STX Set-Up Sharing & Results Thread

[renfield90]

Originally Posted by bslate3

Im new to STX. I spent 2yrs in CS, drove a couple of STX twins and drank the coolaid.

I'm trying to figure out what's the best ride height. It seems a sligh positive rake works well with my setup. It looks like a bunch of you are running pretty low ride heights. Or am I just measuring mine wrong? I'm measuring from center of hub to top of fender.

However I feel like measuring from bottom of wheel to top of fender is a little more accurate.

Right now if you measure from bottom of wheel to top of fender it's 22 1/2 and rear is 22 3/4.

What @cjd said (except "tires" not "wheels" lol). Hopefully you also remember how much fuel and other stuff was in the car when you measured since that will affect ride height.

I will also add, I do not make rake changes based on wheel hub to fender measurements - keep in mind that the fender is in an arbitrary location front and rear. Just because one is higher than the other doesn't mean you are actually at positive rake.

For rake, I prefer to measure at the pinch weld near where the scissor jack should go. With a full tank of fuel and OEM springs, rake was 0 measured this way (which seemed far too convenient, so I'm going to guess it was done on purpose and this is the best place to measure). If you lowered all four corners evenly you likely have a very similar rake setting.

A couple mm of rake makes a large difference in handling. If you want to play with this I strongly recommend measuring in mm and making very small adjustments (2-4 mm at a time, generally 1-2 full rotations of your ride height adjustment).

[cjd]

Originally Posted by renfield90

What @cjd said (except "tires" not "wheels" lol).

I meant wheels, and that's what OP said as well... anything that includes tires varies by air pressure if it's the same tires, and probably by more as you look at different tires. I'm honestly not sure there's a 100% accurate way of doing things, as long as you're consistent about all the variables it's close though - especially once you corner balance and it's not really about consistent ride-height anyway. Once you have a baseline, you add or remove at a corner/end, so the repeatable results for your car is really what matters.

I'll be in way over my head this year on alignment study... going to be interesting. I can't say it'll be fun and I may hate myself by the end of the season. First step is getting the risers set up perfectly level... stupid garage with its uneven floor...

C

[bslate3]

Thanks @renfield90. I knew the fender arches were not the same front to rear and I always questioned that method of measurement. Before and after at the pinch welds seems very close to accurate.

There's a local BMW autocross next weekend that gives you tons of laps. I'll try out a zero rake and go up a couple mm in the back like you said and see what the effect is.

[APEXIT53]

Originally Posted by bslate3

Im new to STX. I spent 2yrs in CS, drove a couple of STX twins and drank the coolaid.

I'm trying to figure out what's the best ride height. It seems a sligh positive rake works well with my setup. It looks like a bunch of you are running pretty low ride heights. Or am I just measuring mine wrong? I'm measuring from center of hub to top of fender.

However I feel like measuring from bottom of wheel to top of fender is a little more accurate.

Right now if you measure from bottom of wheel to top of fender it's 22 1/2 and rear is 22 3/4.

Mine doesn't sit that low, the reason being that if you slam these cars the axles pull out from the diff and tend to break. I thought I had my ride height in my setup notebook but I don't.... I think I was about 13.5" fr and 13.75 rr from hub center to fender... but I could be totally off.

as far as alignment goes, personally I get a setup, learn how the car reacts and what its doing an not doing then change the car from there. Seems to work the best and takes a few events but i try not to change it every event to where the car is super inconsistent.

[bslate3]

Brandon Slater
192/92 STX

Suspension -
Shocks: RCE T2
Springs: 400/400
Camber plates: RCE
Rear camber: Mooresport
Anti-roll bars: Whiteline 20mm adjustable front, WRX 16mm rear
End links: Adustable Whiteline front, stock rear
Upper strut bars: None
Bushings: Whiteline rear crossmember bushing inserts, Whiteline diff. inserts, Whiteline trans mount insert.

Alignment & suspension settings -
Ride height:
Rake: +5mm
Alignment: -3.0 front camber 0.06 toe out, -2.0 rear camber +0.08 toe in
Shock settings: still playing with them
Weight: unkown currently
Corner weights: don't know yet
Tire pressures: 32F 30R after one event.

Engine & drivetrain -
Header: stock
Over pipe: stock
Front pipe/cat: stock
Cat-Back: Perrin non res
Intake: Grimspeed CAI
ECU: stock
Crank pulley: Kartboy
Motor mounts: stock
LSD: Stock Torsen
Dyno results: massive amounts of POWA! Lol


Wheels/Tires, etc -
Wheels: 17x9 +35 Ambit RE02
Tires: Bridgestone RE71 255/40R17
Wet tires: HoosierStones
Brakes: Carbotech AX6
Battery: stock for now
Seats: stock for now

[renfield90]

Originally Posted by bslate3

Thanks @renfield90. I knew the fender arches were not the same front to rear and I always questioned that method of measurement. Before and after at the pinch welds seems very close to accurate.

There's a local BMW autocross next weekend that gives you tons of laps. I'll try out a zero rake and go up a couple mm in the back like you said and see what the effect is.

Yep. For a really obvious example of this, check out the BMW E30s. Once you spot the height difference in the arches you will never unsee it. The ideal drop for the car left the rear wheels looking very nicely flush into the fender but the fronts still had a few fingers of gap. You could tell who the stance guys were because they'd cut the front springs to make the gaps look even. "Rake? No, haven't met her."

Of course high positive rake has some aerodynamic advantages (see: RBR F1 car) but you need all the extra aero bits to actually take advantage of it. And the beauty of the E30's handling was that it came pretty close to 50/50 from the factory which made the car a hell of a lot of fun. Those stance guys don't understand what they were ruining. But I digress...

[slyphen]

Jim Zhu/STX 98
Northwest Region SCCA, Bremerton Sports Car Club (BSCC)
Title: 2017 IST Class Champion

Suspension -
Shocks: Off the shelf KW V3 (previously Fortune Auto 500+swift spring)
Springs: Swift Springs 400/400
Camber plates: Raceseng
Rear camber: SPL Rear Lower Control Arm
Anti-roll bars: Whiteline 22mm adjustible front sway bar
End links: Whiteline
Upper strut bars: N/A
Bushings: Stock

Alignment & suspension settings -
Ride height: - 1.5"
Rake: zero
Alignment: (Front)-3.5 camber/0 toe (Rear)-2.5/ .15 toe in
Shock settings: A/R per race condition
Weight: 2995lbs (w/driver) 50/50 cross weight
Tire pressures: 30psi Front - 28psi Rear (BFG Rival S 1.5)

Engine & drivetrain -
Header: Gruppe-s
Over pipe: Perrin
Front pipe/cat: Motiv High Flow Cat
Cat back: Perrin 2.5" Resonated
Intake: K&N Drop-in
ECU: Stock
Crank pulley: Stock
Motor mounts: Stock
LSD: Stock

Wheels/Tires, etc -
Wheels: Wedssport TC105N 17x9 +35 Gunmetal Grey
Tires: Bridgestone Potenza RE71R 245/40R17
Wet tires: Continental DWS 06 225/45R17 (daily)
Brakes: Stoptech Slotted Rotor / Ferodo DS2500 Pads / Stoptech SS Brake Lines / Motul RBF600 Fluid
Battery: Stock
Seats: stock