Bill Lehman

Here's how I set up G-Sum Math Channel on the GT4 and a screen shot of the data with G-Sum

zmon

Does anyone know if the wheel bearings in the road car are the same as in the club sport?

orthojoe

Yup. Very useful. I only realized how to get/use it this past year. Before I was separately looking and long and lat Gs. With Gsum, it gives you the whole picture

RocketGuy3

Can anyone tell me what the factory front camber settings of the GT4 are?

4carl

-1.5

RocketGuy3

Thank you, Carl! I don't suppose you also know the maximum negative camber we can get from the factory? I believe I've read -2.0.

I know these should be easy questions, but my search skills are failing me.

4carl

I do my own set ups and you can get -1.8 to -2.0 with moving the strut all the way in at the tower. That's what I run makes a good compermise . Certainly not optimum probably -2.5 -3.0 would be better for a pure track set up but then your dealing with castor issues. Carl

RocketGuy3

Dang, that's not a lot... I asked the dealer to set it to -2.2 (no, I wouldn't normally take the car to a dealer for this kinda thing, but I had a gift card, heh), guess they're not going to be able to do that (of course the service rep did't know). Is there anything else one can do short of buying camber plates for more negative camber to limit shoulder wear? More toe in? Certain pressure settings? I do think I had the pressure too high last time I was out...

Car is bone stock right now, which I thought would be fine for a while at my experience level, but the car is so easy to drive that I'm already pushing some limits, I guess.

4carl

You probably can get -2.2 with just adding shims to the lower control arm. Don't know about the castor ? Carl

RocketGuy3

Thanks for the info, I'll see what they come back with. Still very much a n00b when it comes to track chassis adjustments... Outside of Forza, of course.

That's pretty sweet that you do your own alignments, though... Prob saves a bunch of money, and possibly even time. Maybe I'll have the confidence/skill to give that kinda thing a try at some point, heh. I didn't even know that was reasonably possible at home without expensive equipment.

Bill Lehman

I got -2.8 F with LCA shims and moving the strut top full inboard. Getting -2.4 R required aftermarket toe links.

orthojoe

Reviving my dead thread with some updates.

I finally decided to give Hoosier R7s a try just to see what they can do. I've avoided them for a very long time because of the cost, longevity, and I didn't think I was quite ready for them.

I mounted 235/35-19 on my 19x8.5 OZs, and 295/30-19 on my 19x11 OZs. Per hoosier recommendations, I did a 'break in' heat cycle 2 weeks ago where I slowly built up speed over 3 laps, did one hot lap, and then brought the car in. At that point, the wheels were taken off the car and sat in a garage for 2 weeks.
Whether or not this does anything, I don't know. We'll see how many good sessions I get out of these tires.

I returned to Thunderhill yesterday and remounted the wheels and gave them a go. Very consistent grip and consistent times. The first session yielded multiple 1:57 laps in a row within 0.2 seconds of each other until I hit traffic.


The second session yielded a 1:57.0 on the first lap, and I flirted with 1:56, but I dropped 2 off at T10.


Here is my best on RE71R


Some interesting points:

1) Despite intake/ambient temps being around 20 degrees higher with R7 (detrimental, IMO), lap time was 2.4 seconds faster on R7. Given equal conditions, I'll bet they are 3 seconds faster

2) Theoretical best based on split times of 5 sectors was 1:56.2. I agree with 24Chromium that someone who really knows what they are doing can do 1:55 in this car on R7s.

3) I switched back to RE71 in the afternoon to save the tires for Laguna Seca next week. While I was slower, I had just as much fun in the RE71R tires.

4) My best in the GT3 on RE71R in better conditions was 1:57.3.

Data on RE71R vs R7:



R7 in blue. RE71R in red.
I'm clearly not taking full advantage of the tires yet, especially at T5,10,11,14/15. I messed up T8 and that cost me a 1:56.

TRAKCAR

Me next R7 :-)

orthojoe

Found a way to get those bad boys on an RS?

Shockwave

Love the data and info in this thread Joe.

Please come join us at Buttonwillow on December 8th if your available! Few of the Socal GT4 guys will be there.

Have u been to Buttonwillow?