track season back seat

B8 S4
#1

From now until May, the S4 is only going from my parking spot to the track (or the shop). I didn’t want to completely remove the back seats but I don’t really need them either. There’s airbag sensors in the seat backings, so you can’t remove them anyway without lighting up the dash. It turns out the pass through / arm rest weighs 16.5 pounds, and the rear foam bench weighs 14.5 pounds. They both can be removed (and replaced) in about 5 minutes. So those are in the garage. Then I took the OE trunk floor and used that to separate the cabin.

More importantly, when the rear bench is out the seats fold flatter and the passenger seat can be reclined and slid back further. This moves the weight where I want it, low and in the center of the car. Technically someone could sit behind the driver for a short trip with a seatbelt where the backrest 1/3 split is, but on a hard bottom.

I estimate my weight with 1/4 tank of gas is 3680 pounds. We’ll find out when I corner balance it. This is based on my previous weighing of the car, minus recent mods. I’ve dumped just under 200 pounds from how Audi delivered the car to me.

http://i58.tinypic.com/rcr3a8.jpg

http://i61.tinypic.com/5lx6ja.jpg

http://i62.tinypic.com/dnhmy8.jpg

#2

Wonder how much the front seats weight, I’m sure they are tanks.

#3

86 pounds, allegedly. But they’re so comfortable and stylish, it’d be crazy to replace them. That RS5 Sport limited edition charges $87,000 to have this exact interior in the A5 chassis. The airbag lights make seat replacement a non starter.

#4

You also get a widebody, brembos, 20" wheels, improved everything, and a 4.2 fsi with forged internals that revs to 8500 rpm for that money.

#5

how well is that trunk board secured? seems like if you brake really hard its going to come flying forward.

#6

I’ll remove it on track, but it’s folded in the seat about 5". It’s not going anywhere even if something in the trunk hits it. You need trunk privacy in a city or someone will break into your car, just to rifle through a gym bag with nothing in it.

#7

This setup is really nice for funneling a lot of exhaust noise into the cabin. All of the exposed steel surface in the trunk really sends a lot of sound forward. I think the loud sound effect I’m getting is also due to the placement of the [Milltek] center muffler directly under the rear passenger seat. Without the foam bench on top of it, it fills the cabin with awesome.

http://i62.tinypic.com/2ai323k.jpg

#8

That back seat really keep some of the noise out. You don’t realize it till you move the seat.

I think with a 5 amp resistor you can remove the rear air bags. And the other part of the seat. Also to cut down on the noise try putting two foam strips in the wheel well. Make sure the go from the hub to the wall in found that helps to

#9

For motorsports I like the sound because you have a helmet on, which is kind of desensitizing.

The B8 has a lot of foam and padding in rear wheel wells, about 3/4 inch thick synthetic wool-like material. If you open the access compartments in the trunk you can feel it. I imagine that mostly cuts down on tire and suspension noise, which is a good thing.

#10

I didn’t think about having a helmet on and how actually getting more noise and feedback from the car would help. That actually makes good sense.

#11

Are you planning to corner balance at this weight and then again in the wpring with everything back in?

#12

Corner balance is tomorrow. Honestly Audi’s factory cross weight was pretty damn close. My ride height hasn’t changed much with the JRZ RS1 suspension and new springs (5mm lower) so the camber is actually the same at -2.6 front and -2.2 rear. The whole alignment job should just be about achieving caster over 6 degrees, and dialing a small amount of toe-out in front (-1/32 per side) and toe-in at rear (1/32 per side).

My variable weight here is only 31 pounds in between the axles. It’s within the margin of a partial tank of fuel.

In previous years I’d balanced it for myself and a 160 pound instructor; lately I’ve been riding solo even when I’m instructing and can take students or passengers (none waiting at the grid). So I’ll balance it for just me, and set the swaybar preload to zero at that weight.