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In terms of shocks, for right now, KISS. No need to keep adding variables until you feel comfortable and confident with what's on the car currently.
997's have a very specific way they want to be driven, but your comments on trail braking and how the car currently feels does have me being ok with setup adjustments before seeing any driving.
Things to remember is that Roll Bars (and shocks, but another story) "only" effect whatever end of the car is being loaded, where spring rates and RH/Rake are changes that will effect the car in every situation.
Mike has the same idea, take some rake out, either raise the front or drop the rear.
"Oversteer is limiting trail and throttle" so that's saying its effecting everything as one of those is front loaded and the other is rear loading. Then making a "static change" (something that effects the weight when static) would be perfect here, so taking out rake and adding a little weight onto that rear would hopefully help.
The thought of the trail braking also has me curious about being more aggressive on the front ARB to help give a little more lateral support on the front going into the corners. I personally drive with priority on the front tyres and love to trail brake deep, always wanting some extra wide shoulders on the front!
Some in-car video would tell all tbh! Post up if you have it
Sounds like you would benefit from adjustable shocks.
Squat is part of the 911 experience.
You need to do sway bar sweeps to understand what they do re. roll coupling and balance, particularly mid-corner.
Being on-throttle before apex is a big hint that a) your Vmin is too slow and in the wrong place, and b) that you feel better with LSD lockup prior to apex likely because you don't feel confident about the rear of the car.
You would probably benefit from having a pro drive the car and help you with setup.
My 0.02
I'm onboard with the ARB sweeps - sounds like the logical next step. Regarding a pro-driver, I did have an extremely experienced driver take the car out while @ Buttonwillow to confirm my feedback. His experience in rear engine cars is limited but none the less helped validate my feel for mid-corner oversteer (but not for trail braking - that might just be my suck ) His notes:
Car does not back in with oversteer but tends to oversteer mid corner and while applying throttle. I wouldn’t call it a snap but a gradual transfer into oversteer. Speed seems to make it worse than throttle input. In other words, it’s induced more with lateral load than throttle load. I don’t recall it doing it so much in low-speed corners but mainly entering first part of bus stop, middle of Riverside and middle of sweeper.
I never got your car to push at all. I did not try to induce it but it never even hinted at that given the pace I was going which was probably about 90% by my guess. I probably could have found some push or other issues if I went faster but I didn’t want the loose rear to bite me in a buddies unfamiliar car during a fun track day. I would dig harder if ultimate lap times was more important than consistent/reliable behavior.
Originally Posted by fleadh
What's the diff break away set to?
Everything you posted about your setup sounds like it should be understeering everywhere, IMO. Apart from having a Pro hop in the car and do 1 lap to verify what you're feeling -- if it were me, first I'd make the rear bar fully soft just to see if that has any improvement (it doesn't matter what you feel or think about too much or too little roll). Then I'd add a bunch of toe-in on the rear (and make both L/F the same... you're not driving at Lime Rock). Also, put the car on jack stands and give both rear wheels a hard wiggle/shake left/right and see if there's any movement.
Also, is the balance the same throughout the age of the tire? Have you tried fresh tires?
The ride height on a stock 997.2 GT3 isn't adjustable is it? If it is, lower the rear 5mm.
-mike
Diff is on the 40/60 ramp. I'm going to do my annual maintenance on the car in the next few days - will give the bearings and all arms a thorough check.
This event was on brand new Nittos. I ran the exact same times on 4-event-old Nittos two months ago. I don't recall the oversteer being as prevalent last time but I wasn't pushing as hard.
Regarding rake, I dropped the rear before my alignment this track season as there was noticeable rake. Happy to take some measurements for reference (from the jack points?).
Originally Posted by audipwr1
Dan just bring it to laguna 4 day event and I'll drive it / they cars do roll and set.
You def wanna be on gas going over bus stop!
4 day event?!?!? Anyway you're welcome to drive my car anytime and I need to do Laguna again. DB limit?
Originally Posted by Apex996
Nobody answered the questions...
Something tells me you want this car to retain it's daily driver comfort ? It's a tough compromise if you want to go fast.
With stock springs its going to roll. A lot... Plain and simple. It's going to roll enough that your -2º camber may not be enough to stop the tire from rolling on to the sidewall. Have you marked the tires to check the rollover?
The bus stop is going to be tamed with shocks as shocks control your transient response. The sweeper is going to be spring rates and camber. Shocks do very little in sweepers once the car has finished rolling.
Thank you for addressing the question (and a lot of other useful stuff that I cut out of the quote for brevity). I'm not concerned about daily comfort - any semblance of dailyness died when I put the 4.0 flywheel on (sounds like a Ducati now). It's really a track first and canyon second car at this point - not that I'm complaining.
Since mid-corner is my issue I'm going to hold on shocks for now and see if I can tune some of the oversteer out first. I have not marked the tires - what would I be looking for exactly? Visually I'm not seeing wear down the sidewalls.
Originally Posted by SkeerRacing
In terms of shocks, for right now, KISS. No need to keep adding variables until you feel comfortable and confident with what's on the car currently.
997's have a very specific way they want to be driven, but your comments on trail braking and how the car currently feels does have me being ok with setup adjustments before seeing any driving.
Things to remember is that Roll Bars (and shocks, but another story) "only" effect whatever end of the car is being loaded, where spring rates and RH/Rake are changes that will effect the car in every situation.
Mike has the same idea, take some rake out, either raise the front or drop the rear.
"Oversteer is limiting trail and throttle" so that's saying its effecting everything as one of those is front loaded and the other is rear loading. Then making a "static change" (something that effects the weight when static) would be perfect here, so taking out rake and adding a little weight onto that rear would hopefully help.
The thought of the trail braking also has me curious about being more aggressive on the front ARB to help give a little more lateral support on the front going into the corners. I personally drive with priority on the front tyres and love to trail brake deep, always wanting some extra wide shoulders on the front!
Some in-car video would tell all tbh! Post up if you have it
I'm with you on the KISS. I'd prefer maxing out this setup before going crazy and it's clear I have some easy tweaks to make. Video next time for sure.
Thanks again everyone. I'll post up any findings during service and welcome any further comments and thoughts. Wondering if I'll find anything given that everyone is expecting understeer and that's just not the case.
This could be a stretch but looking through photos from the event is looks like my rear wheel has positive camber in the turn. At first I thought it was an optical illusion, but you can look at other cars from the same angle in the gallery maintaining negative camber.
flickr.com/photos/speeddistrict/albums/72157708822984556/with/47960107077/ <<-- copy paste, hyperlink keeps breaking the post...
Looks like I'm going to be pulling / pushing / prying on a lot of stuff under the car...
Checked everything carefully today. All rods are tight and static camber remains 2.5 / 2 (nothing moved).
Noticed that the front bar was one from soft (vs hard as I originally thought). Rear bar is in the middle.
Only issue found was a loose axle nut on the drivers rear that resulted in some play. Torqued it and will check to see if wobble returns. I had this bearing replaced last year and it seems the shop didn’t torque is properly.
05-28-2019, 08:57 PM
) His notes:
