Black & Tan 332iT

[karter16]

Early days and not a whole lot of seat time but I can say reasonably confidently that the hypothesis has been validated, and this brace mitigates a lot of that flexibility.

Great stuff! loving following all this and seeing all these rigidity improvements.

(also amused by the growing number of intake scoops on your bench in every new photo)

[Bry5on]

Another win today.

This evening I decided to install the first version of the v-subframe-brace.

As a recap, the hypothesis is that:
1) The remaining rear bump oscillations I felt after installing the X-brace are related to a lack of fore-aft/bending stiffness
2) The subframe can rock forward aft, sort of 'around' the axle axis, under throttle application, related to subframe mount failure, and the stock v-brace is not enough to constrain this movement
3, unstated so far) The m-clunk is related to 2) and additionally, the subframe floor acts as a bit of a speaker, amplifying the clunk






I wasn't thinking for a bit and ended up installing M6 rivet nuts instead of M8 rivet nuts, probably because I decided to do this on jack stands instead of driving the 2 miles down the street and getting on the lift. At some point I may try to remove the M6 guys and go to M8 as the design intended, but we'll see how we get along for now.

Early days and not a whole lot of seat time but I can say reasonably confidently that the hypothesis has been validated, and this brace mitigates a lot of that flexibility.

Response and oscillations following bumps are much tighter, and throttle applications are more 'instant' and don't have that coil-up feeling that the e46 has. You can be a bit rougher with throttle application and removal and it doesn't feel as rough on the chassis, it just follows your foot.

I've only got a handful of miles on the car, attempting to provoke it of course, but so far I haven't been able to get it to m-clunk. You can for sure get it to cluck by going on/off/on/off throttle very quickly, but this is true even on the newer G80 cars. Shifting feels a little smoother? Not so much in the lever, but in the car itself. Definitely need more miles to validate this.

On top of that, it does seem to be even more torsionally rigid when exiting extreme driveway angles. I can tell again that the front is less rigid than the rear. I wonder if recreating the e30 cabrio front strut mount gusseting would be useful. I'm really going to have to do those control arms and a new set of bushings now.

Anyway, pleased with this! The car has really transformed a generation or two in ride feel in the past few weeks.

[Jamesone]

Awesome build..

[Bry5on]

V-brace to subframe brackets showed up today, press fit nuts and powder coat both look great. If I'm lucky I'll get to installation this weekend.



I also ordered stainless pistons for the 996 calipers to hopefully finally get rid of my pad dragging issues. Removing the additional Porsche pad dampers seems to have helped a bit (also with pedal feel) but I've still managed to get that loud brake hum and I'm seeing pad wear differences between inner/outer pads on my freshly rebuilt calipers. Good times.

[Bry5on]

Today another package arrived - powder coat looks great. Also featured here is a hell of a garage hack - a used stainless 8' x 3' kitchen prep table as a nice hard wearing workbench! Pretty stoked with this.


I made a mistake and ordered the spacers as 1/4" instead of 3/8" so I'll need to order more of those before I bond everything into place. Otherwise the M8 holes and slots all fit up really well, so I think the flat patterns are all set. To get the clevises oriented right, you've got to hold the brace up to the edge of the clevis while you torque it down like so:


It's not all sunshine and roses though, the bolt and clamp strategy is not as nice to assemble as the stud and nut version as you've got to disassemble more things and it gets pretty fiddly. I've got another part coming in from sendcutsend that's got powder coat and press fit inserts, so I may try doing press-fit nuts and going back to studs if that works okay. Anyone got any recommendations for press-fit nuts?

Going in:

Seats down:

Seats up:

Cover in place:

I'm pretty sure there's no difference in stiffness, or at least not much, from removing the top bar although I'm driving myself nuts second guessing and trying to feel something.

[karter16]

Very exciting - can't wait for this!


Sent from my iPhone using Tapatalk

[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!

[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]

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).

[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.

[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

[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.

[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]

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.

[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!