Drag Racing Discussions > Front Engine Dragsters
Making a intake manifold for my 4-71 blower
Sidewinder:
We was very pleased after todays workshop
Got a good start making the new manifold for my flathead.
Next up is for me to grind the portholes smooth and to match the block.
Roger is gona make a 1 1/2" tall plenum with the pop-off/burstpanel pointing forward this time
After we have fitted the plenum, we'r gona make the bracket for the blower-belt tensioner. We also need to make some supports for it and for the plenum. Last is to make holes for oil filler and breathers.
Have gotten some heads-up regarding port nozzles, so we'r gona make provitions for them
Kjell
GlennLever:
I like!
Keep the updates coming!
KING CHASSIS:
I love homemade stuff. Keep us up dated buddy. See ya in a couple of years Kjell.
denverflatheader:
Sidewinder – sorry so slow to respond. I had gone back home to islands this week for family business, was pre-occupied all week long. Back in Colorado now. Thanks for your comment on my intro, yep have a funny location for seating on 999 car but is very comfortable with nice view.
Burst panel pointing forward sounds good, little safer direction for you and also helps set the intake manifold height. You could go with a little lower intake manifold height if you designed burst panel at angle (laying back) versus straight up 90 degrees from top of block. I’m guessing it will be set straight up 90 degrees so you have more clearance with your Baron Racing Heads, they’re tall ones. I think you already accepted your vision down track will be obscured : )
Heard before it’s good idea for port nozzles in addition to your hat nozzles with nitro. I think the closer to the intake valve you can locate the better. (You might ask “Spud here” for his thoughts on port nozzle placement). With fh, it’s little bit more challenge compared to oh valve to design. You and your crew chief probably already know this….. port nozzles on fh can be a piston saver. I’ve heard from “excellent source” the four outside corners pistons run a little hotter/leaner than the four middle pistons. Keep one eyeball on it, or you might melt a piston top (actually another good question for you to ask “Spud” how to read spark plugs to prevent melting your piston with 20 lbs boost on 50%+).
Remember how the four outside cylinders’ exhaust are cast and wrap around the cylinders as part of the block casting….. creates more heat. Plus with 4-71, wide open the hat nozzles (2 or 4 nozzles?) might help some cylinders run little bit richer than others (again, another question you might ask “Spud” i.e. rotor clearances, stripped or not, size 4-71 vs. 14-71, how affects fuel distribution).
You’ll have fun troubleshooting and adjusting (increasing) size of port nozzles to compensate for leaner cylinders. Port nozzles aren’t like slicks, they don’t have to match exactly : ) DF
Sidewinder:
Thanks DF:)
You are spot-on. I was thingking of placeing the pop-off/burstpanel slightly downwards or uppwards, to save some space. The plenum will be made with an angle to match the flow towards the outher runners. I'm gona bring the intake to Roger to weld some moore, as i have grinded off abit;)
I have looked at the port nozzle angles, and I think they will match the runner angle and spray straight down towards the ports in the block.
At the moment we have 4x64A Hilborns in the hat. The port nozzles will come a litlebit later. We'r gona tune it with straigt alky, and then we shall see if we switch to pops:)! It's gona be interesting to see if the fuel distribution is working with this design!?:)
Kjell
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