omgpham…
25Mar/173

Velocity Stacks & Airbox Prototyping.

 

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. For now let's talk about my experiences with the intake parts I'm prototyping 🙂

I have no real knowledge in both 3D printing/modelling and engine intake theory, I'm just learning as I go, so there will be mistakes here and there. And therefore, not entirely sure if these parts/designs will make any measurable performance gains, but it's all fun anyway!

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.com, again it's still all a work in progress and I'm not expert in the design theory.

The velocity stacks are 105mm tall and designed for Silvertop AE101 throttle bodies.

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Next up was designing an airbox for the ITBs and 105mm 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.

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Below is my ideal design, will work on that soon.

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The printed spacer for the filter mounting plate, had to be printed in multiple pieces due to the limited build volume of my printer (200mm x 200mm x 180mm).

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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.

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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 200micron layer height and the curved sections were printed at 100micron layer height, varying the layer height like this helps reduce print time as well as reduce support material for the sections with overhang.

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Mid section being printed, by far the easiest part. Only needed support material for the mount flanges, this was printed at 280micron layer height.

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And this is the front section being printed, all printed at 280micron layer height. This part had some design modifications to improve print-ability, also to reduce plastic usage and support material.

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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?

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It's amazing seeing this all come together as one piece, nearly 500mm total length. So happy!

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Photo trying to show the internal clearances with stacks installed, minimum distance to walls is 25mm.

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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.

  1. I added a chamfer on the inside surface to reduce the overhang angles under the "dome", this allows me to print with minimal support material, and the chamfer being only 20% solid means I use less plastic overall.
  2. 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.
  3. 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.

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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!

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11Jan/174

3D Modelling & Printing.

 

Ahoy!

Lately I've been spending more time learning how to model parts in 3D, still new so bare with me. It's not a new concept to me, but I am using Fusion 360 mainly now and sometimes a bit of SolidWorks.

I've done some prints in the past, a good example would be the bulk head connector plate I drew up and printed. Had it installed in the car while I waited for the final piece to be laser cut from steel.

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And now I'm starting to move onto slightly more detailed designs. Starting of with "remixing" a design from Thingiverse.

4AGE Black Top Velocity Stack - http://www.thingiverse.com/thing:25207

And my "remixed" version, which is basically modified for Silver Top engines instead of Black Top and increasing overall length to 115mm.

4AGE Silver Top Velocity Stack - http://www.thingiverse.com/thing:2016083

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I than scrapped that design altogether and did one from scratch, increased the radius lip profile and removed the side bracing. The print below was done in ABS and I'll be testing it for clearance and heat resistance. If all goes well, I'll most likely print my final design in ABS. If not, other materials like Nylon and Poly-carbonate are alternative options for heat resistance.

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And this is another design I quickly modelled. Main differences being the bottom flange, length adjusted to 105mm and the dimpled internal surface. NO idea how that'll work for airflow, good or bad, but it's fun drawing these and 3D printing them! The idea is from dimpled surfaces on golf balls, and I've seen shops machine dimples onto the back of inlet valves and cylinder head ports.

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And this is how the print came out.... About halfway up the velocity stack, the wall was a tiny bit too thin and the dimples were too deep! Not something I was expecting, but I'll learn from this one and make revisions. This print was also done at 300 micron layer height, I think it needs to be 100-200 micro next time.

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And finally, this is an airbox/plenum that will mount to my current Pipercross filter plate. Still needs some work here and there, but I'm pretty set on the general shape of it and the inlet is 4.5" diameter. The final product could be moulded from the 3D print and made with carbon fibre, or possible printed entirely out of fibre infused nylon for strength and heat resistance.

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More to come!

11Jan/170

Toda High Compression Pistons!

 

Welllll than...... A couple new things in this update, and possibly a second post regarding some stuff I've been 3D modelling for the build.

First up, managed to install this 5V oil pressure sender and input it into the Megasquirt for full datalogging and dash display through Shadow Dash. The tablet mounted using two magnetic mounts clipped to the eye-ball vents. Works very well and has a very strong hold.

It was surprisingly easy to get working, the sender needs +5v, ground and signal return to the ECU. I happened to use the AD6 input on my Megasquirt, and TunerStudio has a built in wizard to configure your sender.

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Developed a slight oil leak into cylinder no. 4 so took valve cover off to replace the gasket. Remember to go genuine valve cover gasket! I've had nothing but trouble with non-genuine valve cover gaskets.

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Finally bought some new tyres and fresh alignment done! Hankook RS3 225/45 R15.

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Received and installed my IL Motorsport bonnet lifts, not sure if I like them yet.

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Next up, I had some spare parts accumulating and was able to put together this LED bar kit. It's operated via RF remote control that looks like a bomb detonator, the LED light bar and associated electronics (now enclosed in water-proof case) are mounted just behind the front bar.

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Garage Star Coil-on-Plug adapter acquired!

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Toda forged pistons!!! They are 11.0:1 compression ratio and +3mm overbore, made from a special alloy with very littler thermal expansion which allows it to run factory Mazda piston-to-bore clearances. Toda also designed the skirt to allow usage of factory oil squirters. I also ordered the matching overbore head gasket from Toda.

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Some close ups of the pistons.

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6Mar/164

Manifold Vacuum Rail

 

OK! So last post was positive, engine started up, ran well and idled nicely. But that didn't last long...

While getting the tune sorted, I noticed that the vacuum readings were a little off and it turned out to be a vacuum leak due to a hose not being connected properly. Fixed the vacuum leak and then the engine didn't want to idle anymore... So I fixed the idling issue but that resulted in my brake booster not getting enough vacuum to assist the brakes 🙁

So the real problem was the vacuum set up, I think. So I've come up with a set up that mimics a few other off-the-shelf ITB kits. Haven't had time to finish everything yet, but will post update when I get it running again and report back on the vacuum set up.

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These are the push-to-connect fittings I'm using, swivel tee fittings.

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Marked out the holes and drilled 11.1mm holes so that I could tap a 1/4" NPT thread.

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The fittings tested fitted and measured so I could cut the hoses. The hoses need be installed in the fittings while they're out.

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Vacuum rail installed and the old holes plugged up.

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Also test fitted the filter backing plate, some clearance issues here...

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Installed a Garage Star Wiper Cowl panel, and need to make a new fuel hose because I had to go from dual to single feed fuel setup.

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And finally installed and gapped the headlight covers, hate doing them so much.

28Dec/151

Start Up!

 

This was not a smooth start up.... Ran into a few issues earlier on, car would crank over and sometimes nearly run but never more than than a fraction of a second. Went through and checked through the wiring and grounds, everything was good there, a quick visual inspection of the cam gear and cam lobes to see if they were in the right positions. And a whole bunch of things....

The ECU logs showed consistent sync loss, error no. 31. Something was wrong with the cam/crank sensors. In my particular case it was caused by the crank trigger wheel being installed backwards :P. And I actually did check it earlier on, but checked it incorrectly!

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Once I flipped that trigger wheel around, it started right away! Here's a quick video of it, more to come later!

23Sep/151

Back Home!

 

Happy day! Car has been towed back home and first thing we did was remove all the front panels 🙂 Storing them in a spare bedroom for now, don't want to scratch anything during assembly.

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Colour is Audi's Aviator Grey.

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The entire engine bay was covered in blankets during the engine install.

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Hnnnnggggggggggg!!!

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Colour looks amazing in sunlight, the Audi paint code has a bit of pearl through it but can only be seen in direct sunlight.

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The freshly powder coated radiator and sway-bar brackets fitted up with new bolts.

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A quick mock up panel for the engine harness Deutsch bulkhead connectors.

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I had the front lip painted gloss black, will be interesting to see how well it holds up from all the abuse it cops 😛

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16Jul/152

Respray Preparations.

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As some of you may know, the MX-5 is booked in for a re-spray and engine bay colour change. Body will be painted factory Crystal White and the engine bay will be Battleship Grey. Now the stripping and preparations begin!

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Seats were removed to make it easier to pull the dash out. Dash came out so I could pull the wiring harness completely back in to the cabin.

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Rest of the parts being stored away. The ARP CF mirrors getting sanded back and a new coat of clear too.

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Pop-up headlight assemblies will be disassembled and sand blasted, they'll be painted same colour as the engine bay.

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Part way through the long and slow process of removing everything from the engine bay.

27Oct/132

WTAC Road Trip Update

 

Hey everyone!

Long time no speak, been too busy driving/tuning/enjoying the car. It's easy to get caught up in all the fun and forget to update the blog 😀 . In all honesty, there hasn't been much to post about. I did however just do a road trip down to Sydney for WTAC 2013.

I really enjoyed the 900km each way drive, the seats were surprisingly comfortable. But with no AC, windows down and sitting my 4100RPM, we were slightly deaf from the ITB noise!

I'll post photos I took with my DSLR soon, but here are few I've collected in the last week. Photos were taken by various friends and props to them for the amazing shots.

More photos after the break!

2Aug/132

ITB Build – Part 16

 

More progress today!

Picked up all my Aeroflow fuel fittings from Race Car Engineering. Fittings are all push lock style, black and -6AN size. Thanks to the guys at Auto Xperts for supplying the hose, looks OEM and I prefer it over the black braided stuff I bought earlier.

For extra security hose clamps were also used.

Hoses completed and installed!



31Jul/134

ITB Build – Part 15

For the last week I've been slowly working on the engine wiring. My goal wasn't to tuck anything, but more of a general clean up and make it look neat and easy to access.

Wiring was made from scratch, straight to the Megasquirt and power board. I used brand new connectors/terminals and Deutsch plugs whenever I could.

The air filters and hose clamps will be replaced with better parts very soon.