For all you NASA afficianados, I have a question on classing. . .

I'm starting off in the HPDE's this season and hope to participate in the TT's soon. I was looking though the classing sheet for TTS/TTU/TTR and was surprised at where my car would fall. . .

If I am at near full weight (3125# race weight) with all interior and around 480whp on a Dynojet with just a FP EvoGreen - my "Adjusted Power/Weight Ratio" would be 6.3 which would put me in TTU. . .

If I gut the interior and drop down to about 2775# race weight and keep the same power - that drops my Adjusted P/W Ratio to 5.23 - which apparently bumps me to TTR. . .

If I keep the full interior (3125#) and get an FP EvoRed and make 550whp the Adjusted P/W Ratio would be 5.48 - which also apparently bumps me to TTR. . .

Does that sound right? I've seen some pretty crazy cars running TTU. . . . just surprised it's so easy to bump all the way to TTR. . .

Thanks for any input you can provide!

EVOlutionary

 

Also it looks like for an EVO IX any more than 39 points or more than about 380whp bumps you from TTB up to TTS/T/R. . . correct? I'm used to SCCA Solo2 rules so I'm trying to learn how NASA does all their classing. Thanks!!

 

NASA only uses points based system up to TTA. After that it's all weight/power for TTS/TTU and TTR.

As for the OP, that sounds close to right. Did you add .1 you your bottom line weight/power ratio? You get reward points of .4 for being 4dr. But then you get penalized for AWD of .5, so your real limit is 5.6 lbs/hp. But did you add your RACE WEIGHT? That is what matters, and for TT you can gain or lose 40-50 lbs by how much gas is in the car.

And finally at 2775 you are looking at a substantial penalty for weight. At full weight you get rewarded points for being overweight. From 3201-3299 is the sweet spot with no weight adjustment.

You only gave enough info for one real judgement, and at 2775 (which sounds like it could be without driver), and 480 whp, you'd be TTR. You could run ~2900 lbs and 480 whp and be in TTU.

Give some closer to ballpark RACE weights (driver included) and I can tell you how much power you can run.

Your adjusted weight to power ratio is never constant unless your weight doesn't change, so it's not easy, but not too complicated.

 

Previous posts updated.

Thanks for the info. That's kind of what I thought. I think I got the hang of the Wt/Hp system just fine. I was just surprized that such low powered car or such a heavy car would be up to TTR. . .

Those were RACE weights. "Full weight" for me and my car would be 3125# with 1/4 tank of gas. . .

The 2775# number is possible RACE weight after stripping the car of all non-essential parts. . .

 

you always are looking at your weights with you in the car. and for lbs/whp don't forget you also need to know what tire width you are running because there are pluses and minuses to your ratio based on width. also non-dot tires take a big hit as well.

but yeah it doesn't take that much to push you over into the next class. just for reference i run and evo 9 at 3350 with just under 370whp on a mustang dyno and that is the limit to still fit into tts. they want you to add 10% to your whp numbers if you use a mustang to base your car off of.
this is with a .1 credit for weight and a .4 credit for 275-250 width tires.

 

Surprised how easy it is to get to TTR. . . I thought TTR was the place for Radicals, DSR, CSR, Prototypes, GT-1 cars, etc. . . I'm going to have to plan my attack strategically to try to stay in TTU. . .

 

I think you underestimate those power to weight ratios. They about the same as ALMS GT2 cars. So realistically someone could show up in a F430 GT or RSR on DOT legal street tires and rip a hole in everyone. 5.5 is a considerable amount of power. We just get spoiled by all of these 700 and 800 hp street cars that aren't as fast as a 400 hp true race car on a circuit.

TTS/U and R are meant for these types of cars, and as the sport grows you will see more of them at the events. We see cup cars at TT events in the southeast on a pretty regular basis. Most running TTU unless they have slicks which is a huge penalty.

 

As stated, up to TTA; you have to watch your mod points AND your weight. You can take pts for weight reduction under your min stated; but they cost mod points.

For an Evo IX (like mine);
- TTB: Max of 19 mod points and meet min weight of 3263 pulling off the track and be under the class hp/wt ratio
- TTA: Max of 39 mod points and meet min weight of 3263 pulling off the track and be under the class hp/wt ratio
- TTS/U/R - pure hp/wt ratio's - mod points unlimited.


440whp or 550whp in a road-race Evo (any or car) is pretty crazy. That'd mean top speeds north of 155mph on every lap on some of the tracks I run. I can hit 120+ with 300whp and 130+ consistently on tracks with ~350whp easily. Those aren't slow cars....

 

Thought this might be the thread for this.

I finally have my dyno numbers and it looks like i can squeeze into TTS/ST2. The car is sitting at 337whp/364tq on a mustang dyno. So it looks like with the 1.1 mustang dyno penalty i need the car to sit at 3256. I can make that happen. From what i see my points are add.4(4-door), subtract .5(AWD). That puts me at needing a 8.80:1 ratio.

I did also get my racecar log book. That is just one step closer to fun( if i get sick of sitting on the sidelines watching evo's racing).

 

Correct on the .4 and -.5. But you need to add in your tire! What size tire are you going to run? This will probably help you out assuming you're running a DOT slick.

Add .8 = Anything 245 and smaller
Add .4 = Anything > 245 but < 275.
0 ------> Anything above 275

 

OP, it sounds like you are getting the idea. The NASA points and hp-to-weight ratios work really well. It is much less confusing than SCCA stuff.

TTR is pretty much for purpose built race cars that were never meant for the street. If I were you, I would keep doing the HPDE's to figure out what your times are. With your racing experience, I bet you will move up really fast. If you are setup for TTU and you aren't competitive, just turn the boost down and try TTS.

 

Don't think you caught the date this thread started.

The OP won NASA TTU Nationals last year...

 

Thanks, I'll keep practicing

 

Should that be :

0.8 = 245 and smaller
0.4 = > 245 but < 285
0 = 285 and over

 

Nope. It's listed as 275 in the rules. Technically if someone made a 276; it'd be 0.

Here's it copied and pasted:

Tires:
Non-DOT approved tires = -0.75 (VRL & GAC Hoosiers see App. A)
Size 10.5” (267mm) to 9.6” (244mm) non-DOT approved = +0.4
Size 9.5” (241mm) or smaller non-DOT approved = +0.8
Size 275 to 250 (DOT approved) = +0.4
Size 245 or smaller (DOT approved) = +0.8