Black & Tan 332iT

[jvit27]

The consistent feedback after driving here makes it sound like the braces stop the inherent deflection going through the chassis, essentially like solidifying a bushing. And when you start eliminating each point that 'gives' with it's own respective spring rate then you inevitably start to work the tire and damper themselves more.
(Hmm maybe I just reverse-engineered the secret of the MCL39... 😆)

This certainly does seem to validate precisely the way RACP's fail though!

[Bry5on]

The consistent feedback after driving here makes it sound like the braces stop the inherent deflection going through the chassis, essentially like solidifying a bushing. And when you start eliminating each point that 'gives' with it's own respective spring rate then you inevitably start to work the tire and damper themselves more.
(Hmm maybe I just reverse-engineered the secret of the MCL39... 😆)

This certainly does seem to validate precisely the way RACP's fail though!

Yep! Control is the name of the game here. Hard to control the chassis when it's acting as a relatively soft undamped spring.

I trimmed the isofix cover to clean up the install:


And by popular demand, iteration 1 of the stock M3 bumper to CSL intake duct is complete and off to heinzboehmer for a test fit:

[karter16]

And by popular demand, iteration 1 of the stock M3 bumper to CSL intake duct is complete and off to heinzboehmer for a test fit:

Oh amazing! There were a couple of people working on this who then seemed to give up - I was going to get started on designing my own but won't if this is on the way!!! Very exciting!

[heinzboehmer]

Oh amazing! There were a couple of people working on this who then seemed to give up - I was going to get started on designing my own but won't if this is on the way!!! Very exciting!

Yeeep, same. It was on my todo list, but now I get to copy Bryson's homework! Easiest project ever

I'll report back here when it's done printing and I've test fitted it.

[Bry5on]

Ok, standard M3 brake duct fits great on the car with a factory flap (but has a prior fender bender) and does not fit at all on heinzboehmer's car with the Karbonius snorkel. Time to print another and test fit on a second M3 after adding a couple little tweaks (more core support clearance, air transition into accordion boot).

[heinzboehmer]

Here are some pictures of the first test fit on my car:




That's the same duct (as in literally the same part) that's in Bryson's pictures. There's clearly something off about my car, the scanned car or both. I think these are the possibilities:

1. Karb snorkel is not the same dimensionally as OE.
2. My intake isn't fully seated.
3. My car's bumper fitment is off.
4. My car's stamped aluminum brake duct bracket is far too bent out of shape (I know it is at least somewhat messed up).
5. Scanned car has some tweaked dimensions thanks to the fender bender.
6. Some unknown differences between early and late model years.

Took my bumper off yesterday and found some failed plastic welds. They weren't in a spot that would have affected the duct, but I'm taking this opportunity to fix the fitment, as it's never been perfect.

I've messed with the fitment of the bumper a bit, but haven't fully mounted it back on. Super quick test fit before work this morning yielded much better fitment of the duct. I'll continue messing with it later.

But honestly, (1) above seems like the most likely culprit. Will keep testing.

[Obioban]

Might not actually be the worst idea to have a gap and flexible section, to accommodate the engine twisting under load.

Excuse to print something in TPU :P

[YoitsTmac]

In fact it would be better if you could attach something to the snorkel shaped like a funnel that goes over the intake pipe to decrease the chance of air turbulence and ensure the air gets rammed in regardless of engine tilt.

[heinzboehmer]

Might not actually be the worst idea to have a gap and flexible section, to accommodate the engine twisting under load.

Excuse to print something in TPU :P

Bryson already designed that in

Issue with my car is that the duct alignment is too far off for the TPU coupler to accommodate (hence why I left it off for the pictures).

[Bry5on]

Might not actually be the worst idea to have a gap and flexible section, to accommodate the engine twisting under load.

Excuse to print something in TPU :P

By design there’s a 25mm gap and a flexible ‘accordion’ TPU boot. The boot slips over the duct, then the CSL snorkel ‘clips’ into the boot like factory and pulls the boot up slightly. The boot has 20mm of engagement so it can act like a slip joint and also can deform axially/radially. It’s the yellow modeled part in the section view above

In fact it would be better if you could attach something to the snorkel shaped like a funnel that goes over the intake pipe to decrease the chance of air turbulence and ensure the air gets rammed in regardless of engine tilt.

There is also a lead-in to the TPU boot to transition the ID smoothly instead of into an abrupt lip. I think this makes 0 difference practically but makes my OCD much happier. Also can be seen in the section view above.

[heinzboehmer]

I think these are the possibilities:

1. Karb snorkel is not the same dimensionally as OE.
2. My intake isn't fully seated.
3. My car's bumper fitment is off.
4. My car's stamped aluminum brake duct bracket is far too bent out of shape (I know it is at least somewhat messed up).
5. Scanned car has some tweaked dimensions thanks to the fender bender.
6. Some unknown differences between early and late model years.

Okay so it turns out that none of these were correct. Actual culprit was the wishbone bracket under the airbox. Guess it got bent at some point:



Duct fits great with the bracket bent back to where it should be!

[karter16]

Very exciting - can't wait for this!


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