Black & Tan 332iT

[Bry5on]

Did just fine with the big bike on the highway, no noticeable wind noise even though the bike is a solid foot and a half wider than the car. Trailer hitch is the way to go!

Also, in the full OCD effort to chase every little rattle noise down, I also stripped apart the HVAC controls and felted the buttons to keep them nice and quiet.

[Bry5on]

I almost forgot, I had my inaugural e46 window regulator! And I also put in new front wheel bearings chasing what's probably just worn tires groaning. Oh well, now I've got the peace of mind at least. Thanks mrgizmo04 for the loaner tools

[Bry5on]

And one more crappy job complete! This weekend, with a helping hand from heinzboehmer, I finally tackled the black headliner conversion. I opted to go for it myself using the veteran co material and it actually came out pretty well. This was my first time doing a headliner, and I think I'd opt to have a professional do it next time.

After removing, the first step was stripping off the old felt and plastic bristle brushing the tattered foam. This makes a huge sticky mess, I did not tarp off enough of the garage floor, and I ended up trashing the tarp AND my shoes after I was done.


Then spray foam, work it down, and trim


Then pop it in, complete with all the black euro touring bits


And we're back to regular duty, the longroof party

[jrgatfh]

I went with Amazon for these, they come as a pair: EVIL ENERGY 2.5 Inch Exhaust Clamp,Narrow Band Muffler Clamp Stainless Steel 2PCS https://a.co/d/dStpJ07

For the strap in between them, just make this guy here: https://cad.onshape.com/documents/93...2d931a9bf2f482

You're awesome. Thanks dude.

[Bry5on]

how does one go about getting one of these clamps?

I went with Amazon for these, they come as a pair: EVIL ENERGY 2.5 Inch Exhaust Clamp,Narrow Band Muffler Clamp Stainless Steel 2PCS https://a.co/d/dStpJ07

For the strap in between them, just make this guy here: https://cad.onshape.com/documents/93...2d931a9bf2f482

[jrgatfh]

Before the day started, I took a couple minutes to add another clamp to the SS headers and wash the car. I had a resonance around 1700rpm and had a feeling that it was coming from the headers, as my original clamp was just in front of the cats and there was still some considerable unconstrained length.
I took the exact same laser cut piece from the original strap and clamped it at the headers in a different orientation (I now have a header clamp set and a section 1 clamp set). This fits super closely but works just fine.

Well, it’s smoother yet, which I love. Revving through the whole range is smoother, and I thought I’d already nailed all of the vibration before. Well, another improvement completed! I’ll have to cut down these threads later as they hang a little low.

heinzboehmer you should do this one too.

how does one go about getting one of these clamps?

[Bry5on]

Nice! I'll add this to my car as well. Still have one of the laser cut parts you gave me. Were you able to get the clamps on without unbolting the exhaust?

Yeah, you kinda have to snake them on a bit but I didn’t unbolt anything. All said it took about ten minutes

[heinzboehmer]

Nice! I'll add this to my car as well. Still have one of the laser cut parts you gave me. Were you able to get the clamps on without unbolting the exhaust?

[Bry5on]

Before the day started, I took a couple minutes to add another clamp to the SS headers and wash the car. I had a resonance around 1700rpm and had a feeling that it was coming from the headers, as my original clamp was just in front of the cats and there was still some considerable unconstrained length.
I took the exact same laser cut piece from the original strap and clamped it at the headers in a different orientation (I now have a header clamp set and a section 1 clamp set). This fits super closely but works just fine.

Well, it’s smoother yet, which I love. Revving through the whole range is smoother, and I thought I’d already nailed all of the vibration before. Well, another improvement completed! I’ll have to cut down these threads later as they hang a little low.

heinzboehmer you should do this one too.

[Bry5on]

New feature, because everyone needs more math in their life!

It occurred to me that since I've got suspension geometry and center of mass information, I could now add jacking force calculations to get a true representation of suspension travel (jacking is basically the geometry forcing the body upwards during lateral cornering). This led me to a cool realization! The reason BMW uses an inboard spring is probably all about minimizing jacking travel! Jacking is a force internal to the car, so it acts at the spring rate, where your suspension normally acts on the tires, a force external to the car, so it acts at the spring rate *and* motion ratio. BMW chose to have a high rear roll center for suspension dynamics, and this means that there's a lot of jacking force. To minimize the effects of jacking, you need a stiff spring rate. If BMW had put the spring over the shock with a similar ride frequency (probably the easiest thing to do honestly) then the car would rise about twice as much in the rear during cornering, totally jacking up (pun intended) your rear camber! With the spring in the location the factory chose, it turns out the math shows how little rear compression is used in corners. Most of the rear roll comes from the inner side of the rear lifting in a corner! The front is different, jacking forces are low due to the roll center being just above the ground.

So, PSA: Don't run rear coilovers unless you 1) really know what you're doing and 2) are running super stiff springs (because you have aero is the only real excuse)
Also, PSA: Don't lower the front of your car unless you 1) really know what you're doing and 2) are running super stiff springs and/or sways

In any case, my fancy suspension spreadsheet will calculate jacking forces and suspension travel for various G-loads in corners. Take a peek at the travel numbers for front vs rear and inner vs outer below:


[ATTACH]n219433[/ATTACH]

[Bry5on]

Ah, didn't realize you did the roof rails, as well, you animal. Can it be done without removing the headliner? Big weight savings!

And my back-of-the-napkin says a George Hill carbon roof might drop the same amount in weight and not quite as much CG. Sounds lovely.

Yeah, super easy to remove, all from the top side. I think it looks more appropriate with the rack but I’ll take the weight savings any day!

Things would have to get rather serious to consider a carbon roof - that juice doesn’t quite seem worth the squeeze unless the whole car is going under for a respray and/or fenders.

[tlow98]

Ah, didn't realize you did the roof rails, as well, you animal. Can it be done without removing the headliner? Big weight savings!

And my back-of-the-napkin says a George Hill carbon roof might drop the same amount in weight and not quite as much CG. Sounds lovely.

[Bry5on]

And now the roof is naked. The rack setup ended up weighing 49lbs and removing it dropped the CG height by a half inch.

[tlow98]

That paint job 😋. Tasty!

[Bry5on]

So we're not done with yesterday just yet. After I was free and clear, I headed to the machine shop to knock another thing off my list, because while I was working on the vincebar, my mtech-2 bumper insert with trailer hitch cutout showed up. You can see where this is going.

We're trying to make this here: Onshape

I started with a scrap block of aluminum and cut it roughly to size:


Then migrated my way over to the Bridgeport to start taking shape. First removed a bunch of material to create a clevis:


Then flipped it over and drilled/power-tapped the hole pattern to mate to the euro tow bar (plus a test fit):


Then I flipped it on its side and drilled two 5/8" holes all the way through both sides of the clevis so that it can bolt directly to the adapter used in Stealth Hitch kits (same system we have on the Macan) like this:


After a quick deburr and clean, assembled it all together, threw it in the trunk of the jag and went home:


And that brings us to this morning, where things get exciting between coats of paint on the vincebar. I popped the bumper off, removed the standard mtech-2 bumper insert, trimmed a section of the bumper beam, removed the bumper shocks and installed the hitch. It fit like a glove with just enough room to comfortably actuate the hand lever of the Stealth Hitches adapter:


And here it is in all its glory, no additional trimming required, great placement, centered with plenty of driveway clearance:


And that's it for the hitch install! The factory setup was rated for over 4,000lb of towing capacity but only 165lb of tongue load. Not a problem for me since I'm planning to use this to hold two mountain bikes on a 1up rack, which will total about 120lbs. This 2" receiver is totally removable and can be detached and hidden in about 30 seconds.

It's worth noting that this is the factory BMW version of the hitch, made for BMW by Westfalia, and different from the Westfalia version available today because this one is aluminum and about half the weight. Of course I weighed everything, and after subtracting out the 8lb weight of the bumper shocks, I've added just 18lb to the rear of the car, vs 55+ of the roof rack setup. Once the rack comes off, I'll come in at ~3440lb and 49.4/50.6% weight distribution with a half tank, which is almost dead on for a stock e46 M3. Pleased with this outcome once again!

I'll drive the car tomorrow after a full 48 hours of epoxy curing, but for these two, no noticeable change is best.