802Projects

STI key

Purchase a Key CoverBackgroundMy Solution Installation InstructionsFAQ

Background

When Subaru released the 2004 STI in the US, it came with a very cool Titanium key. The Titanium portion was stamped with the STI logo and at the base of the key was a blue plastic piece. I always wanted one, but my motor swap is from a 2006 WRX. In 2005 Subaru started using their Immobilizer system. There is an Immobilizer control box under the dash, an antenna on the key ring, and a special chipped key (see boring looking key on right) that all works in conjunction with the ECU. Meaning it is not enough to have a key cut for your car, it must have the digital thumbprint inside it that matches everything. If it doesn't, the car will start and immediately shut off.

Some people would find a way to use the 2004 key. They would get it cut and then zip tie the chipped key behind the plastic steering column cover. Doing this negates the purpose of the security feature. I also wonder if it could leave the car in a "wake up state" (potentially increasing battery drain) because the key is in range of the ignition at all times. Another thing people would experiment with is cutting the chip out of the OEM key and gluing it inside the key fob. This seemed to have mixed results because depending on the ring used on the key, the fob could swing in and out of range. I wasn't happy with either of these options.

My Solution

If you are not keen on reading, I created two videos that outlines my solution. The first is a 1 minute short if you don't have a lot of time. The second goes into it in more detail.

My original idea was to carefully remove the blue plastic on the 04 Titanium key. Once removed I could mill out some metal material behind it, slide the chip in, and add the plastic back. I soon learned that this is IMPOSSIBLE. The blue plastic cannot be removed without ruining it. After learning this the hard way, I decided my only option was to develop my own plastic piece. I opted to design one that could house the entire chip without any milling needed. I spent a few weeks developing it and tested 25 iterations before I was happy with it.

Here you can see the chip slid inside the key. It's a 4D62 chip. This chip came from a $10 replica key I bought. You'll also notice the outside of the plastic is smooth. The 3d printer leaves horizontal lines. This is fine for less visible parts, but I wanted the key to have a nicer finish. I experimented with vapor polishing and got mixed results. After trial and error I found that I can dip the part in acetone 4-5 times and it smooths everything out. If I perform a light sand on the part before the dip, it comes out even better.

How to Purchase

Edit 1/06/2024: As of right now I have some black ones ready to go, but I am out of blue. Right now I'm exploring making these with a Resin printer to save me from having to hand sand each one.

All 3D prints are printed with ABS at 100% infill. It's durable, its hard to scratch, and it will not malform like other plastics (PLA) if you leave it in a hot car. I inspect each one after the print. I also do a quick test fit after the dip to make sure they fit well.

Install Instructions

  1. Purchase a 2004 OEM STI key (Part# 57497FE000). They are around $30.
  2. Have the key cut for your car. Aubachon hardware did mine.
  3. Cut off the oem blue plastic being careful not to scratch the key.
  4. Place the 4D62 immobilizer chip into the hollow part of the key. Orientation is important (see photo below). It should slide in like this. Tuck it down and to the left as far as it will go with a little screw driver. (
  5. Slowly slide the plastic onto the key and press it in place. Unlike the oem plastic, you can slide it back off using some force without ruining it. If you'd like to make it more permenant you can add a dab of crazy glue to the round collar of the key before pressing it on.

FAQ

How do you remove the OEM blue plastic from the key?

Very carefully. You will end up destorying the plastic. That is a given. But you want to take your time becuase you don't want to scratch the key. Its best to wrap key blade with masking tape. Then slice the plastic vertically in the cylinder area multiple times with a fresh razor blade. Do multiple cuts with minor pressure. Eventually it will get deep enough where you can pry it open with a small screwdriver. I've cut a few off myself and occasionally key shaft will be lose. You'll be able to slide it out of the titanium end. If this happens you can add a few drops of crazy glue and slide it back in.

What brand 4D62 Chip do you use?

I use the JMD KING blue chip from odbshop: MORE INFO This chip comes from overseas and from my research it is quite common. It is compatible with the Handy Baby 3 programmer, but may not be compatible with all programmers out there. If you plan on having a local locksmith copy it for you; you may want to check with them first to see if it will work. Your locksmith may want to use their own brand or refuse to use your chip. Check with them to see what it will cost. It may be more affordable to send me your key. So far I've had one instance where a person's locksmith said they could not flash the JMD King chip I supplied. The locksmith sold him a different brand chip for $40 which to me is a huge markup. I bought the chips in bulk and they cost me around $3 each.

Who can cut the key?

Any locksmith can cut the key. Most hardware stores can as well and will likely be cheaper. My local Aubachon hardware has cut two keys for me for free. I would not mention anything about a "titanium" key. The only part that is titanium is the part you grip. The actual shaft part they cut is normal metal. If you throw the word "titanium" around they may thing the part you cut is made of titanium and refuse to do it.

Instead of buying and copying the chip, can I pull it from my oem key?

You can sacrifice one of your oem keys if you don't want to deal with copying the chip. If you look under your key you will see a little rectangular door. The chip is behind that. I'm not sure if it is possible to remove without ruining the key, or if it is something you have to cut open. If anyone does go this route and is able to get it out without destorying the key; please let me know.

Are there alternatives to shipping our key to you for a chip copy?

You could try your local locksmith or even Ace Hardware. They advertise online they sell chipped keys. Unsure if they can program them too. You could also try your Subaru Dealer. Maybe someone could buy the Handy Baby III themselves ($140), use it, and then resell it to someone else who needs it. Even if you lost $10-20 doing this, it's likely a locksmith would charge you more. I thought about renting out my programmer with some kind of deposit that I refund when I receive it back. Maybe I could do that in the future, but right now I need it in case people send me keys.

Can you print in different colors besides blue and black?

I have no plans to do this. A roll of ABS filament cost about $25 and the shelf life of about 2 years. Say you want pink and I were to buy a roll of it... I'd never sell enough of them in that color to warrant the upfront cost. Its just not worth it. I use black for other parts so I'll always have that color. It's understandable why most people would choose blue so I bought that color. If you are dead set on another color and want to pay for a roll of filament; I suppose I could print that color for you. If you find someone else who wants the same color maybe you can split the cost.

Can you do custom engraving in the part?

While it is techically possible, this is not something I will be doing. I've never messed with it, but from what I've seen to get a really clean result you want the side that is engraved to face upwards. I print these parts sitting vertically. If I were to try to print one on it's side I would end up with supports everywhere and tons of infill that would have to be dug out and sanded off. It is not worth the effort. Learn to appreciate the STI logo that is stamped on the titanium portion:)

What does the raw version look like on a key?

Here are some pics of the raw version. These come directly from the printer with no finish work (ie sanding and acetone dip) done to them. It's what most people think of when they hear the term "3D printed". Some people don't mind the look though. Or maybe they would like to smooth it using their own process. It's not uncommon for me to have extra prints that are not usable. Maybe the bottom of the print started to lift off the bed, or maybe a glob of ABS got stuck to the print. Provided I have some, I'll throw a few rejects into the package free of charge. This way if you are thinking of doing the finish work yourself; you'll have some to practice on.

Can you ship overseas?

I can ship overseas. It will be more than $5 I have listed above. I shipped some of these in a padded envelope to Sinapore and it was $17.

Can I get one that doesn't have the hollowed out provision for the chip?

I'm not sure why anyone would need this unless option, but I already had someone ask. There is no reason you couldn't use this cover without a chip. You'd just have a little hollow pocket inside that isn't visible. The ABS plastic is printed with 100% infill so its very strong.

Have you considered printing these on a resin printer for an even smoother finish?

I spent several hours researching resin printers and did end up buying one. It's an Elegoo Saturn 3 Ultra. I'm still learning how to use it, but I have a good feel for pros/cons.

Pros:

Cons:

Really its just the scratching hurdle to overcome at this point. I tried standard resin and "ABS-like" resin, and they both scratch easily with my fingernail. I think some kind of clearcoat may be the answer though. It would also help prevent future UV exposure. Here is a picture of my resin prints. You can see where I scratched them both using my fingernail.

What about using Vapor Smoothing on the parts?

I did build a nice vapor changer inside a jar. I added a screen on the side with paper towels behind it that I soaked with acetone. I filled the bottom with a few inches as well. I built a little stand in the jar to suspend the part and left it for an hour with the lid sealed. It would eat away at the part but not evenly. The sharp corners would become rounded (causing gaps) before the sides were smooth. On top of that, the part remained gummy even 5 hours after removing it. I could literally tear it in half with my hands. The Acetone dip is the most reliable way to get a smooth finish and it's quick. I've started sanding the surface of them with some 400 grit before the dip. This makes it even smoother. I also did some research on Tumblers and that isn't an option either.

What about injection molding?

I'm exploring ways to mass produce them. I don't think the demand is there to warrant that big of investment. It would make my life easier though. As of right now maybe 4 out of 10 I make end up usable. Each print takes 35 minutes. The first hurdle to clear is the print sticking to the bed. Maybe 1 out of 5 prints the edge will lift. Printing with ABS is very finicky. I have a heated enclosure, a CR Touch for bed leveling and went to a PEI sheet. It's much better than the glass/hairspray method I once used in a cardboard box enclosure, but still not perfect. The biggest hurdle is the ABS dip. Each part needs to be hand sanded first (maybe 5-7 minutes per print), and then dipped. The dip technically removes a tiny bit of material. After it dries thoroughly I do the test fit. If it doesn't fit snug around the center curve and flush against the key, I toss it in a box. This is where most get rejected.

Can you send me the .STL file so I can print my own?

I will not be releasing the design (.STL) file. I had shared my cabin filter file to the community and now realize that was a mistake. I didn't mind if someone printed one for themselves or their friends. But other people began selling them on eBay. On top of that, I had people contacting me with questions about a bracket I never sold them.