997/996 GT3 dynamics

[Dr S]

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

Always quality comments from you, Steve. Your posts are always highlights on this forum

[Steve Rance]

Thank you. Much appreciated

[lemmingjames]

What about tyre weight and the air inside?

Hasn't anyone looked into jdm wheels, is volks and rays?

[Porsche911R]

Slippydiff said:

BBS E88 18x8.5 = 20lbs : 9.1Kg
BBS E88 18x11 = 21.5lbs : 9.8Kg

BBS LM 18x8.5 = 21.6lbs or 9.8Kg
BBS LM 18x11 = 26.9lbs or 12.2Kg

Mk1GT3 18x8 = 25.35lbs or 11.5kg
MK1 GT3 18x10 = 28.88lbs or 13.1kg

Mk2 GT3 OE 18x8.5 = 27.00lbs 12.25Kg
Mk2 GT3 OEM 18x11 = 29.98 or 13.6Kg

all pretty heavy in todays standards.
when a 20" BBS Fir is 17lbs

and even a OZ cheapo is 17.6 lbs for the 8.5 OZ Alleggerita HLT 11" is 23lbs and only £1,770 as well for 4 , must be the wheel of choice for a track car, or even road car and the cheapest , and maybe strongest.

fitting those over oem is 15kg unsprung and rotation mass saving , that you would feel big time.

LM for show ! OZ for go ;-) E88 for the rich.

Edited by Porsche911R on Tuesday 12th February 08:32

[MDL111]

can't get the FI / FI-R as 18 though I believe

[Slippydiff]

MDL111 said:

can't get the FI / FI-R as 18 though I believe

This ^ and if you could, they’d be £6k plus based on the price of the 19/20” versions.
The OZ are light, but hardly the last word in aesthetics (they’re known to crack, or were) too.

[Porsche911R]

MDL111 said:

can't get the FI / FI-R as 18 though I believe

that's why I said buy "OZ Alleggerita HLT" and still save 15kg for £2k with a nice picture to match :-)

[LaSource]

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!)

Porsche911R said:

all pretty heavy in todays standards.
when a 20" BBS Fir is 17lbs

and even a OZ cheapo is 17.6 lbs for the 8.5 OZ Alleggerita HLT 11" is 23lbs and only £1,770 as well for 4 , must be the wheel of choice for a track car, or even road car and the cheapest , and maybe strongest.

fitting those over oem is 15kg unsprung and rotation mass saving , that you would feel big time.

LM for show ! OZ for go ;-) E88 for the rich.

Yeah fair point the OZ's are a value buy for track use if one needs another set of wheels.
'LM for show' goes a long way with GT3s though

Slippydiff said:

This ^ and if you could, they’d be £6k plus based on the price of the 19/20” versions.
The OZ are light, but hardly the last word in aesthetics (they’re known to crack, or were) too.

Yes I recall disco 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?

Edited by LaSource on Tuesday 12th February 13:10

[LaSource]

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!)

Porsche911R said:

all pretty heavy in todays standards.
when a 20" BBS Fir is 17lbs

and even a OZ cheapo is 17.6 lbs for the 8.5 OZ Alleggerita HLT 11" is 23lbs and only £1,770 as well for 4 , must be the wheel of choice for a track car, or even road car and the cheapest , and maybe strongest.

fitting those over oem is 15kg unsprung and rotation mass saving , that you would feel big time.

LM for show ! OZ for go ;-) E88 for the rich.

Yeah fair point the OZ's are a value buy for track use if one needs another set of wheels.
'LM for show' goes a long way with GT3s though

Slippydiff said:

This ^ and if you could, they’d be £6k plus based on the price of the 19/20” versions.
The OZ are light, but hardly the last word in aesthetics (they’re known to crack, or were) too.

Yes I recall disco 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?

Edited by LaSource on Tuesday 12th February 13:10

[BrotherMouzone]

LaSource said:

Slippydiff said:

This ^ and if you could, they’d be £6k plus based on the price of the 19/20” versions.
The OZ are light, but hardly the last word in aesthetics (they’re known to crack, or were) too.

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?

NXI20 has had a few cracked.

http://911uk.com/viewtopic.php?t=124640

[Digga]

Taffy66 said:

In Slippy's example above, if you compare the lightest BBS E88 to the OEM 996.2 GT3 it translates to a saving of 14Kg unsprung weight.This is a huge saving and would be very noticeable in terms of turn-in,bump absorption and even acceleration.
I'm pretty dumbfounded at this as the OEMs are way heavier than i expected.

Pretty much the weight difference between steel or PCCB brakes and, even with the BBS E88's, for less money too.

[Steve Rance]

Personally, unless I'm racing, I'm not keen on lightweight wheels on track cars unless they are extremely strong and those are generally also extremely expensive

[Slippydiff]

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]

BrotherMouzone said:

NXI20 has had a few cracked.

http://911uk.com/viewtopic.php?t=124640

Beat me to it

[Slippydiff]

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

[isaldiri]

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'

[Porsche911R]

Slippydiff said:

Beat me to it

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

[Harris_I]

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]

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'

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

[BrotherMouzone]

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'

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

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