02 Impreza 2.5 rs.. need some class help/question about cold

[izaakjordan]

I have a Impreza 2.5rs, 2002. I have now been kicked from SI and need to find a permanent home. The only problem is the misunderstanding about a cold air intake.

Aparently, from combing every autocross rules set and the scca rules, cold air intakes seem to be allowed in street prepared. However when i first stared i asked about this and was told verbatim:

"intake manifold.. That puts you in SM"

I didn't know any better at the time (being my first race, i was not at all familiar with the classes) I would really like to go to DSP which is where i think my car fits, and would not like being in SM very much.

but my main point is : a cold air intake is NOT the intake manifold, and mine retains the stock airbox and filter. it essentially only replaces five feet of plastic tubing, and goes into the fender rather than in the engine cabinet. the only rules i could really find were about intake manifolds, which would be an SM feature. considering that stuff like flywheels and pulleys are allowed in this class i find it really hard to believe that my intake wouldn't be.

can anyone give me some insight, or an official statement? cold air intakes are very common modifications and i feel like the rules aren't exactly clear regarding them. Especially ones that dont replace the stock airbox and dont go to directly into the throttle body

Also my other mods include

17 in wheels
Front strut tower brace
eibach srings
falken azenis'
cat back (legal in all classes)
race pedals

That is all. Thanks for the help.

-Zak

[73GT]

Zak

STS (if your rims are no wider than 7 inch) or SP take your pick
STS would probably be a better class with Azenis plus larger class participation locally
SP allows dot race radials which would put you at a disadvantage. Look at past event scores before you decide. I don't know who told you a cold air would put you in SM even with a intake mod you'd still be in SP. I wasn't teching at Mowog 5 as I was the event master.



73GT
Chief of Tech

[MNbiker]

Zak,

Your car should be classed in STS. Your car is a perfect fit for the class.

Additional key STS allowed modifications:

7.5" maximum wheel width
225mm maximum tire width, 140 or greater wear rating
fenders may be rolled for tire clearance
lightweight/underdrive pulleys are allowed
springs/struts/anti-swaybars/strut tower bars are allowed
camber plates/bolts allowed (this is HUGE for Subarus)
air/fuel/timing piggyback controllers or reflashed ECU allowed
Intake, up to throttle body or carb
A/C may be removed
headers, cat back exhaust (cats must remain in place)
engine mounts, suspension bushings
brake lines, rotors (stock diameter), brake pads

Note: clutch/flywheel or differential changes are NOT allowed in STS.

-Steve Garnjobst
Met Council Rules Chair

[StevenMosley]

STS would be perfect for your car. Impreza's were the orginal dominant car in STS
until the 88 Civic Si's became the car to have.

[MattD]

Imprezas can only be dominant in STS if there isn't a Mosley driving an SE-R that day. ;)

[phile]

Originally posted by izaakjordan

"intake manifold.. That puts you in SM"

-Zak


Not unless you want to go there. In Street Prepared rules, the intake is unrestricted all the way from the back of the grill to the plane of the cylinder head and you can use the first inch of the cylinder head for port matching. The only exception is that supercharging equipment of any type may not be modified (no mods to turbo vanes, supercharger pulleys, wastegates, computer controls, the whole enchilada) . The intercooler can be modified, though.

[izaakjordan]

ok so an addendum.

Right now I have sitting on my floor the OEM body kit front lip and side skirts, sent from langston subaru in CT. I am wondering what the rules are on this. I don't want a class bump by putting on what is basically a piece of dress up, and I know that some of the imprezas come with the side skirts as stock, and the front lip is a factory version.

What do the rules say on this, o enlightened ones?

here is the front lip:http://www.langstonspeed.com/images/th_Stifrontunderspoiler.jpg

Here are the side skirts (mine dont have the strakes) http://www.langstonspeed.com/images/th_STIsidespoiler.jpg

-Zak

[StevenMosley]

I'm not sure what the rules state, but if you came out and told everyone that you had those items I'm sure nobody would would punt you out of the STS class. If you would have never said anything, nobody would have even noticed that you had done anything.

Matt, I hate that Datsun. It just goes no matter how bad you treat it. It is just plan sick.

[izaakjordan]

Originally posted by StevenMosley


I'm not sure what the rules state, but if you came out and told everyone that you had those items I'm sure nobody would would punt you out of the STS class. If you would have never said anything, nobody would have even noticed that you had done anything.


yeah, i was pretty sure nobody would have noticed the body kit since it's so subtle, but I want to do everything on the up and up at the same time.I didnt want to have anyone call me out on it, and i wanted to make som permanent numbers, becuase once i find a class, i want to stay there for a while. Where can i get official clearance for my kit so that i'm sure everything is kosher?

I mean, if anything it just adds weight, which is a disadvantage, right?:sarc

[izaakjordan]

Originally posted by MNbiker



camber plates/bolts allowed (this is HUGE for Subarus)


can you explain this a bit more? I have a bit of negative camber in the rear, but how would camber changes make huge differences for me?

[MNbiker]

Zak,

Bodykit - The pices you have are 100% legal for STS. Basically, the rules allow you to add most any bodykit - you just can't REMOVE any stock parts. Hence, no carbon fiber hood, aluminum trunk, replacement fenders, etc.

Camber for Subarus - The stock front camber bolts only give you a bit over -1 degree of camber. Due to the suspension design, Imprezas tend to lose camber under hard cornering. As a result, camber goes positive, cornering suffers and tires get abused. Imprezas are also a bit caster challenged. Therefore, a set of caster/camber plates in front will do wonders for cornering performance. As for the rear, you probably won't want more camber. Most serious Impreza autocrossers actually add camber adjustment to reduce rear camber. Talk to me at an event, and I can give you a lot more detail on this issue & Impreza autocross setup, in general.

-Steve

[izaakjordan]

Already returned my CF hood. It was on order. I figure it didnt look that great anyways...

and popping my hood between runs did do the trick for heat management this time.

I get what your saying about front camber. I do notice the tires losing camber in turns to the degree that it screwing up my tires. It causes the sidewalls to fold sometimes, which puts me off my line, which costs me a few seconds. Although for some reason all I really was used to hearing people talk about vis a vis camber was negative rear camber, but from memories of problems during runs you've hit the nail on the head.

another 2.5 rs autocrosser suggested these things. keep in mind almost every piece of advice i get if for GC8 imprezas and not the new era versions, but i consider them to be very approximate, except the overall structural rigidity of my car's unibody is about 190% stiffer. well anyways they suggested slotted or drilled rear rotors to change the brake bias, and front endlinks, but not changing the front swaybar. ajustable rear sway has been suggested a lot too, and i'm showing up at the next race with one, but wondering whether or not to bother futzing with the endlinks now (it's an easy, cheap mod, but i dunno how worth it it will be without replacing the swaybar)

I appreciate the advice. this is really the first time i've ever set up a car with a purpose, before it was just to add mods i liked (makes it go faster/look better) but suspension stuff is best taken on advice when lacking experience, especially for this kind of application.

well, at least my STi driving friend cheered when i told him i was returning the CF hood. he said it was "too rice" for him. This is from a guy who has a three foot tall spoiler stock :sarc

[MNbiker]

Originally posted by izaakjordan
well anyways they suggested slotted or drilled rear rotors to change the brake bias

Total waste of money. Imprezas are overly front-biased, and shifting some braking to the rear will help a bit. However, slotted/drilled rotors WILL NOT change brake bias. One relatively inexpensive way to increase rear bias by apprx. 10% is to install larger Legacy H6 rotors in the rear, along with the Legacy caliper brackets. However, larger rotors are illegal for STS. You could accomplish the same thing by using a rear brake pad with a higher friction coefficient.


Originally posted by izaakjordan
front endlinks, but not changing the front swaybar. ajustable rear sway has been suggested a lot too, and i'm showing up at the next race with one, but wondering whether or not to bother futzing with the endlinks now (it's an easy, cheap mod, but i dunno how worth it it will be without replacing the swaybar)
The endlinks will help make the effects of your swaybars more immediate and more linear, but the benefits are subtle. Anti-swaybars, on the other hand, will make a big difference - especially on a car with reasonably soft springs. I'd recommend getting both front & rear bars. The front bar will help with initial turn-in (you'll immediately notice the benefits for slaloms & other quick transitions). Counter to conventional wisdom, the larger front bar will also REDUCE understeer in most situations, as it will help reduce camber loss on the Impreza's front suspension. A rear anti-swaybar is a good idea - it will further reduce body roll, and will help you get the tail of the car around. Definitely go adjustable for the rear bar.

-Steve

[izaakjordan]

Thank you so much for the advicce. The cusco sways have just been ordered, and I suppose i might as well throw in a full set of endlinks and do those too while i'm changing the sways. Ugh. Why must cusco stuff cost so much!?!? I have heard whitline stuff is good as well, it's certainly much cheaper, but the rear sway isnt adjustable, and i'd rather go with a mathcing set manufacturer wise.

I mentioned the exact same thing about the brake rotors (i know a couple people with back legacy rotors) and the guys wore to me drilled would change the bias. I told him it would just probably eat my brake pads a little faster. Eh, I dont like the look of drilled or slotted rotors anyways. A pad upgrade does seem sensible though.

[MNbiker]

Originally posted by izaakjordan
the guys wore to me drilled would change the bias. I told him it would just probably eat my brake pads a little faster. Eh, I dont like the look of drilled or slotted rotors anyways. A pad upgrade does seem sensible though.

Drilled rotors will change brake bias a little bit, but not in a very useful manner. A rotor with holes in it will have marginally less braking surface than one without holes. If you were to put drilled rotors on the front only, you could conceivably shift brake bias to the rear a little bit. However, drilled rotors wear your pads faster and are more prone to cracking.

-Steve

[phile]

Originally posted by izaakjordan


Thank you so much for the advicce. The cusco sways have just been ordered, and I suppose i might as well throw in a full set of endlinks and do those too while i'm changing the sways. Ugh. Why must cusco stuff cost so much!?!? I have heard whitline stuff is good as well, it's certainly much cheaper, but the rear sway isnt adjustable, and i'd rather go with a mathcing set manufacturer wise.

I mentioned the exact same thing about the brake rotors (i know a couple people with back legacy rotors) and the guys wore to me drilled would change the bias. I told him it would just probably eat my brake pads a little faster. Eh, I dont like the look of drilled or slotted rotors anyways. A pad upgrade does seem sensible though.

Adjustable bars are a good thing. I had an adjustable on the rear of my Midget and I was always tuning it to walk the line between wheelspin and understeer. Event the same lot would be different on different days.

There is a trick you do to change brake bias, and it's legal in stock. Pads are unrestricted, so you can mill out some of the pad material. Don't breathe the dust...

Changing to different pad material at one end could be tricky, since the pads could react differently to temperature changes and your bias would change during the warmup in greater and more unexpected ways than normal.