Sharpening the scalpel - 997 GT3 Track Rat

[Peter John]

Didn't sound like Kylie Minogue so you're lucky! @Kammo

[spiller]

It just occurred to me that I knew this car when it was in SA from the PCSA track days. Coincidentally I work with the previous owner’s niece. I always remember it being quite a clean car.

[Kammo]

On 11/04/2018 at 6:57 PM, spiller said:

It just occurred to me that I knew this car when it was in SA from the PCSA track days. Coincidentally I work with the previous owner’s niece. I always remember it being quite a clean car.

Well it's good to validate the provenance of the car, didn't spend too much time with him but the previous owner did seem like a pretty genuine guy.

[Track Day #8 - EXE @ Winton 07/10]

After a bit of a chat with @edgy, I'd been keeping my ear to the ground for an upgraded differential. My old 350Z had an aggressive clutch pack which was probably the best track mod I ever did but I could never get the backlash right so it was a bit of pain to drive on the road.

@Mike737 suggested I have a chat with Nick at Cascone Auto Sports and he happened to have a 997 cup car diff which had done a single season with minimal wear and tear. The difference with these diffs is that they have a much higher pre-load and more clutch plates. I believe the preload is around 90Nm versus 15Nm for the stock differential. I was fortunate enough to have a bit of a chat with a Manthey race engineer who suggested dropping that back to 50Nm for semi-slick tyres, though I haven't had the time to get it pulled out and reset.

Nick did the install, custom made the shim stack to get the lash setting just right and trundling about the street there's no difference in feel. If you load the car up a little bit the rear end is much faster to respond but there's no typical locking issues at low speeds when maneuvering around a car park. I think this is probably from not using an organic friction material like the Japanese manufacturers so the slip qualities at low lock are a bit different. Anyway, was pleasantly surprised that's for sure.

Heading back down to Winton there was an overall net gain in time, doing fairly consistent times under 1:33, but the sway bar settings only offered a slightly too tail-happy setup or a setup that pushes a little from the transition from dynamic to steady state on entry. I opted for the latter as a safe option and ran higher pressures at the rear in an attempt to get the car to rotate a little more and finished the day with a 1:32.5, about half a second up the road from the old PB. 

[edgy]

That's awesome to hear man! 

I like that the new LSD makes the car more predictable when transitioning, and helps it rotate better.. also no tail wagging on heavy braking.

I am now onto chasing my suspension setup/alignment, which we are resetting next week ahead of sprint 2, its all stock save for the DSC Sport PASM controller + 3 axis accelerometer... so far I like the improvements I've seen with that DSC module, the jury is still out on the Cup Car 4.0 ratios.... 

[reddahaydn]

Wow that’s some great times for Winton! Love the write up and insight, especially wrt brakes. 

Cheers

[Kammo]

On 17/04/2018 at 9:23 AM, edgy said:

That's awesome to hear man! 

I like that the new LSD makes the car more predictable when transitioning, and helps it rotate better.. also no tail wagging on heavy braking.

I am now onto chasing my suspension setup/alignment, which we are resetting next week ahead of sprint 2, its all stock save for the DSC Sport PASM controller + 3 axis accelerometer... so far I like the improvements I've seen with that DSC module, the jury is still out on the Cup Car 4.0 ratios.... 

Nice! What sort improvements did you feel with the DSC module and are you able to apply some control to the dampers or are they presets? Are the cup car ratios final drive of full gear set?

 

15 hours ago, reddahaydn said:

Wow that’s some great times for Winton! Love the write up and insight, especially wrt brakes. 

Cheers

Thanks, she's coming along, still a bit left I think...have you decided whether or not to come along to the track day in a couple of weeks?

[Pit-stop November 2017]

So a bit after the Circuit Club track day I thought I'd take the car for a drive the clutch pedal felt completely off to the point where it wasn't coming up off the floor. Funnily enough it was fine on the drive home but after sitting for a bit there was a pressure problem to the point where I couldn't select a gear with the engine running. Fortunately I'm a few kms from Porsche Centre Melbourne so I was able to limp the car there by sticking in first all the way.

To me it kinda felt like a master / slave cylinder problem but PCM diagnosed it as needing a new clutch and flywheel...gah. Post analysis it was concluded that general wear-and-tear, though I would have assumed the clutch would have gone more than 48,000kms. Labour wasn't too bad but parts were pretty expensive, especially compared to US prices.

[spiller]

Did you stick a single mass flywheel in it?

[dan_189]

2 hours ago, Kammo said:

Nice! What sort improvements did you feel with the DSC module and are you able to apply some control to the dampers or are they presets? Are the cup car ratios final drive of full gear set?

 

Thanks, she's coming along, still a bit left I think...have you decided whether or not to come along to the track day in a couple of weeks?

[Pit-stop November 2017]

So a bit after the Circuit Club track day I thought I'd take the car for a drive the clutch pedal felt completely off to the point where it wasn't coming up off the floor. Funnily enough it was fine on the drive home but after sitting for a bit there was a pressure problem to the point where I couldn't select a gear with the engine running. Fortunately I'm a few kms from Porsche Centre Melbourne so I was able to limp the car there by sticking in first all the way.

To me it kinda felt like a master / slave cylinder problem but PCM diagnosed it as needing a new clutch and flywheel...gah. Post analysis it was concluded that general wear-and-tear, though I would have assumed the clutch would have gone more than 48,000kms. Labour wasn't too bad but parts were pretty expensive, especially compared to US prices.

I've supplied my own genuine parts for PCM to fit before, they were pretty good about it you just don't get the warranty. If it's preventative maintenance or you can wait for the parts to come it's worth it. 

Awesome shot in their workshop 

[edgy]

On 25/04/2018 at 2:58 PM, Kammo said:

Nice! What sort improvements did you feel with the DSC module and are you able to apply some control to the dampers or are they presets? Are the cup car ratios final drive of full gear set?

The Cup car ratios, I've only installed the ring and pinion which is 4.0 ratio versus our tall 3.44, of course you can change individual gear ratios but that gets stupid expensive! The reason I did this, is because the car felt like it could use more punch on exits.... I really notice this when running with Cayman GT4's that are about similar pace, I am faster on entry and mid corner but those GT4's just put it down and exit pretty hard! Again, I'm still learning the car again with this change... I'll keep you posted after this weekends sprint. 

My anecdotal findings on the DSC are that the car is more stable on high speed braking and cornering, and also seemingly it has taken lots of the "bounce" out of it when it comes to some of the rough stuff. 

This is a copy paste from Tom Chan at TPC on the DSC controller, it basically opens up the operating parameters of the dampers and adds one extra input value (you need to add the 3 axis accelerometer to our 997.1's), you can play with the programming if you like too, but its meant to be a dynamic system, I plan on adding the tractive dampers at some point.
 

OEM PASM modes: 

 

PASM Normal mode, 20-25%

PASM Sport mode, 85-90%

PASM has no access to the percentage in between its two modes.

 

DSC PASM controller: 

 

DSC Normal mode, 10-100% based on inputs such as speed, g-force, and brake line pressure.

DSC Sport mode, 20-100% based on inputs such as speed, g-force, and brake line pressure.

Either DSC mode can be used for track since the inputs on track are in the higher ranges.

DSC Normal mode on track will feel slightly firmer during initial turn-in since its base value is 10% less than in Sport mode.

The 10% less initial stiffness is good for street comfort, and for wet/damp track.

 

Really, you hear people bang on about PASM being a driver aid, but the truth is that is bull shit.... its more of a hinderance on the track in stock form... I've tweaked my alignment now and will see how it all goes! 

Cheers

[Kammo]

On 26/04/2018 at 4:20 PM, edgy said:

The Cup car ratios, I've only installed the ring and pinion which is 4.0 ratio versus our tall 3.44, of course you can change individual gear ratios but that gets stupid expensive! The reason I did this, is because the car felt like it could use more punch on exits.... I really notice this when running with Cayman GT4's that are about similar pace, I am faster on entry and mid corner but those GT4's just put it down and exit pretty hard! Again, I'm still learning the car again with this change... I'll keep you posted after this weekends sprint. 

My anecdotal findings on the DSC are that the car is more stable on high speed braking and cornering, and also seemingly it has taken lots of the "bounce" out of it when it comes to some of the rough stuff. 

Really, you hear people bang on about PASM being a driver aid, but the truth is that is bull shit.... its more of a hinderance on the track in stock form... I've tweaked my alignment now and will see how it all goes! 

That sounds like a clever adaptation of what's already there...I probably would have gone for something like that if I'd known about it earlier but have taken a more traditional path. 

Interested in hearing how you go with the 4.0 final drive. I tend to use second gear a lot because it's so tall, pretty much any low speed or hairpin corner...do you use 2nd a lot up in NSW? I would imagine turns 2 and 9 at EC, turn 8 and 11 at Wakefield? When I had my 350Z I went from 3.5 to 3.7 final drive, it didn't really do all that much...should have gone the 3.9.

[Kammo]

[Porsche Advance Driver Training Open Lap - Philip Island 11/17]

After getting my clutch and flywheel replaced and with the suspension setup running mostly fine (more importantly pretty benign) I booked into one of the Porsche days, negotiating my way out having to do the Level 1 and Level 2 and went straight to open lapping. Three groups were loosely arranged into slowest to fastest by way of volunteer, obviously some potential issues with an honour system like that but it seemed to work for the most part. It was an interesting crowd and it seemed there were a few people who hadn't really tracked before that had gone levels one and two previously and were backing it up with a third day of open track. When I asked where I could my tools in the driver's briefing the gentleman next to me asked whether I could see my engine. When I replied "no" he then proceeded to ask why then, had I brought tools? Not sure if he was being facetious or just naive. Thankfully, met some much nicer people through the day like @DJM , haha. 

It shaped up to be a pretty warm day and a 1:49.1 wasn't too bad for a PI shakedown. The suspension felt pretty soft but I learnt a few things unique to a 911, like when the car is feeling loose on a high speed entry like turn 1, mashing the throttle straightens it right out. Also got one of the pro drivers in attendance to do a few laps in my car where I could take some comparison data. He did a 1:47.xx by getting on the gas earlier out of turn 1 and going flat through Hay Shed. 

Overall a pretty good day but on the expensive side, you could do three trackdays at PI for the price of the 1 day organised by Porsche, but there's a good amount of lap time with not a whole lot of cars on the track. 

[DJM]

7 hours ago, Kammo said:

[Porsche Advance Driver Training Open Lap - Philip Island 11/17]

After getting my clutch and flywheel replaced and with the suspension setup running mostly fine (more importantly pretty benign) I booked into one of the Porsche days, negotiating my way out having to do the Level 1 and Level 2 and went straight to open lapping. Three groups were loosely arranged into slowest to fastest by way of volunteer, obviously some potential issues with an honour system like that but it seemed to work for the most part. It was an interesting crowd and it seemed there were a few people who hadn't really tracked before that had gone levels one and two previously and were backing it up with a third day of open track. When I asked where I could my tools in the driver's briefing the gentleman next to me asked whether I could see my engine. When I replied "no" he then proceeded to ask why then, had I brought tools? Not sure if he was being facetious or just naive. Thankfully, met some much nicer people through the day like @DJM , haha. 

It shaped up to be a pretty warm day and a 1:49.1 wasn't too bad for a PI shakedown. The suspension felt pretty soft but I learnt a few things unique to a 911, like when the car is feeling loose on a high speed entry like turn 1, mashing the throttle straightens it right out. Also got one of the pro drivers in attendance to do a few laps in my car where I could take some comparison data. He did a 1:47.xx by getting on the gas earlier out of turn 1 and going flat through Hay Shed. 

Overall a pretty good day but on the expensive side, you could do three trackdays at PI for the price of the 1 day organised by Porsche, but there's a good amount of lap time with not a whole lot of cars on the track. 

Good day, shame it was a bazillion degrees (I think I saw 35 on the dash).  

How much did it cost?  I negotiated it into purchase of the car from PCM so wasn't sure what it actually cost. Like you I convinced them I've done plenty of laps in other cars so jumped straight into Level 3.

Steve Owen drove my car for a couple of laps and was substantially quicker than me, with my fat arse in the car with him!  it's all about setting the car up right on entry and then driving through corners more quickly rather than ragging it on the way in and fighting it through the corner.  SMOOTH is FAST.  The bastards make it look so easy.

[edgy]

11 hours ago, Kammo said:

That sounds like a clever adaptation of what's already there...I probably would have gone for something like that if I'd known about it earlier but have taken a more traditional path. 

Interested in hearing how you go with the 4.0 final drive. I tend to use second gear a lot because it's so tall, pretty much any low speed or hairpin corner...do you use 2nd a lot up in NSW? I would imagine turns 2 and 9 at EC, turn 8 and 11 at Wakefield? When I had my 350Z I went from 3.5 to 3.7 final drive, it didn't really do all that much...should have gone the 3.9.

Yup, Wakefield and SMP GP has lots of 2-3 corners! 

I need to get a better run at the GP circuit, but I ran Wakefield park on Saturday just passed, and I managed to break into the 1.06's, where as my previous time was in the 1.08's... interesting to note that a couple of GT4's that were similar pace to me are still in the 1.08's & 1.07's so I believe that the 4.0's have definitely made an improvement! @Robert930 also did the ratio change same time as me, and he improved his times too (we're in the same class and run group). 

No doubt the new wheel alignment has helped as it was too aggressive before, I think the new ratios really highlighted that, as I found that I couldnt be as aggressive when putting the power down on exits, the car just lacked the lateral grip to do that. 

All being considered, I am very happy with the ratio change, its made the car easier to drive in traffic too... granted its not a cheap exercise, but well worth doing IMO. 

 

[symsy]

Great info and sharing guys ..

 

[Kammo]

On 01/05/2018 at 11:22 AM, edgy said:

Yup, Wakefield and SMP GP has lots of 2-3 corners! 

I need to get a better run at the GP circuit, but I ran Wakefield park on Saturday just passed, and I managed to break into the 1.06's, where as my previous time was in the 1.08's... interesting to note that a couple of GT4's that were similar pace to me are still in the 1.08's & 1.07's so I believe that the 4.0's have definitely made an improvement! @Robert930 also did the ratio change same time as me, and he improved his times too (we're in the same class and run group). 

No doubt the new wheel alignment has helped as it was too aggressive before, I think the new ratios really highlighted that, as I found that I couldnt be as aggressive when putting the power down on exits, the car just lacked the lateral grip to do that. 

All being considered, I am very happy with the ratio change, its made the car easier to drive in traffic too... granted its not a cheap exercise, but well worth doing IMO. 

 

2 seconds is impressive, especially at Wakefield. 1:06 is blisteringly quick! 

[symsy]

26 minutes ago, Kammo said:

2 seconds is impressive, especially at Wakefield. 1:06 is blisteringly quick! 

Yeah like 20 possibly 30 seconds faster than my best efforts and moments of manic mayhem in a MK1 escort.  Thanks for laying down some rubber, gives me a little traction .. I will get there one day in the GT3 , for now I will just be envious 

[edgy]

5 hours ago, Kammo said:

2 seconds is impressive, especially at Wakefield. 1:06 is blisteringly quick! 

It’s getting there for sure, I think all being considered, it’s a good time, definitely a little bit more left in the driver and some more to be had with good suspension and aero. 

[Kammo]

[February 2018]

Probably one of the last modifications I'll do on this car; a set of KW clubsports. I've always enjoyed pretty good success with KWs but installing them also fixed inherent handling flaws in past cars like the chronic understeer of the TT-RS. There are some minor adjustments that could be made to the 911 especially now with the differential but overall this car is extremely well balanced out of the box so the expectation is actually to go backwards for a while until I get the setup correct. Overall the car sits 5mm lower front and rear and I've been able to extract a bit more camber from the fronts, now just north of -3 degrees and around -2 at the rear.

[Track for days @ Winton 1/03]

As expected the car has gone backwards in time and handling. The new suspension felt pretty twitchy in the rear as the rear spring rate feels noticeably harder than the front. Also, because the ambient temps across the day were well into the mid 30s the tyres were out of their optimal operating range resulting in not many laps to tune before the tyres would overheat. Consequently I was only able to make a few damper changes and settle the car marginally to finish up with a 1:34.2...can't win 'em all. There were a few other Porsches floating around that day so I got to meet some of the PCV folk, coincidentally my old wheels were also there on a 996 GT3.

[Kammo]

[Circuit Club @ Winton 12/03]

Circuit Club at Winton was another highly frustrating day. Knowing the car would be a bit oversteery I continue to work the front dampers on the hope that I'd find a happy place. Unfortunately it wasn't to be as it was another roasting day so I could only really get one or two hot laps in before the rear tyres fell away. In the end I realized that it should probably have been a wholesale swaybar change to correct the attitude of the car as the combination of relatively stiff feeling rear springs and being able to optimize front camber has resulted a car with a lot more front end grip relative to the rear. Managed to get the time down to a low 1:35.xx but the times were inconsistent and all over the place.

Towards the end of the day my frustration culminated in this big off at the elbow (T10) where the car slid and I buried the throttle in a vain attempt to carry the slide. The car bit back the other way and I stopped a few metres from the wall, heart-in-mouth.

 

[symsy]

Love the persistence mate… 

 

[MFX]

Nice save ?

[Kammo]

On 6/6/2018 at 4:01 PM, symsy said:

Love the persistence mate… 

 

Where there is no skill, you make up for with sheer force of will...haha!

 

On 6/6/2018 at 6:43 PM, MFX said:

Nice save ?

In the most liberal meaning of the word ?

[Segue - April 2018]

So the car is not so happy with me after I almost binned her (or maybe it's just coincidence) and the clutch is being dinky so taking the car out of track-action to get to the bottom of the issue, tidy up a few things and make a few little changes.

In the meantime, I've decided to work on my drifting skills and purchase this mint 2002 Silvia Spec S GT. I had one of these years and years ago and never got to really smash it around a track, so it's back to the future! Also took her out to Winton to have crack with my 86-mates...1:44.xx on a set of Bridgestone RE003s. The S-Chassis is such an entertaining platform and the stock speeds on road tyres makes the track feel twice as wide for lots of slidey entries and exits. Had such a great day and ordered a few bits and pieces so that the car will be able to do triple duty as a drifter, track-day and daily car.

[Jason A]

@Kammo with oversteer have you tried backing off the rear sway bar or tighten the front. That is how I dialed it out of my track car

[Kammo]

3 hours ago, Jason A said:

@Kammo with oversteer have you tried backing off the rear sway bar or tighten the front. That is how I dialed it out of my track car

Yep so sway bars are when a large change needs to be made, dampers for smaller changes. I was hoping to be able to make the necessary attitude changes in the damper but it's looking like more of a sway bar change. As the car is feeling nervous on entry I will look to effect a front sway bar change rather than a rear sway bar change, plus I guess having five holes at the front should mean that each change is less acute than the rear's 3 hole setup (based on no actual hard evidence, haha). 

[Teutonic]

Nice work developing the car. I guess if you aren't having the odd spin you're not tying hard enough  Sounds like you have a fair bit of experience setting up cars. One tip I got given was always try to focus on increasing overall grip. Sounds like you have done a good job of that on the front axle, and just need to chase more at the rear. (softer bar, softer spring, softer compression damping, camber change etc.) As opposed say to stiffening up the front which might balance the car, but overall be a slower thing.