Dual cone cold air intake - C4 Vette

admin

Here's some pics of the dual cone cold air intake for my 87 vette. It's made from some 2.5" exhaust pipe I had kicking around. It's a little heavier than I would have liked, but the price was right. I'll trim up the intake pipes and should be able to get two 5-6" K&N filters on it. I have the engine out for a 383 stroker rebuild.
Reply:I see work, but I still see more work.  Looking forward to what you come up with.Common sense in an uncommon degree is what the world calls wisdom.
Reply:Very nice bridge and twin inlet! The 'ol girl is getting a 383...what about paint? John -  fabricator extraordinaire, car nut!-  bleeding Miller blue! http://www.weldfabzone.com
Reply:Thanks Microzone, I want to get the mechanicals in and running first....then I'll make it pretty
Reply:Interesting.  The workmanship from the limited pics looks dang nice.But the flow through that intake piece doesn't look like it will be all that great.  It -may- be adequate, but the geometry of the two 2.5 inch pipes V-ing together into that skinny delta shape before going into the Vette funnel and then into the round actual intake (4 inch dia or so, it looks like).If the round intake is actually 4 inch diameter, then your intake airflow area from your two 2.5 inch dia pipes is only 9.8 in2 compared to the 4 in dia area of 12.5 in2.  You are about 30% under-sized.And that doesn't take into account any actual flow characteristics of the shape and connection geometry.If the outlet is only 3 in dia, then area-wise you are OK.  Still have to check the flow though.Hate to a nice engine trying to suck air through a straw, ya know.
Reply:Moonrise, thanks for doing the math and providing me with a bit of an education. The outlet is 3", I copied the design from what I saw in catalogs and our local performance shop. It is bigger than the stock set up that came on the car. I agree, I don't want it to be sucking through a straw.
Reply:Originally Posted by SWellsMoonrise, thanks for doing the math and providing me with a bit of an education. The outlet is 3", I copied the design from what I saw in catalogs and our local performance shop. It is bigger than the stock set up that came on the car. I agree, I don't want it to be sucking through a straw.
Reply:Gotta agree with MoonRise,...You got a nice cold location there, that´s great...butttt I think that probably instead of the V a straight single tube would provide better flow...and definetively no change of diameters...I´m still learning FLUENT (fluid simulator) can´t do a comparison between both but I´m sure there´s someone here who knows about air flow.My Babies: HF Drill pressHF Pipe Bender3   4.5" Black and Decker angle grindersLincoln Electric PROMIG 175that´s it!
Reply:Gent's, I've ready plenty of your threads, I've just gotten a bunch of respected opinions in a row. At best it sounds like the intake may kinda be OK. That's not gonna cut it. It will look good hangin' off the wall in my garage or I just built the coolest looking eavestrough drain kick out in the neighborhood. Thanks!If you don't want to stand behind our Troops, feel free to stand in front of them.
Reply:Well SWells, it does look very nice!!! Even if you hang it up, the experience gained from doing it as a practice piece is very valuable. It looks great!! Paul.And then, after so much work...... you have it in your hand, and you look over to your side...... and the runner has run off. Leaving you holding the prize, wondering when the runner will return.
Reply:More math.A 383 at 5000 rpm will be sucking in ~280 CFM of air.  If you somehow got each 2.5 inch pipe to actually flow half of the air, the intake air velocity in each pipe would be ~46 mph.No way will you flow that much through your twin 2.5 inch pipes in that geometry, the air has to make too hard of a turn coming in from the 2.5 inch pipe and then make almost a 90 deg turn while fighting the air coming in from the other 2.5 inch pipe trying to do the same.The air velocity of that required 280 CFM through the 3 inch intake section will be moving at ~65 mph.For flow, especially on the intake side, think smoooooth sweeping shapes and nothing sharper than a 45 deg turn (30 deg or less would be better).  Take your idea and lose the delta/manta-shaped Vette plenum and instead run a sharp sweeping V of two 3 inch pipes from the 3 inch outlet up in front of the radiator and stick your K&N 5-6 inch filters on each of them.Or fab up a big rectangular intake funnel in front of the radiator, transition that to a 6 inch pipe section with your K&N in-line, and then transition the down-stream side of the filter to the engine's 3 inch intake tube.  Ram air!  But I don't know if you have enough space in there to cram all that in.
Reply:Nice math lesson.. Look at it this way..Look at any drag car with a aftermarket scoop on it..Big hole...And the hood hole is closed off all around the hood opening and all that air going in that big hole only has one place to go..In the carb..@140 mph how much air is that???...zap!I am not completely insane..Some parts are missing Professional Driver on a closed course....Do not attempt.Just because I'm a  dumbass don't mean that you can be too.So DON'T try any of this **** l do at home.
Reply:I think I would compare what the intake piece can flow to what the throttle body can flow.... To be honest, if the throttle body flows "X" and the intake piece you made flows more than "X", I think you could just run it for a while until you go bigger on the throttle body side?Not sure what you have on there for now, but just a thought.  I agree wholeheartedly with the math shown in the previosu threads and would personally love to know where to see these formulas, but I am trying to say if the intake you made is plenty for the throttle body/intake manifold you have for now, why not give it some run time?  Nice fab work BTW, I like it!!  Looks good
Reply:WOW !!!!!! batman that is a sweet CUSTOM piece. Can't imagine the time it took to fab that but its alot of PRIDE showing there.I think the CFM's quoted above might be a little off, or that is the air volume for each cylinder. My 700cc Pro Stock 2-stroke snowmobile  does over 250 CFM @ 7400 rpms and  over 350 CFM at 9300 rpm.  Maybe since it cycles twice as much . But our intake for top end power is a 4" tube into a snorkel sized down to 2.5" , but for more bottom end we run a straight 5" pipe. See the big pipe allows more cfm instantly but does not benefit from the bernoule principal  without the snorkel, thus loosing top MPH.  Or otherwise known as a velocity stack conical shaped pipe. By forcing the same air into a smaller hole it speeds up thus acting like ram air, but you need to provide a calculated air box with the correct volume for your stroke and intake timing neeeds to pressurize. Without this airbox BEFORE the intake you can't have ram air.  Its like a garden hose stick your finger in the stream and it will speed up thus going farther faster with more inertia.  Your cross sectional area although decieving might be just fine but sizing all along the way will determine this. Also a good way is to get on the superflow or an Eddie Currant dyno and see what is elusive to the eye and math calculations. You will ALWAYS be surprised on the HP truth detector. 1 pipe in a long straight path  per cylinder or carburnator ( sarcastic spelling) is the best intake in a perfect world. you can also find out quickly by using an air/fuel ratio guage, detecting changes in your lean-richness to a very small amount. Thus always allowing you to jet or adjust fuel map to the adjusted air quality and altitude at the track. Your own litle correction factor.  The 2 inlets might actually help creat more vorteces going into the T-bodies, a good thing.  Hope  it does well, and I am sure if you copied this from something some company is making it must do something positive other than looks. ??????500 AMP AIRCO TIG LINCOLN PT185 100% DC @ 128 AMP-WTFSPEED GLASS 9002X MILLER THUNDERBOLT 225HOBBIEST TURNED WELDING JUNKIE8 2ND FIRECAT - SNOWMOBILE RACE CHASSIS FABRICATORPRIDE IS WHAT MAKES YOUR WORK SO GOOD