Here’s the data Dan (CGMDan on IWSTI) collected.

Methodology car was weighed, without driver, starting at slightly less than 1/4 tank indicated. Once on the scales, the car was not moved or shaken. Fuel was added 2.5 gallons at a time and data was collected. Sways were not disconnected as I was only concerned about front to rear weight bias. I did record corner weights at 1/4 tank and again once full. Once full, I reverse calculated the fuel load at each measurement.

1/4 tank starting weights without driver

928.5 | 924.5
660.4 | 650.4 Cross weights were 50.1% LR to RF

Fuel ___fuel load ___total wt. ___Fr wt. ___R wt. ____F/R bias in %
1/4 tank 3.5gal _____3163.5 ____1852 ____1311.5 ____58.5/41.5
+2.5 Gal 6gal _______3179.0 ____1854 ____1325.0 ____58.3/41.7
+2.5 Gal 8.5gal _____3194.5 ____1856 _____1337.5 ___58.1/41.9
+2.5 Gal 11gal ______3210.0 ____1858 ____1352.0 ____57.9/42.1
+2.5 Gal 13.5gal ____3225.5 _____1859 ____1366.5 ___57.6/42.4
+1.5 Gal 15gal ______3234.0 _____1859.5___1374.5 ___57.5/42.5

Full fuel corner weights without driver.

931.4 | 927.4
691.4 | 682.4

For comparison, here is Colin Feidler’s corner weights.
It also shows the F/R weight bias is a bit different.

“My STI with me in it weighed 3294 last time I corner balanced it. I weighed probably about 160 which means the car was 3134. I was able to get it to get a 50/50 cross balance fairly easily with me in the car. We ended up with LF- 997, RF- 958, LR-690, RR-649. I think after I set the ride height we had to adjust the RR spring perch like half a turn so we got really lucky. My ride heights were lower than most people at 13.5″ front and 13″ rear.”

It’s good to see that the overall % isn’t changed too much. I normally suggest people get corner balanced at the fuel load they plan on competing with most often. This shows that you could get balanced with 1/2 tank and be pretty well balanced with 1/4 or full.

We are kind of stating the obvious here, but its still some fun data. The key is still to get corner balanced once you put on a new coilover suspension.

-Drew

Big thanks to Dan and the guys at Flat Out Racing

No offense to alignment techs, but 90% go for the easy way out when it comes to setting up your alignment. Especially when you’re on an upgraded suspension.

For example,

It’s 1000x easier to adjust camber plates to get equal camber left and right, this is a big no no and will negatively effect the handling of the vehicle.

In short the easiest way to make sure your car gets setup the best way possible you can do the following, or make sure the alignment tech does your alignment as follows.

The process really depends on your setup, but here is a few basics to getting your alignment right, the first time.

Subaru Impreza with Stock or Lowering Springs and Stock or Grp N. Top Hats.

Front

1.) Adjust Camber eccentric bolt (Upper bolt that attaches strut to the spindle) so camber is maximized but equal left to right.

2.) Adjust Toe to be Zero left and right

Rear

1.) Adjust Toe eccentric to be Zero left and right

Subaru Impreza with Stock or Lowering Springs and Stock or Grp N. Top Hats and Aftermarket Camber Bolts Front and Rear.

Front

1.) Install Camber Bolt in lower bolt and make sure it’s aligned for negative camber (tab inward).

2.) While on the alignment rack able to see the adjustments. Adjust both Camber eccentric bolts. First adjust the lower camber bolt to around -1.5, then use the upper camber bolt to fine tune to -1.8 or so. Make sure camber is maximized to where you want it but equal left to right.

3.) Adjust Toe to be Zero left and right

Rear

1.) Install Camber Bolt in upper bolt and make sure it’s aligned for negative camber (tab inward).

2.) While on the alignment rack able to see the adjustments. Adjust new Camber eccentric bolts. Use the upper camber bolt to fine tune to -1.8 or so. Make sure camber is maximized to where you want it but equal left to right.

3.) Adjust Toe to be Zero left and right

Subaru Impreza with Lowering Springs and Front Camber Plates.

Front

1.) Adjust Camber Plates equally negative (inward), good starting point for street use is 1/2 way between the middle (0) hash mark and full negative (inward). (Camber #s according to the alignment rack will not have to match, the plates need to match).

2.) Adjust Camber eccentric bolt until camber left and right matches. Try and achieve maximum negative camber you’re comfortable with. I prefer a -1.7 or so front camber for a street driven Subaru Impreza.

3.) Adjust Toe eccentric to be Zero left and right.

Rear

1.) Adjust toe eccentric to be Zero left and right

Subaru Impreza with Coilovers and Front and Rear Camber Plates.

Car As A Whole
1.) Adjust ride height to where you want it. Good starting point 14.25″ Front and 14″ Rear (measured from center of hub to fender).

2.) Corner Weight the car by adjusting ride height and using scales.

Front
1.) Adjust Camber Plates equally negative (inward), good starting point for street use is 1/2 way between the middle (0) hash mark and full negative (inward). (Camber #s according to the alignment rack will not have to match, the plates need to match).

2.) Adjust Camber eccentric bolt until camber left and right matches. Try and achieve maximum negative camber you’re comfortable with. I prefer a -1.7 or so front camber for a street driven Subaru Impreza.

3.) Adjust Toe eccentric to be Zero left and right.

Rear

*if rear camber plates are non existent, skip step 1

**if rear camber eccentric bolts are non existent, skip step 2

1.) Adjust Camber Plates equally negative (inward).

2.) Adjust Camber eccentric bolt until camber left and right matches. A good baseline is -1.5.

3.) Adjust toe eccentric to be Zero left and right.

If you’ve got a specific setup that you’ve got questions about starting points for ride height and camber don’t hesitate to comment or email.