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GRs in STU autocross

116K views 666 replies 57 participants last post by  jesup16 
#1 · (Edited)
Alright, having searched for GR-specific STU autocross info, I found little. Who is running, where, and what kind of setups? Given the heated competition against EVOs (and an E36 M3 in 2012! :p) on the national level, we could provide one another with crucial info.

Thread basics:

-coilovers/struts and springs (with spring rates)
-sway bars (with diameters)
-bushings
-wheels (with dimensions) / tires (with dimensions)
-power mods
-brake mods
-miscellaneous mods (mounts, seats, other weight reduction, etc.)

If available, provide other relevant details concerning your setup, including damper settings, tire pressures, and alignment numbers.

See post #16 for my setup: http://www.iwsti.com/forums/3737885-post16.html

For those looking for additional information, the 2013 SCCA Solo rules can be found here:
The Sports Car Club of America - Solo

Street Touring (including STU) has its own section, so check that out before posting any specific questions. More than likely, the answer is in there.
 
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#2 ·
When I was doing STU autocross in North Carolina in the Eastern region I was doing pretty well (took 1st in class 3 races in a row). The local STU champ who was running an SRT-4 actually switched to an STI mid-year I believe. Now there's a guy running STU and getting FTD's in his 07 STI. Much of it comes down to the driver, but you can get pretty serious times with a GR. Are you planning on racing Nationals in the STI?

If so, James Wilson (you might remember him from forum wars) has an autocross prepped GR STi I believe, and he was an SCCA national champ in his '11 WRX if I'm looking at the books correctly.

So yea, definitely a good base to race from.
 
#4 ·
When I was doing STU autocross in North Carolina in the Eastern region I was doing pretty well (took 1st in class 3 races in a row). The local STU champ who was running an SRT-4 actually switched to an STI mid-year I believe. Now there's a guy running STU and getting FTD's in his 07 STI. Much of it comes down to the driver, but you can get pretty serious times with a GR. Are you planning on racing Nationals in the STI?

If so, James Wilson (you might remember him from forum wars) has an autocross prepped GR STi I believe, and he was an SCCA national champ in his '11 WRX if I'm looking at the books correctly.
Were you running with NCR SCCA? There are a few guys throughout the Carolinas who seem fairly serious about STU, so the competition is encouraging. Nothing would be worse to me than to run by myself in class.

Ultimately, I would love to hit a couple National Tour and ProSolo dates per year, as well as making the trip to Lincoln for nationals annually. In the immediate future, however, I'm limited to events in NC and SC, with the occasional venture into VA and GA. It's great having three SCCA regions and two independent clubs within a three hour drive.

From what I've seen on Nasioc, James Wilson appears to be running a STX '08 WRX until the BRZ he's co-driving is delivered.
 
#3 ·
I dont have an Sti but an 11 WRX and its mildly prepped for STU. It did win the Nashville road tour last year.

My car has:

GTWorx Bilstein RCE yellows (330/330)
Eibach 25mm Front / 22mm Rear
Whiteline diff lock down
17x9" rota DPT with 245/45 dunlop starspecs
3" catback

This is not my dedicated autox car so the prep is very street friendly. I usually run in STR / EP in Honda's so the subaru is a little different for me.

Last year i ran the car 4 times after nationals. My impression is that the set-up has great balance buts needs to be stiffer to be national level competitive. Maybe a 25mm rear bar and 500f/600r springs. Just a guess. Obviously better shocks. Put a lot of front camber in and run a small amount in rear (help rotation)

One of the biggest things that I felt the car was missing was a LSD in back (no concern on an STi. Also a downpipe and STU legal tune.

If you looking for national level I would say seats and any other legal weight reduction would be a must as well. But for just locals a good driver would do well with a set-up like mine. Especially good and fun on asphalt.
 
#5 ·
My impression is that the set-up has great balance buts needs to be stiffer to be national level competitive. Maybe a 25mm rear bar and 500f/600r springs. Just a guess. Obviously better shocks. Put a lot of front camber in and run a small amount in rear (help rotation)

If you looking for national level I would say seats and any other legal weight reduction would be a must as well.
I'm looking at spring rates very similar, but was hoping to get away with as little sway bar as possible. I'm waiting on damper delivery to have coilovers assembled, but I hope to have detailed info concerning my approach in May.

I was thinking a big rear bar would lift too much, and I was having a bit of that on stock suspension already.

For weight reduction, I just bought a battery, and I'm looking at doing Girodiscs. Beyond that, seats are probably next. I already have a muffler delete turndown, as well.
 
#6 · (Edited)
Sadness, no traction in this thread?? I was hoping for some easy answers.

I'll contribute, last season looked like this:
Suspension:
GTWorx Plates
RCE T2 Coilovers 550f/600r
Alignment -2.5*f with 0 zero toe all around, no rear camber adjustments
Power:
Invidia DP
DP Turndown
AEM intake
Cobb AP Tuned by TorquedPerformance.com
Grip:
Kosei K1 TS 17x9
245/40/17 Hankook RS-3
Misc:
Cipher Auto front seats (27lbs with brackets)
Ballistic Performance LiPo Battery
ATE Super Blue brake fluid
Kartboy STS with front and rear bushings
Stickers under the hood good for at least +5hp each

Was my first full season, took 2nd overall in STU with my local SCCA and 3rd in a BMW club within their street tire class. For 2013 I plan on staying in STU and trying to take down the evo that won last year.
 
#15 ·
Sadness, no traction in this thread??
I was disappointed in the lack of interest, too.

I'm thinking of girodiscs (I plan to get on road courses more) and ferodo DS2500's with goodridge stainless lines, motul RBF600 brake fluid, and a grimmspeed master cylinder brace.
I wouldn't want to replace Girodisc centers anymore than necessary ($$$), so they might be a poor choice for track use. Also, master cylinder braces are not STU legal.
 
#8 ·
Here's my current setup. I wasn't able to use it for more than a few events but it performed much better than my stock did.


Suspension:
RCE Tarmac T2's 500/500
GTworx camber plates
RCE sways
Whiteline bushings everywhere.
Power:
Cobb AP
SPT exhaust
Grip:
Stock wheels
245/40/18 Dunlop Z1 Starspec

For next season I plan on adding a TurboXS 4" DP, new intake, possibly EL headers and a few other bits to get some more power/torque. Plus I'd like to get some 05-07 OEM BBS wheels to mount RS-3's to and I'll be addressing braking. I'm thinking of girodiscs (I plan to get on road courses more) and ferodo DS2500's with goodridge stainless lines, motul RBF600 brake fluid, and a grimmspeed master cylinder brace.
 
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#10 ·
I just run locally so I use the OTS stage II tune from Cobb. I'm down about 75hp and over 100tq to the evo that beat me last year so he doesn't care. He's a great driver and his car is close to spec, so even if I take a couple wins from him next season it shouldn't matter. The tune is more for fun and engine health than actually trying to win.

I could run ASP but I think there were a total of 10 people all of last season in ASP, which would be completely boring. STU has way more people and is super fun.

Plus Chris Dorsey (multiple nats winner in EP) is in my region and kills the PAX every time. 2nd place is usually in the 980's and I'm in the 920s.
 
#11 ·
@GA Scooby

GRM did a review on the RS-3 and found that is likes a bit of a stretch to really perform well. The width on a 245 is right at 8.5", so if you go with a set of GD BBS you'll actually be pinching them a bit.

I was torn between the 17x10 +38 RPF1 and the 17x9 +45 Kosei. In the end I went with the Kosei because it was much cheaper and almost 1lb lighter.
 
#12 ·
so you took 2nd in STU but you basically cheated by running higher boost than what you're allowed? I wouldn't call that fair, even if 1st place is way faster. If you're not running for competitive time then just run ASP until you get a stock boost target tune. Is your invidia DP catted?
 
#14 ·
@yman

There isn't a single STi in my region that isn't Stage II, hell some guys are running on e85 conversions. Nobody cares cause it's all about having fun and compared to the guys that go to nats we're slow.

STU is where we all run because we're not on race rubber. Get a Braille and lighten up. :D
 
#16 · (Edited)
As of 03/2014, mods are:

Suspension/steering
HVT internal DA coilovers (728f/896r)
Vorshlag camber plates
RCE tubular adjustable front sway bar
Whiteline steering rack bushings
Whiteline rear trailing arm bushings
Whiteline rear subframe inserts

Wheels/tires
Dry
18x9.5 TR Motorsports MT1
245/40-18 Dunlop ZII

Rain
18x8.5 OEM BBS
245/40-18 Continental DW

Brakes
Girodisc 2-piece rotors
Ferodo DS2500 pads

Drivetrain
Cobb short shifter
Cobb shifter bushings
Torque Solutions engine mounts
Kartboy pitch stop
Group N trans mount
Whiteline rear diff inserts

Power
Cobb Accessport w/ 100 octane STU tune (286whp/353wtq on Mustang dyno)
AEM panel air filter
Perrin crank pulley
Perrin EL header
Perrin "big tube" up-pipe
Cobb catted downpipe
custom v-band 3" 16ga stainless catback w/ Magnaflow race muffler

Weight reduction
Sparco Evo driver seat (mounted directly to Planted base)
Kirkey aluminum passenger seat (custom mounted to steel base)
Ballistic Evo 12-cell battery

Additional specs
-3.6* f, -2.0* r camber
0 toe square


The car weighs 3065# with the fuel light on.

Next up for weight loss:

a turndown to replace the axle-back section of the exhaust
AP Racing front calipers
lighten the driver seat mounting arrangement (at 33# now, 8# over minimum)
exotic wheels (CE28Ns or something comparably expensive; at 19# each now)

The TR Motorsport wheels are the easy button for GR/GV STU cars, since they do not require spacers. Although clearance is tight with AST 4100 front spring perches, they fit fine. Plus, they're relatively cheap and look decent.
 
#18 ·
I'm glad to see someone running softer fronts, how do you like it?? The 2011 come with 10% softer fronts which I've come to enjoy. The car has some nice predictable lift-off oversteer coming into sweepers that helps with rotation.

I'm going to order some T2s and was planning on 550f/600r. There's not a lot of info on GR rates for AutoX. Most of the fast GD guys are running something like 600f/500r. But I don't like following them blindly, since a GR hatch is very different from a GD sedan.
 
#20 ·
I love my coilovers. As I said above, I want more spring rate, but for a first try it's pretty damn good.

My plan has always been to rely on spring and not bar, so I'll end up increasing rates until I'm truly happy. My car is getting close to becoming a trailer queen anyway, so I won't have to compromise anymore. As a guess for the future, I'll try something like 600-650f/700-750r. At that time, I may or may not change dampers to a double adjustable.

If your car is a DD, and will stay that way, 550/600 is probably the absolute highest you'd want to go (provided your seat is comfy). At 500/560, the awesome AST dampers are the only thing saving my back, and NC has pretty decent road quality. With a fixed-back seat, spring rate selection requires a whole new level of consideration. ;)
 
#21 ·
I'm with you on springs over bars.

Thanks for the input on your experience and plans. Any chance you have any vids?? I'd like to compare the pitch and roll vs my car.

Had to dig a bit to find a vid with a decent example of the lift-off oversteer, but at 27s there is a left turn heading into a couple offsets.


Earlier in the day I was steering around the cone, but I learned with a little lift I could get the car to rotate and stay much tighter. I'm sure there will be things I have to change about how I approach a course, but I do like this driving style.

Please don't protest the illegal interior mod. :lol:
 
#28 ·
Any chance you have any vids?? I'd like to compare the pitch and roll vs my car.
The quality for Day 1 sucks for some unknown reason, but this is a long, transition-heavy course. Day 2 was pretty much the same course, in reverse. Video embed is dominating me, so here's a link:

"2012 NCAC 37 STU JOHN WOLF - YouTube"

Earlier in the day I was steering around the cone, but I learned with a little lift I could get the car to rotate and stay much tighter. I'm sure there will be things I have to change about how I approach a course, but I do like this driving style.
There is obviously more body roll visible, but your car appears to turn in well. I'd say some of the good handling could be attributed to the additional front camber. You appear to wheel that thing pretty well. :tup:
 
#27 ·
I figured you'd chime in.

Where'd you get your rotors?
:lol::lol: I've had great success with them and have no problem letting the community know that. You would think I work for Girodisc and Carbotech...haha.

I believe I got them from THMotrosports. They were great to work with and I bought the 2pc Fronts and 1pc rears from them at the same time.
 
#30 ·
Thanks for the vid, your car is definitely much flatter in the transitions and doesn't unsettle as much when transitioning on and off throttle. I swear, sometimes when I hit it hard coming out of a sweeper it feels like the front of the car is floating. Stiffer rears will hopefully get me on throttle sooner and with more predictability.

Here's a pic showing the roll. I even have about 200lbs of ballast in the passenger seat. :D
 
#32 ·
Thanks for the vid, your car is definitely much flatter in the transitions and doesn't unsettle as much when transitioning on and off throttle. I swear, sometimes when I hit it hard coming out of a sweeper it feels like the front of the car is floating. Stiffer rears will hopefully get me on throttle sooner and with more predictability.

Here's a pic showing the roll. I even have about 200lbs of ballast in the passenger seat. :D
Image Link

200lbs...is that guy missing his legs??!! That looks to be a 250-275lb'er you have there.
 
#31 ·
Lifting the rear inside seems to be rather easy. I've done a burnout mid turn more than once and feel my self sitting not going anywhere every now and then loosing time. This is on RCE blacks (which iirc are 300lbs) with 24f(hard)/22r(medium).

I've had camber bolts put in a couple months back and managed -2.5 camber up front. I've noticed on the street the car is much more likely to have the rear stepout now, which I assume is resulting from the extra grip up front. I haven't tried this out yet at autox but I'm going to try both sways to full soft for next season and see how that works, lifting that wheel is lost time.

Im in BSP but mainly because I don't care enough to detune the car for autox and this is on 275 star specs.
 
#36 ·
ASP is a dead class this year with the new PAX:

ASP: 0.866
SM: 0.867

It's just 0.06s on a 60s course, which would be less than the difference in just removing the back seats for SM. For PAX I don't see ASP being competitive at all. I doubt my club will have more than 10 people total show up and register ASP this year.

On a brighter note I placed my order for 550f/600r T2s!! I worked with Dan at RCE, super cool guy and really flexible. He told me the KW Clubsport bodies they use are going up in price after January 1st. So I ordered the T2s now and got the lower price, but they will assemble them for me in February when they get in a new batch of RCE front and rear plates. Winning!!
 
#42 · (Edited)
Not sure on the sways. Here's some info I've either calculated or collected. Feel free to jump in if you see something that needs adjusted. We can use this for future reference:


GR SWAY BAR INFO
OEM Front (.67 Sway Motion Ratio)
2010 STI bar: 20 mm (400 lbs/in)
2011 STi bar: 21 mm (486 lbs/in)

Eibach front: 25 mm tubular and 2 way adjustable (not sure this is correct)
Position 1 = 82 N/mm (465 lbs/in)
Position 2 = 93 N/mm (528 lbs/in)

RCE front:
25.5 tubular and 2 way adjustable,

Position 1 = 22.7 effective rate (664 lbs/in)​
Position 2 = 23.5 effective rate (762 lbs/in)


Perrin front:
22mm solid and 2 way adj
50% Higher Rate than 20mm / Effective Rate =600 LBS/IN
85% Higher Rate
than 20mm / Effective Rate =740 LBS/IN

Perrin front: 25mm solid and 2 way adj
160% Higher Rate than 20mm / Effective Rate =1040 LBS/IN
215% Higher Rate than 20mm / Effective Rate =1260 LBS/IN


OEM Rears
(.59 Sway Motion Ratio / .78 Shock & Spring)
2012 WRX bar: 16 mm / bar rate: (178 lbs/in)
2010 STI bar: 18 mm / bar rate: (285 lbs/in)
2011 STI bar: 19 mm / bar rate: (354 lbs/in)

Eibach rear: 22 mm tubular and 2 way adjustable
Position 1 = 58 N/mm (332 lbs/in)​
Position 2 = 76 N/mm (432 lbs/in)


RCE rear:
25.5 tubular and 2 way adjustable,
Position 1 = 22.7 effective rate (721 lbs/in)​
Position 2 = 23.5 effective rate (828 lbs/in)


Perrin rear: 22mm solid and 3 way adjustable,

Position 1 = 140% (527 lbs/in)​
Position 2 =
185% (656 lbs/in)
Position 3 = 240% (869 lbs/in)​


Adding thread Mind started with good info: http://www.iwsti.com/forums/gr-susp...3-springs-swaybars-wheel-rates-frequency.html
 
#43 ·
Here's some info I've either calculated or collected.
Excellent! Thanks for the contribution.

Koni DAs and 700/900s sound like the start of something awesome. Are you getting the valving done by Lee?


As a side note, I'm thinking of picking up a set of RCE bars soon to run until I step up spring rates. I'll post thoughts if/when that happens.
 
#44 ·
Some additional observations after a busy season (30+ events :eek:):

- The GR chassis loves front camber. No surprise there, as the GD loves it, too. Having experienced a significant increase in camber, I now feel terrible for those poor souls running STIs in B Stock... :lol:

- Star Specs + Carolina summer heat = grease. If you're running summer events south of Anchorage, get a nice water sprayer and keep that mf full. I have to soak my fronts between runs, and the rears require at least a quick spritz. Thank goodness I did Evo School in November -- all that hot-lapping without time to spray would have murdered my tires.

- Leave the center diff in auto. I like a neutral to loose car, so I tried out full open (one bar) in the beginning, but eventually gave up trying to beat the computer.

- Feel free to run the car close to empty on fuel. I've made up to four 60 second runs after the fuel light came on, and never experienced starvation.

- Get wide wheels. The 245/40 Dunlops stretch nicely on my 9.5" wheels and look a hell of a lot wider than 245s! As previous research indicates, turn-in and transitioning is quite crisp.

- Stick with 18" wheels. I really wanted to run 17s (cost, weight, cost, gearing, cost), but had issues running into the rev limiter in second on most courses when I was still using the OEM BBS wheels. Given the big concerns of prolonged limiter-banging in our cars, I thought it wise to keep the same overall diameter. In fact, I would gladly give up some gearing advantage to run a larger diameter setup, were it feasible.


I'll add more as I get even more familiar with the car.
 
#45 ·
Very good notes; and yeah, Lee/Gordon are always willing to help. I haven't run much autox the last 4-5 years, just a couple Pro's this past year in a WRX, so will be good to get used to the STi and it's diff magic. Did you run more ashpalt or concrete running auto? Did you try auto- at all for concrete or auto+ for colder/rain events?

I like the idea of the RCE sways. I'm considering getting a set along with some springs with rates similar to yours to compare to 700/900 with stockish sways. The overall wheel rate should be similar.

I've taken my limiter from 6750 to 7200, but left the limiter light so it'll come on at 6750 and had everything taper off so no hard limiter. I'll have a set of 17's and 18's, but will more than likely run 18's for all but tight courses.

I'll keep adding thoughts/etc as well. Feel free to pokes holes in ideas as I typically explore a bunch of possibilities to find the right mix.
 
#47 ·
Did you run more ashpalt or concrete running auto? Did you try auto- at all for concrete or auto+ for colder/rain events?
All the sites I ran this year were asphalt except one, which was concrete. I think there were three or four events where it was either raining or there was standing water on course in spots. In all of those cases, I kept it in plain auto.

I did mess around with Auto - in a few events, but ended up just leaving the diff alone in the end.

I like the idea of the RCE sways. I'm considering getting a set along with some springs with rates similar to yours to compare to 700/900 with stockish sways. The overall wheel rate should be similar.
That is my thinking as well. I'm pulling the trigger on them today, so I'll have them before the first event of 2013. Now, if Dunlop will just come through with some ZIIs...

I've taken my limiter from 6750 to 7200, but left the limiter light so it'll come on at 6750 and had everything taper off so no hard limiter.
I think raising the limiter with a tune is more appealing to me than gaining power/torque. We'll see if I grow a set this year, and forsake the factory warranty.

I'll agree with the stretch but not on the 18s. It might be the courses I run are tighter and more technical, but the gearing and weight advantage for the 3.5mph top speed loss is well worth it.
It is definitely course-dependent, but from my experience, a lot of transitions around here are just out of reach for our second gear (with stock rev limit). On our bigger courses (ZMax Dragway in Charlotte, Cherry Point Marine Air Station), a decent amount of each course is often spent in third, but the "tweener" spots make staying in second more advantageous than two shifts.

On smaller courses, there is no question that more speed in second would pay huge dividends. Again, this is simply my experience around NC/SC/VA.

Depending on the course you can get the car to rotate better by either putting it in Auto+ or increasing rear tire pressure. Auto+ is great for tight technical courses but is unstable at high speeds. More rear tire pressure isn't as drastic, so is better for fine tuning rotation.

Auto- is worthless unless it's a super fast and open course and the car needs more stability.
You've got them backwards.
 
#46 ·
Good stuff, I'll chime in too. Close to 20 events this year with two clubs. FYI, both of our venues are on bumpy asphalt.

-2.5* camber is totally fine for DD, no strange wear patterns.

Bring a sprayer and wet down the intercooler and radiator, especially for two driver cars.

Hankook RS-3s for the summer, they love heat and only get faster the more they are abused. Good starting pressure is 38psi all around.

Get the lightest wheels you can find in 9"-10" width.

I'll agree with the stretch but not on the 18s. It might be the courses I run are tighter and more technical, but the gearing and weight advantage for the 3.5mph top speed loss is well worth it. If I'm constantly on the limiter I'll short shift to third and heel toe in the next braking area. This season we had about 8 courses where this was necessary, in each situation I was hitting 70+ so shifting would have happened no matter what.

Depending on the course you can get the car to rotate better by either putting it in Auto+ or increasing rear tire pressure. Auto+ is great for tight technical courses but is unstable at high speeds. More rear tire pressure isn't as drastic, so is better for fine tuning rotation.

Auto- is worthless unless it's a super fast and open course and the car needs more stability.

Power through everything and get on the throttle as early as possible. The diffs can only do their voodoo under power so stop being a pansy and use the pedal on the right. The car will hold, just plan ahead and rip it.

Good mounting point for a camera is on the dome light. Use one of the slightly curved adhesive mounting clips and attach it to the right (passenger) side of the light. This way you can see how well you are looking ahead, if you have smooth inputs and check your line all in one video. Winning!!
 
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