2007 Subaru WRX STI

[Fair!]

Re: 2007 Subaru WRX STI

Added Ferodo DS2500 series pads, ATE Blue fluid and Goodridge SS brake lines. HUGE difference here. I think the brakes are now race ready.

Mr. Frodo!

Hope this helps the mushy pedal. The exhaust definitely picked up some oomph! Maybe with the bigger rear bar the rear spring rate can drop to reduce ride harshness.

[hancheyb]

Re: 2007 Subaru WRX STI

Maybe with the bigger rear bar the rear spring rate can drop to reduce ride harshness.

Actually the ride is almost liveable. I've decreased rebound signifcantly in the rear and it feels VERRR REE niiice. I think we can go down slightly with it and it will ride like a Cadillac.

[Paul]

Re: 2007 Subaru WRX STI

While the Fairs were representin' at the Divisional, I did some work on the STI.

Weekend update.

• Beta testing a "special sauce" map from a tuner. I received it Friday afternoon. Not sure if they want it known yet. Seems to have fixed most of my complaints about throttle response and low end torque. No more surge at 4k rpm. The power is very linear and builds from 3000 rpm in all gears.
• Added Cobb rear sway bar. Can't tell if this did much till we go run it. Thinking about a mid week trip to Mineral Wells before the BMW event at LaGrave, similar surface to Topeka.
• Added Ferodo DS2500 series pads, ATE Blue fluid and Goodridge SS brake lines. HUGE difference here. I think the brakes are now race ready.
• Added stock exhaust back on. The Fairs dropped it off last night around 9:30. I think it took me 30 minutes or less to swap them out. My hearing is recovering. I have to say, driving around with the open pipe all weekend was quite fun. The exhaust burbles and pops on the overrun btwn shifts and deceleration. I found myself downshifting through each gear just to hear it. People will definitely know when you're on or off the gas.

Sounds like your car is just about done. =)

[Tommy R]

Re: 2007 Subaru WRX STI

I think one of you STi drivers needs a tire b!tch for one of the upcoming divisionals. *whistles innocently*

[hancheyb]

Re: 2007 Subaru WRX STI

Allrighty. We installed the prototype Vorshlag FRONT camber plates last night. Rattle and squeak free (of course) . We got about 2.2 degrees of adjustment out of the current slots. We could go more, but might move the strut mounting back for more caster instead. It lowered the car about 1/2" from the AST plates that were on it due to our extreme attention to stack up.

With the car lowered it ranged from 2.2* to 4.4* on one side and a little less on the other most likely because I didn't pay close enough attention to the eccentric on the strut. The other side was in the -1.5* range in the least setting (very streetable). We adjusted both sides to -2.2* and set the toe to about 1/4" in for street use. That will give some toe out at full camber, probably too much but we can adjust it at the track.

Production run will begin shortly!

The rears have been fine since installation. We have about ~7k miles on them. Since they use proven BMW pieces (plus adjustments for Subaru struts), we're pretty happy with them "as is".

Fair and Amy drove it a few weekends ago. The rear Cobb bar helped cure some low speed understeer, but with a few runs they didn't try to dial out the oversteer experienced in the slaloms. I'm confident turning down the rear struts can fix that. Looking for a day during the week to go rent Mineral Wells for some skidpad and course work.

[hancheyb]

Re: 2007 Subaru WRX STI

OK, my kidneys could not wait till after Nationals so I'm trying an alternate setup. We corded the inner 3/4ths of the fronts so that says to me we have too much camber and/or too much spring rate. Since the fronts are at 680 lb/in (and pretty brutal), I went down to 630. Not a huge change.

Since we put the bigger bar on the back, I went down from 513 to 400 lb/in in the rear. This was a HUGE change in ride comfort. It is still firm, but it is definitely driveable now. You don't even have to be crazy to drive it. Is it a Cadillac? No. Autocross is Sunday so we'll see what happens. Naturally this will be finalized at our August 25th practice at Mineral Wells. We'll do full pyrometer/skidpad testing and get a good feel for where the car is at.

BTW, at that practice there should be our M3, 2 STIs, an Evo......AND.....our STU prepped E46 M3! Suspension goes on next week along with 18x10 265s. We'll do full DL-1 testing on all the cars on the same course. Should be some good info.

[hancheyb]

Re: 2007 Subaru WRX STI

Autocross on Sunday wasn't so great. First off we didn't plan on hosing down tires. The Bridgestones pulled 1.2g then 1.08g by the last run in the 100 degree heat. We made a mistake and didn't shave them either. That will be fixed this week though.

The car had a bad push on corner exit which is where it shines. Probably part of this has to do with the tires, but it was doing it with the factory tires too. I went ahead and put 80s on the rear instead of 70s. That's 450 lb/in AND I revalved the compression in the rear tonight. No dyno results yet, but it is definitely more firm. The idea was to get more weight transferred to the rear on corner exit. Car didn't hop or skip on some of our torture test roads.

Fair and I did the test loop a few times. It was uneventful in a good way. The car just pulls hard out of corners and steers where you tell it. Perhaps we fixed it or atleast it is better than before.