Hi all,

Just picked up an 04 AP2 a few weeks ago...




I am in the process of setting up my car for B Street and was wondering what your advice is on a few things. I recently did my first autocross in this chassis and LOVED it. I have done a handfull of events in other cars in the past but this was my first time in this chassis. Really really love how it feels in stock form but I'd like to do a few things to the car to help me become more competitive. Will probably do a couple track days per year as well.




My mods thus far are:
Tanabe Medalion Touring Catback
Eibach Adjustable Front Swaybar
Cosworth High Flow Intake Filter
ALL fluids are Motul

Current tires are:
Continue Extreme Contact DW OEM sizes (F215/45/17 and R245/40/17) good for rain but not much else

Now I am already aware that this catback exhaust is not optimal (titanium single exit seems to make the most sense for weight reduction) but I almost got it for free... and I don't have much $ for parts so it is what I'm stuck with for a while.

And I also got an amazing deal on an Eibach adjustable front swaybar, so that is what I'll be using. I hear that the gendron, moddiction, etc. sways are good middle of the road bars but I can't afford them.

Now I am getting ready to upgrade my pads, rotors and tires. What do you guys think?

I am looking at:
Hawk Street-Race Pads
Adam's Rotors G4000 Slotted rotors
Bridgestone RE71R's

What size tires should I be running on my AP2 V1 wheels? 225/45 F and 255/40 R ?

Should my alignment specs be max negative camber front and rear, 0 front and rear toe, 6.0 caster?

Also, should I have the sway bar in position 1 or position 2?

Here are the Eibach specs:

Front: 32mm Adjustable (HOLLOW)
Pos.1 - 65 N/mm (368lbs/in)
Pos.2 - 73 N/mm (416lbs/in)
Weight - 4.8kg (10.6lbs.)

I just want to make sure I am going in the right direction here...any suggestions???

 

Sway and Catback

 

I wouldn't call the Gendron a middle of the road bar, as far as I can tell it and the Karcepts bar are on the high end bars available for the car.

I would recommend if you really want to be competitive in BS

Alignment, and better tires. I think I've seen people running 245s up front and 255s in the rear. I would search that a little more before buying tires.

All the fast guys have big front sway bars and hi end dampeners. I would say the more important thing is the bar... I run a Karcepts lots run Gendron... I can't speak for small fortune racing, but Karcepts is the single best customer service and buying experience I have ever received. I'm also really happy with the bar.

Hope this helps a little... Oh and the exhaust makes absolutely no difference without a tune, and I don't know if tuning is BS legal.

 

It isn't so much the power gains as reduced weight. The stock system is practically made out of lead, a decent aftermarket custom system can save 30 pounds, with titanium singles shaving 40+. And no, tuning isn't legal for BS.

 

I don't think the rotors will be legal, and doubt the brake pads will make that big of a difference.

You need tires. RE71r is this year's tire. The rear will be 255/40. The question is what front size to use. I have 225/45. Others have 245/40. I think there are some 245/45s and in A/Street 255/40, although I don't know if anyone has made that work in B/Street. I've been thinking 245/45 square may be an interesting setup. It would raise the car 1/2 inch.

The question is: is your current front bar enough. It seems similar to the Moddiction (formerly Saner) bar. I have the Karcepts. But the people using Karcepts and Gendron bars aren't using the stiffest settings. I think the Karcepts bar is very well designed with a very unique adjustment concept.

I'd leave the shocks alone unless they are bad. The top 2 Street S2000s at the 2014 National Championship were on OEM shocks and I don't think anyone has presented a conclusively better autocross shock. Note that nearly any monotube can be revalved (at least if it has a Schrader valve on the nitrogen). We just don't know what the valving should be.

Last, data acquisition including video. You need to see what you are doing to find the weaknesses...where time can be made up. SoloStorm, a 10Hz or faster GPS, and a GoPro seem to be the minimum. The SoloStorm uses an Android phone so you will need one of those...or a tablet...and an in car mount.

Most of your speed will come from tuning control unit between the seat and the wheel.

 

Ditch the Eibach bar and get, at least, the Saner (Moddiction) which is actually quite stiff.

 

You'll probably want the eibach bar on full stiff.

You can only do oem replacement rotors, no different sizes or slotting/drilling. I like centric premium, they're high quality stock legal rotors.

You want at least a small amount of rear toe. How much is arguable, but you want at least 1/16" or so if not more.

Other than that it all sounds good. Top priority is tires for sure. The exhaust isn't a big deal at all, all the weight's down low and you don't get any power from it.

 

There is power to be gained (or lost) in the cat back but as mentioned above the main gain in swapping systems is the weight savings

We documented a 7-8 hp swing between systems:

https://youtu.be/hkW4-iEHj0c

 

Nice video...but you left off what the third system was!

Those are still relatively small power gains...about 1%. I wonder if the ECU had enough time to adapt. Did you reset the the ECU before the runs?

Note that AP2v2 will be different than AP2v1...in addition to DBW, there is no air pump, the intake manifold has a larger inlet (69mm vs 64mm) and it has a larger throttle body (65mm vs 62mm).

BTW, are you having success with the 225 front with the RE71r? The jury seems to be out on whether 225/45, 245/40, 255/40, or 245/45 is the best front option. I went with the 225 but I'm not fast enough to use as a reference.

 

Ok so slotted rotors are not permitted?

And for front tire, should I just go 225/45? Def going to get the RE71R's

I'll set the FSB to full stiff

Anyone use Harry's Lap Timer Autocross setting?