rodjac

I woke up a few weeks ago with a bad case of modification fever. After self medicating with a little scotch I was getting better when Alex posted a special deal on RSS suspension parts. So, off went the GT2 to Sharkwerks.

They rotated the camber plates to allow more front camber and replaced the front inner control arm pilot bushings with monoball bushings. The thrust arm bushings were replaced with aluminum bushings which are adjustable(rotating the camber plates lowers the caster and these bushings allow it to be increased).

In the rear the upper control links(dog bones) were replaced with RSS monoball units as were the toe control arms. The eccentric bolts were replaced with locking plates.

The car was sent to TC Design for a track alignment with -3 degrees of camber in front and zero toe and -2 degrees of camber in the rear and 1/4 inch of total toe in(I think this works out to a little over 0.25 degrees per wheel).

Pictures were posted by Alex on 6speed and on the Sharkwerks web site in the project gallery.

I have no idea if this will result in significant improvement in handling or is just a baby step. I really want to get to the track but will have to wait until mid September because of other obligations.

911/Q45

Any feel for street compromise yet?

NJ-GT

Significant improvements replacing the rubber from the suspension. You just need the upper monoball rear strut mounts, and that should take care of all the rubber.

1/4" toe-in at the back is excessive. that's like 0.40 degrees per rear wheel.

0.25 degrees is the ideal rear toe-in in these 996/997 cars (5/32" or 4mm total). Typically, with metal bushings and monoballs you need less static toe-in.

-2.5 rear camber should work better.

rodjac

911'q45 I only drove it back from Sharkwerks so it was hard to tell. There is probably a little more road noise but the rear tires make so much noise that the difference isn't a problem.

NJ-GT The toe of 1/4 inch is the total toe so the toe per wheel is more like 1/8. Not sure of the conversion but that didn't seem excessive. Let me know if you don't agree. Thanks for all your input.

mooty

rod,

as long as you told tony how you drive the car and what experience you have had, he will have your car dialed. his set up isn't the same as other ppl, but he really knows his stuff.

moton is calling your name.....

you at PCA GGR first weekend of sept? i will be there racing.
and you will see my new toy box

rodjac

mooty I have heard that Tony is very good and will set up the car for great track use. I am trying not to listen to Mr. Moton until I have some track time on the current configuration. PCA in Sept. is maybe 50/50 as I have a lot of family stuff during the summer. I think that 27 track days so far(your other post) must be some sort of record or sickness.

iLLM3

They didn't do the solid/adjustable toe links with bump steer?? Definitely needed, what a big difference upgrading the toe links !!

That setup camber/toe wise is where my GT2 is at, maybe a little more rear camber in rear (2.4-2.6) how does the car track in a straight line? What is the caster at?

Motons should definitely be next, you won't even be able what you can do in that car with some motons fully setup

NJ-GT

I disagree, it is excessive. These cars use anywhere from 2mm total rear toe to 4mm total rear toe (0.25 degrees per side, 0.50 degrees total). With the rubber removed there is less need to run high static toe-in. Balance the car with sway bars not with toe, toe kills tires and steals power. 1/4" is 6.25mm of total toe or 0.4 degrees per side or 0.8 degrees total. Too much rear toe-in and the car feels very stable braking, trail braking, corner exit, bumps, etc but the lap timer will show times not too impressive, due to the additional understeer and the speed getting scrubbed.

Using the metric system or degrees (even better) is more precise than using the imperial system

Z06

I have rear 1.5mm per side with the solid links...as well as the Cargraphic DA Bilstein Race dampers.. it's a fantastic handling car.

If I could do it again I would still chose the Bilstein Race shocks over the Motons, Cargraphic has dialed it in nicely!

sharkster

here you go fellas in terms of the pix.



We've been using the RSS suspension parts for a while now on our cars this White 997GT2 also came in for a dose of suspension work, including our full track-orientated suspension components. The first step was to turn the camber plates to get more camber (an old trick from the 996 days):


Next the bushings are pressed out/removed:


And the RSS monoballs kit gets installed in their place. This kit replaces the four pivot bushings (one per corner) on the inner side of the lower control arms with steel monoballs, increasing the precision of the pivot motion of the control arm as it travels up and down under cornering.


And in go the adjustable thrust-arm bushings. The aluminum adjustable thrust arm bushings replace the neoprene factory units on the other end (outside) of the control arms. This allows for adjustable caster.



And on go the dog-bones. This kit replaces the four upper links (two per side) on the rear end of all 996/997 models. The RSS kit allows for sufficient adjustable camber on lowered cars (the factory adjustment is insufficient on lowered cars, resulting in improper camber settings). The links also replace the neoprene bushings with steel monoballs, reducing movement in suspension components and increasing road feedback and "feel".:


On goes the adjustable toe-steer kit. On lowered Porsches with a factory toe steer link, the limited adjustment results in incorrect toe geometry in the rear. This kit is designed to fix that problem. It also replaces the inner neoprene bushing with a steel monoball.


With a full race alignment by our friends at TC Design this car is fully ready for some track-action...

Here's the project page: http://sharkwerks.com/porsche/997-tu...-upgrades.html

Also in terms of the alignment with Tony's conversion rate it comes out to .56 degrees (which is within .02) and as he'd say with RWD and power on a GT2 it's what you'd want.

sharkster

Just did his magic on the RS again. He translates what you say on to suspension to the T:P

NJ-GT

How does the GT2 compares to your old Z06 and your nicely modified 996 GT3?

Correct. 3mm rear total toe-in is what I would use if running full metal bushings and bearings, and 4mm total with the stock rubber pieces. Ride height depending on tires used, springs, toe arms types, etc.

rodjac

So, after the input on 1/4 inch total toe I checked the numbers with Sharkwerks. The alignment was done with smart strings and the toe was measures at 27 inches so in degrees the total toe is about 0.56 degrees compared with a Porsche specified range of 0.37 to 0.50 degrees. So on a per wheel basis it is at 0.28 degrees vrs. the upper end of the range of 0.25 degrees. My prior setting was 0.23 degrees per wheel. I will check tire wear very carefully on my next track day.

NJ-GT

Here is where the mismatch is, clearly stated by your explanation. Measuring toe with smart strings at 27" (or 26.7" to be precise with a 997 GT2 stock MPSC) is not reliable, because the distance between the string and the tire outside diameter, is both imaginary and near a flexible surface (rubber), so typically you will measure from the wheel edges and not from the imaginary tire edges at 26.7" (because tires are not squared). Therefore, you will be measuring at 19" (use the tire seat to measure distance to strings as a 19" wheel has a larger diameter than 19" and it is variable as well depending on wheel construction).

In this case a 1/4" (or 6.35mm total toe-in) converted to degrees using 19" and the standard formula: diameter (mm) x Sin (angle) = degrees per corner

482.6mm x sin(.38 degrees) => 3.2mm per corner, or 6.4mm total (1/4")

However, if the toe distance to the string is measured with a 27" tire, and the tire is squared and not flexible (not realistic), or using a frame that has 27" on length and it is placed across the wheel center line and in parallel to the string, in this case you will have two reference points to measure toe at 27" (I have yet to see somebody doing this). Using the reference points at 27" and obtaining the same 3.2mm per corner, the formula will look like this:

( 27" x 25.4)mm x sin (0.265) => 3.17mm per corner, or 6.34mm total (1/4")

Depending on where you pick up the measurement to the strings, you will obtain different toe angles.

rodjac

NJ-GT You are obviously much better at laying out the issues than I was probably because you know a lot more. Thanks.