Wonder if someone has made their own stacks for mechanical injection? I need a set of tall stacks for my 2 7/16 Hilborn, but cant find the money to buy a set right now I have loads of 2 7/16 aluminum tubes, and thought i might be able to make some myself, but not really sure how to do it. Straight tubes want be good for the flow i guess (and doesnt look good either). Also looking for a nice way to integrate a screenfilter inside the stack.
Check out the stacks on my MG lower left in picture, it was 1965 and my friend made them with funnels on end for a ram air effect. We really never noticed a difference over the short, straight ones. They then switched to the tall stacks. Picture is recent. Pat
On the recent pic, are they just duct taped in the middle? I found a website with how to make them all by hand... think i will give it a try. Time consuming, but might work. Just need to find a suitable cone, or make one.. http://www.thefabricatorseries.com/build-blogs//sheet-metal-intake-manifold-entirely-by-hand-p1
I have a 3" Hilborn on my Car, and one of the Tubes became dented in Shipping (they are Aluminum)-I called AlkyDigger to get a replacement, and it took 3 weeks-I asked why, and he told me that Hilborn had to make it, and they aren't a normal 3" diameter (they are a tad larger, maybe they are 3" i.d. instead of o.d.?)-you might want to be certain that the Tubing that you are using is of the correct size, as I cannot find anyone who makes them (other than Hilborn)-
Alu is tricky, the right thickness to flare out but thick enuff so the whole thing doesnt colaspe and the correct temper so it doesnt split. How big of a flare? and if this is a Chevy injector, you are going to have to flatten one side to get them to stand next to each other. I made these with steel tubing and used a press with a cone die, then after the flare was shaped I remove the cone and pressed it again on a flat surface to roll the edge around
You can kinda see the curved stacks I made for my Packard going to the air box. They are made from exhaust u bends mostly. They don't need to be aluminum and in fact plenty of steel stacks came from Hilborn. I also threw in two pictures of aluminum bells I made for the tops of the Hilborns for my Dodge banger. I have made these for the stacks also to go in the air box.
They are steel first off and the bells have a slip on end that goes over the steel tube but they loosen up and I have lost one or two at times so the duct tape just holds the bells in place. Alky digger sells bells of different sizes. Pat Thanks Pat
You might want to contact Member Marty Strode on here. He is a multi talented craftsman and Tin Smith. He's no stranger to injector stacks. He just might be the right guy to make a small job out of your delema from being able to do it for you to advising you how to do it yourself pending your talents. The Wizzard
Those aluminum tubes i have are the exact same o.d as the Hilborns, but i noticed last evening that they have a thicker wall. That makes it harder to make a flare i think. Might work to cut to length and use them as an extension to the short stacks i already have - then i can make different lengths also as i got tons of those tubes. If i can find some alu tubing with the same i.d as the o.d on the stacks.... a piece of that larger tube with set-screws might work to connect and keep them in place? It is a chevy injector. I was thinking about a cone die too, but when i realized the wall thickness compared to the originals, i dont think it will work any good. I could of course try to find tubes with thinner walls, but the money isnt there right now. Nice stacks btw
In my sprint car days , a lot used the alu tube stacks around 6"-8", the problem being that with the heavy filter attached the vibration would work and crunch the stack where it pinched to the injector. racers kept tightening the pinch clamp and after awhile the pinch casting would break and have to be welded. I think that long stacks made from alu and of thin material would have the same effect. Here's what I would do, take the alu tubing you have and bore out the center 2" down to proper thickness for flareing and leave a step. Aneal the end and flare to whatever, and epoxy a screen to the step you left as a register
I've always thought that the stacks' lengths (and possibly diameters) were determined by the engine build / tune on the motor. Not so? Gary
Tall for torque, short for speed . But in Drag racing and the addition of the PG trans and converter science, torque is had so the stacks are short for speed. Sprint cars on the other hand dont run a transmission and rely on tall stacks for torque and "BALLS" for speed
I forgot about this "project" due to some other priorities... but back in business i made a mockup yesterday. What i basically did was to turn down the outisde of the tube i have, and then slide/press the old stacks on to it, just need a few tack welds or "clamps" to secure them. Oh, and a little nicer fit/turning - this is just a test Tubes i have has a been powdercoted, and its a pain in the a*** to get rid of, might leave them as is, or maybe i give it a try in the lathe. Now i just need to determine the length, as i want the top of the stacks to be a above the hood (g***er).
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