SB-100 Success: Plates are on the Car

Ah, my good friends at the California Department of Motor Vehicles (DMV), especially my extra extra good friends on Fell St in San Francisco, how I’ve missed you! It’s been way too long. I really should have come earlier. Maybe we should hang out more often!?

Yes, maybe we should – so I can explain your own processes, regulations and laws to you since you don’t seem to get them. Perhaps I can give you a lesson in customer service too, expert that I am at that (as in been subjected to shitty customer service many times there.) Admittedly, the SB-100 registration is not a common one to be processed, probably even more so in the middle of San Francisco. I guess there are just not as many crazy guys like me building cars in the city.

And so here’s how I got to spend almost four hours there, missing a few work meetings as a consequence.

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SB-100 BAR success, but I limped home

The day finally came to go to the supposedly super-evil California Bureau of Automotive Repair (BAR) station. To go there, you need an appointment, which is easily done by calling the number at To get the appointment you also need you SB-100 sequence number and the VIN from the CHP, so that step needs to come first. I was able to get an appointment within two weeks of calling up. Easy.

All of the stations are at community colleges. The closest one to me is Skyline College in San Bruno. That’s about 15 miles to drive each way involving a traditional commute route on the way there. I was honestly a little bit nervous, not at all about the appointment itself, but about getting the car there. Being stuck in bumper to bumper traffic for an 8:50 am appointment could cause cooling issues again plus I’ve simply not driven the car very far and now I need to be in traffic, on the highway and drive super far from home.

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Motec C125 dash controls via Arduino-powered steering wheel

It ain’t a real race car without lots of buttons on the steering wheel to do cool stuff, right?

I guess, sorta. While coolness is an added bonus, that’s not really what I was trying to do here. Having the Motec C125 dash set up to read data from the Link G4+ Thunder ECU, I needed to find a way to move the screens on the dash. The dash only displays so much at one time and so you have the ability to scroll within a screen, as well as set up multiple screens to toggle between – as long as you can tell the dash to do the scrolling somehow. Here’s the final product:

One way to do this is to buy the ~$450 I/O module for the dash and wire a few switches directly into the dash. But why take the easy route when you think you still got the skillz to code and could learn a new environment in the process? Hey, here’s another project, because I need more.

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VINning at the CHP

At the CHP in San Francisco
At the CHP in San Francisco

Well, step 2 was easy. A few years ago, step 1 to get an SB-100 sequence number at the DMV was pretty easy too. The second step, after finally getting the car roadworthy, is to go to the local CHP station to get a VIN assigned.

I had called a few weeks prior and was told to show up at 10 am on a Wednesday. It’s close by in my case, not even a 15 minute drive to get down to 8th and Bryant. Appointments are required btw – don’t just show up.

The drive down was uneventful, though admittedly I was a bit apprehensive about potentially being in rush hour traffic and simply for the fact that I was further from home than ever with the car. I had asked my wife to be on standby to give me a tow, just in case. So I fill out my 1-day pass from the DMV, drive down, pull in right on time, walk in the door and I get a friendly greeting with a quip of “getting a VIN, huh?”

Yessir! That’s what I’m looking for. Two minutes later another friendly officer calls me up and I hand him my full stack of papers. I show him the ones I knew he’ll really care about, which is the sequence number from the DMV and the receipt with VIN of the car the engine and transmission came from. After not even a minute, we walk to the parking lot together and he starts checking out the car.

This was not a cop checking your car out. It was a knowledgeable car guy asking car guy questions. We joked about the folks trying to pull a fast one with Ariel Atoms or BAC Monos. The CHP is way too smart for that. Don’t even bother. I obviously had my s*#& together and had built this myself. It was obvious from my receipts and the chatter we had as car guys.

Back in, some back office paper work and after 25 minutes total I was out the door, CHP legal with a VIN. Easy and totally painless. Great process. Thank you CHP.

For anyone else looking to do this, here are my groundbreaking tips:

  1. Be organized, have all your papers. Show everything.
  2. Be friendly, they’re good guys and want to help you.
  3. But use the process for what it is: self constructed vehicles, nothing else.

Also, by finally doing a real drive, there were some obvious things I need to work on with the car:

  1. The engine tick is still there.
  2. The shifter throw is too far, so I need to shorten the handle.
  3. The idle is too low. Due to the lightweight Cup flywheel, the engine spins down too fast. The Link ECU can’t seem to catch this fast enough with either proportional gain table without causing a super bumpy idle instead – that’s the trade off there. However, if I set the idle target to 1300 instead of 1200 it has 100 more RPM when spinning down in order to react. I think this will work.

Newly discovered issues aside, step 2 is done and now it’s onward to the Smog Referee for a brake and light inspection. Again, super close for me – either across the Bay Bridge to Alameda or down to Skyline College.

Porsche GT3 (996) engine tick: help!

I’m getting ready to take the car to the CHP this week for its VIN and the engine just developed a little tick. It seems to come from the 1-2-3 bank and perhaps is near the front (chain side) of the engine. A few different people have listened to it and we generally think that’s where it’s from, but we aren’t 100% sure either. I have no clue what it is, but here are a few thoughts:

  • If you watch the attached video, it is 21 seconds long and there are 36 or 37 ticks in it.
  • 36 or 37 ticks in the video means 103-105 per minute
  • The engine idles around 1250 RPM. I know it’s bouncing a bit in the video – the idle hasn’t been tuned to dead perfect yet.
  • 1250 RPM means around 208 strokes per minute per cylinder, specifically 104 strokes of each type per cylinder per minute

So the strokes per type per cylinder lines up with the tick frequency. I don’t know if that’s by chance, but it seems oddly related. Any thoughts on what this could be?

The car runs!

The engine fired for the first time yesterday… whoohoo!

Unfortunately, while it runs very well, it also is good at spitting coolant out the exhaust, which is less than good. Big sad face.

The likely issue is that the engine overheated in the car it came from and damaged the head gaskets which will cause coolant to leak into the cylinders. This unfortunately means pulling the engine and taking the heads off. On a GT3 motor, only the heads are cooled, so hopefully I don’t need to tare it apart further than that, but I plan to do any sensible maintenance that I can while the motor is apart.

Although this is a big setback, I’m still pretty happy that I was able to get it running. All the wiring and setup was very complex and time consuming, so I’m pretty proud to have been able to accomplish it with zero prior experience. Now it’s on to the next learning-by-doing: rebuilding a GT3 motor.

Anyone wanna learn how to rebuild a Porsche GT3/Turbo engine with me?


Coolant leak Coolant leak closeup

Tail light install

Finished tail light installInstalling the tail lights at first feels a bit like “square peg in round hole”. Indeed, you do have to trim some stuff to make the light fit in the opening and then you have to figure out how to mount it. I thought about this a lot and looked at various other builders’ solutions. In the end, it’s an amalgamation of those or unique – the same thing in this case. So below is the step-by-step of what I did.





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Does a Porsche engine fit?

Yes it does! But it’s not easy. This question was just asked on the forum, so I thought I’d write a more long-form answer here.

My drivetrain is from a 2004 Porsche 911 GT3. It’s a 996 Porsche in Porsche-speak, a naturally aspirated engine which can be traced back to the LeMans-winning GT1 Porsche and beyond. The block is known as the “Mezger” engine and it’s proven so durable that it’s even being deployed in the new 991 GT3 coming out this year. It’s also used on the 996 and 997 Turbo or GT2 (also a turbo) models. For this project, you likely can’t do a turbo engine though, because the exhaust routing will be very hard without major chassis modifications. But I wanted a high-revving naturally aspirated engine anyway. Redline should safely be in the low 9k.

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Fan shroud design and installation

Pictured on the left is the front of the car, specifically the radiator as viewed from standing just behind the left front tire. The car comes with this custom radiator essentially installed, but the fans just come on their own without any brackets to mount them. That’s a where a fan shroud comes it. It serves as a mounting point for the fans and it also more or less forces air to go through the fans and not around them.

Enter a piece of aluminum, a jigsaw and some very precise measuring. In the end not a very difficult task, but you have to get a lot of measurements exactly right. Below are the simple steps after purchasing a piece of aluminum cut to the width of the radiator and high enough so that I could screw it into the top and bottom radiator cross-brace.


Step 1: Find the center of rectangle and the center of each fan. Also note that full circles on each fan would make the outside strip between the fans and the outer edges quite narrow, so I kept that a little straighter.
Step 2: Ghetto compass for drawing circles. I held the center in place with a screwdriver and had a hole big enough on the other end to fit a marker pen.


Step 3: Start cutting. I just used a jigsaw. Does the trip you can hide the slight scarring on the inside if you really care. (I did). Note the wider straight strip on the outside.


Step 4: Finish product, holes drilled to mount the fans from the inside.
Step 5: Mount the fans. I used stainless 1/4″ allen key button head screws with lock nuts.
Step 6: Drill the radiator. Aaaaah! Actually, it’s not that bad. There’s nothing but air behind that cross-brace. I had previously put mounting holes in the shroud, so I just aligned using those and then drill-tapped allen key button head screws in.
And the finished product… excuse the wiring mess. That’s since been cleaned up obviously.