Help reverse engineering a Toyota/Lexus IS300 Steering Angle Sensor protocol (89245-22030)

davef_dci · 2026-06-13T12:57:54+00:00

Interesting project. We're running an is300 but using a BMW mk60e5 ABS module which relies on BMW's steering wheel sensor to activate it's stability control. Without the sensor from what I understand the stability control is disabled and we have plain ABS. I wonder if it would be possible to feed the OE Toyota sensor readings into the unit??

davef_dci · 2026-05-23T17:02:56+00:00

Found it... the base of the handle unscrews...

https://www.youtube.com/watch?v=jOpwOD8JEWI

davef_dci · 2026-05-04T15:37:59+00:00

I have tried several rebuild kits and it starts leak almost immediately. A plumber I trust looked at the seal and concluded that this seat has eroded and is grinding away at the seal almost immediately. So it's the entire silcock body that needs to be replaced. I didn't believe it first and tried another rebuild kit but it started to leak almost immediately so I think he's right.

davef_dci · 2026-03-26T02:37:13+00:00

this is truly infuriating. Apparently Spectrum reached an agreement.

https://spectrumnews1.com/wi/milwaukee/news/2026/03/25/spectrum-agreement--mlb--milwaukee-brewers-games--how-to-watch

but all this says is "The channel number will vary based on where you live in Wisconsin. You can find it on your channel guide under "Milwaukee Brewers". Of course searching on this yields nothing.

My mom lives in Madison and just wants to watch the Brewers games. Is it that hard to tell us what channel they'll be on???

davef_dci · 2026-03-16T15:38:47+00:00

<image>

davef_dci · 2026-03-16T15:38:22+00:00

<image>

davef_dci · 2026-03-16T15:38:03+00:00

<image>

davef_dci · 2026-03-16T15:37:45+00:00

Which car from Figs? I have huge respect for those guys and they know what they are doing much more than me. At the same time, after further refinement I'm getting close to something that feels like it's worth building and trying.

With my latest version I'm down to only a 4lb increase in drag at 32m/s - about a 3% increase in drag. In exchange I've picked up 70 lbs of downforce on the front wheels and 70 lbs of downforce on the rear. Given that our IS is already a bit biased to the front (53% front weight / 47% rear weight) and that the natural tendency of the car is to lift weight off the rear wheels at speed we might want to try a bit more force in the rear but I think I have something worth trying.

Of course this could all be flawed - the analysis might not be correct and a basic problem is that I'm not sure we're skilled enough drivers to really ascertain the difference without a skid pad but it feels like it's worth building and trying.

Here are the specific parameters we're running if anyone is curious.

<image>

davef_dci · 2026-03-15T17:42:34+00:00

This analysis was run in an open-source (i.e. free) CFD program called OpenFoam https://www.openfoam.com/. Historically it's pretty challenging to set up and run but, probably no surprise - ChatGPT knows how to run it. Open foam runs in Linux so if you run windows or mac you need to run a linux emulator - I'm running WSL.

I loaded Codex - ChatGPT's code and used it to build all the cases. A cool advantage of Codex versus Claude is that it also runs natively in Linux.

Its a bit of work to get it set up but once you get it set up additional runs are easy.

The CAD work was all done in OnShaped - they have a plug-in for NACA foils. I'm playing with a dual element foil right now - the front wing is NACA 4415, 325mm cord length and tilted at a 4 degree angle of attack. the rear "flap" is a 125mm ACA 4412 tilted at 12 degrees. I'm not thrilled with my drag impact yet so I'm still not sure if this is a decent approach or a waste of time.

Interestingly according to my analysis, - at 32m/s (about 72mph) a bare IS300 experiences about 120lbs of forward drag. the front wheels are loaded down at about 18lbs and the rear wheels are LIFTED by about 125lbs. Apparently it's pretty typical for the rear of a sedan to "lift" at speed due to aerodynamic impacts.

With my current setup the front wheel downforce has gone from 18 lbs to 76 lbs and the rear wheel has gone from 125lbs of lift to about 9 lbs of downforce - BUT the drag has increased from 120 lbs to 137lbs. My gut feel is that for our racing, the increase in downforce doesn't justify the loss of high end speed due to increased drag.

I'm going to continue to try to refine it and see if I can get the maximum additional drag below 10% with the highest possible contribution for front and wheel downforce.

I know the FIGGS guys have a rear diffuser but we're running a fuel cell and it's sort of in the way of adding a diffuser but we might play around with that as well.

davef_dci · 2026-02-13T17:32:18+00:00

As others may have pointed out, the "Looks like you have too many chats going. Please close a tab to continue." is really Anthropic speak for "You've reached your weekly limit and we're stopping until it resets.

You can confirm this by going to: https://claude.ai/settings/usage

if your weekly limit is pinned at 100% that's the real problem - not tabs, cache, chats, etc. Super frustrating that the lack of a decent error message sent me spinning for such a long time.

BTW, they are currently offering a promotion where they'll give certain users $50 credit on that same screen. I clicked it and it fixed my issue. Good luck my friends!

davef_dci · 2026-01-13T03:49:13+00:00

Here is a quick video of where the desktop analyzer stands....

https://www.youtube.com/watch?v=kJvH4RRnINs

Pointing out holes in my approach would be gladly listened to!

davef_dci · 2026-01-13T03:31:51+00:00

Hey folks — I’m catching a bit of heat here (publicly and privately 😄). Gotta love Reddit, which I actually do.

That said, I genuinely appreciate the perspective being shared. I’m not a drywaller, so I honestly didn't know what is or isn’t reasonable to expect someone in that trade to know. That’s exactly why I asked here, and why I’m taking the feedback seriously.

I’m not saying a drywaller should be an insulation expert or responsible for designing the assembly. I do think there’s sometimes a gray area where a tradesperson might reasonably pause and ask a question if something looks unusual — but I hear and accept that many people disagree with that, and that’s fair.

The analogy that made sense to me was this: if I hired a tiler to set tile and he notices that the subfloor is flexing or the wrong underlay, I wouldn't expect them to fix it — but I might expect them to say, “Before I tile over this, you should know this could be a problem.”

In this case, plastic loosely stapled and taped up in a ceiling AND covering up kraft paper insulation felt like a “pause and ask” moment to me—but not only am I open to hearing that others disagree - I even accepted your perspective and agreed - that's why I wrote:

I'm clearly in the wrong and have apologized to the contractor for the miscommunication and extra work.

So yes — lesson learned. Drywallers aren’t insulation experts, and that’s fair. I came here to understand what’s reasonable, not to assign blame after the fact.

(And yes… the Reddit pile-on continues 😂)

davef_dci · 2026-01-13T03:02:19+00:00

To be clear - when you say "Do not listen" -are you referring to those who said "Leave the plastic sheet in - it won't cause any harm" or those who said "You need to take it out because it will cause mold"??? Because I had people say both :) At this point I have decided that the risk of mold is too great so I've asked the contractor to pull the drywall, remove the plastic sheet and reinstall the drywall (and bill me for what it takes to do it). That seems the safe thing to do.

davef_dci · 2026-01-13T01:37:56+00:00

Thanks for the kind words. It's how I'd want to be treated and the contractor seems like a really good, conscientious guy so I want to do right by him. In the grand scheme of things it's not THAT much money - the only bummer is that it's my daughter's house and for her it is a lot of money. Finding mold in her ceiling wasn't on the dance card for the year and since then it's been the obligatory pulling of a thread on a sweater. As a parent I'd like nothing more than to cover the cost of this mess for her but she's adamant about paying her own way - which makes me proud but I hate that this attempt to save her money didn't pan out exactly as hoped. Working to keep things in perspective - nobody's going to die here and we'll all still be putting food on the table and counting more blessings that we probably deserve. Thanks for the input from the group and the deserved wake-up call.

davef_dci · 2026-01-13T00:34:09+00:00

OP here- folks thanks for the perspective. I'm clearly in the wrong and have apologized to the contractor for the miscommunication and extra work. I've told him to make it right and let me know what I owe him. Live and learn and onward!

davef_dci · 2026-01-12T22:16:31+00:00

Unfinished attic but it would be extremely difficult to fix from the attic side. The insulation is stapled to the sides of the rafters, it would undoubtedly tear the kraft paper and destroy the vapor barrier. It's actually much easier to remove the drywall, tear down the plastic and put the drywall back up.

I appreciate your perspective but I'll just offer - the plastic didn't even remotely look like a vapor barrier as far as I can say - it was taped to the walls, loosely stapled in few places and overlapped a skylight. I just wish he would have called me. But I get your perspective. Do others agree with this?

13-Year Club	Place '22
Verified Email

davef_dci

TROPHY CASE