997/996 GT3 dynamics

Author
Discussion

Slippydiff

10,090 posts

161 months

Tuesday 12th February
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LaSource said:
Yes I recall discocolin posting about cracking his OZ's spokes at the ring (but perhaps that was an after effect of an off and not the cause of it). Are there other reports of cracks?
I think Nick R had some crack too. They may have modified the design to address the issue now (but that's conjecture)

LM's ? I've never seen or heard of one cracking to date, so not just for show (and the fronts are sufficiently lighter than the OE wheels to make them a worthwhile upgrade).

The Girodisc front disc upgrade saves 2kgs in weight over the OE 350mm steel boat anchors, fit the LM's or OZ's and you'd be knocking on the door of 5kgs on each front corner (where it matters) ...

Get the front wheel off motorcycle wheel (without a tyre) and spin it up to 80mph whilst holding the spindles that protrude either side of the hub, then try "turning" it left or right... (good luck with that by the way !!)

For sure, you have the benefit of PAS and its gearing (that gives you a massive mechanical advantage) when it comes to overcoming the resistance of turning the spinning wheel, but we're talking about a 5kg motorcycle wheel. On the front of the GT3, you have a wheel that weighs 4X that motorcycle wheel, a tyre that probably weighs 3x as much, a brake disc that weighs twice as much, and the hub that all that lot is mounted to as well.

And then we get onto the benefits of roadholding and handling on bumpy roads/tracks due to the reduced unsprung weight the dampers and springs are having to control ...

Slippydiff

10,090 posts

161 months

Tuesday 12th February
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BrotherMouzone said:
NXI20 has had a few cracked.

http://911uk.com/viewtopic.php?t=124640
Beat me to it smile

Slippydiff

10,090 posts

161 months

Tuesday 12th February
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Digga said:
Pretty much the weight difference between steel or PCCB brakes and, even with the BBS E88's, for less money too.
Fitting PCCB's along with E88's and the lightest decent quality tyres you can find, along with some decent high end dampers would transform ANY 996 GT3 smile

isaldiri

4,221 posts

106 months

Tuesday 12th February
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LaSource said:
Steve Rance said:
The LM are a good compromise for road track. To be honest, although unsprung weight savings are useful, the biggest changes in driving experience in these cars is found by set up and damping. If I were looking at £ for £ rewards on. 996/7 GT3 I’d start on dampers and chassis. £4K will bring a lot more marginal gains there. The best is simply a set up the 997 really benefits from a diff upgrade which is around £1500 for guards internals. I saw track wheels as really merely something to protect the OEM units from constant tyre changes and litter rash
Totally agree. Diff, dampers, geo (I guess maybe front brakes as well)….all you need to make a 996/7 from a great car to a superb one for road and track use. The spring stiffness will determine whether it becomes more track than road, but even a track orientated car is good fun for a sunday drive (but perhaps not on the most pothole-ly B-road or London zone 1 20mph speed bumps!)
very much so but changes to the diff and dampers aren't visible mods that people can show off about and talk about 'unsprung weight' wink

Porsche911R

16,242 posts

203 months

Tuesday 12th February
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Slippydiff said:
Beat me to it smile
but not the whole story, to quote:

"I should also mention that those cracks only developed after several years of use with slicks"

wheels are fine imo and the cheapest good quality wheels on the market.

bit like saying all GT4 top struts will break ! a Bit of forum scare stories most of the time.

I don't agree with any Slick run cars on track days, they ruin the day for every one and also the cars cannot cope on slicks without mods.




Edited by Porsche911R on Tuesday 12th February 12:37

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Harris_I

2,979 posts

197 months

Tuesday 12th February
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My E88s are probably around 10 years old now. They've hit many a track kerb at speed and are still round! I was expecting them to be fragile, but they really have held up well over the past decade (albeit on the rare occasion I'm on a public road I drive around potholes to the extent I can).

The absence of lacquer doesn't seem to have been a problem so far. Admittedly not exactly showroom fresh, but then my car has a sort of battle scarred look to it anyway.

As for how differently they drive, I concur that money is much better spent first on suspension and diff.


Slippydiff

10,090 posts

161 months

Tuesday 12th February
quotequote all
isaldiri said:
very much so but changes to the diff and dampers aren't visible mods that people can show off about and talk about 'unsprung weight' wink
Good gracious, don’t think for one moment the lack of visibility of said diff and dampers in ANY way reduces their “bragging rights” amongst the cognoscenti hehe

BrotherMouzone

2,073 posts

112 months

Tuesday 12th February
quotequote all
Slippydiff said:
isaldiri said:
very much so but changes to the diff and dampers aren't visible mods that people can show off about and talk about 'unsprung weight' wink
Good gracious, don’t think for one moment the lack of visibility of said diff and dampers in ANY way reduces their “bragging rights” amongst the cognoscenti hehe
Ha ha ha. Guilty.

I specifically opened the front boot to show my friends where the shiny orange/gold remote canisters were for the Moton.

I’m such a loser

laugh

nxi20

705 posts

143 months

Wednesday 13th February
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Porsche911R said:
but not the whole story, to quote:

"I should also mention that those cracks only developed after several years of use with slicks"

wheels are fine imo and the cheapest good quality wheels on the market.

bit like saying all GT4 top struts will break ! a Bit of forum scare stories most of the time.

I don't agree with any Slick run cars on track days, they ruin the day for every one and also the cars cannot cope on slicks without mods.
I was merely pointing out to people who were praising the OZs that it's not all upside - posting picture evidence isn't a "story", it's fact. I know you're easily confused about the difference between opinion & fact so I thought it worth pointing that out for you.. The fact that I went out & bought another set when I chucked the cracked ones away shows I don't have a problem with the OZ, they are very good value for money. I tend to break stuff faster than most due to the number of trackdays / miles my GT3 has done; I didn't post a "scare story", merely a report of what happens to the wheel over time. Slicks just made it happen faster. Smashing over potholes will also do damage but you do need to look at the wheels periodically before they fail catastrophically.

As to your fatuous comment about running slicks on trackdays - they ruin the day for everyone? Really? Or maybe it's just you? Strange that I've never even had someone approach me to say that (or anything else detrimental about my driving standards come to that) in the 100+ days I've done on slicks & I can't for the life of me see how what I chose to run can possibly affect anyone else on track provided the rules are observed.

LaSource

2,155 posts

146 months

Wednesday 13th February
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nxi20 said:
As to your fatuous comment about running slicks on trackdays - they ruin the day for everyone? Really? Or maybe it's just you? Strange that I've never even had someone approach me to say that (or anything else detrimental about my driving standards come to that) in the 100+ days I've done on slicks & I can't for the life of me see how what I chose to run can possibly affect anyone else on track provided the rules are observed.
Well, to be fair, you may ruin the day for other 996GT3s on road tyres when they realise they can't keep up biggrin

My mission this year is to take the 6GT3 out on slicks...possibly at Portimao (in plan) or Silverstone (any dry day once I've sorted out a support car and driver!)

Digga

26,073 posts

221 months

Wednesday 13th February
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LaSource said:
My mission this year is to take the 6GT3 out on slicks...possibly at Portimao (in plan) or Silverstone (any dry day once I've sorted out a support car and driver!)
Have you tried it on the Pirelli Trofeo R yet?

LaSource

2,155 posts

146 months

Wednesday 13th February
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Digga said:
ave you tried it on the Pirelli Trofeo R yet?
No I haven't. I've been quite happy with Cup 2s as they are a known quantity and I feel I know how to settle them down. Plus should it get wet they have plenty of tread for that too (as long as not terribly worn).

Figured full blown slicks would be more fun than Trofeos. My car is running a stiffer suspension and relatively aggressive geo (albeit still for road tyres) so my thinking is it should bear up well to some light slick use smile

Steve Rance

4,834 posts

169 months

Wednesday 13th February
quotequote all
LaSource said:
No I haven't. I've been quite happy with Cup 2s as they are a known quantity and I feel I know how to settle them down. Plus should it get wet they have plenty of tread for that too (as long as not terribly worn).

Figured full blown slicks would be more fun than Trofeos. My car is running a stiffer suspension and relatively aggressive geo (albeit still for road tyres) so my thinking is it should bear up well to some light slick use smile
Slicks are great when they are in the sweet spot but they go off quickly and performance can drop below that of a road legal track tyre reasonably quickly

Digga

26,073 posts

221 months

Wednesday 13th February
quotequote all
LaSource said:
Digga said:
ave you tried it on the Pirelli Trofeo R yet?
No I haven't. I've been quite happy with Cup 2s as they are a known quantity and I feel I know how to settle them down. Plus should it get wet they have plenty of tread for that too (as long as not terribly worn).

Figured full blown slicks would be more fun than Trofeos. My car is running a stiffer suspension and relatively aggressive geo (albeit still for road tyres) so my thinking is it should bear up well to some light slick use smile
I only ask because at the Outlon RS day a few years back, I was pax in Mike from Sports & Classic's 996.2 GT3 CS. He'd not been able to get CUp2's so had gone to Trofeo R's by default. He was impressed with them. They certainly produce a lot of grip! IIRC the 'word' on them was they were better on track, but did tend to go off a bit quicker, although someone else here might correct me.

LaSource

2,155 posts

146 months

Wednesday 13th February
quotequote all
Steve Rance said:
Slicks are great when they are in the sweet spot but they go off quickly and performance can drop below that of a road legal track tyre reasonably quickly
Yes I am aware slicks have a particular sweet spot when new. However 6GT3 trackers who use slicks tell me that used slicks are still quicker than road tyres. I do not have personal experience on the 6GT3 to counter otherwise - but I also note your point above. It would not be very exciting if the drop off is too fast - any suggestions what this timeframe might be in whatever metric?

I have used slicks on a KTM X-Bow a few times last year which were fairly old and they were really cool - both in terms of pace but also in terms of the surety of how the car brakes and handles which gives the driver a lot more confidence...so just wondering if the same experience will be replicated with the heavier GT3.

Edited by LaSource on Wednesday 13th February 14:15

LaSource

2,155 posts

146 months

Wednesday 13th February
quotequote all
Digga said:
I only ask because at the Outlon RS day a few years back, I was pax in Mike from Sports & Classic's 996.2 GT3 CS. He'd not been able to get CUp2's so had gone to Trofeo R's by default. He was impressed with them. They certainly produce a lot of grip! IIRC the 'word' on them was they were better on track, but did tend to go off a bit quicker, although someone else here might correct me.
Yeah I've also heard the TrofeoRs are quicker in the dry but wear faster, not great for wet, and used to be dearer to buy (but not sure if that is still true)

Digga

26,073 posts

221 months

Wednesday 13th February
quotequote all
LaSource said:
Yeah I've also heard the TrofeoRs are quicker in the dry but wear faster, not great for wet, and used to be dearer to buy (but not sure if that is still true)
No, just looking the the tread design (which I admit can be deceptive) they don't look likely to work as 'well' (relative term) as Cup 2's in the wet.

isaldiri

4,221 posts

106 months

Wednesday 13th February
quotequote all
Digga said:
I only ask because at the Outlon RS day a few years back, I was pax in Mike from Sports & Classic's 996.2 GT3 CS. He'd not been able to get CUp2's so had gone to Trofeo R's by default. He was impressed with them. They certainly produce a lot of grip! IIRC the 'word' on them was they were better on track, but did tend to go off a bit quicker, although someone else here might correct me.
I'm not sure trofeos go off faster. A good friend has used them a lot, he reckons they are a lot more heat stable than a Cup2 so they don't go off on a very warm trackday but by the 2nd trackday the difference in pace is largely eroded and by the third the Cup2 is faster (assuming you haven't already worn down the trofeos to the canvas biggrin)

Digga

26,073 posts

221 months

Wednesday 13th February
quotequote all
isaldiri said:
Digga said:
I only ask because at the Outlon RS day a few years back, I was pax in Mike from Sports & Classic's 996.2 GT3 CS. He'd not been able to get CUp2's so had gone to Trofeo R's by default. He was impressed with them. They certainly produce a lot of grip! IIRC the 'word' on them was they were better on track, but did tend to go off a bit quicker, although someone else here might correct me.
I'm not sure trofeos go off faster. A good friend has used them a lot, he reckons they are a lot more heat stable than a Cup2 so they don't go off on a very warm trackday but by the 2nd trackday the difference in pace is largely eroded and by the third the Cup2 is faster (assuming you haven't already worn down the trofeos to the canvas biggrin)
Thanks for the correction! I knew someone would know better and it's useful info, just in case I'm ever stuck for Cup 2's too.

Cheburator mk2

2,415 posts

137 months

Wednesday 13th February
quotequote all
LaSource said:
Yes I am aware slicks have a particular sweet spot when new. However 6GT3 trackers who use slicks tell me that used slicks are still quicker than road tyres. I do not have personal experience on the 6GT3 to counter otherwise - but I also note your point above. It would not be very exciting if the drop off is too fast - any suggestions what this timeframe might be in whatever metric?

I have used slicks on a KTM X-Bow a few times last year which were fairly old and they were really cool - both in terms of pace but also in terms of the surety of how the car brakes and handles which gives the driver a lot more confidence...so just wondering if the same experience will be replicated with the heavier GT3.

Edited by LaSource on Wednesday 13th February 14:15
I used to drive my brother’s E46 M3 on slicks. Used quali BTCC slicks were something crazy like £25 per tyre. While they weren’t great for Matt Neal & Co they were perfect for us mere mortals. The M3 was close to 600bhp, around 1370kg with a full cage and properly race prepped. We used to “race” with a mate, who runs perhaps the 2nd most sorted 997.1 GT3RS in the World courtesy of Schutz Motorsport. We both noticed that slicks would give us 5 to 7 sec per lap on a 1min30 lap on a very technical circuit vs Pilot Cups. Just as you said, the slicks added extra predictability and “smoothness” to the cars. My biggest problem would be flat spotting them as the M3 didn’t have ABS and I tended to be very Fred Flinstone like in the application of the brake pedal. My 996.1 GT3 has the Cup ABS pump, btw... My mate’s GT3 would use 2 sets of slicks over a weeekend if track driving. If you have the chance - go for it. You wouldn’t believe how good a we’ll sorted 996/7 GT3 is on slicks... Just like an E46 M3 in fact smile