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Pontiac - Boost Turbo, supercharged, Nitrous, EFI & other Power Adders discussed here. |
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#21
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I will say that there is no IDEAL injector "Point" location for the spray based on that very accurate, engine dyno Research Study. Way too many variables involved. The key thing is that: depending on the speed of the air/fuel charge as it approaches the valve seat (engine rpm), the air flows differently around the valve seat and into the chamber. That is why ports will have tumble which may change to swirl and vise versa depending on the head design. A 4 valve head has much better control of the flow patterns into the combustion chamber/cylinder vs a 2 valve head. That is why there are so many variables in 2 valve head design. But I guess Generic Statements are as good as anything else in injector placement and angle. The reality is you would probably be with-in a couple of HP if the injector rails (from an end view) were vertical on the intake vs trying to get the injector pointed exactly at the back of the valve. If you were doing Emissions work, maybe you create 4 or 5 designs and see which one gives the lowest emissions for the EPA Testing. Just my experience on this topic. Tom V.
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"Engineers do stuff for reasons" Tom Vaught Despite small distractions, there are those who will go Forward, Learning, Sharing Knowledge, Doing what they can to help others move forward. |
#22
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I would still think pointed down the port towards the valve would be better than pointing straight down at the floor of the runner, or at least that would be my line of thinking. Maybe a 45 degree 'lean', down the port even.
But suspect you're right about not much of a difference. I was parroting what Marren told me in previous conversations. Guess it's more of a general' or 'generic' statement as you mentioned Tom... .
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. 1970 GTO Judge Tribute Pro-Tour Project 535 IA2 http://forums.maxperformanceinc.com/...d.php?t=760624 1971 Trans Am 463, 315cfm E-head Sniper XFlow EFI, TKO600 extreme, 9", GW suspension, Baer brakes, pro tour car https://forums.maxperformanceinc.com...ght=procharger Theme Song: http://www.youtube.com/watch?v=7zKAS...ature=youtu.be |
#23
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If you are running in a water craft at a given fixed speed then you can design the fuel spray for spending most of the time at that engine rpm point.
Same deal with a Drag Race engine. Not the case with a Road Race Engine or a street driven application. So you are correct, for Drag Racing pointing the injector at the center of the valve bowl might be better but cannot believe that anyone using a Offy dual quad intake is assuming max power and needs more than a simple vertical Injector Position. Tom V.
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"Engineers do stuff for reasons" Tom Vaught Despite small distractions, there are those who will go Forward, Learning, Sharing Knowledge, Doing what they can to help others move forward. |
#24
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#25
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hahahah...then you trow i running a batch fire system.....where it gives 3 aquirts with the valve CLOSED.....
bigger issue of what size are the holes...I know all mine are for standard dowel sizes! still a PITA .. obviously work in machining? |
#26
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"ONE PIECE OF DATA, TOM, IS WORTH MORE THAN 1000 OPINIONS. Tom V.
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"Engineers do stuff for reasons" Tom Vaught Despite small distractions, there are those who will go Forward, Learning, Sharing Knowledge, Doing what they can to help others move forward. |
#27
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Never thought about combining vectors for the injector nozzle spray. Kinda like compensating for windage at the gun range. The faster the intake port velocity the farther upstream it needs to point?
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#28
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James 1970 Trans Am Spotts Built 484" IA2, Highports, EFI Northwind Terminator X sequential EFI fabrication and suspension by https://www.funkhouserracecars.com/ |
#29
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All of the Offy Manifolds have very short runner lengths.
They built the manifolds for easy installation. Manifolds tune by harmonics. 1st harmonic length was long, like the old Chrysler Cross Ram Intakes. See Picture below. Other Runner Length manifolds were designed for racing speeds. The Offy intakes fit that situation but are good because of the Injector Placement options, not the tuned length. Tom V.
__________________
"Engineers do stuff for reasons" Tom Vaught Despite small distractions, there are those who will go Forward, Learning, Sharing Knowledge, Doing what they can to help others move forward. |
#30
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This is an illustration of what a 1st harmonic, 2nd harmonic, 3rd & 4th harmonic waves look like.
Tom V.
__________________
"Engineers do stuff for reasons" Tom Vaught Despite small distractions, there are those who will go Forward, Learning, Sharing Knowledge, Doing what they can to help others move forward. |
#31
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Just as an update I called Luhn about these intakes last week. Unfortunately they are waiting on some small parts to finish them up. Iirc he said he had several (6-7) very close to finished up. I called to inquire of the rpm range of the intake. He believes it will be great in the 1500-6500 rpm range with very strong torque production.
__________________
James 1970 Trans Am Spotts Built 484" IA2, Highports, EFI Northwind Terminator X sequential EFI fabrication and suspension by https://www.funkhouserracecars.com/ |
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