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Pontiac - Boost Turbo, supercharged, Nitrous, EFI & other Power Adders discussed here. |
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#21
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Quote:
The second plenum is where the Intake Runners feed the engine. It is a large plenum too. The slot would be between the 1st plenum and the second plenum. It would be clocked to point about 5:00 and go into the second plenum, Air would go thru the slot, bank off the roof of the second plenum, then the air would continue on to the runners at a much lower velocity and higher density. I lot of monkey motion trying th kill the air from all packing up at the rear of the first plenum. Center feed, bank off the roof, seems to work the best and uses only one plenum. 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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Quote:
https://www.youtube.com/watch?v=MXW_W5Sh47U
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My Half AN Injun..... |
#23
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A Lot of Circular Motion where the fuel could separate from the air (if it was in a combustion chamber) but because you are EFI and it is an intake manifold it will probably be ok.
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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So would you rather it be a square plenum over what I got figured ? I thought being it is a dry setup with efi that spinning the air would be the thing to do.
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My Half AN Injun..... |
#25
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Spinning the air is like a car passing by an intersection and really needing to turn right or left on the cross-street. The air has to change direction and make the sharp turn into the port.
Tunnel Rams work because of a concept called "Line of Sight". With Carbed Engines you want the Air and Fuel to have the most direct path into the runner. Not doing a shallow left sweeping turn back to the right or a a shallow right sweeping turn back to the left. There are Pontiac intake runners out there that do this going toward the valves in the heads. EFI intakes that have the right bend radius can have the port on the right side, point at the left side, make a sweeping turn back to the right, and have the opening into the plenum flare on the right. The deal is the air is "sweeping around the bend, not doing a sharp left or right hand turn into the port. You want a water filled swimming pool effect plenum, you can get the bucket of water from anywhere. You don't want the sink whirlpool effect when you are trying to get smooth calm air into the port. It might accelerate quickly into the port when the valve opens, notice I did not say it was sucked into the port. Air Pressure pushes it into the vacuum. 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. Last edited by Tom Vaught; 12-01-2017 at 11:15 AM. |
#26
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So Tom, does the funnel shaped plenum with the slot sort of create a back pressure where it actually pushes back against the incoming air flow to slow it down enough to equalizes the distribution through the slot to create a more even balance between the back and front runners?
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My Half AN Injun..... |
#27
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YOU ARE CLOSE ON THAT STATEMENT.
The air travels to the back, packs up there, tries to escape upward thru the slot. air continues to pack up in the first plenum, more of the slot feeds to the second plenum, finally the whole lower plenum has a higher pressure vs the second plenum due to the restriction of the slot. So the 1st plenum sees a higher pressure vs the second plenum. The air might be more even to the runners but you take a hit on the pressure across the slot. The bigger the slot the more uneven the airflow is until the restriction builds up. So the design sound cool but in theory has flaws with delay to the runners initially under boost and wasted work (pressure higher in the 1st plenum vs even in one plenum design.) We screwed around with the slot dimension for about 100 hours on the dyno and never could find the magic spot for the different Boost pressures we were running. Drag car / 1/4th mile race might be different for a 6 second run. 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. |
#28
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Quote:
What do you think of this design Tom . Here's a few variations of it.... Which one do you like better if you liked any of them.. ?
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My Half AN Injun..... |
#29
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Would not do #4 at all.
Built a Intake Plenum like #1 that worked ok on the dyno and street. Built a Intake Plenum like #2 that worked really well and had great distribution to the runners. Second Pic gets my vote!!!! Plenum #3 would tend to pack up the air at the back of the plenum even though the feed to the 1st runner is good, Charlie. 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. |
#30
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#2 has like a Y shape to it . So is this a better one because the short turn on the left of the Y will create a drag that will pull and direct air flow to #1 an #2 ?
And what part of the design of #4 is bad ? The throttle body flange resting right on the plenum floor right in front of #1 runner and pointing to the roof maybe bypassing it.?
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My Half AN Injun..... |
#31
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#2 has an expansion right after the throttle body.
Somewhat like Marcella's TR type roof. That expansion lets the air spread out as you said and feed the 31 runner properly. The short turn does create a smooth flow to the #1 runner just like a proper short turn in a cylinder head runner. The #4 design blows air right past the #1 runner and could even suck some air OUT of the #1 runner like a car wash hose pulls water into the wand. #4 is a poor design all the way around. If the throttle was 4" farther forward then you might get better flow to the #1 runner if the radius turn was right. MIGHT! 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. |
#32
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Tooth Jerker's bottom fed intake.
From what I have seen the slot is way too big. But it's a cool design, and some inspiration. |
The Following User Says Thank You to thirdgen455 For This Useful Post: | ||
#33
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Has it been tested yet ? I like it......
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My Half AN Injun..... |
#34
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That is the intake from that fast leaf spring Dart posted on the first page.
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#35
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Oh cool. Thanks for posting it.
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My Half AN Injun..... |
#36
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No problem, I've been obsessed with the Lehmann style intake manifold since you started this post. Here is another LS version.
http://www.yellowbullet.com/forum/sh...php?p=59465457 |
#37
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Thanks . Ive seen this one . Very nice manifold...
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My Half AN Injun..... |
#38
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charlie66 do you have another 195 build in the works?
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DragStarLeMans |
#39
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No. Im building a 406 slowly as I get the funds for the parts.
The 4 cylinder is at a point where I need to spend a lot of money on a Billet crank or just leave it as it is. I started building this manifold because I felt it needed more plenum and thought I could manage the tune better for more power. But now im not sure if its worth all of the work im going through when I can make the same power out of a 8 cylinder with a whole lot less effort and that would live for a long time.. I have found that if I keep the 4 cylinder set at around 550 - 625 hp It will stay together reliably. If i turn it up to where I like it, 750 - 800 hp its short lived because the crank starts to fail and the bearing will soon turn to copper. The thing that really gets me is if I did have a good crank I know I could make over 1000 hp but the next weak link will be the block . I wish when I had the chance that I bought that super duty block that I passed up and basically gave to Nunzi. That block had more nickel content and would of been good for what I was trying to do. I wanted to build the first 194.5 that could of broke into the 8's in a 64 Lemans at Norwalk.. That was my dream to do that. But the money and resources as well as the recourses involved to do it is just too much for me. I tried calling Bob and Frank at all Pontiac but they couldn't help me to make a 4 cylinder block. Im really the only one around here doing this , so it wouldn't pay for them to make one I guess.. So ill probably build this manifold just to finish it and give it a try . But in the end ill probably just end up with a 8 cylinder making 1000 hp. What I will miss though is the look on a guys face after beating his low 10 second car as he finds out he was beat by just a old school 4 banger... That's the stuff that keeps me at this thing trying to make it faster and more reliable... .....
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My Half AN Injun..... Last edited by charlie66; 12-28-2017 at 09:20 AM. |
#40
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Pre-Production unit
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6.98 @ 199mph 4.53 @ 164mph |
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