middle of next week.
The plan is to run these heads on a 427-440 engine in the future. I am trying to build my top end for that upcomming larger motor. I am just stuck with a 383 for right now. They were also basicly free. I got a ported 90/90 from a friend in trade for some work so the intake is taken care of. The only bolt on I am missing is an EWP. I have an awsome set of headers now thanks to Tony, so this thing will only be limited by the heads. I was making around 480/455rw with the 205's and LS6 intake.
To tell the truth I was dissapointed in the big heads flow numbers. I was especially dissapointed when I saw the size of the intake runner. I didn't even bother ccing the exhaust. It has alot of porting done there as well. But the flow numbers are almost exactly the same as the 205's.
I was told by the porter and the engine builder that originaly had them ported that flow numbers aren't everything. We will see. Like I said I will have these heads on the car this weekend and get it street tuned with my WB and EFI live. I will try to hit a dyno next weekend for some tangible results. Then to the track middle of next week.
Last edited by Pray; 07-26-2007 at 07:32 PM.
07-26-2007, 07:47 PM
#9
Originally Posted by Pray
Thanks for the input guys. I know the big heads made 550rwhp on a 347 before I got them. They were ported for a 3.90 bore. The guy that flowed them only had a fixture down to 4.155" so I can't do any thing about that. We did use a 6.0L gasket to try to shrink the bore some. He also did not have a flow tube for the exhaust. I was told that the exhaust was ported for a tube and would pick up substantialy with one. But I think both heads would pick up substantialy with a flow tube. I tried to keep the test as fair and impartial as possible. Both heads were flowed exactly the same on the same day.
The plan is to run these heads on a 427-440 engine in the future. I am trying to build my top end for that upcomming larger motor. I am just stuck with a 383 for right now. They were also basicly free. I got a ported 90/90 from a friend in trade for some work so the intake is taken care of. The only bolt on I am missing is an EWP. I have an awsome set of headers now thanks to Tony, so this thing will only be limited by the heads. I was making around 480/455rw with the 205's and LS6 intake.
To tell the truth I was dissapointed in the big heads flow numbers. I was especially dissapointed when I saw the size of the intake runner. I didn't even bother ccing the exhaust. It has alot of porting done there as well. But the flow numbers are almost exactly the same as the 205's.
I was told by the porter and the engine builder that originaly had them ported that flow numbers aren't everything. We will see. Like I said I will have these heads on the car this weekend and get it street tuned with my WB and EFI live. I will try to hit a dyno next weekend for some tangible results. Then to the track middle of next week.
The plan is to run these heads on a 427-440 engine in the future. I am trying to build my top end for that upcomming larger motor. I am just stuck with a 383 for right now. They were also basicly free. I got a ported 90/90 from a friend in trade for some work so the intake is taken care of. The only bolt on I am missing is an EWP. I have an awsome set of headers now thanks to Tony, so this thing will only be limited by the heads. I was making around 480/455rw with the 205's and LS6 intake.
To tell the truth I was dissapointed in the big heads flow numbers. I was especially dissapointed when I saw the size of the intake runner. I didn't even bother ccing the exhaust. It has alot of porting done there as well. But the flow numbers are almost exactly the same as the 205's.
I was told by the porter and the engine builder that originaly had them ported that flow numbers aren't everything. We will see. Like I said I will have these heads on the car this weekend and get it street tuned with my WB and EFI live. I will try to hit a dyno next weekend for some tangible results. Then to the track middle of next week.
No matter how you slice it this will be a really interesting test...will the compression be exactly the same?? Thats important....
Also, considering the mill, the peak flownumbers you have look a bit better.
Tony
07-26-2007, 09:29 PM
#10
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550 on a 347 explain?
Solid roller?
If not then I am a non believer.
I am interested to see the results as well. There should be a gain switching to the ported 90 and IMO I would have to keep the LS6 on until you made a hit or 2 on the dyno to get a more accurate dyno comparison. Then add the Fast and see the total gains. 252 is a large intake port, but can work on a 383. The question remains
"will" it work.
As far as on a 427-440 cubic inch motor. You will have some work to do to get these heads to work really well on that size motor. Its hard to beat the LS7 combo stuff from ETP or even GM. The heads flow some much and really destroy a LS1 style port once you add the manifold.
Good luck and let us know how it turns out.
Solid roller?
If not then I am a non believer.
I am interested to see the results as well. There should be a gain switching to the ported 90 and IMO I would have to keep the LS6 on until you made a hit or 2 on the dyno to get a more accurate dyno comparison. Then add the Fast and see the total gains. 252 is a large intake port, but can work on a 383. The question remains
"will" it work.
As far as on a 427-440 cubic inch motor. You will have some work to do to get these heads to work really well on that size motor. Its hard to beat the LS7 combo stuff from ETP or even GM. The heads flow some much and really destroy a LS1 style port once you add the manifold.
Good luck and let us know how it turns out.
07-26-2007, 10:16 PM
#11
The 347 I believe was a solid roller car with probably a sheet metal intake. I would have to check with the builder to make sure. But that is a normal number for him and his combos. I agree that I need to make two tests. One with the LS6 and one with the FAST. I just don't have the funds. Plus I think the LS6 was tapped any way and I would see no gains with more head flow regardless. Now if I put the FAST on the 205's that would give me a more accurate number. I would say at this level the FAST is worth a solid 20rw though. I will just factor that out, which I know is not scientific by any means.
Tony. I agree that the bench is right on with your numbers almost to the number. I was hoping that they wouldn't be. I was shocked when I saw the runner volume. I figured it would be around 235cc or so. The compression will take a .28 bump. It is 11.8 right now and will go to 12.08 useing the same math. I was figureing with the cam I have with .651 on the intake and the 112+2 lobe sep that the more intake flow and larger intake valve might help me make more power up top. I was reading that with 112 cams the top end suffers with with a smaller intake valve. The 205 heads started backing up at .600 and lost flow at .650 as where the 252's kept flowing. I know the cam doesn't spend much time at peak lift but the numbers at .400 and above are as much as 30cfm better. Shouldn't that help?
Tony. I agree that the bench is right on with your numbers almost to the number. I was hoping that they wouldn't be. I was shocked when I saw the runner volume. I figured it would be around 235cc or so. The compression will take a .28 bump. It is 11.8 right now and will go to 12.08 useing the same math. I was figureing with the cam I have with .651 on the intake and the 112+2 lobe sep that the more intake flow and larger intake valve might help me make more power up top. I was reading that with 112 cams the top end suffers with with a smaller intake valve. The 205 heads started backing up at .600 and lost flow at .650 as where the 252's kept flowing. I know the cam doesn't spend much time at peak lift but the numbers at .400 and above are as much as 30cfm better. Shouldn't that help?
07-26-2007, 11:39 PM
#12
Originally Posted by Pray
The 205 heads started backing up at .600 and lost flow at .650 as where the 252's kept flowing. I know the cam doesn't spend much time at peak lift but the numbers at .400 and above are as much as 30cfm better. Shouldn't that help?
The small bore will kill some of what looks like a big advantage and the intake will add to the loss. Airspeed plays into the picture as well (huge port volume disparity). I wouldn't be surprised if the big head made 15 more peak HP and I wouldnt be surprised if it made close to the same as the 205 headed combination although Im getting the feeling this really wont be a great A-B test due to different intakes and slightly different CR. One thing for sure however is the airflow gains in the higher lifts you quoted are not going to actually be realized in your particular combination mainly due to the 3.900 bore.
As I said....Looking foward to the results....LOL
Tony
