ptuomov

yes and exactly what sound it makes depends on that idle ignition map

the gurgle got old for me, so develop fuel cut off it is for me. my AMGs do that in some modes, don’t really like it there either

we worked hard thinking about the exhaust and making it never pop, even when you see a flame

Thom

40-50° sounds enormously excessive... at least on my crank plane I4 I only need a couple more degrees when rpm dips below the target.

ptuomov

The factory stock idle map ends at 42.5 degrees of ignition advance at high rpms and my effective compression is maybe 6.7 compared to factory 8. It’ll misfire or burn in the exhaust without a lot of advance.

Thom

Interesting... How much timing are you running at idle speed?

What spark plug heat range and gap are you running?

ptuomov

The younger generation... So I picked up my oldest daughter (14y) from swim practice today with the twin turbo 928. She was looking at it a bit funny as it’s louder than other parents’ cars. A quite a bit louder if I am perfectly honest. Did a loop around the parking lot, too, just to see her squirm. Merging onto my test track (I-95) on the way back, I lit up the tires on the first gear, then on the second gear, and finally on the third gear. I let them spin for a couple of seconds on each gear, you could hear and feel it but not smell it as we had some speed at that point already. Now she likes the car.

SwayBar

P, perhaps a budding car-girl? As we know, a rarity for the car-guys of the world...

ptuomov

The main driving impression is that the car is very fast once it’s in the 4000-8000rpm range. I haven’t driven it that much at higher than the lowest boost setting, and I’m not sure if all of the circa 1k crank hp are ever strictly necessary. The lowest setting that delivers about 700 crank hp is already pretty fast and overwhelms the traction at lower gears unless the throttle is modulated carefully.

I’ve been fixing little things. Traced down a problem with the windshield wiper fluid spray, that’s working now. A knock sensor connection shook itself loose, reconnected that. Added a lot ignition timing at the low load regions of the map to quiet the car and to reduce under hood temperatures. Have been working on idle controller algorithm parameters and the cold start up parameters, those are still work in progress.

I friend of my decided to drive it with the hand brake on, and after that the rear brakes started squeaking a little. Any ideas how to fix that?

Chalkboss

He probably glazed the pads, you can try removing and sanding them down a little. Amazing car and design work!

ptuomov

Thanks, might be, although I’ve taken some off the pads driving already. I hear more low speed noise when I’m not on the brakes, which makes me think something might be dragging instead. When I put a little pressure on the brakes the noise disappears, which is the opposite of what usually happens with squeaky pads.

ptuomov

The driver side is much weaker in terms of spray than the passenger side. Tried a couple things, any ideas?

Resolution: there’s some sort of restriction that makes the system better with the hoses swapped one way around. I used compressed air to blow everything clean and then hooked the hoses the way that make the system work more evenly.

The rear windshield wiper started working again with a tightening of a nut.

Strosek Ultra

You can switch the nozzles and se what happen.
Åke

ptuomov

It appears that the system has a restrictor on one side and the hoses were the wrong way around. Switching them around seems to have fixed it. Or it was the compressed air.

Equal spray on passenger and driver sides now.

dr bob

Tuomo --

On the 928, the parking brake shoes fit inside the mini "drum" part of the rotor. Calipers off and suspended, then the rotor comes off after the hold-down screws. That exposs the shoes. You'll see if they are glazed. If so, some coarse sandpaper with just eneough pressure to break the glaze. Then the shoes get centered so the disk fits over them. The shoes are not self-centering nor self-adjusting. So drums on and parking brake off, you get to reach in with a sctewdriver or brake adjusting tool. Tighten the shoes with that tool, then back the adjustment off until there's no drag, plus one or two more teeth on the adjuster. Then adjust the other the same way. Check the lever, and verify the parking brke engages where you want it to. The WSM has some guidance, but in the end it needs to not drag, and you don't have the lever higher than the seat bolster when engaged, so you can get in and out of the car.

ptuomov

Thank you. I’ll read this again when looking at the brakes with the rear wheel off.

Rob Edwards

If you end up needing new parking brake shoes, don't get roped into buying new ones, the replacement parts now are a 996 part number that requires some additional new pieces (different adjusters) for them to fit. Much easier to get 4 good used from Mark Anderson. He's got a preposterous number of good used ones.