[TrackRat]

Lime Rock Park, April 9th, 2004, Performance Drivers Assoc. HPDS

This was my second Track Day outing with the STi. Scott Duncan, one of my colleagues at work came along with me for the day.

For both this outing as well as the initial March 25th outing, I drove the car to the track with not much more than a tire pressure gauge, an air tank and a torque wrench and a “brown bag lunch”. Quite a switch from the “traveling circus” theme that trailering a car seems to involve.

Before leaving my home, I looked at the local Doppler weather radar on line, and saw that there were widely scattered showers, primarily in one band moving toward Lime Rock from the northwest. I was pretty certain that we would see a shower at some point during the day.

Scott met me at my house at 6:15 AM. The car was loaded, and with Scott at the wheel, we took off for Lime Rock under mostly cloudy skies.

We stopped at a Citgo station on Rt 7, close to Lime Rock to fill the car up with gas, and also fill two 5 gallon jerry cans of gas for “top-off’s “ while in the paddock.

We pulled into Lime Rock, signed our names to the legal release form (that could have included the deed to my house…) and proceeded to drive across the WWII vintage “Bailey Bridge” to the infield. In addition to the PDA regulars, we saw a number of VSCCA cars already there or being unloaded, from their trailers. Lots of cool Lotus 11’s Lotus 6 , Ginettas, Sunbeam Tiger, Alfa’s, D and E type Jaguars, etc. etc. Ahh… I love the sweet smell of Race gas exhaust first thing in the morning…. I learned that the following day was a VSCCA race meeting, and we would be running some joint practices with the VSCCA cars. It looked like it would be a busy circuit.

The STi is a great car as delivered. My only change was to replace the stock brake pads with Performance Friction(PF) 01 compound in the front and 97 compound in the rear, and raise the tire pressures.

Brakes: These are the same compounds I run on the 47 car, and which I really have liked. The advantage of the 01 compound as compared to other PF compounds is that they have good torque from cold right on up through 1200 degrees F. While Lime rock is not particularly hard on brakes (when compared to WGI), the feel and ability to modulate the pedal with this pad combination is excellent. Also, the capability to “trail brake” and rotate the car’s tail end with these pads is pretty forgiving. When removing the stock pads, I noticed that my car was delivered with a flat “anti Squeal” shim, plus a separate stainless steel plate. This stainless steel plate is the same shape as the pad backing plate, but has a portion missing- the shape is like a brake pad that is cut off in a band saw. The location of this cut is made to cover only a portion of one of the two pistons on each of the calipers. These ”tuning plates” are symmetrical from the inside to the outside of the caliper. I believe this “tuning Plate” would be specific to the STi when fitted with the Brembo calipers. My belief is that this tuning plate will cause the pads to wear more evenly that if it were not present. It was probably developed by the STi technical “boffins” when they were track testing these cars before release to the buying public.. (THAT must have been a rip!!!)

I have run other track cars with fixed calipers like the Brembos and have seen significant tapered wear on the pads when the full brake pad is in contact with the twin pistons, i.e. without these “tuning plates”. This taper causes the pads to wear thin at the leading edge of the pad and will cut short the useful life of the pad set. This stainless steel “tuning plate” alters the caliper piston pressure as applied to the pad in an effort to cause a more even pad wear pattern. I left these tuning plates in place when I installed the PF pads.

I am certain I will try other pad combinations on the STi. However this combination seemed to be a “winner” right out of the box. The only downside is the brake squeal… it sounds like a stuck pig.

Tires: I was happy with the RE 070 tires. I have found that hot pressures of between 40 and 42 front and 38 to 40 PSI rear seems to work well. I saw no chunking of the front tires, as I have read about on line. The wear pattern on the tire’s tread was just up to or shy of the “arrows” on the tire shoulders. Consequently, I believe these tire pressures are pretty close to optimum. The RE070 tires have a similarity to the older BFG TA R1 tires in that if you over-drive the tires and get them too hot, they get a bit slippery. If you develop that heavy, grinding understeer, take a lap to let the tires recover a bit. An easier lap will immediately bring them back. I am in no hurry to change these tires.

Overall handling balance. The car is clearly biased toward understeer. However, It is fairly easy to control that understeer by using certain techniques. FYI, I have kept the DCCD in the auto setting for all events so far. To minimize the understeer, I found it best to use a combination of the following:


1. Enter at a speed slow enough to be “on the throttle” moderatly from the turn in point up to the point at which you approach the apex. Trailing throttle is not good for the first half of the corner - the car will push. However, this car is very stable under power in a corner. Just before the apex, roll on the throttle more agressively, and drive the car through to the track out point. Like any car, holding a good line that allows constant unwinding of the steering wheel from the apex on out, without “pinching off” the track out portion will set the car up for it’s forte, which is hauling a$$ out of the corner. On that short chute out of Big Bend, this car really honks. Throttle applications that would have me “going off the track backwards” in my 65 Mustang are “absorbed” just fine with the STi’s AWD.

2. Modify your line on a decreasing radius turns (like Lime Rock’s “Big Bend”). I experimented used both the “single apex” and “double-apex” lines at Big Bend, and found my style of driving with this car was better suited using the double- apex approach. This “double-apex “ line uses a faster, shallower entry with a more pronounced sharp radius at the mid point of the turn, and allows a late apex at the exit. This line seems to minimize the chance for that heavy understeer that one can find in the first half of the turn. At Big Bend, this line allows you to capitalize on the car’s strength, which is its strong pull out of the corner.

3. Trail brake into a corner. The brake pad combination I used was very forgiving while trail braking into a corner: you can dial out the understeer with the brakes when moving along at speed. Use care here, because if you screw it up by being too rough, you will likely be going off backwards, and see the tire barrier, Armco or other hard stuff approaching you through the rear view mirrors.

I had both dry, drying and rain track conditions on both track days ( Not to mention oil, dirt and grass on the surface, too…). This car is absolutely brilliant in the rain. There is not much that is faster out there on a rainy day, save for another Subie or an Audi or an Evo. The understeer that may seem to haunt you in the dry becomes a really good reference point in the wet. I found that charging into the corner until you feel the front end start to push, then hold your line, feather the throttle, and as the push starts to disappear, roll on the throttle. The front wheels hook up and the car hurtles out of the corner doing a little squirm and wiggle, but always quite tidy overall.

I met a guy named Lenny? when I was studying the Subarus parked in the paddock closest to the Left Hand turn. Lenny told me that Pisan, and several other of their fellow subaru buds were there. While we were runnig with each other on the track, Every time I went by their parking area, they were not around. See ya next time....

I had a student driver named Frank . He was driving an STi for his fourth track outing. However this event was his first with his STi and also his first at Lime Rock. Frank’s Dad was there with his Porsche 911 Turbo. Frank’s Dad had watched my “drives” in March with my STi the first time out, and asked if I would Instruct his son at this event. Apparently, my ability to keep the STI out of the deep weeds, in both the wet and dry that day impressed him enough to ask for me as an instructor. Frank did really well. His lines were nice and smooth, and he was really cranking along. It was a blast to ride with him. He finished the day running really nice, consistent laps at speed.

Overall, I believe the Subaru STi suspension development engineers did a superb job with the set-up of this car. It is a high powered car delivered with a conservative set-up bias to make it relatively friendly for us amateurs to drive. However it is still an extremely capable car in any condition. If it were delivered to the US market with more of an aggressive handling edge, I believe it could really be “a handful”, and people would be sliding these cars off the road at a furious rate. I suggest however, that if you plan on driving this car in road race type conditions, try it in its “as delivered” condition for several events to develop an understanding on what the STi developmental guys really had in mind.

I agree with the idea that there is a lot that can be done to develop the car more; that is what the aftermarket tuners are in business for. I believe they will have a great market with this car and the owners of them. Personally, I will not make any changes until I feel that I have gotten all that I can from this “as delivered set-up” . I do belive, however that there is a set of "pink " springs and and adjustable ARB in my future. Oh ... and an additional 30 HP would be nice too

Yours In the Smell of Hot Brakes,

Track Rat

(7000 miles and I STILL don't want a radio)

[fry_ed]

sounds FUN!!

great write-up. thanks
very informative.

[TRM]

glad to hear the tip regarding the cool down for the tires. should come in handy since i plan to run them until they are at the wear bars :-)