SCCA Solo C Street Discussion
 

A few of us running C Street currently and it seems a few more are interested. Just thought I'd start a thread we can update with information.

What is C Street?

C Street is a stock based classed for low to medium power cars that are upper-lightweight. Main competitors are the 370z, 350z, RX-8, twins and non-MSR MX-5.

Modifications

This class has limited modifications. You can modify/add:

*Any exhaust behind the last Catalytic converter (Aka you can add an Catback or Axleback exhaust). It must be full length, reach the rear bumper
*Any drop-in filter (you cannot change the intake or modify the airbox or intake tube)
*Any shocks/struts that mount up as stock replacements (though you can currently have external reservoirs).
Change, replace or remove ONE sway bar. One of the two bars must remain *OEM and attached though it is your choice of which one to modify (though a front bar is the only one that makes sense for this car)
*OEM Crash/Camber Bolts. These allow you to add a small amount of front camber. Some cars vary in the amount of camber you can gain. I reached -1.4 while some people could not pass -0.8 and others saw -1.5. Get an alignment after install!. This is likely to throw the Toe off in your front end. Large tire wear, pulling to one side or poor handling can occur from this. OEM part numbers are as follows:
Toyota: SU003-02818
Subaru: 901000394
*Any brake pad you want
*Any fluids you want (brake, oil, coolant, transmission, differential)
*Stock sized wheels within 6mm offset. This means 17x7 with an offset between +42 and +54. Spacers to count for offset reduction. Example, with a +48 offset wheel (such as stock), you can throw on a 5mm spacer (never use bigger than 5mm on our stock studs!) and have an effective offset of +43 and be legal but you cannot use a +42 wheel and use a 3mm spacer. That would equal +39 which is too low of an offset.
*Tires. This is the biggie. You can use a 140 treadwear or higher tire in this class. This only rules out RCompound tires.

Common Upgrade Parts

This will be a non-comprehensive list, meant to give you guys an idea of what the more popular parts are for the major modifications for C Street

Tires

This is the key to this class (as any autocross class). The competitive tires in this class are Hankook RS3, Dunlop Starspec Z1, Dunlop Z2, BFG Rival, Bridgestone Potenza RE11 and RE11A, Toyo R1R. There are others but that covers 98% of street tire SCCA cars. Different conditions and driving styles call for different tires. Please do not ask "What tire is best?" as there is no one answer. The short answer is the three top tires are the Rival, Z2 and RS3 but each one is better for different drivers and different conditions. And other tires can be competitive, those three are just the most popular for a majority of the faster drivers.

Front Sway Bars
These will reduce oversteer and give a more planted front end feel to the car. Different bars are preferred by different people and different setups. These are the most common bars I see around the RTR world.
Strano 22mm Hollow - 85% stiffer than stock
Hotchkis 25mm Hollow adjustable - 180% or 245% stiffer than stock
Whiteline 22mm Solid adjustable - 118.5% or 174% stiffer than stock
Cusco 20mm - I know little about this bar. Will add more when I get information
Whiteline 20mm - Unknown stiffness

You can also add aftermarket endlinks to the front bars to provide additional stiffness and adjustability.

Air filter
Air filters are mostly the same in that no one will make huge gains over another, despite the claims. Just know that there are two kinds; oiled and dry. Oiled tend to let slightly more air through and thus slightly more powerful (but negligible amount). However, many people believe that the oiled filters can lead to damaged MAFs after a while (I myself am in this camp and use Dry because of this). I won't list individual companies here so just look for dry or oiled air filters for sale from your favorite vendor.

Shocks/Struts
There are two big choices at the time on writing. Koni Sport/Yellow at $600-800 a set (which require you to cut up your front struts and insert new cartridges) or MCS at $3000-4500 a set. MCS is obviously expensive and at ~$3000 gives you single Rebound adjustment, as the Konis do or at ~$4200 MCS give you Rebound and Compression adjustment (as well as an external reservoir).

Konis are what most people are using due to the cost and they are working well. There are many people who believe trick shocks just don't provide enough value during your autocross runs. But then again, many do. Do your own research and make your own decisions.

Throughout this thread, hopefully there will be shock setting discussion to help all of us learn, especially those of us trying to tune these Konis in still.

Wheels

With any 17" wheel with a width of 7" and an offset of +42 through +54 legal, you now have a handful of choices. As I cannot list all of these without a huge thread just for it, I suggest you check out @DarrenDriven's EXCELLENT wheel thread over here. Darren spent countless hours listing every known wheel for our cars. Go there and do a search in your browser (CTRL+F) for 17x7.0 to browse through your options

I will put that the most popular options is the Enkei RPF-1 as it is decently priced and very durable while being one of the lightest options.

Shock/Strut/Sway Bar Tuning

These are not gospel but just a general rule of thumb to get you started.

Corner entry over steer: Soften rear rebound
Corner entry under steer: Stiffen rear rebound
Corner exit over steer: Stiffen front rebound
Corner exit under steer: Soften front rebound
Mid corner over steer: Stiffen front bar
Mid corner under steer: Soften front bar

RTR Build Threads/Progress Logs
@Kido1986 - http://www.ft86club.com/forums/showthread.php?t=31456
@TRev - http://www.ft86club.com/forums/showthread.php?t=33074
@trippinbillies40 - http://www.ft86club.com/forums/showthread.php?t=34493
@DylanFRS - http://www.ft86club.com/forums/showt...444#post919444
@Dezoris - http://www.ft86club.com/forums/showp...45&postcount=5



More to come...
I am at work adding as I can. Anyone please throw up sections you'd like added to the first post and I'll make it happen

Reserved

Very helpful. I won't do a build thread, but with such a limited amount of prep allowed, it might help to list the options available for each, and maybe even who has them:

Sway bars:
20mm Cusco (des)
20mm Whiteline (TRev)

It wouldn't hurt to include alignment, tires and wheels in the mix, either.

There's no point in repeating each others' mistakes, right?

I will just add my build to this thread:

Dezoris RTR AutoX Build Thread

Shocks: OEM
Front ARB: Strano (From Stranoparts)
Camber Correction Front: OEM Crash/Camber Bolts (Subaru)
Tires: 225/45/17 Hankook RS3s (Discount Tire)
Brakes: Project Mu HC800 (Vendor CSGMike)
Alignment: (Private)
FR (Camber -1.5 - Toe Out -.05)
FL (Camber -1.5 - Toe Out -.05)
RL (Camber -1.3 - Toe In -.08)
RR(Camber -1.3 - Toe In -.08)
AutoX Video: (Forward to 11m:19seconds)

[ame]http://youtu.be/rsWHuEUVK3k?t=11m9s[/ame]


Final Thoughts:
In all honesty if you are strapped for cash, I would not even consider doing more than this, as it is completely competitive in local clubs for 1-3rd place in class. I have had 4 events and so far its even good for competing with your STX competition. All you need is some seat time to improve.

The car feels excellent, on the street and autocross. Very impressed.
It's a setup I stand behind for daily driving and driving right to any event no drama. (Brake pads are totally optional as they made fractional difference for me in performance overall)

However I doubt this would be competitive on a national level but, I have yet to try.

I felt the build pages on this class were still good so you can list events and behaviors of particular changes. Let others get an idea of what setting changes have what effect.

I will be adding common parts sections for the mods later (most common FSBs, Shocks, Tires, wheels)

Yeah, I definitely like the idea of build threads to keep track of what the individuals are doing, This thread will be nice for us to do actual discussing of what we are thinking, comments, concerns, plans, etc so we aren't just constantly jacking the build threads with long discussions and this leaves a lot of the discussions in one places instead of 6 different threads.

Looking forward to this thread. :thanks:

Anyone making Nationals this year?

2014 in C(?) Street but not this year for me.

I will be at Nationals along with these events Lincoln Spring Nationals, Peru Match Tour, Milwaukee Match Tour, and Northern States Championship.

If I add something that is wrong, let me know. Of course I am doing my best to stay as neutral as possible but of course everyone has biases as well as I am not an expert mechanic nor expert on every part for this car.

I can and will make mistakes so help me keep the first post as topical and accurate as possible.

How are your tires lasting with that toe setup? I plan on running no toe as I need my tires to last.

May be a stupid question, but are the rears adjustable for camber?


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I have no issues with wear as that toe is still within factory spec.
With all my cars I run on the street and track I always setup slight toe out in the front as it improves turn in/steering feel.

Toe in on the back for braking stability.

I have done this on my Lotus, Atom and S2000 and have been very confident. There are benefits to zeroing toe in the rear on this car but not many for street driving aside from potential wear. As always this is driver dependent, but that's why I do it in short.

No only toe. Sucks big time.

With the multi-link rear there really shouldn't be any need to add significant camber to the rear anyway, the camber curve is not nearly as bad as with a Mac-Strut. Most people who need to adjust camber on the on rear are those who change ride heights, and that is more for camber correction than needing additional camber. Since stock doesn't allow it, I wouldn't consider it a disadvantage to the rest of the field... I can't recall any OE multilink rear suspension vehicles which come with an OE rear camber adjustment.

Andrew and Sam posted info on how to adjust rear toe through the subframe bushings if you find your car came from the factory with left to right toe imbalance.

For the forseeable future I'll be running RTR/Street. We'll see where it goes from there.

Thanks! So how were you able to do -1.3* of camber in the rear? Or does it come from factory that way?

Why would you adjust at the subframe bushing rather than just evening the toe out through the toe adjustment?

I think it's important to note that you can only use OEM Subaru or Toyota crash bolts. Dedicated camber bolts aren't allowed in stock class.

I said OEM. I plan on finding the part # later to post in the OP.

I wonder if he was mistaken and meant Camber? Since toe is easy to adjust on rear.

Toyota: SU003-02818
Subaru: 901000394

When you get a chance, please add Whiteline 20mm bar under the front sway bar section as well as adjustable end links.

Also maybe a shock/strut tuning section that includes this info?
Corner entry over steer: Soften rear rebound
Corner entry under steer: Stiffen rear rebound
Corner exit over steer: Stiffen front rebound
Corner exit under steer: Soften front rebound
Mid corner over steer: Stiffen front bar
Mid corner under steer: Soften front bar

Doh, got distracted while writing and lost my train-of-thought... (is that the proper spelling of train in that context? Oh well) yes I meant camber.

Yet... if street class passes it would become legal in 2014.

With that said, would anyone in Street be daring enough to use something like the Whiteline 14mm camber bolt? I don't think I'm going to be that brave. Not to use daily, especially in MI. I will probably just slot one of the strut bodies personally once that allowance is legal.

Is the 14mm Whiteline bolt the one with the adjustable cam lobe? Are you worried that the bolt will slip?

I have OEM crash bolts and camber top plates and can get more than -3.5 (estimate). Without the top plates, I was only able to get about -1.2 with just the OEM bolts.

If they leave the adjustable camber plate allowance in the proposed rules, I will definitely be going that route (caster).

Since our cars are currently allowed to use the factory adjustable camber bolt, do the proposed rules imply that we can use those bolts along with the camber plates?

Nice! Thanks for the information! :happy0180:

My concern is those bolts are smaller diameter than OE in order to offset the holes with the lobe so you are reducing the capability of the bolt in that joint when it comes to bolt shear and clamp load. I'll admit I'm being a little over cautious, but I'm not interesting in taking a chance of shearing off a strut bolt on my 28,000 vehicle because I was trying to get an extra .75 degrees of camber with a $40 dollar fastener. Michigan's roads are particularly what have me worried about it more-so than an autocross or track setting where most places are relatively smooth and your inputs are mostly mid and low frequency inputs.

which top plate are you using?

I was a bit weary about using the OEM crash bolts for the same reason but since they are factory approved I figure they must have a decent safety factor built in even on the smaller bolt.

I was planning to use these, which are the same as the ASTs according the posts in the thread. But supposedly they maintain stock ride height.

The Whitelines also look nice, here, but they don't say anything about whether or not they maintain stock ride height.

The factory recommended OEM crash bolts are also 14mm if I recall correctly. I'm not an engineer, but if Subaru engineers recommend using it, then I won't be arguing. :iono: If it helps, the bottom bolt doesn't have any play, and I think that bolt takes more punishment than the top bolt.

I'm using the top plates that were included in the Eibach R2 coilovers.

Any of you guys see the Street Tire comparison in the June issue of Grassroots? I just got mine in the mail yesterday and am looking through it a bit today at work.

I am kind of bothered that they didn't test the RS3 and that the test they did was on a STS prepped CRX. It sucks because last year when they did this tire comparo I had a ST Civic and they used a BMW. Now I have a car closer to the BMW and they did it on a car that is almost the same as the Civic... also, why no RS3s?!

I can scan in the article and post it up if anyone is interested and it isn't available online.

Please scan it, thanks!

Might be using this as my alignment setup as well.

re: the FR-S/BRZ crash bolts

the Twins come with two different sized bolts to hold the steering knuckle to the strut.
(14mm and 16mm?).

the factory authorized crash bolt is the 14mm bolt. all you are doing is replacing
the larger OEM bolt with the smaller one. so you end up with two 14mm bolts.

There should be no worries about the crash bolt being strong enough.

Whiteline and SPC claim the bottom hole is more critical for load bearing.
Sheering the top bolt should be not a major concern. As long as they are installed properly and torqued I don't see how it is much more different than the OEM bolt. I would be more worried about small allen head lock nuts on camber plates slipping over that strut bolts.

Hahaha... for sure...

Everyone who is racing will soon be running both the crash bolts and top hats anyways. The real question is, how did you get 1.5* of camber out of them Dezoris?

I need to recheck for clarification but I believe the lastest Fastrack clarified that you may use Tophats OR Bolts. Not both

To me, that reads as one OR the other.

I was reading that as "camber bolts" being defined as aftermarket. Technically the crash bolts are just there in case of a suspension problem after an accident. So the car is 100% OEM with them in right? Thus the only mod from stock would be the upper camber plates.

I think it is worth talking about because it is not completely clear to me. :happy0180:

This is the way I interpreted as well.

Perhaps it is not too relevant, but could we also add what popular aftermarket rims/wheels are available and legal for the class?

I had a bear of a time finding 17x7 42-54 rims last year, so I'm still running the OEM rims. I still have not pulled the trigger, but I assume the Enkei and Kosei options are best?