This is going to be a big photo dump of my latest adventures into 3D printing, both for prototyping and hopefully end usage. I purchased myself a 3D printer, Wanhao Duplicator i3, and I'll do a separate post for that soon.
In my last post , I had just commissioned some prints of velocity stacks. Well I did some redesigns, and they can now be found on thingiverse. The velocity stacks are mm tall and designed for Silvertop AE throttle bodies. Next up was designing an airbox for the ITBs and mm tall stacks, I pretty much modelled it using the same external dimensions as my Pipercross filter.
I did this because I know for sure that it would clear all the brake and clutch parts in the engine bay and I also wanted the ability to easily change from filter to airbox.
I can and will make a better design once I have this design fitted and tested. For the Pipercross filter and this airbox to clear the stacks, a new mounting plate needed to be made. So I chose to print out a spacer that would be sandwiched between two laser cut plates, you can see it in the previous screenshot. Below is my ideal design, will work on that soon.
The printed spacer for the filter mounting plate, had to be printed in multiple pieces due to the limited build volume of my printer mm x mm x mm. Before doing the actual prototype print I decided to use some rubbish filament for a test print without support material, just to see how far it could go. It failed pretty quick when it got to the dome part, it recovered slightly towards the end though.
Here you can see the rear section of the airbox being printed, tried to minimise the usage of plastic and support material. This was printed at mostly micron layer height and the curved sections were printed at micron layer height, varying the layer height like this helps reduce print time as well as reduce support material for the sections with overhang. Mid section being printed, by far the easiest part.
Only needed support material for the mount flanges, this was printed at micron layer height. And this is the front section being printed, all printed at micron layer height.
This part had some design modifications to improve print-ability, also to reduce plastic usage and support material. Since this is a prototype for test fitting, sections are glued together using Cyanoacrylate. Final part will either be epoxied or plastic welded together, not sure yet. Or maybe just use the print as a mold for carbon fibre? It's amazing seeing this all come together as one piece, nearly mm total length.
So happy! Photo trying to show the internal clearances with stacks installed, minimum distance to walls is 25mm. Some lessons I learned during this entire print are that overhangs causes prints to look like crap.
So I've made the following design changes to help reduce overhangs. The highlighted flat sections at either ends of the flange remove the overhangs and allows my printer to simply bridge that section, which my printer does very well. This makes the print look cleaner and also reduce support material. I found that printing holes on a vertical plane produces nasty overhangs and causes imperfections in and around the hole, so I opted to print only dimples instead of a through-hole.
This improves the finish and I can just simply drill the holes post print anyway. I also modelled this catch can and printed it out for test fitting. Unfortunately, the filament ran out before it completed printing. Was still able to test fit though! Enjoy this article?
You can get faster presses to print more pages and forms per hour, and you can get more automation and labor to box and package the final magazines. But it will do no good. If the bindery can fold and bind , magazines per hour, this bottleneck sets the maximum performance level. Having a page form printing and packaging capacity beyond the limits of the bottleneck bindery does nothing.
You will either print more pages that sit and wait for the bindery or you will have labor waiting around for more bound issues to come out for packaging. Just about any system can be broken down to highlight the bottlenecks. In the case of the above example, doubling the capacity of the printing presses or the capabilities of the packaging department may become the bottleneck.
So, how do we find the bottleneck? Some platforms have been around long enough that the proper mix of upgrades to eliminate the bottlenecks are well known to reach a desired performance level, other platforms may be too new or underdeveloped to be fully understood. On a vehicle, engine performance can be limited by bottlenecks in either the air flow or fuel delivery systems. This month, we will highlight all of the components that either affect the delivery of air into the engine or combustion products exhaust out of the engine.
The Bottlenecks Engine performance is limited by how much air can be ingested by your engine. This amount of air is combined with the optimal amount of fuel to produce the maximum amount of energy through combustion. Getting more air into the cylinders allows more fuel to be burned and more energy and power to be realized. These may be great parts that will add performance once the bottlenecks are addressed, but they may show no increase in performance at all with the bottlenecks in place.
Path to Airbox Before the air even makes its way to your factory airbox, it may need to pass through an opening in the bumper, traverse a grille element, enter a duct and navigate through this duct to the engine compartment or the airbox itself. To improve this path, first take a hard look at the OEM layout. Why did it take such a path? Could the ducting be increased in size? Could the initial source for the air be taken from a cooler location?
Can the number of turns and twists be reduced? If there is an opportunity to improve this path, improve it. OEM air filters generally use a paper or carpet-like media that is pretty effective at filtering out dust, dirt and contaminants when new.
Over time, the filtering properties remain good but the filter itself begins to become an impediment to air flow. Upgrading these panel filters to high-performance aftermarket units will typically deliver 2-to-5 horsepower on most applications. When the factory airbox leaves much to be desired from a performance standpoint, an aftermarket intake system may deliver substantial power gains on the order of 10 to 20 horsepower.
It all depends on the application. Dyno results show barely measurable improvements with an aftermarket intake system in place. However, once the turbocharger is upgraded, all bets are off as the limits of the factory airbox at higher power levels may become obvious. On older models, a vane type of mass air flow meter is used.
This system uses a flap that opens using the incoming air. The more air is coming through, the farther back the door is pushed. Behind the first flap is another vane used for a more accurate monitoring. As you can imagine, the force needed to push the flap open works as an added restriction for the air. To eliminate the bottleneck, there may be a modern hot-wire mass air flow meter conversion available.
In lieu of that option, a conversion to speed-density eliminates the MAF all together and uses a MAP sensor to determine engine load could do the trick. Ensuring the inlet pipe from the intake filter to the turbo or throttle body is large in diameter can free up some air and improve power. Inlet Pipe The inlet pipe connects the airbox to either the throttle body naturally aspirated or compressor inlet boosted.
On a naturally aspirated engine, the inlet pipe will go directly from the intake to the throttle body perhaps including the MAF meter along the way.
If you have a turbocharged or centrifugal-supercharged engine, the inlet pipe will go from the intake to the compressor inlet of the turbocharger. This pipe plays a big role in air flow. The larger its diameter, the higher its air flow handling capabilities.
Be sure your inlet pipe is large enough in diameter to support the amount of air needed for your target power level. Most of the time, the inlet pipe provided with the aftermarket intake system will be large enough for the application. Compressor Turbo or Centrifugal Supercharger Application The compressor side of a turbocharger consists of a compressor wheel and compressor housing. The size of the compressor wheel and its aerodynamic design determine the amount of air flow the compressor section will provide at a given pressure ratio, shaft speed and compressor efficiency.
The R35 GT-R is a great example where one may realize psi of boost pressure at lower engine speeds, only to see it drop off to psi near redline. Increasing the flow potential of the compressor side of the turbo or centrifugal supercharger with a larger wheel and housing combination will eliminate this bottleneck, but there will be repercussions in many cases. Bigger turbos will generally have reduced boost response target boost pressure cannot be reached at lower engine speeds while bigger compressor sections on centrifugal superchargers will require more power to be stolen from the crankshaft to be driven.
Its size, placement and construction tube-and-fin, bar-and-plate will all effect how well it performs in reducing charge air temperatures. To save weight and cost, OEM intercoolers are generally designed to be as small as possible to deliver a measurable but not necessarily optimal charge air temperature reduction at OEM power levels.
Larger aftermarket intercoolers when properly designed can provide exceptional charge air cooling benefits, especially at elevated power levels.
As with anything in the intake path, the diameter of the charge pipes can also influence power output. Pipes that are too small in diameter may become a restriction to flow and limit the power output. When more air than factory is being forced into the engine, sometimes using a larger throttle body is beneficial.
Before any air can enter the intake manifold, the throttle body and the position of the throttle blade itself will regulate the amount of air allowed into the engine. Up until about 15 years ago, almost all engines used a mechanical cable or linkage to put a 1-to-1 ratio between the position of the acceleration pedal and the position of the throttle blade.
When the diameter of the body and the blade were smaller than optimal, some of the flow to the engine would be choked off even though the throttle blade was fully open. The remedy was to replace the smaller diameter throttle body with a larger diameter replacement. More recently, mechanically-manipulated conventional throttle bodies have been replaced by a Drive-By-Wire DBW throttle body, which uses an electric signal generated from the pressing of the accelerator pedal.
Intake Manifold While the throttle body acts as the crossing guard in allowing air flow into the engine, the intake manifold attempts to direct an equal amount of air to each cylinder. The shape, length and taper to each of the intake runners to each cylinder will influence the behavior of the engine.
The length, shape, cross-sectional area and taper to these runners will influence at what engine speeds RPM optimal tuning occurs. The size of the common plenum where all of the runners join also influences performance.
Since the exhaust manifold, camshafts and cylinder head characteristics also play a role in determining at what engine speeds the engine will be most efficient, successful engine developers spend a great deal of effort matching these components for the desired torque curve. Despite being costly at times, porting the intake ports can realize more power and improve response. Intake Port The air is distributed from the intake manifold into the head. The cross-sectional area and the shape of the port make the biggest difference in air flow.
The goal is to develop a port that balances flow and velocity to maximize the filling of the cylinder. The optimum size of the intake ports depends on engine speed, displacement, and whether forced-induction is used.
During porting, careful attention has to be paid to the transition area from the intake opening to the bowl area. The shape of the port is critical. The more direct the path for the air into the cylinder the better, all other factors being equal. Like everything else, bigger is not always better. Having a percent increase in air flow through porting can equate to a percent increase in power, only if the port is close to the optimum size and velocity of the flow has not been affected.
Intake Valve Before the air is ingested into the cylinders, the intake valves have to open to let it through. The size and shape of the valve will affect the flow through into the cylinder especially at low valve lifts. No matter how well the intake port in shaped, it is always a challenge to get the air to flow around the valve and through the opening between the valve and seat as it opens. The valve job will also influence reliability and longevity. Valve jobs that use ultra-narrow seating surfaces may show flow improvements, but these narrow seats may not be able to transfer heat out of the valve quick enough.
This can lead to warping of the valves and damage to the seats. In a number of Japanese engines, the valve diameter is large enough or sometimes too large for the intake port itself. If oversized valves are being used, be sure that the port shape has been optimized for the larger valve. Exhaust Valve Similar to the intake valve, the exhaust valve is the route where the exhaust gases exit. Proper flow into the engine is just as important as the flow out of the engine.
Any air flow restrictions on the way out can cause exhaust back pressure forcing horsepower to be wasted pumping out the exhaust. During the exhaust stroke of the combustion process, the exhaust valve opens as the piston goes up to force the exhaust gases out of the cylinders.
The same approach for intake valves can be taken for exhaust valves to ensure proper air flow. Exhaust Port When intake porting is done, usually exhaust porting is done as well. Similar to intake porting, exhaust porting also increases the diameter of the ports and improves the angles of the areas where the exhaust gases hit on the way out. When both intake and exhaust ports are optimum, the engine is more efficient and more power is the result.
Exhaust Manifold Once the exhaust gases exit the cylinders, they go through the exhaust manifold. All of the exhaust gases flowing through the manifold are collected into one pipe. Factory exhaust manifolds can create a bottleneck as more exhaust gases are forced out of the engine. The bottleneck creates exhaust back pressure, which decreases efficiency and power. Using an exhaust header is a good upgrade to reduce the amount of exhaust back pressure.
Instead of forcing the exhaust gases into a shared manifold, an exhaust header gives each cylinder its own pipe.
The pipes are usually the same size, which lead all exhaust gases from the cylinders into a larger pipe known as the collector. The diameter of the pipes and collector, as well as their shapes, determine the air flow potential of the manifold.
Mid section being printed, by far the easiest part. Only needed support material for the mount flanges, this was printed at micron layer height. And this is the front section being printed, all printed at micron layer height. This part had some design modifications to improve print-ability, also to reduce plastic usage and support material. Since this is a prototype for test fitting, sections are glued together using Cyanoacrylate.
Throttle Body Kits
Final part will either be epoxied or plastic welded together, not sure yet. Or maybe just use the print as a mold for carbon fibre? It's amazing seeing this all come together as one piece, nearly mm total length. So happy! Photo trying to show the internal clearances with stacks installed, minimum distance to walls is 25mm. Some lessons I learned during this entire print are that overhangs causes prints to look like crap. So I've made the following design changes to help reduce overhangs.
The highlighted flat sections at either ends of the flange remove the overhangs and allows my printer to simply bridge that section, which my printer does very well. This makes the print look cleaner and also reduce support material. I found that printing holes on a vertical plane produces nasty overhangs and causes imperfections in and around the hole, so I opted to print only dimples instead of a through-hole. This improves the finish and I can just simply drill the holes post print anyway.
I also modelled this catch can and printed it out for test fitting. Unfortunately, the filament ran out before it completed printing.
BMW M44/M42 Complete ITB Kit Includes Gloss Carbon Airbox
Why a cold air box? Because power! Like other engines, L6s love cold air, with greater density increasing flow. The standard Z engine bay gets hot, so the typical carb setup triples or SUs is drawing hot air in with less efficiency.
The airbox design negates this.
Engine Tech | Air Flow Bottlenecks
Also, whether you can fit one is dependent on your intake manifold dimensions. Specifically, if you have a Cannon brand triple carb intake manifold, you will need to change it! The Cannon has runners an inch longer than most other options, leaving no room for the airbox between carbs and inner wing. It is also great value for money versus the extortionate U. Beyond that, it becomes a case of what components you want to use to filter and feed cold air from in front of the radiator support.