Adjustable Cam Pulley Cores

Cam Pulley Millwork

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Airbox Painting

A little bit of masking, and a little bit of paint.

Filterbox Installed

Filterbox installed in the engine compartment. You can start to see how the Fiat’s relatively “open” design engine bay starts filling up!

Filterbox Snorkel

The snorkel adjacent to the headlight, should provide plenty of cool air. For a better ram effect, however, the area should be sealed better. This would also promote better airflow through the radiator.

Finished Weber Airbox

The airbox, hinges installed and painted, ready to rest atop the Webers.

Latch Detail

A little more detail of the hinges. They’re stainless and will always stay this nice!

Airbox Seal

I used a silicon bulb seal between the upper and lower halves.

Airbox Installed

You can see more of the seal detail in this installed picture of the airbox. Note the air horns which are yet to be installed.

Hose Connection

I used some silicone hose to connect the filter and air boxes. I also use t-bolt clamps when possible, they’re a remnant of my turbo days. They’re very reliable and aesthetically clean,  sometimes cheaper than the worm style hose clamps.

The Finished Product!

The finished product! Time to take it for a test drive ..and then to the dyno!

Finished Form

Then I cut the fiberglass fabric to fit over the form. I found this step imperative in order to avoid wrinkles in the final product.

Dry Fiberglass Fit

It was then time to mix up some epoxy and lay down a few layers of fiberglass. I found the best method to apply layers was to first put some epoxy on the part, then dab the fiberglass into the epoxy. The fiberglass soaks up the liquid and sticks well to the form. I found that “wetting” the glass before applying generally resulted in too much epoxy.

First Layup

Once the epoxy cured and I had some rigidity, I smoothed things out with some Bondo.

Bondo Filler

Here you can see copious amounts of Bondo were applied as filler on the inside of the box. This makes things much heavier. In the future I would use a honeycomb material instead.

Box Inside

Once I had enough rigidity, I cut the box open to remove the foam and tape from the inside.

Lid Detail

Once I had everything smoothed out, I added a final couple layers of glass. This time I also tinted the epoxy with black dye. You can see how much smoother and consistent the finish ended up.

Final Layup

This next picture shows what the insides looked like.

Inside Airbox

Next up was the filterbox. I employed a similar process as the airbox above and with extra practice, my fiberglass skills produced a much nicer finished product!

Filterbox Fiberglass

Unfortunately I chose to work on this project in the dead of winter. In Houston, this only meant 50 degrees. The epoxy, however, is designed to cure in 24 hours at 75 degrees. For every 10 degrees different, it is a factor of 2 in cure time. I couldn’t wait 4 days to cure, so I put it in the oven! The light bulb inside maintained a nice 110 degree temperature, and the part was done in a few hours.

Airbox Baking

Waiting for the epoxy to harden.. stay tuned to see the finished results!

The first problem to tackle was to define the hard constraints such as the firewall, hood, carbs and overall engine compartment. I machined up the baseplate shown below as a reference plane.

Aluminum Baseplate

Once I had a plane of reference, I used expanding foam packing material to measure the clearances.

Instapak Mold

Here you can see the impressions in the foam.

Instapak Impression

Once I knew how much room I had to work with, I began to shape the foam form. I had to figure out the best shape for proper airflow, while also allowing access to the Webers for tuning. What good is an airbox if you can’t adjust your idle!

Foam Form

The form further developed, and I decided to place the inlet high in the engine compartment. This allowed for smooth flow from the inlet to the base plate, no bumps, no restrictions, no turbulence!

Developing Form

This is the final form the airbox took. The more I cut away, the more fragile it became, so I used masking tape and wooden dowels to hold it together.

Finished Form

The other part of the project was the filterbox. I wanted to keep the filter as far away from the carbs as possible, reason being, is that filters create a large amount of turbulence which is exactly what we are trying to prevent. This is yet another reason why those mesh screens on air horns are about the worse thing you can do to a Weber carb!

Filter Box Frame

Like the airbox, I had planned to build the filterbox from scratch. This turned out, however, to be very difficult. I decided to start with a BMW 850i filterbox instead. These are very well built, and filters are easily available. I would retain the lid and latching mechanisms but reshape the rest.

Filterbox Shaping

Simple, everyday cardboard was used to fill in the holes in the box, and shape it to something more useful.

Filterbox Bondo

The joints were sealed up with Bondo and sanded smooth.

Snorkel Shaping

The final step in forming the filterbox was to add the snorkel to draw air from the front of the car. The theory being that as the car moves along, the pressure at the front of the car increases with speed. If we’re lucky, we might even get a bit of a ram air effect and push 1-2% more air into the engine and push 1-2% more power out!

Stay tuned for part 2, fiberglass!

Honda NR500 Oval Piston

Who doesn’t love seeing innovative ideas like this? Back in the late 70′s Honda pushed the limits to compete in MotoGP. This was one of those rare occasions when a team of engineers was let loose to dream without limits. The result was an engine design that was quirky at best: a 500cc, 4 cylinder with 8 valves per cylinder and, get this, oval pistons! Find the time to check out the full story of the 1979 Honda NR500 on Honda’s website.

If you were to spin a distributor through an engine’s operating RPM and then record the degrees of advance it generates, you would get a graph similar to the one below.

2d Ignition Map

Here we see our engine has an operating range from about 500 to 7500rpm. Max advance of 32 degrees is achieved at about 3800rpm, and static advance is 12 degrees at about 800rpm. This is the exact terminology used to describe ignition curves of mechanical distributors. Now we just need to translate this terminology into a map or spreadsheet that MegaJolt can understand. This looks like below:

RPM vs Advance Table

RPM bins are represented across the top while the colorful numbers represent degrees of advance. Lets say your engine is running at 2000rpm. MegaJolt will look at the table above, and say “oh! we need 29 degrees of advance!”

However, if you open the MegaJolt Configurator software, you won’t see a table like above.  You’ll see one like what I have pictured below.

Table View

MegaJolt only understands maps with 100 bins. It likes to also use load sensing (MAP or TPS) to look up advance values. We can trick MegaJolt into not caring by copying our simple 10 bin map down each row.

MegaJolt will turn this into a 3d map like below. If you look at the profile of the curve/surface though, you’ll find it is exactly like the curve at the top of this post!

Megajolt Configurator View

You could copy all of the data above manually. Luckily though, MegaJolt works off of a settings or configuration file.  You can download a copy of the above generic RPM only configuration here and then load it into your own MegaJolt! Easy peasy!

For a more advanced map, try Mapping MegaJolt: MAP and RPM, or Mapping: TPS and RPM.

• RPM Only
  This mode is often overlooked, it only uses the RPM input to calculate advance. This mode is most like a standard mechanical distributor with weights and springs. This will produce a 2-dimensional map (RPM and Ignition Advance). You only have 10 bins to work with though. See: Mapping MegaJolt: RPM only
• MAP and RPM
  This mode calculates advance given Manifold Air Pressure (MAP)  and RPM as inputs. This will produce a 3-dimensional map. In this mode there are 100 bins (10×10) to work with. MAP and RPM is ideal for most applications such as single carburetors, mechanical fuel injection, and early electronic injection (Bosch L-Jet etc.) It is the only way to go for boosted (turbo or supercharged) applications.
• TPS and RPM
  This mode calculates advance given Throttle Position Sensor (TPS) reading  and RPM as inputs. This will produce a 3-dimensional map. In this mode there are 100 bins (10×10) to work with. TPS and RPM mode ideal for situations where a steady vacuum signal is not available such as with dual carbs, or individual throttle bodies (ITB’s).
• Adjustments to Advance (Advance Correction)
  In addition to the modes above, you can add another layer of complexity to adjust ignition advance. This can be done via just about any external sensor sending a voltage signal to the MegaJolt. The most popular, and usually most effective, is through the use of an Intake Air Temperature (IAT) signal. This will act somewhat as a multiplier, giving you extra depth to each bin, producing a 4-dimensional map with 110 bins (10×10+10).

Amazon Web Services

Miller’s Mule now lives on Amazon EC2!

Bye bye slow site!

Christmas Crate

Here at the shop we receive packages nearly every day, no big deal.. well.. until this one showed up!

Peel back the shrink wrap, cut loose the straps and we find an array of patterns to cast Abarth bits.

Abarth Casting Patterns

Oil Block Pattern

Slide Throttle Manifold

First and foremost will be dry sump oil pans, then we’ll move forward into producing Abarth 131 slide throttles.

Here’s to a productive year!

Axiom1 Racing Development

Here’s a site from a fellow engineer I met a week ago. He has more than a few interesting projects including a project Corvette paddle shifter conversion!