Side vents/ducts, and now Snorkels!

[Dr.Jeff]

I had a thought for a duct design that could allow for a much larger opening area (increased air flow) while still blending with the X's body lines....let me know what you think.

One aspect we have discussed is trying to keep the stock body lines in tact, by integrating the duct into the 'recessed' portion on the sides of the X as it is in stock trim. However this greatly limits the overall size of the duct; going taller (top to bottom) crosses over those body recess lines, and going wider (extended further out to the sides) makes them stick out too far and therefore not proportional. But looking at the drawings offered by Janis earlier, I wonder if proper proportions and a continuation of the body lines could be done on a larger duct/scoop. The thought is to make the duct larger by some ratio (designers need to input here), say 1/3 of it above the upper body line, 1/3 of it below the lower body line, and naturally the last 1/3 the same size as the recess. Then add the same recessed lines (from the body) onto the duct itself. See how Janis did this on the lower portion of the circled image:

But my thought is to do something like this to both the top and bottom portions, with the overall size being proportioned as just described. So the duct is twice (3 times?) the height but has both body lines (upper and lower aspects of the recess) in it. This added height allows for greater surface area (intake size) without having to go wider (further out) to the sides. And the continuation of the body lines help integrate the added size of it into the X's general design. Naturally the underlying bodywork will need to be modified to allow for a greater opening into the engine bay. Unfortunately I cannot draw or Photoshop this, hopefully someone gets the idea and helps with some sort of image to visualize it. But I'll make a feeble attempt to use "Paint" and add some grey and white lines on Janis' illustration to help convey the idea (although it needs to have more 'rounded' contours than I can do with "Paint"):

Apologizes to Janis for the 'graffiti' on his illustrations.

 

[Janis]

It’s Ok,no pretensions
You can print out pictures and scetch on them or “eco friendly” put thin paper on screen, turn on brightness, and switch off light. And draw what imagine - it’s easier than struggling lines in Paint.

That scoop doesn’t have to pass through chassis in same size. Air can be collected in bigger area and little bit pressurized as tunnel gets smaller. Won’t work in traffic jam.
I will be persistent with my first idea

 

[Dr.Jeff]

That is what I was describing for the duct, thank you. I would have to experiment with some models on the car to visualize it, but I might like the "scoop" portion to come a little more forward...possibly something similar to one of these examples shown earlier, but with the same style as you drew (if that makes sense):


Wish I could draw a single line let alone a nice picture. But I like the idea with a "light box" to see through to a real image.

 

[lookforjoe]

Problem in part is there is no where to extend the inner opening downward (beyond tapering the feed)- it's already basically on the frame rail at that point.

Need a pic of a stripped bay to examine the area above the existing sheet metal aperture to determine if there is room. As pointed out, working with just a larger intake area would likely prove beneficial when in motion.

 

[Dr.Jeff]

That photo is helpful to see exactly what's behind the scoops. Previously I took a quick look at mine and it seemed the passage into the engine bay could be opened up a fair amount. Naturally it would require cutting but that doesn't bother me or I wouldn't be considering any customization (obviously cutting doesn't bother you either Huss ).
True, if the frontal area of the outer scoop is larger than the passage-way (opening) then it would need more of a 'ram-effect' to pass the maximum volume of air possible. However there isn't a lot of air passing through the side vents when the car is standing still anyway...other than if any blowers/fans are connected, in which case the same amount will be drawn in regardless of how big the ducts are.

 

[bpimm]

I have an open engine bay sitting here, as soon as the pouring rain stops I'll go out and get a pic of it from the inside. I think we can open it up quite a bit from where it is. this is from memory but the highlighted area is what I think we can open it up to

As you can see it lines up with the bottom body line so any vent below that line would not have a strait shot into the engine compartment, but there is a fair amount of space between the outer body and the frame rail to add a sloped floor to the duct and their may be room inside to raise the upper side of the duct as well and make the whole thing slope up.

 

[bpimm]

Here are pics from inside, the ducts are still there but you can kinda make out the shape of the possible opening.

 

[bpimm]

Kinda hard to see in these pics but I highlighted the area above in this one that can be used, there is also some room below as well. with a little metalwork I think a doubling of area is attainable.

 

[Dr.Jeff]

Thanks Brian, that's about what I recall when I looked previously...it would have to slope upward from the outside to the inside to get the maximum opening. Even a 50% larger opening would be a significant increase in air volume that can flow through when the vehicle is moving, and I think it can be made greater than 50%.

The other half of the equation is allowing hot air to escape (exit) the engine bay. This will be a topic in upcoming threads regarding customization/redesign of the engine cover (lid) and the rear-trunk/rear valance. But for now consider if the engine-bay's cover allowed significant upward air movement, then the engine compartment would get a considerable increase in air circulation even when the car is standing still; large side openings toward the lower portion of the engine bay combined with free upward movement through the top cover will allow cool air to be drawn in the side vents as hot air rises up and out the lid. The property of physics for hot air to rise has a powerful potential; it is the basis for power generation and many other uses. As an analogy, my dirt bikes have a water cooling system similar to a car (radiator and cooling jackets in the engine) but no water pump at all. The differential in temperature between the cool water in the radiator and the hot water in the engine causes it to circulate and is very effective.

Naturally movement of the vehicle will create a much greater air-exchange effect as the side scoops force cool air in from the bottom and the low-pressure area above the engine cover (behind the rear window) draws hot air out.

 

[bpimm]

I've seen 3 different mods to the engine cover, removing the rain tray which opens it up a bunch, spacing the rain tray further away from the cover allowing for larger passages out of the engine compartment, and on one of my 80's the rubber strip across the back of the engine cover is missing which gives you a big opening at the back that runs all the way across. On the one I'm going with the Dallara body on I'm thinking of squaring out the backs of the rear fenders to incorporate air vents there to help evacuate the hot air as well.

 

[Dr.Jeff]

I'll get more into it later when I create new threads on the topic of modifications to the engine cover and the rear valance. But since I live in a very dry climate, and I'm not adverse to getting an engine wet if it does rain, I am planning a complete replacement engine cover made of stainless mesh screen by using the early style 'side' covers (either side of the engine lid on '74-'78 models). With this set-up the two 'pocket' areas on either side of the engine bay (under those early engine lid side covers) will likely be eliminated. The ignition box will be replaced as part of the stand-alone ECU and go in the spare tire well. Therefore those pockets will be empty. By cutting them out the side-duct openings could possibly be brought up considerably.
I'm also considering opening up the wall between the engine bay and the rear trunk (allowing me to mount components like a remote oil-cooler and filter, inter-cooler, coolant reservoir, etc in the trunk) and adding the same stainless screen material to replace the rear panel (where the tail-lights, license plate, etc mount). Might even consider moving the radiator and/or AC condenser there with fans. The rear trunk will not be of much use as a trunk by the time the air-suspension components are mounted anyway.

Off topic, Brian how did the manifold flanges work out?

 

[motoTrooper]

Dude, no water pumps? How old are your dirt bikes?

 

[Dr.Jeff]

Almost as old as me.
I think that design continued on until rather recently. I had a Suzuki 500 Quad (last year them made them before death-related related lawsuits stopped production) without a pump. I haven't been in the go-kart scene for awhile but they also had no pump for the water cooling system, likely still the same way.

 

[darwoodious]

Maybe I can help with the engine bay view - ignore the cuts/welds etc for K20.

Driver side engine bay:

Passenger side engine bay:

There's not a lot of room lower than stock, but you could certainly go higher a bit. As mentioned, there is a box-frame structure above which connects the structural wheel-well arch to the rear bulkhead/sail at the top side as well as the even larger lower box-frame structure *with* the thick sandwiched plate running from the lower rear wheel-well arch to the front wheel-well arch. You don't wanna mess with those. Here's the passenger side of the same taken from the outside of the car in the stock air scoop area:

Looking up:

Looking down:

It's an interesting discussion, but I personally wouldn't do it - I think the best option is to open up the flow by cutting the horizontal plastic slats from the scoops - maybe remove the verticals too?

Hope this helps.

 

[Janis]

Maybe I can help with the engine bay view - ignore the cuts/welds etc for K20.

Driver side engine bay:
View attachment 6379

Passenger side engine bay:
View attachment 6380

There's not a lot of room lower than stock, but you could certainly go higher a bit. As mentioned, there is a box-frame structure above which connects the structural wheel-well arch to the rear bulkhead/sail at the top side as well as the even larger lower box-frame structure *with* the thick sandwiched plate running from the lower rear wheel-well arch to the front wheel-well arch. You don't wanna mess with those. Here's the passenger side of the same taken from the outside of the car in the stock air scoop area:

Looking up:
View attachment 6381

Looking down:
View attachment 6382

It's an interesting discussion, but I personally wouldn't do it - I think the best option is to open up the flow by cutting the horizontal plastic slats from the scoops - maybe remove the verticals too?

Hope this helps.

I think same, interesting, but questionable.
Already have cut horizontal slats, if it wont be enough for turbo setup in summer climate here, will add fans (UT injector cooling) into scoops.
I have lying radiator in the trunk with fans at the top, which takes air from bottom and help a bit ventilate engine bay too.

 

[Dr.Jeff]

Thanks 'big-D' for the good photos. If the pockets on either side above the vents are partially removed (short of cutting away from any structural box sections), then I think quite a bit can be opened up. I will need to take a closer look at mine but here is an idea of what I'm thinking (red areas):

A replacement 'floor' would be added to the cut-out section of the pocket for reinforcement (along the top of the upper red line). Its been awhile since physics class, but I seem to remember that the volume (rate) of air flow increases exponentially as the surface area increases. Or am I confusing that with other physical laws?

 

[rjplenter]

A mock up in cardboard.

Opinions on size?

 

[bpimm]

Off topic, Brian how did the manifold flanges work out?

I haven't done any more on them, my printer has pretty much crapped out and I haven't gotten another one yet. I'm thinking of cutting the flange out with the plasma then putting it in a jig and letting the cnc mill drill the holes for a cleaner more precise pattern. Just as usual I need to clear some other projects out so I can get back to it.

 

[Janis]

perfect size, I would move it all a bit down, to march line.

to get in more dirt in engine bay

 

[motoTrooper]

I've been reflecting on Bernoulli's principal as I read this thread and it seems to me that you would require a small duct or scoop that transitions into a larger inner chamber. NACA ducts seem to be a design specific to this principal for drawing fast moving, low pressure air into an engine bay. Certainly scoops will work also as long as they aren't choked down into smaller ducting. Scoops may be less aerodynamically efficient however. I am enjoying this discussion deeply as I have been working to design aesthetically pleasing ways to increase air flow for cooling and intake to the Lancia's engine bay with the larger engine. I may have an easier time with this with the slightly different construction of the Scorpion.