DATN510 Posted November 19, 2011 Author Report Share Posted November 19, 2011 I used some channel locks to pull the metal out of the bit. I used some metal oil on the first hole I cut. On the second 3rd and 4th I didn't and it cut alot better. Then I switched to a 3/8 drill bit for the bolt holes. Quote Link to comment
DATN510 Posted November 19, 2011 Author Report Share Posted November 19, 2011 These items I also got at HF made this next task go alot easier. Most important is to hold on tight to the melal and ware thick gloves. When I had small cuts I just went to the edge and broke the piece of so it wouldn't get caught in the blade and go flying. This is as far as I got for now it took me about 2 hours to get to this point. More to come Quote Link to comment
DATN510 Posted November 19, 2011 Author Report Share Posted November 19, 2011 So begins the EFI manifold, here is the materials I'm using that cost $70 The materials I go are a 5' piece of aluminum tubing with an inside diameter if 1.490" with a 1.650" outer diameter. With. 0.140 wall thickness. flange and pleneum base I got. .5" x 4"x 4'. And a 3'x2'x0.140 (1/8 inch) for the outer part of pelenum. Quote Link to comment
DATN510 Posted November 19, 2011 Author Report Share Posted November 19, 2011 Got my second wind after dinner and started back with the project. Finished rough cut on flanges, and started measuring for runners. I measured the runners at 5.5" with a .5 for flange. I cut each runner with a 5 degree angle to even out from the slant of the engine Quote Link to comment
DATN510 Posted November 19, 2011 Author Report Share Posted November 19, 2011 I then cut the pleneum base @ 16". Here is where I need some info. Do I taper the end of the pleneum base at the #4 cylinder or #1 or if any. With the outer cover do I make the entrance wider and go smaller at the end to compensate for the #4 cylinder getting the same amount of air? Tired now need to go to bed, goodnight all. Quote Link to comment
dennis Posted November 19, 2011 Report Share Posted November 19, 2011 looks cool so far. Quote Link to comment
datzenmike Posted November 19, 2011 Report Share Posted November 19, 2011 Is this going to clear your strut tower ok? Quote Link to comment
DATN510 Posted November 19, 2011 Author Report Share Posted November 19, 2011 Yes it will clear the strut tower. I have 6" clear next to the master brake cylinder and 8" to strut tower. Quote Link to comment
datzenmike Posted November 19, 2011 Report Share Posted November 19, 2011 You should also think about flaring the tube ends inside the plenum. This aids in high speed high flow. Quote Link to comment
DATN510 Posted November 19, 2011 Author Report Share Posted November 19, 2011 I have that part covered. You'll like what I'm planning. Any advice on the size if the pleneum? Quote Link to comment
datzenmike Posted November 19, 2011 Report Share Posted November 19, 2011 Not sure what the popular wisdom is on this, I would think the bigger the better. The port and runner length can be tuned for length. A very very rough formula is 79200 divided by the peak torque RPM you want. Very very rough but a starting point... Quote Link to comment
DanielC Posted November 19, 2011 Report Share Posted November 19, 2011 79200 / 3600 RPM = 22. 22 what? inches, CM, some other measurement? Quote Link to comment
Z-train Posted November 20, 2011 Report Share Posted November 20, 2011 CC's i believe. Quote Link to comment
datzenmike Posted November 20, 2011 Report Share Posted November 20, 2011 79200 / 3600 RPM = 22. 22 what? inches, CM, some other measurement? This is a very rough formula and is intended just to make it easier. The real formula involves the speed of sound in relation to air temperature, port cross sectional area and can easily be upset by radical cam timing. In effect the vacuum pulse from the intake must travel up the intake port and runner to open air (in this case the plenum) where it 'echos' back as a pressure wave. The trick is to get the length of the runner so that this pressure wave just barely sneaks back into the cylinder past the closing valve like Indiana Jones. The speed of sound will remain fixed so at low RPMs the runner will have to be many feet long, but as the RPMs go up the time is shorter so the pulse needs to get back sooner and a shorter pipe is needed. Port tuning only affects a fairly narrow RPM range. Try 6K... now it comes down to 13.2 inches. When you subtract the head port to valve face distance, (4-6" just guessing) the runner length is about 9" or less. 7,000 RPMs would be just over 11" long minus the head port length for a runner of around 6-7". . As I said this is a very rough and simplified formula. You can tune for a specific RPM range to take advantage of a small increase in free cylinder filling. Quote Link to comment
Z-train Posted November 20, 2011 Report Share Posted November 20, 2011 Now here are some runners.And it's EFI to boot. :blink: Quote Link to comment
datzenmike Posted November 20, 2011 Report Share Posted November 20, 2011 Bill! Exactly! From a 413? My slant six was supposed to be 'ram tuned' also. :lol: The intake runners were quite long. Quote Link to comment
DATN510 Posted November 20, 2011 Author Report Share Posted November 20, 2011 That's pretty cool. I dud some more work on the Mani yesterday. Ill post pics later. thank you all for your input. Quote Link to comment
albyneau Posted November 20, 2011 Report Share Posted November 20, 2011 I had a video at one time of a fella that had a variable runner length EFI system where the runners would shorten as a function of throttle opening. I also had a rather dry & heady book from the 50's or 60's that was on the science of frequencies as applied to intake and exhaust design. Can't find either now.... dammit.:angry: Quote Link to comment
DATN510 Posted November 20, 2011 Author Report Share Posted November 20, 2011 I did some more work on the manifold yesterday, first ill show you a mistake I made useing the table saw. I used the table saw to cut the middle part of the flange and this is what happeded. First I centered the holes on the penum base with the gasket and drilled the holes. I was planning on having the runners fit into a slot at the hole for more strenght but I drilled the hole to big. But it will still work Then I drilled the port holes in the plenum base. I first got a 2x4 and cut a larger hole then the hole I was routering so the bearing wouldn't hit anything. Then came the tedius part of routering air horns into the plenum base, I first did a few practice runs and it was a good thing I did. Cause the bearing on the router bit came off and screwed up my test piece. After putting the bearing back on I started the routering. I took it very slow, just took a little off at a time and held tight on the router. The routering went perfect on this stage, but the router didn't go deep enough to where It. So I went to home depot and picked up a round bit with a smaller radius to get the lower part of the bowl. Sorry didn't get pics of this,but I will explain. I cut a smaller hole in that same piece of wood for the bearing to hit so I could router the bowl lower to about .02 which was perfect. Look at that like one long volocity stack with no air restricktions. Then I cut the lip out on the plenum base with the table saw. This cut was just right. Plenum cover fit perfect. Then I started working on the plenum cover, I started with some thin strips of cardboard to get the general size I wanted and cut it out on a bigger piece of cardboard. I went with 11" wide on the front and 8" on the back for beter flow to the 3 and 4 cylinder lenght is 16" I then rolled it some and taped it to theplenum base for a sample mock up. And this is what I ended up with. Now I need to figure out how to roll this sheet of metal without spending any money. I'm leaving for Ashland Oregon on Tuesday so I need to save my money. And please coment on this build your input is important as it is helpful. Later Mike Quote Link to comment
Z-train Posted November 21, 2011 Report Share Posted November 21, 2011 What's the I.D. of the tubes? One thing to remember,the main reason the Z manifold runners curve toward the rear of the motor is so the TPS will clear the distributor. Quote Link to comment
DATN510 Posted November 21, 2011 Author Report Share Posted November 21, 2011 The runners are 6" from head. I also checked the clearance for the dizzy. Thanks Quote Link to comment
Z-train Posted November 21, 2011 Report Share Posted November 21, 2011 The runners are 6" from head. I also checked the clearance for the dizzy. Thanks Diameter of the tubes, i meant.One other thing,you don't want a "straight shot"into #1 runner from the throttle bore. Quote Link to comment
DATN510 Posted November 21, 2011 Author Report Share Posted November 21, 2011 1.375 diameter. Please explain why and how to fix? Quote Link to comment
Z-train Posted November 21, 2011 Report Share Posted November 21, 2011 1.375 diameter. Please explain why and how to fix? You want the flow to all the cylinders to be equal.If there is a straight "run" to one cylinder and not others,that cylinder will run lean as it will get more air flow.Is the TPS going to be mounted perpendicular to the head-flange or on a slight angle,pointing towards corner where the fender & radiator support meet? And the diameter is the same as a L-20B maifold runner-but you knew that...right? :cool: Quote Link to comment
DATN510 Posted November 21, 2011 Author Report Share Posted November 21, 2011 The Tps will be mounted on the front of the penumbra that end will have a 25 degree angle Quote Link to comment
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