Classing Question

SCCA technical discussions and classing discussions.

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Classing Question

Post by bfrance » Fri Dec 21, 2012 7:23 am

So, I've got some winter upgrades/maintenance planned for my car and I'm wondering where it will leave me class-wise for next season. My goal for the car is to make it fun for me everyday, not building it for a class-specific set-up.

The car is getting close to needing brakes and I figure why not upgrade instead of just replace. So, Here goes:

Car: 1994 Acura Integra LS (non-vtec)

I'll be swapping to 5-lug hubs from the stock 4-lug to facilitate my future wheel choice and brake upgrade (17x8 RPF-1's with hopefully 235's.) Initially I'll be running stock S2000 front 16" rims on all 4 corners.

Brakes will be upgraded to S2000 front calipers, ep3 ('02-'05 Civic Si,) rear calipers, front rotors from a Rsx-S, rear rotors from a ep3, stainless lines and an upgraded master cylinder from a '98-'01 Integra Type R (1" piston diameter, increased from my stock one.) Yes, I know that this is quite the frankenstein set-up, but it all bolts on/is proven to work together and it gives me 11.8" front rotors, 10.2" rear rotors, bigger/stronger calipers, and 5x114 bolt pattern for wheel choices.

So, the question becomes, where does this leave me class-wise? SM?



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Post by FlatBlack » Fri Jan 04, 2013 2:05 pm

Sounds more like a ST* than street modified.

You normally won't get bumped into that unless you're fooling around with the engine.
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Post by flogger » Fri Jan 04, 2013 11:37 pm

Sorry, but that'd put you in Street Mod. Your planned wheels and tires are both too wide for your car's ST class. I don't remember any provision in ST for changing hubs and wheel bolt patterns. I also don't think you can change master cylinders in ST.
Are brakes really an issue for your car stock? Generally the only significant benefit you'll get from bigger brakes is with repeated HARD use, which is not something they should be subjected to in the daily commute.

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Post by SilverYota » Sat Jan 05, 2013 4:00 pm

I completely agree with Scott on this, and I think you will find that it makes you car slower. You will have more unsprung mass to accelerate (and decelerate) and with wheels that large you will more than likely be using tires that are taller, which will hurt your acceleration because it effectively gives you taller gearing. But wait there's more, since the hoop of the wheel and therefore the tire are moved further out (remember these are the heavy portions of this assembly) you now have increased your moment of inertia. To give an example if you spin 2 different tops of the same mass with one having twice the diameter you would notice the large diameter top is much harder to accelerate.

Especially with the modest power your car makes, you should see a greater improvement in speed and braking by using a high friction pad on your stock brakes and staying with a more reasonable size wheel diameter, like 15", with sticky rubber.
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Post by bfrance » Tue Jan 22, 2013 3:37 pm

Thanks for the input guys.

I know that I'll be gaining some unsprung mass with this set-up, but I'm trying to plan for the future, which will include a K-series swap, so the car will be making significantly more power than it does now.

As far as stock brakes, they are pretty so-so. Even on fresh pads and rotors the car is woefully underbraked, imho. (Of course, I always prefer to take the German route of overbraking a car, as opposed to underbraking or having it just "adequate".

Longt-term the car will be K-swapped, making 200-220 to the wheels n/a, with full suspension, etc, etc. So, I figured that if I need brakes anyways...

So, it looks to be SM with this brake set-up then?


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Post by JimR » Wed Jan 23, 2013 1:36 pm

Everything you've mentioned says Street Modified.
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Post by stanbell » Thu Jan 24, 2013 12:48 pm

second Matt's very-well-explained points, and recommendation.

would add you should also work to minimize total vehicle mass. all else equal a lighter car will generally be faster, less accel/decel inertia, fore, aft, but way more important lateral. true even if you have big fat sticky tires.

braking like every other traction-related auto-performance thing depends on your tire patch. you may find you're just locking up/hitting abs sooner. probably harder to modulate. you'll have to drive with a softer touch, hence less forgiving. size of the brakes can't change the amount of traction your tires have. small increment in braking performance usually requires big increment in tire performance to break even. compare your time- or distance to stop to same for acceleration.

apologize for the lecturing tone. looking forward to big classes/good competition in SM.
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Post by bfrance » Thu Feb 21, 2013 10:52 am

Okay, for anyone wondering, I took everyone's advice (for this season, at least,) and stuck with stock sized brakes.

I just received Centric blank rotors, Hawk HPS pad, and Motul fluid that will be going into the car this weekend, weather permitting.

Looking forward to the coming season, I've been gone from auto-x for WAY too long!!! :)


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