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HappyPuppy · Posted: Sat Oct 22, 2005 4:08 pm Post subject: SCCA D Prepared for my 924?

Vaughn, wake up! I've got a question for you. My silver 924 is finally, after two years of agony, going to the paint shop. I want to build it into a streetable SCCA racer (ie, legal enough to drive it to the race w/o being stopped). It's still all metal, but the engine sports the carb conversion and the interior is almost all gone. I want to make it competitive for relatively little bucks. Should I set it up for D Prepared, or should I go go ITB? I read somewhere that ITB requires a full interior, but since you run it, I figure you'd know best.

thanx
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My frequent desire to perform violent acts on select other drivers is not road rage; it is simply preemptory self-defense.

924RACR · Posted: Sat Oct 22, 2005 10:30 pm Post subject:

LOL.

I'm a little confused; Prepared is an autox class; Production is a race class. Do you mean D Prod where the car used to be raced? No longer exists. The car is now legal in E Prod as a full-prep car, where you'll likely get spanked (Andy Franklin is building a car for this class) and in F Prod as a limited-prep (aka LP) car. LP means you're basically running an IT car with slicks, slightly more compression, but not much more. The GCR is available for download now from the SCCA website IIRC. (www.scca.org)

If you want a streetable car, ITB. ITB also makes far more sense for cost, it's far more economical.

Biggest problem I see for you is the carb conversion - must be reverted to stock. Very little interior is still required; we could go into details, but the main requirement is the dash. Take this information as only the rough basics, not as approval to remove bits - you must consult the rulebook for all the ins and outs.

Any other mods? Wondering what else might cause problems.

Obviously you'll need the usual safety equipment - cage, harness, seat, etc. I don't recommend spending too much on the paint if you're going racing. Furthermore, consider having it painted AFTER the cage goes in. Get Maaco paint and match it to readily available spray can paint. You'll need it.

Beyond that, I'd recommend rebuilding the motor, balance it while you're in there (that's cheap). Oil cooler and good radiator, plus Accusump if you can budget it - these are all needed for longevity. And you're not going to learn to race if your car keeps breaking down.

To make it driveable, you'll need suspension work. The rubber stock suspension bushings will be shot, so you'll want to replace those with plastic. Critical points are, in order, a-arm bushings, upper strut mounts (KLA makes an inexpensive non-adjustable spherical mount), rear spring plate bushings, and rear trailing arm pivots (I've only seen these available as a monoball insert, about $300, but those could wait till later).

Then you need shocks and springs. I don't recommend the Koni Yellows unless you have them revalved; off the shelf they're not up to the abuse of racing. Bilstein HD's may be, and can actually be gotten cheaper, I think. Obviously anything cheaper is just going fo fail sooner, and you need a good shock if you even want to be able to drive the car.

For springs: the 400# front spring 30mm rear torsion bar is a great balanced setup, very driveable and not too bad on the pocketbook. You'll need to swap those torsion bars in - IT does not allow use of coilovers. That's a major PITA of a job, and a great time to replace the rear spring plate bushings - not expensive, but hard to get to. To put the front springs on, you'll need the front coilover kit like Paragon's, with adjustable spring perches. The T-bars and spring setup each run about $300, so about $600 total, but necessary. Rough on the street, but manageable, and not worth compromising your driving experience on.

You will likely want an adjustable swaybar; I found that sticking with the stock front swaybar and only using the 19mm rear adjustable Porsche (not Weltmeister) bar was much cheaper, still very effective.

How's that for a start?
_________________
Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype

HappyPuppy · Posted: Sun Oct 23, 2005 1:03 am Post subject:

Well, I was talking about D Prepared, not D Production. It's in the SCCA rulebook, and our favorite German is in there with a very strange listing. Let me show you:

924RACR · Posted: Sun Oct 23, 2005 1:45 am Post subject:

Well, I can't speak to the Prepared classes, since that's all Solo stuff - I only do road racing, can't stand autox. ITB is IMO the least expensive way to be competitive in a 924 in road racing.

Perhaps some of our autox'ers can answer your questions.
_________________
Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype

HappyPuppy · Posted: Sun Oct 23, 2005 3:57 am Post subject:

I'm actually more keen on road racing than auto-x, myself, but right now, I'll take what I can get.

I was looking through the ClubRacing rulebook, and I noticed that F Production seems somewhat close to what I want. Improved Touring would have been nice, except for the fact that I shudder at the thought of trying to piece together a working CIS system. If I ever have the fuel distributor go out on my 931, it's gonna get Megasquirted, without fail.

Anyway, I would like to run ITB, and I don't mind the stock manifold, but is there any way I can Megasquirt the car? CIS has to be where the term "Coyote Ugly" really came from. Should I try calling the SCCA and seeing if they'll make an exception? Or should I just go to F Prod and try to find 400-lbs of stuff I can rip out of the 924?

thanx
_________________
My frequent desire to perform violent acts on select other drivers is not road rage; it is simply preemptory self-defense.

John Brown · Joined: 07 Nov 2002 Posts: 903 Location: Leesburg VA

You could also run with the SE region of the 44Cup. The carbs are allowed. If so, I suggest consider before changing the brakes as the 4 bolt setup is lighter and we have not (yet) had problems stopping with the stock non-471 setup running at around 2200 lbs. If you can drive the socks off the thing you can just about keep up with the back of the pack. So you'll never podium but the racing is fine.

Vaughan, I was looking at ITB times at the Summit Point track here. While ITB is a few seconds slower than the 44Cup, we would still be far from the front (especially at the higher weight). I think you're success may be partially benefitting from the short tight track at Waterford. In fact that was part of the reason we did not do this final weekend up at Watkins Glen. WG is a non-technical high speed layout that would just accentuate our shortcomings in the power department.
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John
80 931 - #931 44Cup
99 Escalade - tows track cars
gone but not forgotten: original 924.org car - 82

HappyPuppy · Posted: Sun Oct 23, 2005 1:31 pm Post subject:

After reading up on 44cup, ITB, DSP, and F Prod, I think I might want to go the F Production route. I worry about 2000 lb Miatas eating me for breakfast, but I think that with enough seat time, I can show them what their predecessor can really do.

I'm still going to grab the 944 parts--I mean, it would be foolish NOT to get them while they're at Pull-A-Part (can you say 15" fuchs for 10 bucks a piece?). I 've got to paint the car first, so there's plenty of time to decide anyway.

OTOH, anyone got any fiberglass parts they don't want anymore?

thanx, and keep it coming--I can use the advice.
_________________
My frequent desire to perform violent acts on select other drivers is not road rage; it is simply preemptory self-defense.

924RACR · Posted: Sun Oct 23, 2005 10:34 pm Post subject:

John Brown · Joined: 07 Nov 2002 Posts: 903 Location: Leesburg VA

924RACR · Posted: Mon Oct 24, 2005 9:52 pm Post subject:

I know, we all are...

_________________
Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype

ryoji · Joined: 10 Oct 2003 Posts: 168 Location: NNJ

924RACR · Posted: Tue Oct 25, 2005 2:45 am Post subject:

I know, I know. You should've been there at Mid-O where I was taking on and beating the 944's and 924S's...

I normally leave my car alone on the race weekend, other than basic checks and tire rotation. The very last race weekend was unusual, because we had brake problems (probably due to weak maintenance) and a new suspension that wasn't set up properly (due to lack of time). The engine hasn't really been getting anything all season except oil changes - checked bearings halfway, but buttoned it back up, they looked fine.
_________________
Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype

HappyPuppy · Posted: Tue Oct 25, 2005 4:55 am Post subject:

I've been looking over ITB again, this time a little more thoroughly, and I think I see what you mean. The only problem is with the K-jetronic--do you think I can convince SCCA to let me run in ITB w/ a Megasquirt setup? I've got a stock manifold, and some of the parts for CIS, but putting that system back together and getting it to work...I'd rather try circumcising myself with a butterknife.

Everything else is doable for ITB, but I do have a few more ideas and questions:

Can I use a 931 head?
5-bolt suspension?
DIS system, or at least a crank trigger to time the distributor?
Aluminum arms?
Plexi/Lexan?

I know I must sound pretty flaky, but I just want to make sure that my car won't be holding me back.

thanx
_________________
My frequent desire to perform violent acts on select other drivers is not road rage; it is simply preemptory self-defense.

John Brown · Joined: 07 Nov 2002 Posts: 903 Location: Leesburg VA

924RACR · Posted: Sat Oct 29, 2005 1:32 am Post subject: