Das Beast: My E30 track / street build

[sampayne]

It was already sort of mentioned in the link you posted, but I was curious about your opinion regarding the safety of going to a solid shaft and loosing the compression of a stock unit.

[TimeMachinE30]

We only pressurize to 10 psi. Works fine and no risk of fluid everywhere.

I keep pressures low, too. But I have only had success with the BMWs. Ford and Chevy the seals of the black line (the CNC, expensive fittings) just ruined the reservoir threads.

[dvallis]

If I'm in a collision bad enough to collapse the entire front of my 1.75" x 0.120" DOM cage, drive the steering column 3' back through the quick release, through the steering wheel, pinning me to the seat like a bug, then a collapsible lower shaft will be the least of my worries.

[kronus]

The thing that ends up mattering is the size of all the problems added together, not just the biggest one.

I’d guess that it’ll be easier to get out of a burning, half-collapsed car without two broken wrists.

[dvallis]

Track schools taught me to let go of the wheel if it all goes really sideways

[sampayne]

If I'm in a collision bad enough to collapse the entire front of my 1.75" x 0.120" DOM cage, drive the steering column 3' back through the quick release, through the steering wheel, pinning me to the seat like a bug, then a collapsible lower shaft will be the least of my worries.

Lol, true. I forgot das beast has that beefy cage

[dvallis]

Wire!

Ordered all the electrical harness wire today. No affiliation but Wirebarn rocks. They have a huge selection of GXL automotive wire gauges and colors. They'll sell it by the foot, or in multi-packs. Decent prices too. I got 100' of AWG16 GXL black for $13.

I wanted to do German wire color coding, but could not find anywhere selling spiral striped multi-color GXL wire in less than 500 - 1000 ft rolls. Meh.

[dvallis]

Electrical Extravaganza

Proper wiring harness for a race car is fairly involved. Not hard to understand, just a lot of moving parts. It's a lot to keep in your head, so best to write down the plan. Thought I'd share my latest. It might help someone out one day.

First, you need to get high current to the right places in the car. We are starting with a battery in the rear right stock location. This is good, because the rear right is typically the lightest corner of the car. We'll start with a stock Bosch Type 49 battery, which unfortunately weighs 45 lbs. However, it's bullet proof, so we'll use that to shake down the electrical system. Lighter always means faster. Eventually the Type 49 will get converted to a 10 lb ETX12 motorcycle battery. That's why there are two external pos/neg main bus posts. We will just make adapter cables for whatever battery is in the system, without changing everything else.

Next thing you'll notice is we are running a dedicated ground wire from the trunk to the engine bay. This creates a much lower resistance return path than chassis ground. Added bonus is we get some free ballast on the right side of the car where it's needed. Calculated peak load on the harness will be 100 A (more on that later), so we chose 2/0 cable. It is rated for 145 A at 140 F. We could have gone down to 1/0 or 1 gauge, but wanted the extra safety margin for peak loads.

The 12V main runs to a four terminal 500 A bus bar in the engine bay. This is needed to accommodate a dual pole race spec kill switch. Race sanctioning bodies require that when the switch is off, neither the battery nor alternator will power your wiring harness. Have a look at the diagram below and you'll see how that works.

Starter gets a direct connection to the battery via the same 500 A bus bar. We did not want starter loads going through a switch. This is an elegant way around that. The starter is still killed by the cutoff switch, since its solenoid is energized off a relay.

Grounds in the trunk, cockpit and engine bay are all run to dedicated bus bars or ground strips.

You can see the control structure for every load in the car. The 12VALW bus feeds resettable circuit breakers, which supply switch controlled relays, which connect to each load. (They are called out next)



There is also a very cool feature build into the system. Three split ring hall effect current transducers (circles with arrows) convert current in the alternator, main and battery bus to a low analog voltage which is fed to the data acquisition system. This data will be displayed on a dash page and recorded in real time. During testing we will be look at strip charts of each bus voltage versus time and overlay with things like engine RPM, speed or temperature. Talk about an invaluable tool for electrical diagnosis! :devil:



The plan actually needs to get more detailed. We require a physical layout of each load, how many wires and where they are routed. That's shown below. This enables conduit sizing for each of the AB, CD, EF runs.



To actually buy wire, you must estimate the current in each circuit, length of the run, pick wire gauges, assign a unique color and tabulate all the data. That took a lot of freaking work. The letters are small but you get the idea. Wirebarn saved my ass. They have everything. Would have liked striped spiral color selections, but I'll take the eleven colors they had.



I bought the 2/0 cable locally since the stuff is heavy and shipping would be a pain.



Rest of the stuff will be coming in this week. Stay tuned.

[dvallis]

Steering .... again

So, tired of messing around with the steering. We're just going to fab custom linkage and be done with it. Here's the starting point: two E46 lower linkages.



Propane torch breaks down the glue and plastic binding the shafts together. They hammer apart easily enough after that.



Here's a comparison of the original knuckle and new parts. Remember, the assembly has to be about 1/2" shorter because the Z3 rack has a longer connection to the steering shaft than an E30 rack. The two bolts on the original knuckle would have to be cracked and spacers added to shorten the linkage.



Final pieces cut to length.



Test fitted on the car. Very smooth with no binding. It was easiest for us to remove the steering column for assembly, not the rack. We have already drilled out the steering column shear bolts and replaced with removable hardware.



Fully assembled. It takes a 0.018" aluminum shim on each side to make a tight fit. Aluminum siding works great. We are leaving a 1/8" gap to allow for TIG welding, and make the shaft a bit longer.



Will take it to a welding shop tomorrow and final assemble later on this week.

[apostate]

You may want to rethink the positioning of the fuel cell.
It is quite high and influences the inertial vectors of the car.

[dvallis]

Per NASA Racing safety specs "Installing a fuel cell that hangs significantly close to the ground or one that is mounted closest to the rear of the vehicle, even if the installation meets with these rules, may be deemed unsafe and therefore excluded from competition."

Dropping the cell through the floor means moving it aft of the diff, i.e. very close to the rear of the car. NASA tech inspector had a look and was not loving it. Failing tech would be an ignominious non-start for Das Beast racing career. Leaving fuel cell over the diff only gives us 3" - 4" of drop. Meh.

We'll see ........

[apostate]

Why not place it where the original reservoir was?
Would this be OK with the NASA Racing safety specs?
Cheers.

[dvallis]

No. Steel bulkhead required between driver and fuel for FIA/SCCA/NASA.

[dvallis]

Final steering shaft, TIG welded. That's looking better.

[dvallis]

Current sensors arrived. They are nice! Quality work.