I think that this effort may have a better chance of not leading to power loss than the previous, failed extrude hone efforts. I think this is because in this effort the runners didn't get bigger and the amount of material that was removed must have been minimal. I was expecting the complex runners to get worse by extrude honing because it's a total crap shoot where the process removes material. Instead, the process seems to have been run in a way that only changed the runner surface and didn't really change the size of the runners. It'll be interesting to see how this pans out on the dyno.

A minor note: I believe that terms laminar flow and turbulent flow are terms of art with specific meanings in models of flow regimes. My guess is that the flow in these runners is always in the turbulent flow regime. When discussing geometric features of ports or runners that cause excessive turbulence and flow losses, I'd avoid calling the flow turbulent or laminar because that means something else. I think.

 

I thought this car would be relevant to the discussion; one assumes Porsche never intended the 928 to be a race car, and yet there is a 928 race car in the Porsche Museum. Cool stuff!

 

There was a unofficial 928 racing campaign done by Porsche through their relationship with Max Moritz racing.

It is discussed under "Special Versions" near the bottom of this page:
https://en.wikipedia.org/wiki/Porsche_928

 

SUBSCRIBED.... boom.

 

Been a little remiss about posting builder pics as of late, so here are a few.

The bee-hive valve springs are all in to match the hi-lift cams and rev range.

The forged 10.4:1 pistons are on their rods and installed, the rotating assembly was dynamically balanced after the rods and pistons were balanced to within 0.1 gram. Note the "knife-edge" treatment of the crank - bull-nose forward, tapered edge to the lee side.

Next the head studs will be installed and the heads on the top end, and the crank scraper will be installed tomorrow on the bottom end.

 

Wow! Beautiful work Carl.

 

Alright well I'm back from Europe, which was not really a planned trip. Back to work on the car, after a couple days of rest!!!!!

 

Thank you, Chris. The pictures never do it justice, but I am please they are at least interesting to the reader.

 

On more than a few builds, I've hesitated a while to reassemble so I could enjoy the beauty of all the parts and pieces on the bench. They are engineering artforms unto themselves. I don't get into that level of fun much these days. Keep the pictures coming!

 

Took an assessment yesterday on what's left to do on Der Panzerwagen. I do a lot of projects, and I have found that a series of lists is the only way to track all the outstanding items on a build.

Lists are essential when you are working on more than one build at a time, or there are gaps in time when you don't work on the build. I don't prioritize or order the lists, I simply write down what needs to be done.

Since I am not doing the motor on this build, I have more or less put that piece out of mind for now. Here is the current list on the car, in no particular order:

- Mount aero bits; skirts, winglets, splitter, etc.
- Install fire suppression system
- Install 12 volt main power system
- Wire accessories (fuel pumps, PS pump, etc)
- Install seats and harnesses
- Purchase and install tires (close to the last thing I will do)
- Remove old decals, replace with new ones
- Inspect each and every dzus fastener for wear, replace if necessary
- Fab tow hook for front of car
- Bleed brakes
- Plumb power steering pump
- Finish installing accusump (when engine gets here)
- Replace quarter windows with lexan
- Install Electromotive ignition and ECU
- Install virtual dash


That's it, more or less. The heavy lifting mechanically speaking is complete; what remains is really finishing bits and little projects.

 

Hey, Carl - any secrets on sealing exhaust joints? Specifically where the headers meet with the collectors? Mine continues to have issues.

 

Looking nice Carl. What are the seated and open valve spring pressure? How much valve lift?
Åke

 

One of the few things automotive related that I have formal training in is with 12 volt systems. As a wayward kid, Dad sent me off to the local technical school where I was more or less forced to obtain a 2 year certificate in electronics engineering. It sounds fancy, but it is not a degree nor am I an engineer. It was basically a two year course on the design of 12 volt systems, batteries, soldering, wiring, and a bunch of other crap. I hated it at the time, but 25 years later I can't believe how lost I would be without a solid foundation in DC systems design.

So I normally don't sweat electrical issues in cars, and I have built more than one wiring harness from scratch. The Devore car has ZERO existing wiring, which is great because lots of race cars still have the heavy stock harness in place. In this case, Devore = blank slate, which I like the best.

Some months ago I put in an optima gel battery and box in the right rear passenger seat, left unwired for the time being.

Today was the day to begin the foundation of any DC system - the battery connections. I always do the battery first, and then branch from there.

In another career after school, I spent 10 years in the marine industry and thus the way I do things in the cars is very marine-like. For example, I am a fan of Blue Sea systems products and Ancor wiring connectors. Both are exclusively boat products, but they are WAY tougher than equivalent automotive stuff.

I don't much care how much weight the DC system adds to the car. I always go with a full sized battery and a minimum of 2/0 cables for power. Sure, it adds weight, but who wants to chase ground and power issues because you're trying to save weight.

In this case, I began by routing the old battery cable to the new location by drilling a hole in the bulkhead and putting in a grommet.

I used a Blue Sea battery disconnect for maintenance purposes. It should be noted that this off switch is NOT the emergency disconnect used by first responders. The Devore car already has such a system, with two separate disconnects, one external and one close to the driver. The switch I installed today would be upstream of that, and it's basically a maintenance and storage disconnect.

The Blue Sea stuff is overbuilt and this switch has a 1500 amp cranking rating, which is an order of magnitude more than will be needed.

Next it was time to tackle the ground. People get wrapped around the axle on grounds. In this situation, the ground can be anywhere you want it to be, so long as it's good and solid. I sanded away a convenient location, then welded a bolt directly onto the chassis for a firm, solid ground that I could bolt a battery lug to. It doesn't get much better than this for good grounds.

Finally - and this is super important - once I bolted by negative battery cable down, I immediately painted over the whole assembly with the same undercoater the interior is done in.

Corroded grounds are a MAJOR issue in a multitude of electrical problems that plague many cars. It's important to immediately protect the area from corrosion, so the paint covers everything, while the metal to metal connection is still preserved underneath.

Some of my practices are:

- always use split loom one wiring to prevent chafe
- all heavy gauge wires get hold downs as necessary
- Always use marine grade crimp on lugs with a marine crimper on battery cables.
- Cover the cable almost to the end with electrical tape to prevent corrosion

So now we have the foundation of the battery system. Now onto the accessories!

The undercoater paint in the picture hasn't laid down yet and looks lumpy.

 

Grommets on cable passing through battery box?
Nice work,
Dave

 

Great minds think alike! I really wanted to put grommets there but the box is cut out in the lid as well as the body, so I settled for split loom.....we'll see if I can figure a way to put some in!

Secretly, I love grommets.....