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I love the movie Days of Thunder. Even the fictional references in the movie are entertaining. Here's my tribute to Harry Hogge building Cole Trickle's car with the theme music. Set the rez to HD crank up the volume!
Tom, my RS (997.1) has wheel spacers approx 5mm thick. Does the non-RS GT3 have these as well? Is it possible for .1 RS owners to simply remove the 5mm spacer to gain the additional clearance to upsize to a 325 rear tire (roller still required?), and maybe a slightly wider front as well?
Tom, my RS (997.1) has wheel spacers approx 5mm thick. Does the non-RS GT3 have these as well?
997.1 GT3 came with OEM 5mm rear spacers as well. But I removed the spacers and factored in the offset when I ordered my Forgeline wheels.
Originally Posted by HarmonyJim
Is it possible for .1 RS owners to simply remove the 5mm spacer to gain the additional clearance to upsize to a 325 rear tire (roller still required?), and maybe a slightly wider front as well?
Yes, 997 WB(Wide Body) cars can definitely fit 325 "Hoosier R7" rear tires on 19x12 ET45-51 wheels without wheel spacers and without fender rolling.
Fitment really depends on the brand/model of tire, the car's the ride height, and the offset/width of the wheels.
Even 997 NB(Narrow Body) cars can fit 325 "street" rear tires.
Originally Posted by HarmonyJim
and maybe a slightly wider front as well?
245 (and some 255) front "street" tires will fit on 19x9 ET52-48 wheels without fender rolling.
Most "street" tires have have curved profile for more clearance whereas track tires do not.
See image below. Street tire on left, Track tire on right. You need to look at the published thread spec and the cross-section spec.
I am sure you guys have read the news stories about the 2019 991.2 GT3 RS turning record-breaking laps at the 'Ring. What an impressive machine!! The factory spring rates on 991.2 RS is a radical departure from the 991.1 RS, according to one automotive news source:
991.2 GT3 RS Front spring rate, 45 N/mm (256 in/lb)
Rear spring rate, 120 N/mm (685 in/lb)
991.2 GT3 RS Front spring rate, 100 N/mm (571 in/lb)
Rear spring rate, 160 N/mm (913 in/lb)
After seeing these spring rates on a factory spec road car I just couldn't resist giving these rates a go on my street car. Actually I am going a little bit high at 672/992 in/lb (these are actual rate per our tester).
New fronts, 672 in/lb.
New rears, 992 in/lb.
I had the helper spring below the main spring(like on a 997 Cup).
This time I flipped it around so that the helper spring is on top(like on the 997 RSR). There's no difference in performance on this car, the helper springs are fully collapsed to the car's own weight. In some other application where the main springs and the shocks are much shorter its a way to stagger the position of the spring divider to prevent blinding . On this car it does't matter whether the helper spring is on top or bottom. I did it just to be different.
Put 50 miles on so far, the ride is very smooth, very well damped, and not harsh at all. No change was made to the DSC Sport controller, its been the same map for the three other spring rates changes before this. So far I like!
First oil sample after engine rebuild. The oil sample is from the second oil change after rebuild, this sample has 10 dyno runs, 2 tracks days, and some street miles. Nothing alarming from the magnetic drain plug. So far so good. I even put a new oil filter housing on because the newly built engine deserves one!
P.S.- I changed the title of this thread by adding the parenthesis. More fun stuff to come!
Knock Knock. Who's there? Its Anti-Knock springs and friends
I was getting some pad knock(aka knock-back) so here's what I did:
1) Checked wheel bearings for play.
2) Make sure floating hardware are indeed floating, not blinding.
3) For extra measure(just because I that type of guys), install 6-lb anti knock back springs behind each one of the brake caliper pistons. And I became aware that there's Titainum puck race option, so of course I want that!
The Ti puck is factory-pressed into the aluminum piston which came as an assembly. The Ti puck isn't available by itself since each piston is machined precisely to fit each puck.
The bigger OD flange of the Ti puck should promote air cooling. The 991 Cup caliper pistons have a similar large OD flange.
The back of each piston is machined to center the anti-knock back spring.
I decided to delete the dust boots on the calipers while I am in there.
Removing the standard aluminum pistons.
Installing the Ti's, one bore at a time, one caliper at a time.
I started with the rear caliper first, here's a finished one.
Four and half hours later, during that time I completely forgot to eat dinner and go #1...sorry TMI, on to the fronts.
While I'm in there, I proactively replaced the brake master cylinder as a maintenance item and cleaned out the bowl.
There are the take-off standard aluminum pistons. I can throw them at people who annoys me...LOL
I took Tango lessons many years ago. Here's the Piston Tango.
Here's the Demon Speed Motorsports mid-height wing upright next to the factory 997.1 Cup wing upright.
Bolts up good to the Getty Design .1 Cup replica deck lid. At first I wasn't sure if I'll like the looks but after installing and seeing in person I like the more modern look of the "vented" uprights.
When I did the .1 Cup replica deck lid conversion last year I was running out of time so I didn't machine proper spacers, instead I cut down thin steel tubes and used large washers to fill the gap. Drove the car for a year will no issues with the thin tubes and washers serving as spacers. Proper aluminum spacers are in order for this round of mods.
The dive planes are also from Demon Speed Motorsports. They should guide the air nicely over the fender flares. If you look closely you'll see where I trimmed off the clear film just ahead of the dive plane.
Tom, I see you're running into knock-back as well. Really curious how your Ti + antiknockback works out. I like to do one thing at a time, so I started with the floating hardware. Haven't had a chance to drive it though.
Here's a vid I did for anybody interested in swapping to floating hardware on their ST kit.
Tom, I see you're running into knock-back as well.
Yeah, I lightly tapped the brake pedal with my left foot just before brake zone. After a day of doing that it became a habit and doesn't affect the laps.
Originally Posted by ngng
Really curious how your Ti + antiknockback works out.
The springs are effective. The Ti pistons don't do anything for knock-back but they do make the brake modulation pretty awesome through the run session by retarding heat transfer to the fluid.
Replaced the steel seat brackets for aluminum and replaced TeamTech harnesses(with steel camlock) for RaceTech harnesses(with alum camlock).
The old mounting setup with steel seat base and steel brackets weights 18.7 lbs per side.
The new setup weights 10.9 lbs per side (that's 5.0 lbs for the harness + 5.9 lbs for the new mounting hardware).
That saves 7.8 lbs per side, 15.6 lbs total. It'd take like 10 weeks for not eating tasty food and drinks for me to lose that weight.
The aluminum brackets were literally rough around the edges...a smooth finish on the edges was called for.
The new seat base adapters and aluminum brackets are too wide for both seats so "filler" pieces or spacers were required. I wanted to buy generic spacers online but didn't come up with any that I liked so...make my own it is with 1.5" OD T6061 round stock. Like there aren't any custom made parts on this car. LOL
Taking advantage of this opportunity the spacers offset the seats to closer to the center of the car(like on a Cup car) by 13mm.
06-12-2018, 11:19 AM
