VidViper

So, last year I ran a couple of autocross events with the local Corvette group and because of my mods, I got put in a class that I can't compete in. So, having come into some cash recently, I want to make my car a serious competitor for next year. Note: I will be running in the "MODIFIED" class with a 1999 coupe. I already have a Vararam CAI and LG Pro longtubes (thus the reason I am in this class). However, I am open to changing those out as well. I really don't want to modify the motor, plus that would move me into the "RACE" class. The local Corvette club rules are listed below.

Please let me know everything you would do within the confines of the MODIFIED class including suspension, brakes, intake, exhaust, MAF, TB, tires & wheels, etc. Don't hold back because of money (I'll be the one doing that )

NOTE: I have included all the class details for reference (not just Modified).

Thanks




Modifications
Listed below are the ways to determine Stock, Modified, Race, and Unlimited.

Updating and backdating within the vehicle class is allowed. (I can use any part that was offered from the factory on any other 97-04 NON-Z06 Corvette.)

MODIFICATIONS NOT LISTED SHALL BE GROUNDS FOR DISQUALIFICATIONS, IF AFTER A PROTEST IS FILED, THE PROTEST COMMITTEE DETERMINES THAT THE MODIFICATION PROVIDES AN UNFAIR ADVANTAGE TO THE COMPETITOR.


1. STOCK
a. Legal tires in stock class are tires with a D.O.T. number and a uniform tread wear rating of 150 or more and tires size is within 5% of factory original specifications, for cross section and diameter. Tire must not be marked for “Competition Use” or Racing Purposes.”
b. Parts replacement: Worn or damaged parts may be replaced with parts that are the same type and dimensions.
c. Cars originally equipped with catalytic converters may run any mufflered exhaust system after the catalytic converter. Non-catalytic converter cars may run any exhaust after the stock exhaust manifold.
d. Wheels:
1) 1963 to 1982 - Any wheels are acceptable to a maximum allowable rim width of eight and one-half inches, and a maximum of sixteen inches in diameter.
2) 1983 to current year - Any wheels are acceptable to a maximum allowable rim width within one-half inch of factory specification, and the factory diameter within the vehicle generation.
e. Fenders may be modified to provide tire clearance. Top of tire must be covered by fender.
f. Spare tire, jack and carrier (cover) and tire inflator kits may be removed.
g. Normal engine rebuilding procedures shall be allowed. Maximum overbore cannot exceed 0.0472.
h. Transmission shifter and/or linkage may be changed. Cars with overdrive transmissions may be equipped with a manual override switch. Computer Assisted Gear Selection (CAGS) may be overridden.
i. Top(s) may be removed.
j. Any air filter element may be used.


2. MODIFIED
Legal changes in modified classes shall include all Stock class modifications plus:
a. Tires: Any tire with a D.O.T. number with measurable tread or wear indicator may be used.
b. Maximum allowable rim width is 11 inches or factory width, whichever is wider, and any diameter may be used.
c. Any brake pads can be used. Any rotor of original size diameter and thickness may be used.
d. Minor body bolt on modifications (ground effects kit, rear spoiler, wing, hood, etc.) are allowed. Spoilers and wings to be no more than six inches in height and cannot extend beyond the width of the car.
e. Any air cleaner assembly may be used.
f. Computer chip and programming changes are allowed. Any ignition may be used.
g. Add-on gauges and /or instruments are allowed.
h. Any seats can be used and harness bars with racing harnesses are allowed.
i. Any sway bar mounted to the factory mounts including any end links, may be used.
j. Replacement of stock shocks is allowed with parts that are of the same type and dimensions. The new replacements must use the stock mounting points. Shocks with remote reservoirs are not allowed.
k. Chassis and suspension changes can be made to springs, steering, and stabilizer bars. Polyurethane bushings are allowed. Changes can be made to sway bars including solid (heim) joint links. Spring rates can be modified. No engine repositioning and no modification to any suspension pick up point is allowed. Modified tunnel plates are allowed. Offset trailing arms are allowed. No engine repositioning or relocation of suspension mounting points is allowed. Modified factory trailing arms are permitted.
l. Any type and number of fuel pumps and/or regulators may be used.
m. NHRA, AHRA, or SEMA approved scatter shields are highly recommended on
n. Any intake manifold with any carburetor/fuel injection may be used. Any MAF sensor and any throttle body may be used
o. Any muffled exhaust may be used


3. RACE
Legal changes in Race classes shall include all Modified class modifications plus:
a. Air cleaner may be removed.
b. Any tires may be used.
c. Battery may be relocated but must be secured and contained in a leak proof container if installed within the passenger compartment.
d. Any exhaust system may be used.
e. Bumpers and bumper brackets may be removed.
f. Any engine modification is permitted (must be naturally aspirated). No nitrous oxide may be on board or used.
g. A passenger seat is not required.
h. Any modified wheel wells are permitted. Any wing or spoiler may be used as long as it does not exceed the width, roof line or rear of the vehicle body.
i. NHRA, AHRA, or SEMA approved scatter shields are very highly recommended on manual transmission cars and explosion proof blankets or SFI 4.1 Certified Safety shields are very highly recommended on automatic transmission cars.
j. Maximum allowable rim width is 12 inches or factory width, whichever is wider. Any diameter is allowed.
k. Any brake rotor/caliper is allowed as long as original quantity per wheel is maintained
(i.e., one rotor and one caliper).
l. Any rear-end ratio and any transmission or transmission may be used.
m. Any shock is allowed. Suspension changes can be made to springs and steering. Suspension pick up points can be modified. Chassis stiffening devices are allowed.


4. UNLIMITED
Highly modified Corvettes with frame and body numbers that do not comply with the above classes, including all swing axle and solid axle Corvettes with GM frame or tube frame and all non-naturally aspirated Corvettes
a. Roll bars are required. (Attachment by welding recommended). Specifications include:
1) Tube size - minimum one and one-half inch outside diameter by .120 wall (1/8 inch). An inspection hole of at least 3/16 inch diameter must be drilled in the roll hoop at least three inches from any weld or bend.
2) Mounting plates - 3/16 inch thickness minimum.
3) Bolts and nuts - bolts shall be at least 3/8 inch diameter, Grade 8.
4) One continuous length of tubing may be used for the hoop member with smooth continuous bends and no evidence of crimping or wall failure.
5) Welding - All welding must be of the highest quality. All welds will be subject to very critical inspection.
6) Roll bars must not exceed one-half inch clearance from top of any roof structure.
c. NHRA, AHRA or SEMA approved scatter shields are required on manual transmission cars and explosion proof blankets or SFI 4.1 Certified Safety shields are required on automatic transmission cars.
d. Competition five-point or six-point harness is required.
e. A minimum two-pound on-board dry chemical fire extinguisher must be securely mounted within reach of the driver.
f. Windshields and frames may be removed from open (non T-Top) cars if the driver has adequate shatter-proof eye protection (i.e., goggles or face shield).
g. Any racing type seat is allowed.

wallyman424

remove vararam and LG longtubes and run in the stock class till you're winning.

then take money, insert into incinerator like the rest of us.

rfn026

Stock class is your best option. Then spend your money on travel and motels. Run every weekend. It's all about seat time.

Richard Newton
Intervention Motorsports

napacruzerc5

The best thing you can do to your vette to fit in D1 class with the WSCC rules is to run serious Hoosier tires or equivalent. I run that class with nothing more than a Vortex intake and catback B&Bs, C6-Z51 sway bar (right now just front; I plan to install the rear Z51 bar by the next event in late Oct.). Not running Hoosiers; just the Kumho MXs tires on stock wheels and sizes. Can't afford Hoosiers? Try the Kumho XS tires which still should give you dual purpose tires (street and autocross) and get you closer to the front. I bought the MXs right before the XS tires came out (poor timing in my part).

Part of running WSCC events is that the really fast guys run the last 2 groups. By then the course is nice and clean. I usually run the 1st or
2nd group (out of 4). Since I'm not optimized to the class rules, I don't worry about butting heads with those who are. On a 40sec course I'm usually 2-3 seconds back. A large part of that difference is running early and another is my tire limitations. Some WSCC member clubs will post times by run group. I take great satisfaction in being one of the faster ones in an early group when they do post these times. Right now I'm just running for fun. While winning would be nice I don't care to spend the $$$ and effort to run in front.

I've been autocrossing since the late 70's from Formula type cars to a BP Corvette at the Solo II National Championships. So I've been there; done that. Now just having fun and enjoying myself more.

Rhys Cruz
Torch Red 2001 C5 #784

VidViper

Yeah, I also have poly bushings and a harness bar as well as some nice Sparco seats. I really don't want start de-modding my car. I have driver a friends car that is moderately set up, and I can be competetive. I just want advice (based on this code) as to what I can do to have the best car possible.

VidViper

That is good advice. I definitely have some big Hoosier A6's on lightweight 17x11 or 18x11 wheels on my list.

What are the best springs and sway bars for autocross? It seems like the serious guys like a soft swaybar in the rear? Or none at all?

dbratten

You'll find more used 17" than 18" tires in 315 & 335 sizes. New tires ($$$$) are nice but not needed to be competitive at this level. I've had good use from used Kumho 710s ($). ZR1/GS 17x11" 50mm wheels are a good deal ($$) and fit both those sizes well. In 18s you can find 305s & 315s used.

Maybe get stiffer springs, good shocks, and a bigger F bar and you'll be close to good enough. I found with OEM bars (Z51 added), shocks (Z06 added) and springs (base) the car was better with the base R bar or none at all.

Then just get out and drive. You don't need any more power.

I've been running my base model C6 A6 with a CAI and a tune w/350 hp & tq to the rear in the E2 class. Beyond that, 710 tires and Pfadt suspension. It works pretty good when the driver isn't the weakest link.

--Dan

worldsaway

Think about getting more grip to carry more momentum through the course. Big hoo A 6's first. From the rules I can't tell if you can run coilovers and lower/cornerweight the car, but you could probably do just as well with springs/shocks/sways. Match your shocks to spring weights. I find I do better with the rear sway connected. Even though it's more tail-happy it seems more predictable, but I'm not wearing a nationals jacket either.

AU N EGL

Grip yes and no.

many times you want to slide though or around corners. BIG tires or WIDE tires sure look cool but may not be the best option for auto-x

worldsaway

I run 295/315 in V710 and A6. I agree with a little loose at the back and get it to rotate. I know you get less understeer with the square setup (315 f/r) and I hate plowing. But big grip also helps in the mental aspect for me, as I THINK I can go faster. Ed

rfn026

You should talk to Donna Littlejohn. She just got her Championship. If you want to know what it takes to win at Autocross consider that she put 5,000 miles on her tow rig last month. Did I mention seat time?

Richard Newton
Intervention Motorsports

fej

Wow I think this is a first, I disagree with AU N EGL, but only in a roundabout way. You won't see any nationally competitive AutoX cars on 265/295 set ups. Pretty much every car is at least 275 fronts, most are 295-315 fronts, and 315/335 rears. The main topic of conversation at an autox event is about grip, basically every time, followed closely by setup and how to get more grip

I think under these guidelines, and depending upon your commitment to getting seat time (and this means running more than just WSCC events), I would run a sticky set of street tires for a season and work on car control, walking/memorizing the course, and talking/riding with experienced drivers. This route saves you money, and gaining experience will help you decide which way YOU want to go with your car under that rule set, or if you may want to go to a more national/SCCA type of rule set and run with SF Region etc, while still being able to run under WSCC rules.

No replacement for seat time, period.

I was originally told when I first started messing around with AutoX, that R rubber was worth 4 seconds on a 60 second course, IMO it is worth 2 -3 seconds, but that is just my opinion. A lot will have to do with the course type, your driving style, and surface you are on. (concrete vs asphalt)

I am personally still going with the "used" R compounds, but there is no doubt that new R rubber is at least 1 - 1.25 seconds faster vs 70+ run R rubber.

Did I mention seat time?

Also looks like "stock" tire rules exclude Hoosiers for sure, and the treadwear might now allow the Kumho V710 either. Seems to be set up to be a street tire class.

Fluid change and car inspection (bearings, brakes, suspension etc), seat time, seat time, seat time, race seat and harness, seat time, seat time, seat time, decision next year where you want to go, lay out plan for modifications under "class" guidelines, set race budget, seat time, seat time, seat time, mod #2, seat time


Oh, and seat time

G'luck
Fej

c4cruiser

Were those two events your only experience at autocrossing??
I would stay in your current class for now in order to get seat time. Arrive early at an event and walk the course as much as you can. Ask other drivers in that class if you could give you some pointers. You might want to ask about car setup and driving techniques.

The chances are that the experienced drivers are going to be much faster and their cars are going to be well sorted out so being "competitive" is going to take some time on your part.

While race tires appears to be allowed, it can be a challenge to get them to the event. If you decide on tires like Hoosier A6's or Kumho V710's, they are not suitable for street driving so you have to figure out how to get them there: maybe get a friend to haul the tires, tow a small tire trailer, or tow the car.

I would continue on for next season and gain driving experience and a good understanding of how your car works. When you start to further mod the car (especially with suspension components) do it in stages. Doing too many things to the car all at once can be counter-productive and then you have to go back and sort everything out.

Returning the car to a stock condition could cost more to do than to add shocks or swaybars to the car as it sits. In any event, it's seat time that will make you become competitive. And that only costs you the event entry fee

gkull

I used to do that 20 years ago burning up every summer hitting every meet in the division for the points chase.

Then I took a hard look at what entertainment value was I really getting for my money. Maybe 3-6 runs per day or about 5 minutes or so of track time for a whole day. then add up travel time and expenses. It is a no brainer to just go road racing.

You live within a couple of hours of three very fun race tracks. Laguna Seca, Infinion, & Thunder Hill. The PDX and HPDE events are only a couple of hundred bucks per day. No rules, it's run what you brung if it is safe. Then with time, skill level, and mods just move up to one of the competition cats.

SCCA Track Trials are a good time or Club Trials. That is close wheel to wheel racing with passing zones. Just one level below full comp.

Just a couple of weeks ago I was at laguna Seca flat tracking through turn one and pitching the car sideways over the top of the hill at the cork screw. This weekend I was tearing around the Reno Fernley track in two different Vettes

Jason

You'd think it'd at least keep the garage warm in the winter.

Pylons

totally disagree...sliding through or around corners is pretty much never the fast way

wide tires is very much where it's at...especially if you're in a class that allows enough wheel to really use the width. if tall comes with wide, then it may be a different story, depending on the gearing of your car

tjZ06

I've run with the group you're talking about, and think I had to run "Race" due to my cam etc. I think I won, I don't remember. No offense to anybody on here from that Club but for the most part competition is soft. There are some very fast dudes (RichieRich, Dave from Northstar etc.) but for the most part it's a laid-back fun group that doesn't run that fast.

Again, no offense meant the Club in question is a super cool group of people and are fun to run with. However, I can NOT see building a car to their spec. The facilities they use (mostly Solano CC) are small, slick, have lightpost/islands etc and just don't make for the best courses. If you get more serious about AutoXing you'll want to run SCCA, AAS (best group to race with in the Bay Area hands-down), UFO etc who all follow the SCCA Solo II rules. If you're going to build the car your best bet (assuming you just won't stay in a Stock class) is ASP. SM2 would be interesting, but see my thread here: http://forums.corvetteforum.com/auto...mpetative.html

Just go out, have fun and learn some more. If you want to be serious about AutoX (and therefore build a car specific for it) you'll grow beyond that Club.

-TJ

VidViper

Ok couple of things. I used to run regularly with the Porsche club so while everyone can use more seat time, I am not a beginner by any stretch. I do plan on running AAS but my biggest interest is running with the all corvette events. SCCA - forget it - I'm not into miata courses.

Now, keep the advice coming. Specifics are what I am hoping for

tjZ06

Well, again AAS uses SCCA Solo II rules so if you build a car to the rules above you are not necessarily optimizing. That being said it looks like "Modified" aligns pretty close with ASP rules. ASP is a darn fast class though (good luck with Joel V ). So... if you want optimal for Modified/ASP I guess my advice for your C5 coupe would be to do whatever you can to duplicate Joel's car. Specifically that'd be:

• Poly Bushings (he has VBPs, but it sounds like the Pfadts might be a bit nicer)
• VBP Springs (I have to refresh on rates, but I believe Joel runs their most agresive pair)
• At least 2-Way Adjustable Penskes (source from Harbar or Ankeny)
• Lightweight 18x11 & 18x12 Wheels (CCW, Bogart, etc) though I think Joel runs 17s but I believe that's for cost not necessarily optimal setup
• 315/30-18 & 335/30-18 A6s
• Pfadt or T1 Front Bar
• Stock or no Rear Bar (yes, really, that's the setup though w/ the Penskes you can probably run more rear bar then tune for rear grip w/ the shocks)
• Maximized "stock" '02+ LS6 Build (you can blend the heads 1" in and things of that nature for ASP, doesn't sound like that is technically legal for Modified)
• Your intake/headers
• Light Race Seats
• Harnesses
• Aggressive Alignment

That should cover it.

-TJ

fej

Joel is running 1200lb fronts and roughly 1000lb rear springs currently. Stock z06 bar. 315 30 / 335 30 17 A6's on his car. Double Penske's like TJ said.

I would wait on the bushings a bit, as I have heard rumors that another solution is in the works.

To save some money, some less expensive upgrades would be OEM z06 rims, OEM z06 pads, used z06 bars and metal end links (02+).

Still recommend seat time, many of the AAS folks have been running for 20-30 years or more. Many of those same people are multiple time national champs as well. Most of them consider you a noobie until you have been running the majority of the events for 4+ years heh.

<~~ still a noobie

Fej