mooty

i understand the logic.
but since u are physicist, or astro physicist, thing springs as electron that are quantized. it's not linear. you have to hit certain level to be effective .until you hit that level, there is no change. the oe spring is really good, no issues if you are smooth, but most of us are not smooth. so we use spring as crutch. you should drive my car. i have 700/800 springs on aftermkt shock. it's really comfy. yes amazing but true.

we removed the tarett spring from my and chansen car, otherwise you can drive them. on street, you wont know the springs are changed. on track you just dive less.

usctrojan is on tarett springs he can tell you that is a DD type of spirng.

and on my race car it's over 1000# spring ;-)

the COMPROMISE is

let tires wear, and put up with dive
learn how to drive like pros
get the right springs
get hign end shock
or you can keep testing it and chase your tail.

i no longer ride on triangular tires, bc round tires really works and triangular tires no so much

NOT DIRECTED AT YOU KEITH, but i test things very fast. that's why i have SH*T loads of GT4 parts for sale..... i even have spare gearboxes if you blow up yours. dont ask what i was testing.

245, 265, 285 RE71R all tested
forgeline BBS offsets all tested
255/296/30 and 295/35 R7 all tested
there are rub and there are RUB. some of our cars had to pull then fender out 2", yes, we cracked the paint and other things.... but i KNOW what rub what doesn't.

if it's not on one of my cars, it most likely DOESNT' work!!!
but i know experiment is fun.
have a go at it

usctrojanGT3

I drive my GT4 on weekends all the time and the car has over 10k miles on the stiffer springs. The ride feels like you put it in sport mode, still very comfortable for the street.

mooty

^ did you mention you didn't spill your mc'd coffee on your lap with driving with stiff springs?

usctrojanGT3

I hate coffee but yeah the cup holder definitely kept my iced tea and vitamin water in place doing some hot laps.

trebien

Well then, ultimate success is finally within our grasp. Good work.

Bill Lehman

Regarding spring rates, I developed my 987 Cayman S over many years and after running the Spec Boxster 450#F and 500# R on PSS9s went to Swift 500#F and 600# R purchased from Tarett. Car was still street driven and the spring rate was tolerable on NE roads. The most effective change was moving from the PSS9 to MCS 2-Way remote canister shocks.

Eric5280

Thanks Joe. For a $180 spring pair, I will take less tire wear all day. Can always add rear later. This forum is the worst support group ever for trying to keep your car close to stock.

Yargk

That makes sense, some may be happy with a little better tire wear by doing front springs only, however I can see others being disappointed because they really wanted a bigger change in the driving experience and so will regret not doing the 448/560 setup... (And I should drive your car )

I did get a short ride in a 448/560 equipped car, the feel was pretty close to stock, even on quite bad roads. (although I'd like to try it on the highway, sometimes weird rutting on the highway can be bad without very well matched damping)

It does seem good to go straight to round tires. Some may like to try square, then pentagonal, hexagonal, heptagonal, octagonal, and so on. Each is better, but it's a bit of a waste of time.



What's your opinion about 9x19 ET50 vs. ET54? (54 seems better if it will fit on the inside, there was a set for sale recently that was claimed to fit, however, most people with 9X19 got ET50)

Always something else to experiment on (I like the idea of dive planes and a gurney flap, I bet the dive planes would fix the window buffeting too without the "air foiler" thing, I did try your window up an inch trick, better than all the way down, but I still got some buffeting).

usctrojanGT3

Friends don't let friends drive their cars stock.

Eric5280

Haha. I'm approaching original MSRP total investment on my '98 M3 track car that was supposed to only be a $10k toy...yeah, it IS possible to do that. I see all you guys and your fancy GT4 mods and just have to walk away before I get in deep. Headers? Sure! All new suspension?? Why not! Intake? Of course I need that. Dangerous place here.

mooty

^ dont worry, 10k mod on a porsche buys you next to nothing usctrojan is into 30k now. and its fairly stock, my privous cayman R mod was $80,000

welcome to the land of porsches. hahaha


keith,
you can drive mine car. but often times, after ppl drive my cars, they end up divorce, broke, suicide or buy the same car.

9x19 et 50 vs 54.
if you run 265 front, the tires stick out from fender. it wont rub, but it sticks out. look at my car next tie.
if you run 245 it looks oem
if you have et54, i thikn 265 still sticks out
so if sticking out of fnder is a concern then run 245. 264 sticks out quite a bit, b/c at -3.2 or so, you can see me sticking out so if you had less camber, it really sticks out.
245 if fine.
54 vs 50 is essentially the same. you just need to see if it clears inside springe. but visually given same rubber, you can't tell the difference really. well maybe physicist can but 4mm is too small for me to see

orthojoe

I was at Sonoma Raceway this past Sunday with the GT4

The RE71R continue to impress. I ran 2 days on the tires, flipped on the wheels, and ran another 2 days. By flipping the tires on the wheels, I was able to even out the tire wear and get one extra day out of the tires for a total of 4 track days (20 sessions). If you don't flip the tires, then I can only get 3 days, just like the cup2s. Almost 1/2 the cost and one extra track day over cup2. Once I get the springs installed, I'm hoping to get my 4 days without having to flip tires on the wheels.

The tires never seem to lose grip throughout the entire session. It took me 9 laps to find some open space, and I managed to get my best times during laps 9-11. Best lap on lap 11! That is unheard of with cup2 or NT01.

It's tempting to try one more day on these tires, but the braking was starting suffer at the end of the day from the inside and center tread wearing. The front left tire in this pic shows the center tread almost washed away:


The front tires are still wearing faster than the rear, but not by much. Only marginally more. I think the extra day, flipping the tires, and the DSC are helping with balancing out F/R wear.

Front tire:


rear tire:


The pic of the front tire doesn't look bad at all, but when you look closer at the center tread, it's washed away. Braking ability is really suffering. The car was going into ABS too easily during my last session. It's a bummer too because lateral grip is still really good. Maybe I should run lower tire pressures, but these tires seem to do well at 34/35 psi hot.

orthojoe

My best session at Sonoma Raceway. Prior best was 1:51.0. New best is 1:50.5.
Take note that I was able to get three 1:50 laps in a row on laps 9-11, which is a real testament to the RE71R tires. On cup2s, if you don't get a fast lap in before lap 5, you're done.

Best lap time is lap 11 at 1:50.5. Lap 10 was on pace for 1:49.8, but I had to adjust my line in order to get around my own GT3 and a S2k. At 3:47 you can see the predictive timer reading 1:49.8 and at 3:50 you can see me swinging my arm in disappointment as the timer drops to 1:50. LOL. Theoretical best based on best 4 sector times throughout the day was 1:49.0. I think in ideal conditions and if I can improve my line, this car could dip into 1:48.

usctrojanGT3

Joe, what size RE71Rs are you running up front? I'm going to try out the 265/35s up front for the first time at TH this weekend.

orthojoe

245 up front. My wheels are only 8.5" wide, so they can't support the 265, unfortunately. Let us know what you think of 265 since you've run 245 already. Have fun this weekend. Weather should be good. Wish I could join you, but I have plans already. I might be tempted to head up there monday. Will you still be there?