AFR milling
#1
TECH Enthusiast
Thread Starter
AFR milling
I have two questions for anyone in the know:
1-why does flow suffer if you mill a head
2-If you need 64cc's on the 205's, how many thous. need to be milled off the head? I assume they come with 66cc's originally.
1-why does flow suffer if you mill a head
2-If you need 64cc's on the 205's, how many thous. need to be milled off the head? I assume they come with 66cc's originally.
#3
TECH Addict
iTrader: (4)
Originally Posted by Spinmonster
I have two questions for anyone in the know:
1-why does flow suffer if you mill a head
2-If you need 64cc's on the 205's, how many thous. need to be milled off the head? I assume they come with 66cc's originally.
1-why does flow suffer if you mill a head
2-If you need 64cc's on the 205's, how many thous. need to be milled off the head? I assume they come with 66cc's originally.
...and like the other guy said, close to 0.006" milling per cc.
#4
LS1 Tech Administrator
iTrader: (14)
When you mill, you cut out some of the ramp that leads to the valve seat. Low and mid-lift flow suffers because of this although high lift flow is less affected.
__________________
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.
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.
#5
Originally Posted by Spinmonster
I have two questions for anyone in the know:
1-why does flow suffer if you mill a head
2-If you need 64cc's on the 205's, how many thous. need to be milled off the head? I assume they come with 66cc's originally.
1-why does flow suffer if you mill a head
2-If you need 64cc's on the 205's, how many thous. need to be milled off the head? I assume they come with 66cc's originally.
Essentialy the chamber is the completion of the "marraige" of valve job and port design (all three work in conjunction with one another) and helps shape the cone of air coming off the valve (at very high speed)....changing that shape can change the way it effects the cone causing typical flow losses in an already highly optimized port/chamber configuration. Sometimes a mill can help flow depending on the cylinder head but the more optimized the design is to start, the greater the chances a mill will hurt it.
Tony M.
#7
Originally Posted by Tony Mamo @ AFR
Insignificant amount of flow loss (if any) at the mill amount you have in question....
Essentialy the chamber is the completion of the "marraige" of valve job and port design (all three work in conjunction with one another) and helps shape the cone of air coming off the valve (at very high speed)....changing that shape can change the way it effects the cone causing typical flow losses in an already highly optimized port/chamber configuration. Sometimes a mill can help flow depending on the cylinder head but the more optimized the design is to start, the greater the chances a mill will hurt it.
Tony M.
Essentialy the chamber is the completion of the "marraige" of valve job and port design (all three work in conjunction with one another) and helps shape the cone of air coming off the valve (at very high speed)....changing that shape can change the way it effects the cone causing typical flow losses in an already highly optimized port/chamber configuration. Sometimes a mill can help flow depending on the cylinder head but the more optimized the design is to start, the greater the chances a mill will hurt it.
Tony M.
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#8
Originally Posted by DavidNJ
Ok, Tony, what is optimal for the AFR heads?
Milling up to .030 usually doesnt hurt things much.....Over .040 will start to dip into the flow curve more....best to get a different piston if you really need alot more than that (and are trying to build a VERY optimized package). Sometimes the availability of shelf components is weak (especially if your building a combination that isn't very common)....thats where a few more dollars spent for custom pistons can certainly pay off.
Tony
#9
So the smallest heads would be the 225cc port 62cc chambers, followed by the 205cc port 66cc chambers? .030 would take the 205cc 61cc, which is more than the common 59cc. Is that correct?
#10
Originally Posted by DavidNJ
So the smallest heads would be the 225cc port 62cc chambers, followed by the 205cc port 66cc chambers? .030 would take the 205cc 61cc, which is more than the common 59cc. Is that correct?
Mamo OUT