Surfbum

After two years of building my Cup S in my avatar, NASA has effectively pushed me out of the ST1 class into Unlimited. (I am not going to go off on that rant). So now its time to bring out Car B, a well sorted and fairly refreshed 996 cup. The plan is to get the car into ST2 (since I would be the only car in GTS5 or GTS4 due to low German car count in our region).

I would really love to get some feed back since our first race of the season is going to be in three weeks (again I am not going to rant about their timing of the new rules for next season).

Alternate 1: Ballast car to 2935 lbs (don't need to add lead) put a throttle restrictor to get 350 rear hp gives me a power to weight ratio of 8.39 subtract .2 (porsche penalty) subtract .1 (weight less than 3,000 lbs) give me an adjusted power to weight ratio of 8.09, just above the 8.0 limit.
Here is the catch, I would need to run Hoosier R-6's

Alternate 2: In order to run slicks I would have to ballast the weight to 3,000 lbs and restrict the hp to 337, that would give me an unadjusted power to weight of 8.9. subtract .2 (porsche penalty) subtract .7 (slicks) 8.0

Tracks are short (under 2 miles) and tight, sprint races of about 30-35 min.

Which would you run and why?

Thanks for your thoughts/experiences.

911racer

Here is my experiences.

I have been running NASA GTS since it came to my area about 10 years ago. Ballast, restrictors ... I have done it all.

I have a 6cup. I run almost no ballast other than adjusting the fuel to match what the scale happens to say for a weekend. I am a strong believer in the lightest car is the fastest car even with less hp. Takes less work to get it though the corners (by work I mean work in the engineering sense. Energy. Heat) So, the lightest car uses less gas, less tires, less brakes. Even if you are talking about a few hundred pounds, it makes a difference.

Tires. I tried running DOT Hoosiers for a year. Had a heck of a time trying to get them to fit and align on the cup car to what Hoosier wants them to have for camber. I would stick with slicks.

Restrictors. You can do about anything you want with these. One of the guys here has a restrictor in his 6cup that puts him in GTS3. Still great air/fuel ratio with no ill effects. He made this slick little EDM'ed out shutter plate that allows us to change out restrictors (or just remove one) fairly quickly. It sits between the air filter and the cf housing. (he has a machine shop, so easy for him). I then had a bunch of different sized holes laserjet cut out of stainless plate. I even tried different designs to see if something might cut Hp and keep Torque up, but I did not have success at that. I had thought about manufacturing his design for the up and coming Demon Speed Motorsports store, but decided that the demand would be so low that it would not be worth while.

Also, not sure what the rules say in ST, but GTS allows unlimited aero. Areo is great. Especially on shorter tracks. Big tall wings (I run a GoodAero wing with a set of my roof height uprights) and good sized splitter up front. I even had a semi-tube frame 87 911 (with a 993 rear suspension) with a full flat undertray for a few years.

Thanks

Ed

wanna911

How much does the Cup S weigh? (raceweight?) And how much power? I thought cups were still pretty heavy (in the 2600's no driver).

Seems like you should still be able to get it into ST1 with that car.

jrgordonsenior

Restrict a 6-cup to get to 350? What's your WHP now?

claykos

Dave make sure you read the rules carefully especially Appendix A by my count Porsche Zilla should be able to have a couple more rear wheel horsepower than last year

Surfbum

JR, 373 as it sits now, PMNA sealed motor

Clay & wanna, If I am reading the rules correctly the mods that I have made to the body pushes me into a modified status. Even though I used all PMNA parts ($$$$$$$$) it wasn't offered as a production car.

2,500 lbs empty, put in a sequential box, slicks, engine location penalty, modified penalty, weight penalty, blah, blah, blah

I can ballast up for GTS5 but I would be the only car. ST rules different.

I built the car for 2013 GTS5 Nationals, but the gearbox we put in at the last minute came with Daytona gears instead of the shorter gears I was lead to believe. I was 20 mph slower on the end of the straight than with my short geared H pattern box, I never even got into 6th gear on the main straight at Miller.

North Coast Cab

My 6Cup is set-up for GTS4. Slicks and restricted, just like Ed said, down to the 315-320 range. I run the factory wing with Intermediate Height Uprights I bought from Ed. They get your stock wing up in the air and provide nice rear visibility. I've run a couple different splitters and have not decided on the best set-up yet, and I also am debating running a bigger wing.
The only downer in GTS4 for the Cup is the lack of torque vs. the E46/E92's. Their tune produces incredibly consistent power across the band.
And I'm with you on Super Touring and was part of the online discussion. I guess running in ST is not much of an option for 911's...maybe that's how NASA wanted it.

roketman

Sounds like SCCA .Not leaving room for P cars.They need to come more in line to get more P racers.

bgiere

Too much math for me…I can't do math after hours….I restricted mine down to 318 HP and run in GTS 4 with Ed and Northcoast…The restrictor that we run is a very trick piece…Demonspeed should offer them on the website.

claykos

Dave... last year for st1 you had to take the .4 cup penalty, .2 sequential penalty, .75 slicks, and a .2 for weight. This year you'll take .4 for modded rear wheel tubs (but no rear engine penalty because youre already taking .4 - see appendix a), .7 for slicks, .1 for weight and .2 for sequential. So you can actualy end up with more hp than last yr.

Surfbum

Clay it was explained to me that I had to take both .4 for tub/aero and .2 or rear engine.

What is upsetting to me is the total lack of logic behind the new rules, and now to add insult to injury if the car is pre 99 their is a different rule for that. THAT is just cronyism that got that change.

I have spent years to develop the car, and the rules are ever-changing.

The irony is that even if I can figure out how to get the car into ST1, the proof of the injustice is evidenced by the ST2 car posting a faster lap time than the GTS5 cars at Nationals. Peter, the GTS5 winner is having the same hard time trying to get into ST1.

So my point is if there are other non rear motored cars that are beating cars in a class above them, where is the logic in penalizing rear motored cars, then after fielding several complaints giving the older cars a break.

It just stinks, sorry about the rant.

Zuluracerx

Come race with us the POC Dave.

Zuluracerx

"in"

claykos

No doubt it's completely arbitrary...

Appendix A:
Rear Engine Location:
This Modification factor applies only to vehicles with engines that are behind the rear axle, with model years from 1999 to present, and with the listed Minimum Competition Weight. Vehicles with rear engine location that are from prior to 1999, or weigh more than 2900 lbs or already take the Modification Factor assessment for Non-Production vehicle are not assessed a Modification Factor for Rear Engine Location.

See the bolded part. You don't take a penalty for rear engine because you already take the non-production penalty since you modified the inner fenders.

I don't think it would be too difficult to get porschezilla up to 2900 lbs with a bit of ballast - remember it's with driver. Put the weight in the front to help weight distribution like the world challenge cars do, the car will handle even better. Then you could run at 5.5 + .4 (non prod) + .2 (sequential) + .7 (slicks) +.1 (under 3000 lbs) = 6.9. Which at 2900 lb is 420 rwhp.

Surfbum

Clay, thanks you are right, I can ballast PZ up to 2901 lbs.

I think Ill keep the 996 cup bone stock for GTC3 and Silver class in Pirelli Cup.

Zulu, as your ex gov says, "I'll be back", but it aint going to be without a 4.0