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Cayman The Destroyer!
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Discussion Starter · #1 ·
Well I finally decided to try driving without PSM. I can't believe how much better the car is near the limit. What a pleasure to have the car do what I want it to. Less push & so much smoother. Did I mention 1.5 sec faster at the glen!
 

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Hey dog!

Glad to hear you're having fun. Post some videos if ya got 'em!
 

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Cayman The Destroyer!
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Discussion Starter · #3 ·
Had some trouble with the camera but I do have some video. I hope I have the run where I passed the two Cayman Interseries cars that where at the event. I was suprised how fast they where on the straights an amazed that I could keep up on the corners.
 

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What changed? Was PSM cutting the throttle or applying braking?

When was this WGI event? I thought the track has been under repair since the Grand Am race in early June. I am supposed to be driving there right NOW! But they cancelled the event due to repairs :(
 

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Not surprised. I enjoy the car MUCH more at the track without intervention...or as little intervention as possible when turned off :)
 

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Cayman The Destroyer!
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Discussion Starter · #6 ·
PSM was doing both. Niagara advanced Wed & Thursday this week. The braking zone into turn 1 was coned on the left side so we didn't have a good shot into turn 1. It was an awesome event, after the first two sessions it was open track for two days.

You gotta be there next year!
 

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Divebuddy, PSM is good at slippery hazardous conditions... other than that it is always off from the moment I turn on the engine! Glad you're enjoying the drive... cheers my friend!
 

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Cayman The Destroyer!
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Discussion Starter · #9 ·
PSM on in sport mode 2:11.414 PSM off 2:09.776
 

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Another item to think about is your brake pads. Depending on how hard you are driving you can wear down a set of pads pretty quick with PSM on.

diverdog, good time at the Glenn (2:09.776)
 

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Cayman The Destroyer!
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Discussion Starter · #11 ·
My left rear caliper was getting discolored from heat. One of the key reasons I shut PSM off. I was pleased with the time considering that we had to stay way right into turn one since the pavement was new and they had it coned off
 

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My left rear caliper was getting discolored from heat. One of the key reasons I shut PSM off. I was pleased with the time considering that we had to stay way right into turn one since the pavement was new and they had it coned off
Yup. It overheats the rear brakes and it can cause ice pedal when the ABS gets overwhelmed. PSM uses ABS to do it's work.

PSM will help with inside wheel spin if you don't have limited slip, but if you have enough roll stiffness, it's not much of a problem. I put TPC bars on my car and the difference is really amazing...and I've got the wimp setup with the quiet f / stock r end-links and no lowering.
 

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Well I finally decided to try driving without PSM. I can't believe how much better the car is near the limit. What a pleasure to have the car do what I want it to. Less push & so much smoother. Did I mention 1.5 sec faster at the glen!
Glad to hear that someone else has finally figured out the car is faster and easier to drive at the limit with stability control turned off. So do you think that PSM was "teaching" you anything when it was on and intervening?? (as has been said by others in the past)
Congrats on making the jump to the next level of driving skill!
Tom:cheers:
 

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Cayman The Destroyer!
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Discussion Starter · #14 ·
No I don't think it was teaching me much. I think it was just hitting threshholds and saying "this isn't normal driving don't do that".

I'm going to leave it off in the dry from now on. As I hit each track for the first time I'm going to work up to the limit gradually. thunderbolt is next.

I have the TPC bars & a guard LSD so no issues on rear tire slippage. The car takes all the power I can put down smoothly at corner exit
 

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Don't you have issues with over steering?!! I thought the LSD causes oversteering more often than not having it.

On the other hand, since I do drive with the PSM off all the time please make sure you keep in mind the risk you are taking by doing so... I don't promote doing so and in certain conditions I immediately switch the PSM back on. Because this car has so much power even without the stock.
 

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Interesting discussion, I was at the Glen on 6/21 and 6/22 with CVR running in the White run group. I talked with a few instructors Monday evening at dinner about running with PSM on since it has always been recommended to me. They felt you weren't really learning with it on and suggested I try with PSM off the next day. Tuesday for the first session I had a different instructor take ride a with me and he wanted me to leave the PSM on, he didn't want me to make any big changes in the cars handling. I asked him to see if he could tell if PSM was activating during the run session. After the session he said he couldn't feel it kicking in nor could he see any indication on the dash that it was activating. The instructor felt I was pretty fast, to go faster I should consider track tires and suspension. Right now I'm totally stock, including PS2's except PAGID pads. Unfortunately I have no way of timing my laps so I can't compare times. Diver do you know what your speeds were at the end of the back straight?
We had rain in the afternoon of the second day so the PSM definitely stayed on for my last session.
 

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Cayman The Destroyer!
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Discussion Starter · #17 ·
144-145 at the end of the back straight
 

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Don't forget Jayman, the Dog here has a TPC onboard, a bit of an apples vs. oranges comparison, right? :hilarious:

Oh yeah, I think I saw 110 at the end of the straight...in my 1998 Audi A4 V6 back in 2005. I think the Infiniti G35 broke 120, but it was hard to see with all the dash warnings on. ;)

At the Glen, the G35 computer would puke every time I braked for the bus stop and disable all the stability control systems for the rest of the session (or until I restarted the engine, but never had to do that during a session). So a novice like me got to run the Glen for two days with no electronic nannies as well!

I don't think my front brakes and tires were ever the same on the Infiniti after thrashing it at the Glen. Rotors and pads have been replaced at 15,000 miles and I just noticed my front tire shoulders (Bridgestone RE-050A) are starting to chunk at 10,000 miles. I use winter tires some my summer tires have less mileage on them.

I wonder how the Cayman would feel at the Glen vs. a 4-door luxo barge like the G35?

OK, enough of my stories, back to the real drivers on here...
 

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Don't you have issues with over steering?!! I thought the LSD causes oversteering more often than not having it.

On the other hand, since I do drive with the PSM off all the time please make sure you keep in mind the risk you are taking by doing so... I don't promote doing so and in certain conditions I immediately switch the PSM back on. Because this car has so much power even without the stock.
A friction type LSD will typically cause a push (understeer) at corner entry if it affects handling at all. At corner exit, under power, the car will also tend to want to push as both rear wheels are trying to rotate at the same speed. To overcome the push you can apply more power, if available, to convert to power oversteer.

On a different note, how did we ever survive driving before stability control was developed?!? Why this great "fear" of shutting PSM off???? I just don't get it. When I get into my '95 vintage track car I don't think "I don't have stability control, I am probably going to crash." I get in knowing I am in charge AND responsible for what happens. So why are people so fearful of turning it off in newer cars???? Drive sensibly and within your limits and learn car control. Much more rewarding than saying "I ran so and so lap time with the electronic nany saving my but at every corner." Doesn't DE stand for "driver education"?
Instructor telling you to leave PSM on...... he/she does not want the liability of you crashing and blaming it on "the instructor told me to shut it off".:eek:
JMHO,
Tom
BMWCCA and PCA instructor
:cheers:
 
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