[Mboi235i]

I need help trying to lock down a square 255/35r18 setup that is guaranteed to work on street and track.

I have tried to be rational about my life and enjoy the car with minimal upgrades but I cant help but be drawn to the track. The car will be dual purpose street and track so I want to be a little conservative in my fitment.
From the hours of research I have done the 3 most impactful upgrades that can be done are:
1) Camber plates
2) Square set up with wider tires
3) LSD

Camber plates:
I will be purchasing MCA Sport coilovers - its a mid-tier coilover setup from an Australian company -- I live in NZ hehe. The coilovers have ride height adjustment and camber adjustment so I have camber plates sorted. Its going to cost me around $2200 with install.

LSD:
The local shop quotes a $1000 install cost for wavetrac LSD so the whole LSD may cost me around $2500. Not too bad.

Wheel/Tire Setup:
Now this brings me to the square wheel/tire set up. I've been crawling through the forums to find a set up that works in terms of the wheels, camber, spacers, width and offset. It seems like everyone has an almost unique set up that works for them and this is driving me crazy.

It seems the 245/35R18 tires have a horrible selection of tires that are available in NZ. Cant find any performance tires except the MPS4S and I was thinking of putting on some more hardcore tires. So unfortunately I will need to fight through the headache and find a square 255 set up that works.

Is there a setup that is going to work that has been tested on track? I was trying to find 18x8.5 wheels but the crazy offset required, its not easy to find wheels that work. Im trying to get at least flow formed wheels and its around $1000 for a set of 18x8.5 ET35's, but 35 offset seems to be short and it would be better to have around 40-45.

These are the specs I've been able to find so far
Square setup 255/35/18
* 18x8.5J ET 35-38 | Front: -2.2 | Rear: -1.8
* 18x8.5J ET40 | 5mm spacers | Front/Rear: -2
* 18x8.5J ET45 | 12mm spacers | Front/Rear: -2
* 18x8.5J ET45 | 5mm spacer
* 18x8.5J ET45 | 7mm spacers | Turner hub extenders

But yeah, can anyone help me find a square 255 set up that works? Can't have any wheel poke its not street legal here. Or alternatively, has anyone found a street/track set up that works for them well? Preferably without fender rolling - but if requried I am willing to do it.

All currency quoted above are in USD (rough calculation at 1.6NZD to USD)

[Jaik]

18x8.5J ET42 up front works with F8x LCAs and some camber plates. 18x8.5J in the rear you'd want ET40-ET42. If you get stuck in the rear its not very expensive to get a rear camber arm to facilitate ET35 . I rate all the CMP gear I've purchased over the years. Close to you over the ditch in Brisbane

https://cmpautoengineering.com/colle...ble-camber-arm

[Dom147]

Ideally you'd want to run 18x9 ET42 for the extra sidewall support and a grater contact patch. I run this setup with 2.7 degrees of camber and a 12mm spacer. looks great and feels ever better.

How are you getting the LSD for so cheap??? Are you doing the install kit from wavetrac directly? I'm kind of a noob when it comes to anything beyond just replacing the entire diff.

[Mboi235i]

Originally Posted by Dom147

Ideally you'd want to run 18x9 ET42 for the extra sidewall support and a grater contact patch. I run this setup with 2.7 degrees of camber and a 12mm spacer. looks great and feels ever better.

How are you getting the LSD for so cheap??? Are you doing the install kit from wavetrac directly? I'm kind of a noob when it comes to anything beyond just replacing the entire diff.

Thanks for the info.
I am just curious, is it better to go 9" wheel for the 255? The 255 should fit on a 8.5" wheel as well according to wheel tyre fitment guides.

re the LSD: I was just estimating. Ill give a breakdown of the research I just did after you asked your question.

Wavetrac website quotes $1530 NZD for the install kit with VAT (that's UK's sales tax)
https://wavetrac.eu/products/wavetra...2-m235i-r-3-08

Shipping is $141 to NZ

NZ then takes their cut by applying import duties. 15% on top of part price, which adds ~$230 to the price.

My shop has a diff guy who is somewhat a specialist in wavetrac lsds and he quoted me "around" $1500 labour for installing the wavetrac into my current diff.

$1530 wavetrac parts
$141 shipping
$230 NZ import duties
$1500 labour
= $3400NZD
= approx $2000USD

This is a very optimistic price, and I am sure I will get a surprise somewhere down the line. I sort of dont believe it myself. It seems too good to be true. I would buy it right now if I had some more cash.

[Dom147]

Originally Posted by Mboi235i

Thanks for the info.
I am just curious, is it better to go 9" wheel for the 255? The 255 should fit on a 8.5" wheel as well according to wheel tyre fitment guides.

yes it's better to go with the 9" wheel for the sidewall support. In an 8.5" wheel there'll be a lot of sidewall bulge which will leave you with a slightly mushier sidewall and if you track, you'll feel the difference.

Also when using a tire contact patch calculator, you'll notice that the contact that the tire makes with the ground with an 8.5" wheel vs a 9" one, is less even when going with the same tire size and all.