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The 18s are 18x9+46 in the front and 18x10.5+44
The 19s are 19x9+50 in the front and 19x10.5+44, I've also run a 19x11 in the rear, but you need lots of camber.
Tires are complicated. I run a lot of different tires but in general:
18s: 255/35 or 265/35 in the front and 295/35 in the rear.
19s: 255/35 or 265/35 in the front and 285/35 or 295/35 in the rear. People run the 305/30, but I'd have to get the car realigned to do that since the sidewall height is so different. And I don't want to change my current rake.
A few notes, I like to run the 295 with an 11" wheel and I prefer to run the 265 with a 9.5" wheel. This is doable on a 19" (albeit with a LOT of camber), but isn't really doable on the 18". I'm sure you are curious why I have a set of 18s that are so close to the 19s. Well, two reasons. 1) tire cost 2) much more availability for semi slicks/slicks on 18s. You can run a Hankook 250-640-18 (F) and 280-660-18(R) or a Pirelli 265-645-18 (F) and 305-660-18 (R).
Hopefully this helps!
Thank you! I want to run 18's as well because of the tire availability and cost. This is super helpful.
The 18s are 18x9+46 in the front and 18x10.5+44
The 19s are 19x9+50 in the front and 19x10.5+44, I've also run a 19x11 in the rear, but you need lots of camber.
Tires are complicated. I run a lot of different tires but in general:
18s: 255/35 or 265/35 in the front and 295/35 in the rear.
19s: 255/35 or 265/35 in the front and 285/35 or 295/35 in the rear. People run the 305/30, but I'd have to get the car realigned to do that since the sidewall height is so different. And I don't want to change my current rake.
A few notes, I like to run the 295 with an 11" wheel and I prefer to run the 265 with a 9.5" wheel. This is doable on a 19" (albeit with a LOT of camber), but isn't really doable on the 18". I'm sure you are curious why I have a set of 18s that are so close to the 19s. Well, two reasons. 1) tire cost 2) much more availability for semi slicks/slicks on 18s. You can run a Hankook 250-640-18 (F) and 280-660-18(R) or a Pirelli 265-645-18 (F) and 305-660-18 (R).
Hopefully this helps!
Does the 18" set up with stock 380mm OEM brake setup? If yes, which wheel set up clears the stock brakes. Thank you
Does the 18" set up with stock 380mm OEM brake setup? If yes, which wheel set up clears the stock brakes. Thank you
Not sure, I don't run the stock brake setup. I have an AP BBK. You should reach out to either @Apex Wheels or forgeline (those are the wheels I have), they are all super helpful and willing to chat.
Does the 18" set up with stock 380mm OEM brake setup? If yes, which wheel set up clears the stock brakes. Thank you
The stock brakes in the S/GTS have up to 350mm discs and fit most 18" wheels like Apex, Titan, Oz Racing, etc.
If you want to go to 380mm discs then you need to replace the discs and brakes to something like AP racing, PFC or maybe Brembo GT kit.
The 981/718 GT4 with stock 380mm discs/brakes due to the large caliper does not fit 18" wheels.
How much rake / wing angle are you running? My car felt really oversteery on entry of high speed corners at my last track day, so I added a click of wing (now at setting 3 of least aggressive) which seemed to have made a big difference in settling the rear. It's got me thinking about underbody/diffuser to try to reduce lift + get some drag free downforce.
I've also noticed the car seems to scale a lot with heat management, so I have some side scoops coming as well. I also got some verus dive planes, which their data suggests should help feed the intake ducts higher pressure air.
"Another goal of the dual dive plane kit was to feed the intake ducts clean, high-pressure air to improve engine power. At high rates of speed, this high pressure can build-up in the intake and create a small supercharge effect (positive pressure) in the intake manifold to improve horsepower and torque. This also ensures that the GT4 is receiving the coldest air possible at the intake filter."
Thanks! Good looking build you've got, we are definitely twin-ing it haha
Originally Posted by jacktli_982
How much rake / wing angle are you running? My car felt really oversteery on entry of high speed corners at my last track day, so I added a click of wing (now at setting 3 of least aggressive) which seemed to have made a big difference in settling the rear. It's got me thinking about underbody/diffuser to try to reduce lift + get some drag free downforce.
I believe I'm at around 3-degrees, I'm not running a whole lot of angle. You may want to look into sway bars. I found that the sway bar settings had a huge impact on understeer/oversteer. I played with some more wing angle at the sacrifice of top end speed and found that making a sway bar adjustment allowed me to keep lower angle, keep top end speed, and solve my oversteer issues. I trailer my car so I couldn't add the verus underbody panels as they interfere with my tie downs, but I think it would make a decent difference. I'm hoping the addition of the 4RS style fenders will also help as relieving the air pressure build-up in the wheel well should also aid in more downforce. Time will tell, literally.
Originally Posted by jacktli_982
I've also noticed the car seems to scale a lot with heat management, so I have some side scoops coming as well. I also got some verus dive planes, which their data suggests should help feed the intake ducts higher pressure air.
I too had heat management issues. I, like you, initially did not have the scoops as I, incorrectly, assumed they were more aesthetic in nature. But once I added them they made a big difference ...
Amazing, seems like I have the right next steps! Tarett swaybars and links have been sitting in my garage, time to get those on.
Very curious on the difference the 4RS fenders will make for you. Do you need to do any cutting/routing of the fender liners to make that work? Not sure if 4RS has any special ducting or anything.
Amazing, seems like I have the right next steps! Tarett swaybars and links have been sitting in my garage, time to get those on.
Very curious on the difference the 4RS fenders will make for you. Do you need to do any cutting/routing of the fender liners to make that work? Not sure if 4RS has any special ducting or anything.
Yup, sure sounds like you are going in the right direction! Get em on, try them out, and let me know what you think!
I suspect I'll need the 4RS fender liners - when I look on PET I didn't see any ducting, but there is definitely venting. I'll probably buy the liners vs cutting. The fender liners are different part #s too:
Hey, time to remove the 'GTS' letters. Or at least the 'S'. Ha ha. Your car is basically a GT now, and a unique one at that, with an H4T. Just curious how your car compares to a stock GT4 at the track. Have you raced one?
Hey, time to remove the 'GTS' letters. Or at least the 'S'. Ha ha. Your car is basically a GT now, and a unique one at that, with an H4T. Just curious how your car compares to a stock GT4 at the track. Have you raced one?
Haha, thanks! Yea it's a pretty unique build, I think that's half the fun of it. I haven't wheel to wheel raced a GT4, have done TT though. This is going to bother some people, but against a stock GT4, I've got a decent shot at outrunning it. Here's a video from last year where I'm chasing down some decently driven GT cars. I'm a decent driver at best.
12-14-2023, 03:10 PM
