heinzboehmer's 2002 Topaz 6MT Coupe

[D-O]

More like 25 HP - plus the weight savings.

[heinzboehmer]

More like 25 HP - plus the weight savings.

Oh man, how could I forget about the weight savings? Don't even need a carbon roof now.

[heinzboehmer]

Some more Gauge.S progress. Was made aware of these two repos recently, so decided to take the nuclear option and write my own validation firmware for the board:

https://github.com/handmade0octopus/Gauge.S-sd-updater

https://github.com/handmade0octopus/ds2

First thing I did was build the DS2 library as a standalone to unit test it. Fed the tests some real data coming out of my DME and fortunately the logic in that library seems good. Test code snippet:



I then set up the programmer and PlatformIO in VSCode to flash the board. First time using PlatformIO for Arduino stuff and it's pretty nice. Feels a bit more professional than the official Arduino IDE.

The Gauge.S board is surprisingly simple. At its core, it's just an ESP32 connected to a TJA1021 for handling D Bus communications. This means I can write some super quick Arduino code to send out DME requests and then listen to what comes back. Code is written, just need to find some time to test. I should start billing for the time spent debugging this...

Anyway, onto some other stuff.

Decided I didn't want the cooling efficiency tradeoff of the Rogue power pulleys anymore, so swapped them out for stock. Old stock PS pulley was cracked, so brand new one is in. Don't want to think about what that part is gonna cost in a few years.

Power pulleys:



Back to stock:



Didn't order new idler pulleys because the ones on the car are fairly new, but of course I found them both to be bad with the belt off. It's crazy how little these things have lasted. Think I've gone through four sets since I bought the car? Oh well, new ones ordered.

Then met up with Bry5on and Slideways to do some tuning. I mean, in reality I just provided another set of hardware to experiment with and Bry5on did all the work, but still

Newest version of the mullet tune is even better. There used to be a bit of a torque dip at 2-3k rpm, but now that range feels awesome. Need more seat time to find any nuances, but so far feels great.

And then on the way back home I heard the dreaded failed CSB rumble under load. Incredible timing with a track day less than a week away. Parked in the garage and immediately took things apart. Interestingly, I found the CSB in great shape. However, the real failure more was way, WAY scarier:



I have no idea how this happened. I always torque this bolt with the driveshaft in the car, so that I can get as much torque on it as possible. Maybe another case of the track rattling things apart?

Fortunately, both the bolt and the threads in the driveshaft were perfectly fine, so I poured two gallons of threadlocker on the bolt and did the double wrench thing to torque it to 750,000 lb-ft. Hopefully this doesn't come undone again.

Perhaps unsurprisingly, torquing this bolt back up cured about 95% of my drivetrain clunk. It's crazy how much quieter the car is now. I thought it had been extra noisy recently... Will keep an ear out for similar noises in the future.

And lastly, here's a photo dump of the dust boots on my front calipers. Want to run an experiment with the scoops, so swapped some fresh GiroDisc boots in.

Old GiroDisc on FL caliper:




Old GiroDisc on FR caliper:




New GiroDisc on FL caliper:



New GiroDisc on FR caliper:



Interestingly, the rear caliper boots are still the stock Porsche/Brembo ones and those are showing absolutely no signs of failure

[heinzboehmer]

Alright, time for a bit of science. Did some testing to qualify whether the brake scoops help the dust boot problem at the latest track day.

This whole experiment is based on the assumption that my driving is consistent enough to draw somewhat reliable conclusions from. Thunderhill 3mi is definitely the track that I know the best, so I don't see much of an issue with consistency. Also, the two track days I'm comparing did happen at different times of the year, but the day with scoops was MUCH hotter, so the scoops needed to be extra efficient to make a difference. Here's a quick overview of the experiment design:

No scoops track day:
- Mar 2024
- Thunderhill 3mi bypass configuration
- 3.5 hrs of track time
- Ambient temp: ~15 C
- Cloudy skies
- ~2:05 min/lap
- More pad life

Scoops track day:
- Sep 2024
- Thunderhill 3mi bypass configuration
- 3.5 hrs of track time
- Ambient temp: ~35 C
- Sunny skies
- ~2:05 min/lap
- Less pad life

Car setup (same both days):
- ~3200 lbs
- ~315 whp
- MK60
- RBF600 (purposefully did not flush fluid so that the only potential difference would be worse thermal capacity on the scoops day)
- Bridgestone Potenza RE-71RS
- Cerakoted 996 calipers (finish supposedly helps dissipate heat)
- Girodisc titanium pad shims
- Brand new girodisc dust boots installed before each day
- Same PFC08 pads front + rear (as in the same exact parts, not just the same compound)

The experimental results are meant to be qualitative and not quantitative. Basically just trying to see if having the scoops makes the dust boots survive.

I found one cooked dust boot on each side of the car after the no scoops track day. Scoops track day involved thinner pads and higher ambient temps, so zero cooked boots would point to working scoops and not increased thermal capacity in the system (in reality thermal capacity decreased).

Aaand the results:






Success! Dust boots seem totally fine We'll have to see how many more track days they last.

Also, a few entertaining things I found when dressing the car back up for street duty.

These used to be rotated 90 deg:



These pins and screws used to be centered on the rotor holes:



And these tires used to work:



Man, this last track day really made me remember how hard this sort of driving can be on the hardware. Tons of fun, but it really does age parts very fast.

(and yes I'm aware I need more camber, more on that soon)

[Bry5on]

You had blanked the bumper brake duct holes for this one right? Ie: only clean air coming from under the car, not through the factory ducts, same as my testing?

[D-O]

How can we get some of those scoops?!?!

[davidinnyc]

How can we get some of those scoops?!?!

Cash. Lots of cash.

[heinzboehmer]

You had blanked the bumper brake duct holes for this one right? Ie: only clean air coming from under the car, not through the factory ducts, same as my testing?

Yep! The outlets I added to the stock ducts for brake cooling hose were taped off and the openings in the fender liners were covered with the stock clip in covers (used two of the solid ones, not the one with the holes). Also trimmed the pork chops. Basically just replicated the setup on your car cause that's what you tested with.

How can we get some of those scoops?!?!

Gonna need to talk to Bryson for that