997/996 GT3 dynamics

[Slippydiff]

JMo22 said:

Took my 996.1 GT3 to Brands last month. Just a phenomenal car - every part of the car just feels so perfectly balanced and it felt as though it could just pound around all day.

The feeling when you nailed Paddock Hill bend and it grazed the tarmac at the bottom with the Mezger engine heading towards the red line and then H&T into druids was pure motoring nirvana!

The perfect GT3 in the best hue

[evodarren]

Slippydiff said:

JulierPass said:

996's wear red and yellow soooo well. Cherry on the cake has to be gold BBS LM's

I was rather partial to silver LM’s

Hi Slippy
Was out with a friend call Jamie this morning for a breakfast meet. He said he brought you red gt3.

[Slippydiff]

evodarren said:

Hi Slippy
Was out with a friend call Jamie this morning for a breakfast meet. He said he brought you red gt3.

Hi Darren, small world !! A fine car and and a fine gentleman.

[Dammit]

I think the ex-SD car looks superb on those BBS LM's, and have been having a chat with Centre Gravity about them. Their strongly held view is that less is more when it comes to tyres, if you are not being paid to drive a car that is covered in sponsors logos.

What's the view here on the width of rubber best suited to fun on the road?

[JMo22]

Thanks for comments guys.

Does anybody know what weight savings the BBS LMs offer over the standard 996.1 GT3 BBS wheels? Only been able to find a decade old PH thread, which surprisingly given their popularity seemed to suggest no difference? Seems to be easier to pick up spares of the original wheels these days vs LMs so probably worth carrying on risking using those?

Also debating whether to replace front discs with Alcons when the time comes but not sure the £/kg saved stacks up as they are made in such low volume nowadays.

Appreciate any thoughts!

[Slippydiff]

JMo22 said:

Thanks for comments guys.

Does anybody know what weight savings the BBS LMs offer over the standard 996.1 GT3 BBS wheels? Only been able to find a decade old PH thread, which surprisingly given their popularity seemed to suggest no difference? Seems to be easier to pick up spares of the original wheels these days vs LMs so probably worth carrying on risking using those?

Also debating whether to replace front discs with Alcons when the time comes but not sure the £/kg saved stacks up as they are made in such low volume nowadays.

Appreciate any thoughts!

BBS Japan don’t supply spares for LM’s. Trash or buckle one and you’ll need a complete replacement wheel.
The LM’s are strong, as are the OE Sport Design wheels (which are made by BBS Germany) The rim section of the OE Sport Design wheel is incredibly light, the star however is like a boat anchor.
The issue with the OE wheels is the conservative offsets which really don’t fill the arches out convincingly. The LM’s in 9 and 11” widths do.

Edited by Slippydiff on Saturday 9th February 19:47

[Slippydiff]

Dammit said:

I think the ex-SD car looks superb on those BBS LM's, and have been having a chat with Centre Gravity about them. Their strongly held view is that less is more when it comes to tyres, if you are not being paid to drive a car that is covered in sponsors logos.

What's the view here on the width of rubber best suited to fun on the road?

You could stretch 225 section tyres on 9” fronts, but I think the 235 is better fit.
A 285 on the 11” rear is probably ok, but a 295 is nicer. Both the 235 and 295 are Mk 2 996 GT3/RS standard fitments, albeit the Mk 2 used an 8.5” front (rather than the 8” the Mk 1 used) and an 11” rear as opposed to the 10” wheels on the Mk1.

[Dammit]

I think I'll delay the wheel decision until we've got the engine in, that way I can test the 17's I've still got in the garage, the 18's that are on the car, and then work out if I want to put an inch of diameter on or take it off.

Did you get my email btw? I'm never sure if they work when responding to a PM.

[evodarren]

Slippydiff said:

Hi Darren, small world !! A fine car and and a fine gentleman.

He regrets selling it. Keeps telling me to keep mine. I said you don’t have to tell me. Mines not going anywhere

[Cheburator mk2]

JMo22 said:

Thanks for comments guys.

Does anybody know what weight savings the BBS LMs offer over the standard 996.1 GT3 BBS wheels? Only been able to find a decade old PH thread, which surprisingly given their popularity seemed to suggest no difference? Seems to be easier to pick up spares of the original wheels these days vs LMs so probably worth carrying on risking using those?

Also debating whether to replace front discs with Alcons when the time comes but not sure the £/kg saved stacks up as they are made in such low volume nowadays.

Appreciate any thoughts!

I must really compare the weights, but my LMs - 11” and 9” are definitely lighter than my OEMs. I use 295 rears and 235 fronts. The car is very pointy and quite oversteery with aggressive front alignment. I am running -2deg 45min camber and all the caster that you can get, while toe in is set at 2min per side, which is almost negligible. At the rear I am running -2deg 15min camber and 12m in of toe in per side. We also shortened the effective wheel base of the car by 10mm, which made it quite pointy. Manthey/PMotorsport arms all round so spherical bearings and not a rubber bush in sight.

In terms of dynamics - it makes me laugh out loud every time I drive her, which is not that often sadly. If it was good enough for Olaf, it is good enough for me

[Slippydiff]

evodarren said:

He regrets selling it. Keeps telling me to keep mine. I said you don’t have to tell me. Mines not going anywhere

The TVR, the GT2 and the AMG Merc, he may regret selling. However the GT3 he WILL regret selling it.

[JamieG]

Afternoon H - thanks for the kind words...!Hope all is good with you.

[evodarren]

Jamie

You can have a drive of mine anytime to get your fix. I need to go out in your wife's SC

[LaSource]

JMo22 said:

Thanks for comments guys.

Does anybody know what weight savings the BBS LMs offer over the standard 996.1 GT3 BBS wheels? Only been able to find a decade old PH thread, which surprisingly given their popularity seemed to suggest no difference? Seems to be easier to pick up spares of the original wheels these days vs LMs so probably worth carrying on risking using those?

Also debating whether to replace front discs with Alcons when the time comes but not sure the £/kg saved stacks up as they are made in such low volume nowadays.

Appreciate any thoughts!

I have done some weight comparisons between BBM LMs and 6GT3 Mk2 wheels...will need to find where I wrote down the numbers! IIRC the LMs were lighter but can't say off top of head whether a material difference or not.

[Slippydiff]

LaSource said:

JMo22 said:

Thanks for comments guys.

Does anybody know what weight savings the BBS LMs offer over the standard 996.1 GT3 BBS wheels? Only been able to find a decade old PH thread, which surprisingly given their popularity seemed to suggest no difference? Seems to be easier to pick up spares of the original wheels these days vs LMs so probably worth carrying on risking using those?

Also debating whether to replace front discs with Alcons when the time comes but not sure the £/kg saved stacks up as they are made in such low volume nowadays.

Appreciate any thoughts!

I have done some weight comparisons between BBM LMs and 6GT3 Mk2 wheels...will need to find where I wrote down the numbers! IIRC the LMs were lighter but can't say off top of head whether a material difference or not.

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

[ttdan]

Is there some magic formula to convert un sprung weight to the equivalent sprung weight?

[isaldiri]

ttdan said:

Is there some magic formula to convert un sprung weight to the equivalent sprung weight?

Not really because the distance from rotational centre is also relevant ie the further the more important the saving. Having seen numbers range from 3-8x sprung weight saving, basically just assume anyone who makes anything that saves unsprung weight anywhere tends to claim a rather high multiple

[Taffy66]

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.

[Slippydiff]

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.

OE’s are heavy (ish) but strong and durable. E88’s are featherweight in comparison, but one good pothole impact would see a rim section consigned to the scrap aluminium skip. You pays your money and takes your choice...

[Steve Rance]

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