PSM on or off? How do you drive your 996tt?
12-08-2015, 11:41 PM
#61
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12-09-2015, 12:36 AM
#62
MarkWavetrac/Quiafe/Guard TBD are arguably better for autocross and slow/technical tracks as they typically allow for greater rotation off throttle.
Both clutch and TB styles will universally benefit on-throttle
The clutch style/CUP/Guard benefits are better seen under hard breaking/fast corner entry
Always love the way a 911 can snort out of a corner
You know better, I'm gonna drive her forever! lol WELL insured if anything very unfortunately happens to it, and when all the garage queens are sucked up by the collectors in 50years when I might consider selling, whose is left...
Cheers,
Rob
preach! again, even though a tbd isn't *exactly* the same ( yes, i'll admit as a guard or even a cup, my TBD has utterly transformed the car and i am rwd so... but, the truth be told, i should always have gotten a gt2 in the first place, but i'm either cheap/broke or some variation of both, so I've compromised when/where i could! yet, i'm all about p'sliding out of corners. that is fun that is indescribable with this much power on a small two lane blacktop. cant do that w/out some form of rear wheel lock!
..and hey side note rob.. there's a medium high mile $150k '02 6gt2 FS right now in your neck 'o the woods. keep that sucker garaged! lol
as a guard or even a cup, my TBD has utterly transformed the car and i am rwd so... but, the truth be told, i should always have gotten a gt2 in the first place, but i'm either cheap/broke or some variation of both, so I've compromised when/where i could! yet, i'm all about p'sliding out of corners. that is fun that is indescribable with this much power on a small two lane blacktop. cant do that w/out some form of rear wheel lock!..and hey side note rob.. there's a medium high mile $150k '02 6gt2 FS right now in your neck 'o the woods. keep that sucker garaged! lol
You can lift throttle, but know the weight transfer is coming...an effective tool if you can work it.
In comparison, the 996's are very fast AND 'effortless' to carry cornering speed.
12-09-2015, 02:55 AM
#63
I had my C4 with PSM at Laguna Seca. First few sessions with it on, finally turned it off when it started chopping the throttle in turn 1 when i finally had the guts to not lift. In the turbo it is very reassuring to have the PSM on when driving in the rain. I am sure i will turn it off after several sessions at the next Laguna track day unless it is raining. Experienced driver at the track, off is best. Normal everyday driving i leave it on because it is safer, no brainer. Some might say Paul Walker would still be alive if his GT had it and it had been on, Maybe.
I personally don't mind it coming into 1. PSM saved my *ss in that section once when I ran wide and put 2 wheels off cresting the hill well over 100 and over corrected. Risk/return-wise, since you are almost at the brake zone, car very light cresting hill at very high speed (120-130 in a turbo), and walls both sides, it's not the place to mess around.
Laguna without PSM is definitely more fun and faster, but of course more risky as all these spots mentioned have close walls on the inside where you usually end up if you oversteer on exit.
12-09-2015, 04:46 AM
#64
Guys, pushing the PSM off button doesn't really turn off PSM, it just dumbs it down. It will still interfere under larger slip angles especially when off throttle or under braking when you really need the car to rotate under braking. You need to physically disconnect the PSM plug to truly "turn OFF" PSM. The problem is that the car will end up squirly under braking with the stock open diff. as there is no lock up to tie the rear axle together guys stabilizing the car. An LSD with a moderate preload and the ability to lock under braking really helps here in turning the car into a pussycat..
12-09-2015, 11:24 AM
#66
RL Community Team
Rennlist Member
Rennlist Member
With PSM selected "OFF", the system still sits in the background collecting data. If you have not exceeded the levels of slip allowed (I believe it's 7 degrees) and apply the brakes (no matter how hard), PSM will not engage and activate its outputs. If you have exceeded the levels of slip and apply the brakes, PSM will activate until the car has returned to the "no intervention" criteria, or until you take your foot off the brake, at which time PSM again stops intervening.
12-10-2015, 10:47 AM
#68
when braking with a tbd,.. as the "rumour" is that they "dont "lock" under braking. according to wavetrac and my limited experience, that's not so.. and i've done my best to re-create those situations! lolbut would that be the "open diff" scenario that plate type lsd's eliminate?.. i'm not certain in any technical sense but wavetrac ( at least ) has claimed to have solved that mechanically and forgive ( or skip over the reasons why this TBD IS different than the older torsen type's available that cited the "open wheel" situation. i have too much time on my hands, and the following is further proof...: some of their explanatory sales spiel!
The Wavetrac uses high quality ARP hardware for all of the bolts and fasteners. It uses torque biasing worm gears instead of clutches to control the rear axles in the event of uneven traction at the wheels. In clutch and plate LSD rear ends, the unit is trying to lock up and simulate a spool when a wheel loses traction and ensure that at least 50% of available torque is sent to the wheel with traction. A worm gear limited slip differential uses it’s gearing to try to send more than 50% of the torque to the wheel with traction. In other words, when one wheel begins to slip a worm gear LSD uses the mechanical leverage of its worm gears to try to multiple the torque the slipping wheel is receiving and send it to the other side.
The Wavetrac differs from other torque biasing LSDs due to its unique and patented wave cam. But before we explain what a wave cam is, let’s look at why it’s needed. All torque biasing differentials have a problem when faced with a zero axle load on one wheel. torque biasing differentials basically multiply the torque available to the slipping wheel back to the wheel with traction. But what if the torque at the slipping wheel is absolutely zero, as can occur in corning and over bumps? Well, we all learned in grade school that anything times zero is zero. Therefore, under zero load conditions torque biasing differentials can’t send any torque to the non-slipping wheel.
And now we come to that wave cam. In the center of the Wavetrac unit are two cams with nested “wave” cam profiles on them. At zero or near-zero axle load the two sides of the unit start to turn at different speeds and one cam rides up on the other creating a clamping force that locks the axles together.
Left, Wavetrac wave cam under normal axle load. Right, Wavetrac wave cam at zero or near-zero axle load. Under zero or near-zero axle load, the Wavetrac’s patented wave cam rotates and rides out of its nested profile applying pressure and locking the axles.
The Wavetrac unit plays well with late model traction control systems, it is transparent to the factory system. The stability system just knows that it’s called upon much less and the rear brakes see less wear. The Wavetrac has a lifetime warranty which is transferable and even applies to racing applications as long as it’s used for the intended vehicle and rear end. Of course, some limits apply, like you have to have oil in the rear end and it has to be the correct type of oil. And speaking of oil, no friction modifier is required. In fact, you should not use any friction modifier or gear oil with modifier in it.
so all that appears to be true, as i have felt the difference, and there is NO "open diff" situation i've been able to re-create since i installed it, and i did so to eliminate wheelspin AND tailwag, and it has served me well in that regard though i was initially dubious about whether the wheels WOULD lock under hard d'shift downhill braking.. but perhaps and i'm sure there are other reasons that plate type lsd's are all around "better', or else plate types wouldn't be the only thing used on the track by REAL TEAMS and in the last few days i've seen about 3 brand spankin new gt3rs', and try as i might to find one, not a wavertrac to be found! one not even one of 'em hah.
Both clutch and TB styles will universally benefit on-throttle
Always love the way a 911 can snort out of a corner
You know better, I'm gonna drive her forever! lol WELL insured if anything very unfortunately happens to it, and when all the garage queens are sucked up by the collectors in 50 years when I might consider selling, whose is left...
You know better, I'm gonna drive her forever! lol WELL insured if anything very unfortunately happens to it, and when all the garage queens are sucked up by the collectors in 50 years when I might consider selling, whose is left...
) and i have nothing but the utmost respect for anyone that drives the snot of a collector porsche! i figure mine's worth about 1/8 the $ of yours, but i'd be right on yer a** at speed, in spite of my advancing age LOL.. ( sh*t, that didn't READ right either.. i'm out! lol )
cheers bud
Last edited by "02996ttx50; 12-10-2015 at 11:07 AM.
12-11-2015, 01:08 AM
#69
saved this reply for the night-cap cocktails...isn't there a rule about multiple paragraphs on a single RL reply? lol 
the Wavetrac cam 'preload' might be the trick to gain the off throttle/load response that is otherwise essentially non-existent on normal TBD.
A 'strong' clutch style diff makes the rear of car very stabile, guess the way to explain the feeling is like someone has a towrope attached to the rear and dragging the car towards the rear quarter...you lose some directional flexibility but gain stability. A lift-throttle in corner creates strong rotation but doesn't cause major upset in the chassis.
Driver's cars deserve drivers, collectors can collect the 'art' cars
Cheers,
Rob
the Wavetrac cam 'preload' might be the trick to gain the off throttle/load response that is otherwise essentially non-existent on normal TBD.
A 'strong' clutch style diff makes the rear of car very stabile, guess the way to explain the feeling is like someone has a towrope attached to the rear and dragging the car towards the rear quarter...you lose some directional flexibility but gain stability. A lift-throttle in corner creates strong rotation but doesn't cause major upset in the chassis.
Driver's cars deserve drivers, collectors can collect the 'art' cars
Cheers,
Rob
i'm sure you're right, and your experience exceeds mine, i only know from these hillclimbs, and downhills at speed with a quick 2nd gear d'shift, i don't get that "wag" one usually associates with an open differential scenario under hard braking that some folks are certain is the downside to a tbd. but i would think that tracking might tell a different story, or perhaps not?
yes, that tailwag/snap thing again when braking with a tbd,.. as the "rumour" is that they "dont "lock" under braking. according to wavetrac and my limited experience, that's not so.. and i've done my best to re-create those situations! lol
but would that be the "open diff" scenario that plate type lsd's eliminate?.. i'm not certain in any technical sense but wavetrac ( at least ) has claimed to have solved that mechanically and forgive ( or skip over the reasons why this TBD IS different than the older torsen type's available that cited the "open wheel" situation. i have too much time on my hands, and the following is further proof...: some of their explanatory sales spiel!
The Wavetrac uses high quality ARP hardware for all of the bolts and fasteners. It uses torque biasing worm gears instead of clutches to control the rear axles in the event of uneven traction at the wheels. In clutch and plate LSD rear ends, the unit is trying to lock up and simulate a spool when a wheel loses traction and ensure that at least 50% of available torque is sent to the wheel with traction. A worm gear limited slip differential uses it’s gearing to try to send more than 50% of the torque to the wheel with traction. In other words, when one wheel begins to slip a worm gear LSD uses the mechanical leverage of its worm gears to try to multiple the torque the slipping wheel is receiving and send it to the other side.
The Wavetrac differs from other torque biasing LSDs due to its unique and patented wave cam. But before we explain what a wave cam is, let’s look at why it’s needed. All torque biasing differentials have a problem when faced with a zero axle load on one wheel. torque biasing differentials basically multiply the torque available to the slipping wheel back to the wheel with traction. But what if the torque at the slipping wheel is absolutely zero, as can occur in corning and over bumps? Well, we all learned in grade school that anything times zero is zero. Therefore, under zero load conditions torque biasing differentials can’t send any torque to the non-slipping wheel.
And now we come to that wave cam. In the center of the Wavetrac unit are two cams with nested “wave” cam profiles on them. At zero or near-zero axle load the two sides of the unit start to turn at different speeds and one cam rides up on the other creating a clamping force that locks the axles together.
Left, Wavetrac wave cam under normal axle load. Right, Wavetrac wave cam at zero or near-zero axle load. Under zero or near-zero axle load, the Wavetrac’s patented wave cam rotates and rides out of its nested profile applying pressure and locking the axles.
The Wavetrac unit plays well with late model traction control systems, it is transparent to the factory system. The stability system just knows that it’s called upon much less and the rear brakes see less wear. The Wavetrac has a lifetime warranty which is transferable and even applies to racing applications as long as it’s used for the intended vehicle and rear end. Of course, some limits apply, like you have to have oil in the rear end and it has to be the correct type of oil. And speaking of oil, no friction modifier is required. In fact, you should not use any friction modifier or gear oil with modifier in it.
so all that appears to be true, as i have felt the difference, and there is NO "open diff" situation i've been able to re-create since i installed it, and i did so to eliminate wheelspin AND tailwag, and it has served me well in that regard though i was initially dubious about whether the wheels WOULD lock under hard d'shift downhill braking.. but perhaps and i'm sure there are other reasons that plate type lsd's are all around "better', or else plate types wouldn't be the only thing used on the track by REAL TEAMS and in the last few days i've seen about 3 brand spankin new gt3rs', and try as i might to find one, not a wavertrac to be found! one not even one of 'em hah.
ain't THAT the truth
me too, and i snort daily!( umm, that didn't sound right ) and i have nothing but the utmost respect for anyone that drives the snot of a collector porsche!
i figure mine's worth about 1/8 the $ of yours, but i'd be right on yer a** at speed, in spite of my advancing age LOL.. ( sh*t, that didn't READ right either.. i'm out! lol )
cheers bud
yes, that tailwag/snap thing again
when braking with a tbd,.. as the "rumour" is that they "dont "lock" under braking. according to wavetrac and my limited experience, that's not so.. and i've done my best to re-create those situations! lolbut would that be the "open diff" scenario that plate type lsd's eliminate?.. i'm not certain in any technical sense but wavetrac ( at least ) has claimed to have solved that mechanically and forgive ( or skip over the reasons why this TBD IS different than the older torsen type's available that cited the "open wheel" situation. i have too much time on my hands, and the following is further proof...: some of their explanatory sales spiel!
The Wavetrac uses high quality ARP hardware for all of the bolts and fasteners. It uses torque biasing worm gears instead of clutches to control the rear axles in the event of uneven traction at the wheels. In clutch and plate LSD rear ends, the unit is trying to lock up and simulate a spool when a wheel loses traction and ensure that at least 50% of available torque is sent to the wheel with traction. A worm gear limited slip differential uses it’s gearing to try to send more than 50% of the torque to the wheel with traction. In other words, when one wheel begins to slip a worm gear LSD uses the mechanical leverage of its worm gears to try to multiple the torque the slipping wheel is receiving and send it to the other side.
The Wavetrac differs from other torque biasing LSDs due to its unique and patented wave cam. But before we explain what a wave cam is, let’s look at why it’s needed. All torque biasing differentials have a problem when faced with a zero axle load on one wheel. torque biasing differentials basically multiply the torque available to the slipping wheel back to the wheel with traction. But what if the torque at the slipping wheel is absolutely zero, as can occur in corning and over bumps? Well, we all learned in grade school that anything times zero is zero. Therefore, under zero load conditions torque biasing differentials can’t send any torque to the non-slipping wheel.
And now we come to that wave cam. In the center of the Wavetrac unit are two cams with nested “wave” cam profiles on them. At zero or near-zero axle load the two sides of the unit start to turn at different speeds and one cam rides up on the other creating a clamping force that locks the axles together.
Left, Wavetrac wave cam under normal axle load. Right, Wavetrac wave cam at zero or near-zero axle load. Under zero or near-zero axle load, the Wavetrac’s patented wave cam rotates and rides out of its nested profile applying pressure and locking the axles.
The Wavetrac unit plays well with late model traction control systems, it is transparent to the factory system. The stability system just knows that it’s called upon much less and the rear brakes see less wear. The Wavetrac has a lifetime warranty which is transferable and even applies to racing applications as long as it’s used for the intended vehicle and rear end. Of course, some limits apply, like you have to have oil in the rear end and it has to be the correct type of oil. And speaking of oil, no friction modifier is required. In fact, you should not use any friction modifier or gear oil with modifier in it.
so all that appears to be true, as i have felt the difference, and there is NO "open diff" situation i've been able to re-create since i installed it, and i did so to eliminate wheelspin AND tailwag, and it has served me well in that regard though i was initially dubious about whether the wheels WOULD lock under hard d'shift downhill braking.. but perhaps and i'm sure there are other reasons that plate type lsd's are all around "better', or else plate types wouldn't be the only thing used on the track by REAL TEAMS and in the last few days i've seen about 3 brand spankin new gt3rs', and try as i might to find one, not a wavertrac to be found! one not even one of 'em hah.
ain't THAT the truth
me too, and i snort daily!( umm, that didn't sound right
) and i have nothing but the utmost respect for anyone that drives the snot of a collector porsche! i figure mine's worth about 1/8 the $ of yours, but i'd be right on yer a** at speed, in spite of my advancing age LOL.. ( sh*t, that didn't READ right either.. i'm out! lol )
cheers bud
12-11-2015, 02:17 AM
#70
With PSM selected "OFF", the system still sits in the background collecting data. If you have not exceeded the levels of slip allowed (I believe it's 7 degrees) and apply the brakes (no matter how hard), PSM will not engage and activate its outputs. If you have exceeded the levels of slip and apply the brakes, PSM will activate until the car has returned to the "no intervention" criteria, or until you take your foot off the brake, at which time PSM again stops intervening.
12-11-2015, 07:49 AM
#71
[QUOTE=993GT;12832471]saved this reply for the night-cap cocktails...isn't there a rule about multiple paragraphs on a single RL reply? lol
it is, and i have rediscovered eggnog for breakfast given the lack of clarity of my 3 am posts and i'm sure this is self evident!.
yes, it actually works, true to their word and i'm sure the preload is exactly why.. which was the only point of my long winded, albeit cut and parsed and pasted majority reply. cheers! 'tis the season for long winded babble fueled by eggnog, or the like.
it is, and i have rediscovered eggnog for breakfast given the lack of clarity of my 3 am posts and i'm sure this is self evident!.
12-15-2015, 02:03 AM
#73
anyone have confirmed values on when psm intervenes?
I found it to give quite a big amount of slip angle last winter before it decided that was enough.
more so than any other car I have driven with such systems. it surprised me.
It still allowed for some tail wagging fun.
It did cut in nicely on acceleration though.
I found it to give quite a big amount of slip angle last winter before it decided that was enough.
more so than any other car I have driven with such systems. it surprised me.
It still allowed for some tail wagging fun.
It did cut in nicely on acceleration though.
12-15-2015, 11:53 AM
#74
the thing for me about it's intervention that bothers me most, is.
i'm not sure which is more disconcerting, it's intrusion or the condition or "situation" i may be driving in that triggers it in the first place. while it may help to "settle" the car, it has never "settled" me and i actually find it's intervention intrusive and unnerving.
i'm not sure which is more disconcerting, it's intrusion or the condition or "situation" i may be driving in that triggers it in the first place. while it may help to "settle" the car, it has never "settled" me and i actually find it's intervention intrusive and unnerving.