FE Power Forums > Non-FE Discussion Forum

Intake Manifold Design - Forced Induction (MEL)

(1/6) > >>

FrozenMerc:
A bit off topic, but I would like some opinions from the brain trust on here.  4 or 5 years ago, I got my hands on a 430 MEL core, a 6-71 blower, and an old Weiand Intake manifold to pair the two together.  However, it quickly became obvious the Weiand intake was a race only piece that would require things such as a remote thermostat, relocation of the distributor, and crank breather.  It only had minimal provisions for coolant passages that I felt would not work well on a street motor, and to be clear, my intention was for the motor to be 100% street functional (idling in traffic, 75 mph sustained interstates, etc.).  After researching relocating the distributor and doing the other modifications that it would require to make the Weiand work, I came to the conclusion that it would likely be easier to build the intake manifold I needed instead.

Excuse the dirty engine...


Being the good little engineer that I am, I took the Weiand and made a CAD model of it in UG.  I then started another model that had all the features I wanted, including clearance for the stock distributor, the thermostat in the stock location, better water passages, relocation of blow-off valve, etc.  I have an image of that model below.



Well, that was about 3.5 years ago, life happened, new job, moved across the country, couldn't sell the old house and shop, blah, blah, blah.  Long story short, I am ready to get back on this project by getting a 3D printed plastic model made for fit-up, flow testing, etc.  But before I do, the design of the plenum has been bugging me.  The Weiand was completely open in the center (see cross section of the CAD model below), resulting a very large plenum.  I think this probably worked fine on a drag car that was either idling or at WOT with a healthy amount of boost, but I am concerned that at part throttle operation low boost (or no boost), this is less than optimal. 



What do you guys that have played with forced induction applications think?  My thoughts are leaning towards redesigning it so the plenum is no wider than the opening in the bottom of the 6-71.  This would increase the individual cylinder runner length significantly, and hopefully smooth out the flow.  More along the lines of an FE 6-71 intake.



Not that it matters as I want this to be somewhat universal for any street driven application, but the plan / specs for this motor are as follows.

1958 430 MEL
Offset ground crank to BBC journal size.  4.1" stroke (or as close as possible)
4.35" bore
6-71 Blower, up to 12 psi boost
8:1 compression (most likely custom pistons, although 427 BBC flat-tops will get me close)
Should be right around 485 ci all said and done.  Street friendly tune concentrating on a big, broad torque curve.
I am not sure what it is going in, but most likely something big and heavy.

Finally, The Weiand's intended purpose...

TomP:
Very rare intake there don't cut it up. Longer runners would be better, for a lower height they used a big box with one large hole in the top and eight smaller holes in the sides.

jayb:
+1, no runner length will kill low end torque.  It will be bad enough with the short runners you are stuck with when leaving the center of the manifold open for the blower.  Hopefully it will come up on boost fast and you won't notice the issue.  In the drag car you'd never notice the issue because you would leave the line under boost, but on the street it may be a different story.

cjshaker:
You could enlarge the ports on that Weiand, then slide tubes up inside the plenum and have them welded in, essentially making the runners that you need. Or you could "notch" the opening, have the ports flanged, and simply sandwiched between the head and intake. It wouldn't require any changes or cutting to the outside, and nothing would look different. Just an idea.

As for the water ports, they would flow much better with better fittings, or you could enlarge the port holes. Not sure if there's enough meat there to do that or not. You'd be surprised how much water would flow when you have 2 ports flowing. Seen lots of big HP cars on Drag Week doing exactly that, and they seem to work fine with a good pump.

Cool piece though. Royce needs that for his FED.

FrozenMerc:
I am definitely not going to cut up or really even touch the Weiand.  That is too rare and too nice of a piece to mess with.  Tom and Jay, you confirmed what I was thinking.  Time to go back to the CAD board and draw something up with longer runners and a smaller center plenum.  I don't think it will be too difficult, just take a few hours.  Thanks for the insight, everyone.  If there is interest, I will keep this updated as things progress.  I have got to put this Corn Binder back together first and then it is on to the MEL.

Navigation

[0] Message Index

[#] Next page