Just like Mugen Mojo, I autocrossed my bone-stock Fit Sport MT two weeks after I bought it. Massive understeer, excessive body roll and sidewall flex from the OEM Dunlop all-season tires all made for an unenjoyable experience.

Fast forward four weeks to today's SD Region practice day at Qualcomm Stadium. Since H-Stock was too restrictive in terms of mods, I decided to set up for STS instead. The mods and setup on the last of twelve runs were as follows:

Skunk2 Pro-C Coilovers (lowered 1" rear, 1 1/8" Front, dampers set full stiff rear and fuill soft front)
Progress rear swaybar
Konig Heliums 15 x 6.5"
Bridgestone RE-01R tires 195/50-15 (35psi cold all around)
Hawk HPS Acura RSX Base-Model front brake pads
Motul RBF 600 brake fluid

The good news is that much (but not all) of the understeer, body roll, and sidewall flex are gone with this setup. In fact, once the front tires get up to temperature, the turn-in on corner entry is ALMOST neutral and the rear can actually be pitched slightly sideways to better set up for a corner.

Now for the bad news. First, the car is most likely underpowered for STS. The fast guy locally in STS here is in a 2.5L '01 Impreza RS, and over a 60-second course, there was a 2-second gap. Perhaps on a shorter course that is less horsepewer-dependent, the gap may be smaller, but the Fit's lack of low-end torque is still a liability. Second, as I mentioned earlier, the understeer becomes less as the front tire temps increase relative to the rears. The only problem is that it takes several runs before the tires get up to temp. Normally here we get three runs during a race day, but the tires didn't come in until the fourth run.

Others here have run over 40psi cold in the rears, which would decrease rear grip relative to the front. What I want to do is increase front grip without decreasing grip in the rear. In particular, I need the front tires to heat up quicker. This is my first time running a FWD car, so I'd appreciate any suggestions.

 

Good to hear your results so far. I'm suprised you're having a tough time getting those tires to optimal temp in the front- what are the ambient temps out there?

Raising the pressure in the rears is pretty much a must-do since factory rear camber back there gives pretty good stick. You also might want to try a just a little more forward rake by lowering the front and getting some weight over those front tires. Keep the feedback coming.

 

Are you running the Bridgestone's on the street too? Because I was sort of looking at those for street/auto-x duty.

 

You could knock your front pressure down to around 32 for the first run or two and let the tire move around more to make more heat.

Are you running full tread depth or shaved?

 

OK, I guess I have no choice but to raise the rear pressures. I also have a small amount of camber adjustment with the front Skunk2 coilovers, so I'll make some adjustments there as well. I'm not sure if I want to lower the fronts to 32psi because the front end was very bouncy until the front tires heated up. Ambient temps were in the low 60s during the morning run, and high 60s during the afternoon run. As for the RE-01Rs, I don't run them on the street.

One other question: would raising the rear tire pressures also be recommended for lapping sessions at track days, or is that just for autocross due to the short duration of each run?

 

What are your camber and toe settings in the front? What is the range of camber adjustability in your coilovers? You could add more negative camber by using "crash bolts" (OEM or aftermarket) to the lower strut mounting points.

I also agree you should play with tire pressures. You could also try playing with your shock adjustability to eliminate the bouncy action you experienced.

Any engine mods yet?

Good to see you giving STS a go. You may be cutting a path for the rest of us!

 

The upgrade to Bridgestone Potenza RE-01R in 195/50-15 alone will improve handling and reduce understeer.

Bouncy feeling up front usually means you can set your coilovers a little stiffer, try 20% stiffer front and rear. Try also a little less stiff setting for the front vs rear.

Normally you'd want front tire pressures about 3 psi lower than the rears then adjust. STS class allows for front camber adjustment and you'll do better with -2.0 degrees or as close to it as you can get with aftermarket camber bolts (kit). Crash bolts will only get you about -0.9 degrees vs -0.2 for stock front camber. Rear stock camber is already about -1.6 degrees.

It's tough to get much more power but in STS you can add-
Air intake
Cat back exhaust
Headers
ECU flash (no additional boost)


Suspension mods for STS-
Springs
Shocks
Tower Strut Bar
Any front or rear anti-roll bar
Camber Kits/Crash bolts
Camber plates
Any Wheels to 7.5" wide
Any Street tires with treadwear at least 140

Other mods for STS-
Motor mounts
Spark plugs and wires
Brake pads (stock sized)
Stock sized rotors
Cross drilled or slotted rotors
Stainless steel brake lines
Replace Front seats (15 lbs each minimum)
Any size or shape battery of same voltage
Remove AC
Pedal Kits and gauges
Short Shifter

Not legal for STS-
Carbon Fiber hood
Any seat removal
Gearing/LSD upgrade
Clutch/Flywheel upgrade
Added boost
Subframe Connectors

 

Just autoX'd on Sunday with my Fit. 2nd in STS. The event was Indy at the Park, for anyone with a www.myautoevents.com account. Will post standings later for those who can't see it...here's what I ran on with my base MT fit...
Progress Springs
Progress Rear Sway Bar
Muffler delete

Everything else was stock (yeah, even the 14s and the dunlops).

Pics and some vids on my photobucket:
kmdebit/2008-04-20 autoX - Photobucket - Video and Image Hosting