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just bought myself a 996 C4S. Super happy with the car, I just came across something odd that I'd love to collect some ideas on.
The other day I was pushing it on a country road a bit. The car got sudden understeer, however, it didn't seem like the tires were breaking traction, as I was far from the grip limit, it rather felt like the front differential / AWD system intervened even though it shouldn't have. I wasn't fast, cornering at a medium-grade corner on consistent medium throttle at ~90kph (~60mph), full traction grippy road. Something my old Audi A4 would do easily. It was just for a split second, and I saw something yellow flash in the gauge cluster, but couldn't quite catch it.
I'm not too familiar with the 4/4S platform and am a bit clueless about what could bring this kind of symptom on the front axel.
Any ideas what could be responsible? Really took my confidence out of cornering.
Cheers,
Carlo
Last edited by C_996_4s; 05-28-2024 at 11:12 AM.
Reason: spelling mistak
911s inherently have quite a bit of understeer. Probably the easiest and first place to start would be checking the tire pressure of the front tires. Too high and it will exacerbate understeer.
The PSM came into action and reduced the understeer. That's what the Amber light showed you.
Apart from tyre pressure you'd want to check the age of the (front) tyres. I notice that my 4yr old front tyres (Michelin PS2’s N3) don't grip as well as they used to on my C2.
The PSM came into action and reduced the understeer. That's what the Amber light showed you.
Apart from tyre pressure you'd want to check the age of the (front) tyres. I notice that my 4yr old front tyres (Michelin PS2’s N3) don't grip as well as they used to on my C2.
Thanks! Tires shouldn't be an issue, they are brand new (dec '23; Hankook Ventus S1 evo), and have ~800 miles on them. I'll recheck pressures, but would be surprised if they overinflated.
The PSM came into action and reduced the understeer. That's what the Amber light showed you.
Apart from tyre pressure you'd want to check the age of the (front) tyres. I notice that my 4yr old front tyres (Michelin PS2’s N3) don't grip as well as they used to on my C2.
I had to look that up. I don't have PSM and don't know how it works, but you're right. It will intervene in the event of understeer.
As the guys said, factory understeer, AWD, PSM and tire pressures can mess with you. Let us know what you find with your tire pressures what size tires you are running. Good news is it's curable.
My 911 understeers when I am on the throttle because the weight on the front is lightest. An empty gas tank exacerbates it.
So for slow corners, I trail brake, and for faster corners, I’m off the gas. I’m only on the throttle if I have enough grip.
People may warn you about lifting off the throttle in a 911 because that can cause oversteer, but on a 996, you should not really have to worry about this as much as in much earlier cars.
People may warn you about lifting off the throttle in a 911 because that can cause oversteer, but on a 996, you should not really have to worry about this as much as in much earlier cars.
I’m curious about the reported understeer tendency with these cars. I’m familiar with it from my old GTI, but my 996 corners neutral with just a touch of oversteer at the limit. I would never think of my 996 as understeering. Is it because of my setup? Wavetrac LSD (on rebuilt 6MT), PSM, and 235 19s in the front. 36psi front 42 rear.
I’m curious about the reported understeer tendency with these cars. I’m familiar with it from my old GTI, but my 996 corners neutral with just a touch of oversteer at the limit. I would never think of my 996 as understeering. Is it because of my setup? Wavetrac LSD (on rebuilt 6MT), PSM, and 235 19s in the front. 36psi front 42 rear.
Alot goes into the set up to get certain characteristics. LSD helps the car rotate when cornering as well as provides stability under acceleration and braking. Front and rear coilover stiffness and sway bar stiffness play a huge part, as well as tire pressures and tire sizes. Front tire width changes in relation to rear can also change the characteristics.
To reduce understeer stiffen the rear suspension and soften the front. Opposite to increase understeer.
edit: also I think the understeer characteristic is magnified at higher speeds.
295 in the rear.
Back roads I drive are very curvy, it’s almost all 2nd and 3rd gear. Very possible it’s not fast enough to induce. I also wonder though if the LSD makes the car tend toward oversteer and offsets the factory tendency.
Originally Posted by GC996
To reduce understeer stiffen the rear suspension and soften the front. Opposite to increase understeer.
Back roads I drive are very curvy, it’s almost all 2nd and 3rd gear. Very possible it’s not fast enough to induce. I also wonder though if the LSD makes the car tend toward oversteer and offsets the factory tendency.
Interesting, did not know.
An LSD certainly helps to rotate. But you really won't notice the understeer unless you are on the track and can carry good speed.
05-28-2024, 10:35 AM
996 Corner Instability
