Fadi, '02 996 GT3 RS (not the street RS, but successor to GT3R) has about 50 mm flares each side and runs
-wheels 10x18 et 0,5 (2"/8") & 11x18 et 16 (2"/9")
-tires 265/645 & 305/690

Track width is F 1562mm & R 1578 mm. (Base 996 Carrera: 1465 & 1500 mm)

To get wider front track without using low offset you always can play with LCAs and GT3 top mounts. 20 mm shims and top mount at street position (not rotated), pulled fully outboard, will give you about 3.2-3.3 deg camber. And 20 mm more track each side. With 997 LCA's wider (15mm more than 996's) inner section with 996 LCA's outer section and 20 mm shims you're 35 mm wider / side than street car, with streeet car's offset. Then of course you have to figure out how to move top mounts that 15 mm outboard. Which is actually quite easy...
Thrust arms must be adjustable and track rods might be extented to their limit...I've so far tried that 20 mm shimming, but will know about 35 mm within a month.

 

y I was calculating based of what I have and taking in account a 275 tire. I'm not running as much camber though as John.
like said above this one, going to a wide front lca would probably be best. Helps with scrub radius a lot and will probabaly give you slightly better suspension control up front. That's just my 2 cents.

 

Been covered before, but wanted to check with you experts. I have some 18" CCWs (9" and 12") made for my 997 NB GT3 and want to use them on my 6TT. Fronts will fit as is and looks like 15-20mm spacer is needed in back. I'd prefer a bit wider then stock turbo twists (without spacers). Does that sound like 20s are the right answer?

 

I've run and sold many sets of CCW mono blocks. 18x9 et40-45 front and 18x12 et40 rear is a proven set up.

 

So that would be more like a 25mm spacer then. I'll have to give those a shot. Hoping my wheel studs are long enough.

 

Hi Fadi,
I would push your upper mounts as far outboard as possible. Possibly even have some custom upper mounts that would push the shock even further outboard than what is possible with current hardware. You can also slightly grind out the tub (like I have done) to give you more clearance. Basically you want to do the reverse of what I have done with my set up (see pic below) where I have the shock located as far inboard as possible via motorsport camber plates in order to clear 275s into stock fenders. By going fully outboard compared to where I am you would gain about 3cm in track per side. Running a wheel with a 15mm more aggressive offset than what I'm running would get you 4.5cm greater track per side. That would be a 18x10 et23 (I'm using et 38). Naturally this is just rough math but my gut tells me it's pretty close if you push the shocks as far outboard as described above.

I can't recall what LCAs you are running, but with the 997RSR LCAs you can run the 20mm longer inner bearing and another 15mm of shims to give you 35mm longer LCAs. PMNA makes two version of the 997 inner bearing, the short and the long. I run the short, you'd want the long. Contrary to what you may read, the forged PMNA 997 LCA main body is actually 5mm SHORTER than the stock 996GT3 LCA body but you can easily get that back with the longer inner bearing and shims.

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By running such low / negative offsets, you will certainly place a greater load on the hubs/bearing/and upright. How much greater is hard to say, maybe 10-15% greater but thats just a guess. When you combine that with super wide rubber and or slicks, you will definitely add more stress to the components. Personally I would probably stick to the service interval recommendations that you will find in the Cup manual. 40hrs running time is the maximum specified by Porsche on the rear hubs at which point you would also naturally do the bearings. Uprights do not have a time interval but a visual inspection for cracks is required every 30hrs of running time.

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One thing to keep in mind when running these low/negative offsets is that you will greatly increase the turning radius of the front wheel/tire assembly, on the order of 40-45mm greater radius. This is naturally require 40-45mm more clearance ahead of the front tire to clear the radiator brackets. This is a huge amount as you will basically need to move the side radiators forward by a similar amount, basically about 50mm forward of stock location. I'm not sure this will be an easy feat. I would take a look at that to make sure that is even possible. As a data point, with a 18x10 ET38 front, I had to move the front radiators forward 10mm. You will need to go another 40-45mm further forward. Have you come up with a game plan to deal with that?

The project looks exciting. Looking forward to the results...

 

Hey Pete, Lewis and John the great news is you showed me there are solutions that address correctly my future setup, seems we need to do a lot of measurements and try, try, try before finding the real solution.

Will postpone at least the wheels ordering till getting the flares installed and start working from there, of course will still try to push forward the radiators (did already that, but not sure by how much I have managed to do it, I am able to fit 265/35/19 tire for example, not hitting the radiator)
I have RSS suspension arms, so can add large shims, both turbo and gt3(longer) drop links and good coilovers with new top mount to come in the next days (Intrax), so might have a chance, thanks god you are here, seriously without your help I wasnt even thinking that was the way to go, thanks and will keep you up to date

 

Just some updates regarding various pats going in this winter

Girodisc 380mm F and 350mm R
PFC brake pads 09/11
Gt3 996 front uprights
Patrick Motorsports trans cooler
CSF Radiators
Plex Tuning Dash Display
Rennline track mats and pedals
LI-Ion 18Ah Battery PowerBloc


The stripped car pic isnt actually mine, but might try it in that configuration for a few times to be honest , but guess will end putting back some of the interior later on

 

Are you going with 6pot front porsche calipers and spacers? Or 997 GT3 setup? Only reason i'm asking is because depending on what you end up doing you may be faced with some customer brake line and ABS wire mounting things to resolve. Nothing major, just keep it in mind.

 

Are you referring to running 997.2 GT3 uprights vs. older uprights with spacers? If so, I'd think that running stub axles with 996 trigger wheels and mounting the 996 ABS sensors is the issue to consider.

Has anyone mounted 997 uprights on a 996 yet? As the late 996 GT3 RS and early 997 GT3 share the same uprights, I can't imagine that it is too much of an issue.

 

The early 997.1 GT3 i thought still had the smaller bearing triggered ABS sensors that are not reverse compatible to mount the magnetic 996 gt3 sensors? You can however use the GT3cup however as they still use the older larger type sensors. The 996RSR/RS/997 GTstreet/cup are all the same casting that basically changes casting part numbers(on some), ABS and brake caliper bolt spacing.

 

And I was talking about the brake hardline brackets and brackets that hold the abs sensor cables. Tye sensor themselves are a consideration if the OP is using 997 GT3 street spindles.

 

Going to use the complete brake system from 997 gt3, including brake master pump, brake line,etc. Got the PNs and info from master John



No, I will be running 996 gt3/rs uprights instead of the original turbo uprights

 

If you are running the RS or RSR front uprights, i thought you need to address the rears as well?

 

Here's how 10x18 et37 & 11x18 et5 look like on a narrowbodied RWD, ie I need some flares...

Wheel to spring clearance at front is about 1.8 mm:



Rear: