2012 BRZ/FR-S Stock Class Autocross Discussion

[Scooby South]

I have never been one to race in stock class... just not in my nature... but If I were to compete in Stock class.. Here would be my take:

-Koni's with stock springs... Depending on what spring rate the FRS has Vs. BRZ I might change the springs out to one or the other.

-17x7 Light as possible wheel... maybe the Kosei with a 50 with a 5mm spacer to bring the tire back out away from the strut.

-not sure if 245 A6's will fit due to them running wide...might go with a Goodyear if that were the case.

-Swaybars are gray area right now on this vehicle.. have to wait and see the data.

-Lightweight Exhaust or my personal favorite is the JW2 Exhaust Turn-down..that completely eliminates the muffler... weight saved = about 40 pounds.

-Lightweight battery

-start with a base model FRS for weight savings..since weight is enemy in stock classes.

-crash bolts for front Camber if they become available.

-performance alignment...would definitely have to tinker with that to get optimum balance/turn-in/predictable agility

that would get me started..

Bill

[Draco-REX]

The damper rule has a loophole in it the size of a hangar door. You're allowed only two usable adjustments. Adjustments to damper's gas portion are not counted, and any hydraulic adujstments above two just need to be glued in place. So if you want to spend a crap-ton of money on dampers you can. Just put a dollop of a silicone sealer on the least used adjustments before you bring the car to tech.

[Sccabrz192]

Originally Posted by Scooby South

I have never been one to race in stock class... just not in my nature... but If I were to compete in Stock class.. Here would be my take:

-Koni's with stock springs... Depending on what spring rate the FRS has Vs. BRZ I might change the springs out to one or the other.

-17x7 Light as possible wheel... maybe the Kosei with a 50 with a 5mm spacer to bring the tire back out away from the strut.

-not sure if 245 A6's will fit due to them running wide...might go with a Goodyear if that were the case.

-Swaybars are gray area right now on this vehicle.. have to wait and see the data.

-Lightweight Exhaust or my personal favorite is the JW2 Exhaust Turn-down..that completely eliminates the muffler... weight saved = about 40 pounds.

-Lightweight battery

-start with a base model FRS for weight savings..since weight is enemy in stock classes.

-crash bolts for front Camber if they become available.

-performance alignment...would definitely have to tinker with that to get optimum balance/turn-in/predictable agility

that would get me started..

Bill

you wont be able to spring-swap in stock class. It has to be available from the manufacturer as an available package for the specific model of car you have.

Also I dont have my hopes up for a TSB from subaru for crash bolts. Its not something they typically do afaik. Technically the lame part of it all, if toyota offers them and releases a tsb and subaru doesnt, you will only be able to use crash bolts on the frs.

Last comment, you will want a smaller offset, positive offset puts the hub outboard of wheel center which drives the wheel more under the car. A +42 total offset will likely be optimal for stock class to get the most tire without rubbing the strut

[Dark_Angle]

Originally Posted by Scooby South

I have never been one to race in stock class... just not in my nature... but If I were to compete in Stock class.. Here would be my take:

-Koni's with stock springs... Depending on what spring rate the FRS has Vs. BRZ I might change the springs out to one or the other.

-17x7 Light as possible wheel... maybe the Kosei with a 50 with a 5mm spacer to bring the tire back out away from the strut.

-not sure if 245 A6's will fit due to them running wide...might go with a Goodyear if that were the case.

-Swaybars are gray area right now on this vehicle.. have to wait and see the data.

-Lightweight Exhaust or my personal favorite is the JW2 Exhaust Turn-down..that completely eliminates the muffler... weight saved = about 40 pounds.

-Lightweight battery

-start with a base model FRS for weight savings..since weight is enemy in stock classes.

-crash bolts for front Camber if they become available.

-performance alignment...would definitely have to tinker with that to get optimum balance/turn-in/predictable agility

that would get me started..

Bill

So this is all stock legal?

[Sccabrz192]

Lightweight battery would also technically be protestable because blatant weight reduction is against the stock rules

[Dark_Angle]

Originally Posted by Sccabrz192

you wont be able to spring-swap in stock class. It has to be available from the manufacturer as an available package for the specific model of car you have.

Also I dont have my hopes up for a TSB from subaru for crash bolts. Its not something they typically do afaik. Technically the lame part of it all, if toyota offers them and releases a tsb and subaru doesnt, you will only be able to use crash bolts on the frs.

Last comment, you will want a smaller offset, positive offset puts the hub outboard of wheel center which drives the wheel more under the car. A +42 total offset will likely be optimal for stock class to get the most tire without rubbing the strut

Does this exclude TRD items? They are specific for these cars from toyota.

[Sccabrz192]

Any performance related accessory, even if it is sold from the dealership which is not original equipment as part of an option or trim package is illegal unless it meets the modification guidelines. This includes TRD accessories.

Examples:
Legal: Trd front swaybar (provided you dont install a trd rear swaybar and vise versa.)

Illegal: dealer installed TRD springs. Unless Scion offers a TRD performance variant of the car as an option code. It that case you would need every piece of that equipment package. If the option package came with different seats and springs, you couldnt install the springs without the seats.

[Dark_Angle]

So removing the exhaust and adding the shorty pipe is probably a no no.

[EMguy]

Originally Posted by Draco-REX

The damper rule has a loophole in it the size of a hangar door. You're allowed only two usable adjustments. Adjustments to damper's gas portion are not counted, and any hydraulic adujstments above two just need to be glued in place. So if you want to spend a crap-ton of money on dampers you can. Just put a dollop of a silicone sealer on the least used adjustments before you bring the car to tech.

The rules reads as this:


No more than two separate external shock damping adjustment controls are allowed. This permits the use of shocks which originally came with more than two external adjustments, which have been converted to double-adjustables, only if the additional adjustment controls have been permanently disabled (e.g. via weld-ing, epoxying, grinding off). Gas pressure adjustment is not con-sidered a damping adjustment.


The key is "permanently disabled." I don't think a dab of silicone or glue counts. Moreover, I doubt you'll find many competitors trying to find an excuse to spend more money on triple adjustable, stock class legal shocks. The sipirit of the rule is a cost containment measure.

You're right about the gas pressure adjustment though: tuning gas pressure is one way of working around OEM spring rates.

[jdrxb9]

Originally Posted by Sccabrz192

Lightweight battery would also technically be protestable because blatant weight reduction is against the stock rules

Battery replacement is covered on p71 of the rules - helpfully linked by the OP:

Alternate components which are normally expendable and considered
replacement parts (e.g., engine and wheel bearings, seals, gaskets,
filters, belts, bolts, bulbs, batteries, brake rotors, clutch discs, pressure
plates, suspension bushings, drivetrain mounts, fenders, trim pieces,
etc.) may be used provided they are essentially identical to the standard
parts (e.g. have the same type, size, hardness, weight, material etc.),
are used in the same location, and provide no performance benefit.

[Sccabrz192]

If its after the cat its legal per the exhaust allowance if it replaces or removes or is in front of the cat, yes it is illegal. I am not aware of the part you are referring to so im not 100% what it does.

[EMguy]

Originally Posted by Dark_Angle

So removing the exhaust and adding the shorty pipe is probably a no no.

That depends. You can do anything you want to the exhaust downstream of the catalytic converter. It's common to replace everything from that point on with a turn down pipe. The benefit is not power, but weight.

Since last year, there is an additional rule for national (and some local) events that cars must also pass sound requirements. This is <100 db at 50 ft. It's usually tested at an area of WOT.

In a stock car, with cats in place, I don't think there will be any problem passing sound just a turn down. Personally, I'll be looking for the lightest, single exit cat-back I can find.

[Dark_Angle]

I will probably leave it all alone because changing weight will change the handling characteristics of the car.

[jdrxb9]

Originally Posted by Sccabrz192

you wont be able to spring-swap in stock class. It has to be available from the manufacturer as an available package for the specific model of car you have.

Also I dont have my hopes up for a TSB from subaru for crash bolts. Its not something they typically do afaik. Technically the lame part of it all, if toyota offers them and releases a tsb and subaru doesnt, you will only be able to use crash bolts on the frs.

Last comment, you will want a smaller offset, positive offset puts the hub outboard of wheel center which drives the wheel more under the car. A +42 total offset will likely be optimal for stock class to get the most tire without rubbing the strut

I'll be surprised if we see a TSB from Toyota because: AFAIK they've been putting the alignment/crash bolt info in the FSM for a while now; the FR-S manual shows the procedure with only one alternate bolt (which is actually the lower bolt used in the upper position instead of the normal upper bolt); the bolts do not have part numbers anything like the normal Toyota alignment/crash bolts. (link,link)

Since I'm pretty sure I'm getting a BRZ, I'm hoping we 1) don't need much static camber due to low roll, and 2) I'm right about no FR-S TSB