heinzboehmer's 2002 Topaz 6MT Coupe

[heinzboehmer]

Oh! Parts arrived for another project that I can work on if I need a break from the braces CAD (with, uh, more CAD...).



Found these when driving my in-laws' Mercedes SUV (GLB/C/E/something or other). Collapsible baskets aren't exactly a revolutionary invention, but this is a Mercedes OE part (p/n A2038400020) and it's only $16 brand new!

Here it is unfolded, M1 16" MacBook Pro for scale:



Plan is to design some mounts that the basket can clip into. Underside has a ton of features that I can use both for locating and retaining:



Mounts will likely get attached to the "ceiling" of the trunk (where the stock subs live), maybe even the trunk lid, we'll see.

I do want to make the mounts fairly platform agnostic. Each car is getting its own basket, so want to minimize the extra work required to make these compatible with each chassis.

[heinzboehmer]

Placed an order with one place whose website allowed me to order 5m, but we'll have to see if they actually fulfill my order

Yep, order cancelled because the minimum order quantity is 50m. Damn, I really don't want to have to order that much. Anyone need 49.5m of the stuff?

[bavarian3]

Also, quick side project to give myself a break from all the CAD work.

I've never been fully satisfied with the Kassel MAP sensor solution. It being so close to the throttle bodies means that the sensor sees huge fluctuations in readings with each revolution of the engine. This doesn't seem to affect drivability much, but it's never sat well with me. Additionally, the harness going to the sensor has to make some very sharp bends to make sure it's out of the way of the throttle linkage. Again, not something that affects how the car drives, but I didn't like it.

A week or so back, I noticed the CSL air rail was ~$400 after tax on ECS (and in stock in the US!), but closer to $800 through european sellers. NLA fear creeped in sooo I jumped on it:

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My original plan was to just kinda re-zip tie the harness I had made for the Kassel sensor and call it good. However, I found sketchy patchwork in the middle of the IAT harness that I had forgotten about and this ridiculous choice by Kassel for the MAP sensor connector (on the left):



For some reason, they used the wrong terminals, put no waterproofing grommets in there and picked a questionable wire gauge for one of the three wires. The connector housing is also clearly a knockoff with pretty bad tolerances. I would not be surprised at all if this is the cause for my intermittent MAP sensor code (which, admittedly, never seemed to affect how the car ran).

The stuff I laid out to the right are the closest replacements I could find in the stash. I rewired that part of the harness with those, but I've ordered the correct terminals and grommets and will replace soon.

I was already halfway into building a completely new harness, so I decided to just redo the entire thing. This is how I routed everything:

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As you can see, I ran my sub-harness directly into the bottom of the stock engine harness box thing by the brake booster. Not having that extra conduit snaking down the front of the harness box cleans up the engine bay nicely:

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I did briefly consider running the wires through the stock conduit that runs under the airbox and then making a slot (with a matching 3D printed grommet) in the hard plastic distribution block bolted to the engine for the IAT + MAP sub-harnesses, but ultimately decided that was way too far down the rabbit hole. I'll revisit and do it that way if I ever run out of projects

I, unfortunately, did not have the appropriate terminals for the IAT, so I left some slack in the harness and ordered some of those as well. Slack is tucked into the conduit for now, but I'll be swapping things when I get the parts. Getting the boots over the conduit is gonna be a fun adventure:

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(yes, I also ordered a new boot for the IAT)

Anyway, next up I printed karter16's Bosch MAP adapter out of PET-CF, for it's temp resistance. This filament has a heat deflection temperature of 205 C, so should work well for the application. Also grabbed the complementary hardware:

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Just like karter16 noted, the metal sleeve on the Bosch MAP just barely doesn't line up with the air rail. Dremel + a carbide bit made quick work of this though:

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Gave the sensor and adapter a quick scuff, then bonded them together with some CA glue. This part isn't really necessary, but I did it anyway cause why not.

Here's the final install:

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(yes, I know that's a 90 deg boot, straight one is in the mail)

The screws did start digging into the plastic on install, so they got torqued to "as much as I can turn just the bit with my fingers". I don't think this is gonna be an issue.

Datalogger is picking up readings from both sensors just like before, so I'm calling this a success. Huge thanks to karter16 for sharing the adapter and all the details surrounding it! Made my life so much easier.

You're on it! That was fast. Super helpful for me as I'm collecting parts. One more DM incoming =)

[heinzboehmer]

Yep, order cancelled because the minimum order quantity is 50m. Damn, I really don't want to have to order that much. Anyone need 49.5m of the stuff?

I might have found a place in the UK that will sell me just 1m of the tubing. Shipping is insane (like $50 for $5 of tubing), but maybe.

Remembered I have a scan of the engine bay with the braces installed, so drew up a super rough layout for the tubing to give me an idea of how much I need. I'll likely bring that big bend in a bunch in the real design, but I wanted an upper limit for length:



Measures right about 480mm, so my 50cm estimate was spot on. Seems like 1m would be enough.

To form it, I plan on 3D printing a jig. Here's a rough idea of what that will look like:



It'll be printed in sections so that I can heat the tubing up with a heat gun (away from the next meltable section) and then form it around the next bend. The ends of the jig will also have tapered flaring sections to make sure the tube can slide over the fittings:



<imaginary pic of heat gun heating up length of tubing sticking out of the jig>



The actual jig will have locating features between all the sections, so that they easily slot together and you don't need to be messing around with it while holding the rapidly cooling tubing. Additionally, it'll have clearance on the outside of all the bends, so you can wrap the tubing around the form (think brake line bender), as opposed to pushing it into a groove.

I'll also be printing a tool that clamps the ends of the tubing onto the fittings, to give it that nice OE look:



Wait a second...

All this brainstorming has made me come up with an excellent way to justify buying 50m of the stuff. Might not even need to jump through hoops to get less!

If someone has the OE CSL part (11617833647) installed and is willing to let me scan their car + the part, I can make a jig to recreate it. All of the designs for the tools (jig + crimp) will be open source, so people could just buy a length of tubing from me, print the tools and make themselves a replica part for their regular airbox installs. Will sell for material cost + shipping (likely <=$40 all in), so this should be a great way to save $150 and end up with what is essentially an OE part.

I could also form the tubing myself before shipping for some beer money. Buyers would then just need to heat up the fitting ends and crimp them on with the 3D printed tools.

I bet this will pique the interest of at least George Hill and kaiv!

Edit: I guess I could also recreate the tube for the stock intake, but not sure the market is big enough to justify the engineering time for that version.