XP Limited Prep vs. XP Full Prep?

M

Mike's Competition

For XP, and possibly all the Prepared classes, they show "Limited Prep" and "Full Prep" alternatives for allowed modifications.

Anyone have a good explanation of what exactly this means? (No luck with a google search). Are we supposed to have two separate sets of classes, XP-Limited and XP-Full?

Or, since we have one set of classes, are we supposed to run by the Full Prep rules?
 
Bill I am still looking but I have never heard of this before now. good catch! Considering XP has no other street legal cars in it at the national level, it probably will not apply to XP.

X Prepared (XP)
XP vehicles must conform to the rules in Section 17 except as noted
herein. This class is for almost any production car using almost any
automobile drivetrain. Any vehicle meeting the requirements of 17.A.2,
listed in another Prepared class in Appendix A, specifically listed in CP,
DP, EP, FP, or GP that is not required to run at 17.11.A specified weights
or listed below is eligible for XP. 17.11.A does not apply. “In-excess”
cars per 17.11.A are not eligible for XP.
 
Ok I found a reference on page 223: http://scca.cdn.racersites.com/prod/assets/2013 Solo Rules Book updated 5-1.pdf


G Prepared (GP)
Level 1 (Full Preparation) Vehicles
Maximum valve size is stock if not listed below.
There is no minimum track requirement for GP; Section 17.8.B.5 does
not apply.

And also on page 225:


Level 2 (Limited Preparation) Vehicles
This list of vehicles and the allowances below was developed from
Level 2 (Limited Prep) vehicles listed in the Club Racing GCR under
Production Category. The goal is for these cars to be less expensive
and easier to prepare but allow them to be fully competitive with the
cars currently in Prepared class G (GP).
The following vehicles are classed in GP with the Level 2 (Limited Prep)
allowances per Section 17, Prepared Category and the specifications
listed below.
 
After reading the sections above I think I have figured it out. I believe they are trying to limit the use of the micro cars (ie bugeye sprite) that have dominated for the last several years to make the more normal cars more competitive. Notice that all the cars on the list are micro cars that you can stuff a 3/4 rotor into and make 1000 hp. It is a different set of rules for different cars in the same class. This appears to be an extension to the lower weigh limits for the V8 cars like mine that happened 2 years ago. This rule allowed me to use the 5.7 LS1 and still only weigh 2226 lbs.
 
Looking at rules, you are very lucky with the I-Mark to be allowed in so many classes. I found it on the list in: H stock, D-SP, F-SP, FP, EP, and of course XP.

My Daytona is only allowed in XP or E-Mod.
 
I am still confused about the Limited and Full Prep thing.

The XP specific section in Appendix A starts out with "...must conform with the rules of Section 17, with the exception of the following (specific exceptions).
I'm playing with titanium stuff for resale, and had the general guideline of "banned from most racing classes, check your rules before buying".
Simultaneously, I keep going over the insane, 10,000 RPM race engine build idea (ignore that I would need a 5:1 final drive ratio to take advantage of the higher engine speed). I thought I would check XP specifically and see if I could use any of these things myself. Appendix A has a couple "engine from any source" comments, but nothing about custom making the stuff between the valve cover and oil pan (unless they stretch "drivetrain" to mean engine guts).
I go back to Section 17, and the Limited/Full separation is all over the engine allowances.

G. Camshaft and Valvegear
3. Any metal for valves, retainers, etc.
7.b. Level 1 / Full Prep - valve size unrestricted...
8.b. Level 2 / Limited Prep - stock size valve...

I. Pistons and Rods
2. Level 1 / Full Prep - any ferrous...
3. Level 2 / Limited Prep - stock lightened...

Add to that the new Chevy LS7 (sp?) engine starts out with titanium rods, and they can start another "well, if it has it stock, then it can have it while everyone else is prohibited" arguments.

I found a couple vague references, usually used car listings, stating "Full Prep Chassis, Limited Prep Engine".
And a couple other vague references that this is something adopted or conforming to Club/Road Race Production class rules.

After getting stung on the rear diffuser idea and the prohibition rule, I wanted to read and make sure, even if it is imagineering.
Still looking for another 89 specific (unique for that year) rear bumper to notch, and wondering if I am allowed to make a filler panel between the chassis and the bumper skin, and if that is allowed in the vertical sides of the notch, or that eats up the the vertical wing plates allowance.

Some of the class listings are screw ups. They show "RS", "DOHC", "16 Valve", and "1.6 liter" in multiple listings under the same class. I think the D-SP <-> F-SP, and FP <-> EP are the ones. (There are similar mistakes for the Impulse, Stylus, and Storm, they don't know the cars, trim levels, and engines). It can only be in one of those. If anyone low balled the car and beat someone important, the duplicates would disappear immediately.

Meanwhile, I am waiting on a replacement pump assembly for my floor jack so I can reset my rear camber and toe. Current theory is that the car does not have enough rear tire contact patch for cold days, and toe and camber are too extreme. And I have to switch back over to the manifold and down pipe for winter.
And, I found a source for those discontinued rod bearings for the other engines, just need money to order them.
 
I poked around a little more on this, and may have figured it out.

It may be that they are allowing the same make and model car to compete in two different Prepared classes, a lower tier or slower class under the restrictions of "limited preparation", or a higher tier or faster class without any limitation as "fully prepared".

The references seem to be most concerned with a car that could run in GP as "limited prep" or EP as "full prep".

The only explanation seems to be at the end of the GP car list in Appendix A:
Level 2 (Limited Preparation) Vehicles
This list of vehicles and the allowances below was developed from Level 2 (Limited Prep) vehicles listed in the Club Racing GCR under Production Category. The goal is for these cars to be less expensive and easier to prepare but allow them to be fully competitive with the cars currently in Prepared class G (GP).
The following vehicles are classed in GP with the Level 2 (Limited Prep) allowances per Section 17, Prepared Category and the specifications listed below.
​
And with the year, make and model of each car, the page lists the limits for wheel size, intake/exhaust valve size, front and rear track, induction type, compression ratio, and cam lift.
 
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