Autocross Fun and Weigh-In

Update by Alan Cesar to the Subaru Impreza WRX project car
Dec 9, 2013

We took our WRX for a little autocross action. It was super fun, and fast, too. On a wet course, it's hard to beat all-wheel drive.
Our Subaru's weight distribution is a little nose-heavy. That's not surprising, given that the entire engine hangs ahead of the front axle, and there's all that turbo plumbing up there too.

While we were at the $2013 Challenge, we took a short lull in the day’s activities to jump onto the autocross course. It had been raining all day, so even though we were on moderate-treadwear tires compared to the event-winners’ Hoosier slicks, our all-season tread and all-wheel-drive propulsion made a strong impression on the asphalt. The traction was fantastic, and pulled our car to a 46.6-second time.

That’s good enough for fourth in the autocross! …in a field of cars that cost a quarter as much to build. Well, we can soothe the sting with practicality: Few of those competitors could reasonably have carried an xmas tree home from the hardware store after the event, as we did. (Though it was a Jeep Cherokee that set FTD…)

Oh, right. The scales. We also drove the WRX onto them. What’s it weigh? A flat 3200 pounds with a half-tank of gas and no driver. The scales also showed us that 58 percent of the car’s weight is in its nose, which explains the understeer we’ve experienced—a typical trait of these cars. When we adjusted our Whiteline anti-roll bars, we could only somewhat tame it. The car understeers a bit under power, but with the rear bar set on full stiff, it would start to snap sideways when we lifted off the gas.

The 58/42 weight distribution isn’t surprising, even given that we have have a wagon. Though the boxer design means the engine is not very long, the entirety of it still hangs ahead of the front wheel centerline. There’s also a good amount of turbo plumbing up there.

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View comments on the GRM forums
12/9/13 10:02 a.m.

If I had the cash... Oswald Performance front bumper beam is 6lbs, compared to almost 28lb stock beam. Add his subframe which weighs 10lbs vs stock 24lbs and you'll have taken 36lbs off the front end.

12/15/13 10:19 p.m.

Can you guys change up the tires and see if it effects the understeer (sticker compound or wider all-seasons)? Or the alignment? I think most WRX guys are trying to reduce the understeer, and are trying to decide what the best investment is.

There was an article a long time ago about reducing track times by changing up the tires on a WRX, but nothing about reducing understeer on a street car.

The_Jed UltraDork
12/31/13 2:38 p.m.

Pretty close to a Fox 5.0...make of that what you will. :)

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