I installed Gt2/3 wheel carriers on my turbo today. There are a few things to note. The known items are that the turbo struts will not work. Turbo struts are 55mm thick at clamp up point and the gt2/3 are 52mm at the same spot. The wheel bearings are the same. The retaining plate for the wheel bearing is the same and its hardware is too. The stub axle for the wheel speed sensor is different, part # 996.341.131.04. The center line of the caliper bolt holes to the face of bearing retaining plate surface was 2mm shorter then on the turbo wheel carrier. That is why the GT2/3 rotors do not fit on turbo cars. I also wonder if my hollow spokes will fit with the caliper 2mm closer to the wheels mounting flange? I do not like running spacers. Not sure if this info is even useful to anyone but there is no info out there about this at all. Everyone I spoke to said I needed the whole wheel carrier assembly. When my struts get here I will see about the sway bar too. Brake lines will need to be changed, no big deal. I was also thinking of removing the psm booster pump while I am in there. The carrier felt so close in weight that I did not put them on the scale, however the stub axle for the GT2/3 was very light compared to the cut CV joint stub axle of the turbo. The odd thing is the sensor ring on the turbo is smaller in diameter then the GT2/3 stub axle, will this play havoc on my speedo? ABS? We will Know in a month or two. I was alone as my office is off this week so not to many pics. I will try to get some up tomorrow.

Tim

 

this is some very good info.

So what will you do, you need a front GT2 suspension and a rear turbo?

What was the point in changing to a Gt2 carrier? Seems like there is a lot more than just exchanging two parts

 

I think the suspension pick up points on a GT2 are different than a Turbo. Some one on Rennslist will know if the rest of the suspension parts are interchangible. Ty for the information as I'm starting to look for a set of stock hollow spoke wheels.

 

Do the GT2 stub axles have the same number of grooves as the 996TT? If so the only variable is the distance of the wheel speed sensor from the hub grooves. If it is close enough to pick up the magnetic pulses from the grooves, mathmatically you will be good. It all comes down to grooves per revolution.

You probably already know this. If so please do not be offended by me elaborating. The rotation of all four wheels create a low voltage and low amperage AC signal. The ABS and PSM systems monitor and compare the frequencies of these four wheels. When one wheel by itself either exceeds or drops below the speed of the other wheels based on the programmed parameters that is when the applicable system intervenes. Obviously the steering angle sensor come into play also.

 

The rear shocks are the same on all 996 cars. I wanted the GT2/3 pick up points to see if it changes anything. There is a lot of talk about how you have to convert to rear wheel drive. I have been rwd only since 07 with the turbo front end. So now I will walk the walk and see for myself.

 

Good point! I was going to do a tooth count in the morning. The teeth are different sizes for sure. Do you think the pick ups are different to? I ordered gt2 ones and did not even ask if there are the same as turbo ones.

 

The teeth sizes are not as relevant as the count. As the diameter of the stub axle is scaled down so does the diameter of the grooves. From what my research shows the pickups are the same.

 

The GT2/3 stub axle is about the same size (by memory) as the rear axle stub. The front and rear sensors are the same. I do believe you are right. I will update tomorrow with the counts. btw ALL the parts have the brembo "B" cast or stamped into them and are made in Italy.

 

I think when you are done with this, a thourogh thread describing what is needed to run GT2/3 suspension components to include uprights, shocks & springs, and sways would be a good idea. Kinda like the post about brakes that puts is all out there for the tinkerers like us. I have doe quite alot of research myself and I know you are walking this path. I think a good informative post would be a good addition to the knowledge forum to help people know what is involved.

 

yes please keep us informed, this is a very interesting discussion and DIY. Keep all the part number you bougt and those you finally ended up using this will help people a lot.

 

Tim, you just need 2mm spacers ( yes, spacers ) between the wheel hub and brake disc to use any turbo disc with those wheel carriers:
-996 turbo disc & caliper
-997 turbo disc & caliper or 996 GT2/3mkII caliper
-Cayenne turbo disc with above mentioned 6-piston calipers

Or you can use 996 GT2/3 disc with suitable caliper, but discs cost significantly more than those turbos' ones.

 

Pete I am using GT2 rotors. No need for the spacer in that location. I may how ever need it between the rotor and the wheel as the GT2 calipers were very close with the turbo carrier.

 

OK. As you already ( might ) know, GT3mkI has 5mm spacers at front with longer wheel bolts. OEM. Gives more track and thus lessens understeering. Have you bought GT3's split lower suspension arms?

 

Yes I have the RSS ones front and rear.

 

VAG,
The stubs both have 48 teeth. Also I was going to turn down the struts to the 52mm but why mess with the strut if someone else can use it. The lower part off the tube is under 52mm so I don not feel that shaving down the 55mm step would damage the strut?? Why take the chance on a perfectly good PSS9.. If some one have a bent one to offer up I would love to cut it down and see.