L92 Casting Version Exhaust Port Size Differences
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L92 Casting Version Exhaust Port Size Differences Why has no one brought up the issue with the major difference in exhaust port sizes between the different L92 head casting versions? There is a significant difference in the size of the exhaust ports between the L92 5364 (smooth die cast) and the 823 (rough sand cast). The 823 exhaust ports are almost 3 tenths of an inch wider in diameter than the 5364 ports. It seems that since the only weak point of these heads is the exhaust flow that the bigger ports of the 823 would be more desirable outweighing the fact that the 5364 has a smoother casting finish.
We need someone to flow bench untouched versions of both on both intake and exhaust sides.
We need someone to flow bench untouched versions of both on both intake and exhaust sides.
Originally Posted by Scott5000
Why has no one brought up the issue with the major difference in exhaust port sizes between the different L92 head casting versions? There is a significant difference in the size of the exhaust ports between the L92 5364 (smooth die cast) and the 823 (rough sand cast). The 823 exhaust ports are almost 3 tenths of an inch wider in diameter than the 5364 ports. It seems that since the only weak point of these heads is the exhaust flow that the bigger ports of the 823 would be more desirable outweighing the fact that the 5364 has a smoother casting finish.
We need someone to flow bench untouched versions of both on both intake and exhaust sides.
We need someone to flow bench untouched versions of both on both intake and exhaust sides.
I digitized a stock 5364 port but not a 823. I don't recall the 823 port exit being so much smaller. Three tenths of and inch is a good bit larger in cross sectional area and that much material would cause me concern with our CNC tooling. As it is I don't have any trouble machining through the port. The size of the exhaust port exit doesn't have as much impact on flow as you'd think although three tenths would have a definite impact. The major restrictions to the port are across the seat and throat.
I got dozens of stock head tests for both style castings, but I won't have access to them until the start of the week. As I recall there's a difference of about ten cfm peak between most all the ports I tested. The worst ports were in the high 190's to low 200's while the better ports were around the 210cfm range peak.
Richard
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Originally Posted by Richard@WCCH
I digitized a stock 5364 port but not a 823. I don't recall the 823 port exit being so much smaller. Three tenths of and inch is a good bit larger in cross sectional area and that much material would cause me concern with our CNC tooling. As it is I don't have any trouble machining through the port. The size of the exhaust port exit doesn't have as much impact on flow as you'd think although three tenths would have a definite impact. The major restrictions to the port are across the seat and throat.
I got dozens of stock head tests for both style castings, but I won't have access to them until the start of the week. As I recall there's a difference of about ten cfm peak between most all the ports I tested. The worst ports were in the high 190's to low 200's while the better ports were around the 210cfm range peak.
Richard
I got dozens of stock head tests for both style castings, but I won't have access to them until the start of the week. As I recall there's a difference of about ten cfm peak between most all the ports I tested. The worst ports were in the high 190's to low 200's while the better ports were around the 210cfm range peak.
Richard
The 823s had the bigger ports. Please let us know what you find when you get your next shipment. It seems that people are now getting the 823 casting more frequently than any other from orders from major venders.
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Originally Posted by Richard@WCCH
I digitized a stock 5364 port but not a 823. I don't recall the 823 port exit being so much smaller. Three tenths of and inch is a good bit larger in cross sectional area and that much material would cause me concern with our CNC tooling. As it is I don't have any trouble machining through the port. The size of the exhaust port exit doesn't have as much impact on flow as you'd think although three tenths would have a definite impact. The major restrictions to the port are across the seat and throat.
I got dozens of stock head tests for both style castings, but I won't have access to them until the start of the week. As I recall there's a difference of about ten cfm peak between most all the ports I tested. The worst ports were in the high 190's to low 200's while the better ports were around the 210cfm range peak.
Richard
I got dozens of stock head tests for both style castings, but I won't have access to them until the start of the week. As I recall there's a difference of about ten cfm peak between most all the ports I tested. The worst ports were in the high 190's to low 200's while the better ports were around the 210cfm range peak.
Richard
Any updates???
Thanks,
Scott
Here's what I measured:
At the flange of the exhaut port cast #823 - 1.595" wide and 1.402" tall.
Cast #5364 - 1.571" wide and 1.30" tall.
Measured approx. 1" into the port cast #823 - 1.652" wide and 1.366" tall.
Cast #5364 - 1.730" wide and 1.310" tall.
Also there's an average of 4-6cfm difference in flow between the ports. The box stock 823's have a bit better flow on average.
Richard
At the flange of the exhaut port cast #823 - 1.595" wide and 1.402" tall.
Cast #5364 - 1.571" wide and 1.30" tall.
Measured approx. 1" into the port cast #823 - 1.652" wide and 1.366" tall.
Cast #5364 - 1.730" wide and 1.310" tall.
Also there's an average of 4-6cfm difference in flow between the ports. The box stock 823's have a bit better flow on average.
Richard
Originally Posted by john_sblendorio
would it matter which casting to have if the head was getting fully CNC ported?
Richard
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Originally Posted by Richard@WCCH
Here's what I measured:
At the flange of the exhaut port cast #823 - 1.595" wide and 1.402" tall.
Cast #5364 - 1.571" wide and 1.30" tall.
Measured approx. 1" into the port cast #823 - 1.652" wide and 1.366" tall.
Cast #5364 - 1.730" wide and 1.310" tall.
Also there's an average of 4-6cfm difference in flow between the ports. The box stock 823's have a bit better flow on average.
Richard
At the flange of the exhaut port cast #823 - 1.595" wide and 1.402" tall.
Cast #5364 - 1.571" wide and 1.30" tall.
Measured approx. 1" into the port cast #823 - 1.652" wide and 1.366" tall.
Cast #5364 - 1.730" wide and 1.310" tall.
Also there's an average of 4-6cfm difference in flow between the ports. The box stock 823's have a bit better flow on average.
Richard
Wow, interesting results. So I wonder if someone was going with as cast untouched L92s which version would be better out of the box. It seems to me since they are starved on the exhaust side that the 823s would be slightly better. Or do you think it would end up in a wash for overall HP/TQ output.
I can't say at this point. Some guys are making impressive power with the stock unported heads and some are doing it with ported heads. Either way for guys looking to build an affordable 370-427ci engine the L92's are a solid choice, ported or unported.
Richard
Richard
