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You don't need the intake runners. Those are just to squeeze the last bit out of it. You can get 80-90% of what's left on the 3.8L table for about 5K in parts. And these are not a write off, when you're done with the car you can expect to get like 70% of the money invested back. If you pick up a used kit from the classifieds here you can get away with barely any depreciation at all, but that would take some waiting for the right set to pop up.
Do try the A052, they are exceptional. Especially because they're also extraordinarily grippy in the wet, provided there are no deep puddles. Quicker than cup2 when it's dry, very very much quicker on a damp or wet track.
Slightly reviving this thread @Mvez , as your write up here and in other threads is super informative, and I'm on the same platform.
Shy of dropping the $5k+ for a Clubsport setup, do you have a take on the Tarrett / Swift spring upgrade offering? For ~$800, it seems like it might achieve some approximation of the same improvement for a fraction of the cost?
FWIW, I'm also 981 GT4 with the same power mods, 265/295 - 305 R7s, Tarrett linkage all around + camber plates, and added aero.
I exclusively track the 4, so don't care about street compliance manners, but still not quite ready to pull the trigger on a full suspension. Also considering a Guard or Hollinger 3-6th + LSD, but can't convince myself that the enjoyment / lap time per dollar math really works . . .
Sorry for the delay. The short answer is yes, you can spend $800 on springs and get some marginal improvement, and you'll probably be happy with it, especially if you are the type of person who doesn't want to mess with suspension adjustments. But given the extensive work you've already done, it looks like you've done everything but address the chassis, so it def. needs some attention.
Honestly, if it's a track car like mine is (and I still drive it on the street, with good road manners), then I think it's worth the investment to skip the springs, especially if you enjoy setting up the car or turning ***** to try and improve the handling of the car. With the power and aero your car has, it really needs some suspension work. I just think these suspension kits don't offer much change over the factory setup, all it is doing is raising the front spring rate, the rear is essentially the same. But that's just my .02. Tons of people running spring kits and they are totally happy with them. I've driven them, they are good, but they just don't compare to an adjustable shock setup. That's why it's alot more expensive.
Honestly, after the November event at Barber, I came back from there astonished by what this car can do, and I'm still on the OE LSD. The only reason I'm still running it is because mine is brand new from when the dealer put in a new trans for the 3rd gear break fix, so I'm using it up a bit. Once I put a Giken in it, I expect the car to be even better and more dynamic. Right now, I got a little inside wheelspin in tight 2nd gear corners, and actually a tiny bit of clutch slip as well, so I'll be adding a Sachs Performance clutch kit too.
Turned some low1:33's and had a 1:32 going, and you can't do that with just hp at Barber.
@Mvez glad the Bilstein Clubsports are doing well for you on the GT4! Wanted to ask if you customize your Giken diffs or just go for the standard Spec S setup? Considering a Giken for my e92 m3.
Following up here -- I did end up getting an OS Giken Spec S for my e92 m3, it's excellent on the street, completely silent, and locks up much quicker on track than my original diff.
Your follow up is timely. I think for rear diff mounting, OS Giken is the best, good for you! I actually am taking my car in next week for a new Sach's sports clutch, OE flywheel, and instead of the OS Giken install, I'm going to rebuild my OE LSD with the Racing Diffs clutch pack rebuild kit. They are much more aggressive/better friction/clutches. I really want to see how much better the car drives before I put the Giken in. Giken really likes using the heavy 80W250 oil, and that's just too heavy for a Porsche transaxle, I tried transaxle with 75W140 and even that was too heavy for a dual purpose car. Also, the OE LSD actually has 2 friction discs "deactivated", by stacking 2 on top each other on each side, so it is greatly reducing lock. This is exactly how OS Giken also deactivates friction discs as well. So in addition to better lock from these better internals, I can also arrange them in the traditional alternating fashion, instead of 2 friction discs in a row.
I'll test the new internals in the OE arrangement of Dog ear + Dog ear + Friction disc + Friction disc + Dog ear. If I want more lock, I can then change to the traditional alternating arrangement of Dog ear + Friction disc + Dog ear + Friction disc + Dog ear, which will add a good amount more lockup.
These guys also make a rebuild kit for the 997 GT3/RS, and are well known in BMW land in Europe for these in the track community. Nice to have high quality, relatively inexpensive options to rebuild your GT3 or GT4 diff, for only about $500 in parts. Clutch packs wear, so I think this company is going to be getting my business!
FYI - the LSD is the exact same for all 987 and 981 6-speed cars, including the GT4.
I hadn't thought about that re the Giken recommended fluid and Porsche setup, good to know. Nice to have the option with the replacement clutch packs though, let us know how it goes!
I hadn't thought about that re the Giken recommended fluid and Porsche setup, good to know. Nice to have the option with the replacement clutch packs though, let us know how it goes!
02-09-2022, 11:16 PM
