nasa classes

[Samiam1017]

i was looking for the classes and how they work with engine size but couldn't find the right area i guess. i remember maybe a power to weight thing somewhere but couldn't find that either, does engine size matter? where would the ez30 or 36 fit? or what kind or HP numbers would be needed to be competitive at 1900lbs if thats possible with a 6 cyl? thx

[Zach34]

I'm no expert either, but I believe the classes we'll probably run in are ST2 and maybe ST1. If my understanding is right, it's strictly HP:weight ratio-based.

[Mitch Wright]

Zach is correct the 818R fits into St1-3 https://nasa-assets.s3.amazonaws.com/document/document/4272/2016_ST_and_SU_Official_Rules.pdf

[C.Plavan]

I ran ST2 with detuned motor.

[Samiam1017]

I ran ST2 with detuned motor.

Im working with my engine builder on an EZ30 high compression build, and would like to know what HP range you think we would need to be in for what the weight these cars are coming in at, to be competitive and reliable in ST2. Thanks for your input Chad

[UnhipPopano]

Is it possible for an 818s build to compete in the ST3 class with a NA engine?

[Mitch Wright]

Brandon Pantas has a ST3 2.0T. I believe they just installed a twin turbo JDM engine.

[C.Plavan]

I think a NA motor in ST3 would be perfect. Less complications, no AWIC, less weight. But then again, I would update the R cage for W2W racing.

Someone started a weight thread somewhere. You have to play with the weight vs/HP to get it right. There are also mod factors for non production cars etc, stick under a 245 rear tire for additional point benefit.

[C.Plavan]

Im working with my engine builder on an EZ30 high compression build, and would like to know what HP range you think we would need to be in for what the weight these cars are coming in at, to be competitive and reliable in ST2. Thanks for your input Chad

Dont even trying to race it with DOT R tires without a drysump. I don't know of anyone who makes a 3.0L drysump system. It may not blow the first day, but it will eventually with the exaggerated G's the 818R pulls.

[Samiam1017]

i found a nasa st class calculator online but i cant figure out how to link it here. it asks for a Vehicle Specific Modification Factor--ST Rules Section 8, which i cant seem to find?
seems like you can have as much as 260whp na with 245 dot tires and still be in st3, im thinking it should be a winning car in st3? thx

[UnhipPopano]

Better question is that with a Subaru NA engine, how wide can the tires be and still race in ST3?

[Samiam1017]

Better question is that with a Subaru NA engine, how wide can the tires be and still race in ST3?

engine make or size doesn't make a difference, if its a rotary or has forced induction makes a difference
up to 245 is one multiplication factor 250-275 is another and when used with the weight and hp i input moved it to ST2
google NASA ST class calculator and play around with the number on there spread sheet for more details

[johngeorge]

NASA ST2 calculator 2016: https://nasa-assets.s3.amazonaws.com/document/document/4423/NASA_ST_U_1_2_3_Class_Calculator_2016_v1.xlsx

What I see is ideal is the following:

with minimum weight of 2200lb
start at 8.0
-.2 for light weight correction factor
-.4 for non-production vehicle takeaway
+.7 for 245 or smaller DOT tires giveback
= 7.9
yields 278RWHP @ 2200lb (7.9 raw weight/hp, or 8.014:1 adjusted weight/hp -right at ST2)

If you want to run ST3, 222RWHP @ 2200lb yeilds 9.9 raw weight/hp, or 10:01 adjusted weight/hp.

The issue with NASA ST rules are they really penalize light weight cars, if you are below 2200lb, you need to use -.3 and if you are below 1800lb its a -2.0! thats massive! ex.. at 1900lb, for ST2 max HP is 237RWHP. ST3 its 1900RWHP

[Samiam1017]

john you think the car could be made competative in st1?

[C.Plavan]

john you think the car could be made competative in st1?

Before looking at ST1 or other classes, look to see what class has the most cars to race in your local NASA region. You don't want to be racing by yourself, as that is no fun and you cant cash in on contingency tire dollars and sorts.

That said, ST3 I feel would offer the best class to fit. Just be over 1800lbs. ST2 was tough because the heavy Corvettes had more HP which would turn into higher top speed on long straight tracks. I could catch in the corners, then they would motor away on straights. Also keep in mind, the ST2 Corvettes alot of the time beat the ST1 cars..... ST2 is "Spec Corvette"......

[johngeorge]

NASA North-East is heavy with ST1/ST2 cars, hardly any ST3. I believe you can make these cars competitive in ST1, but it will be tough road with lots of experimenting what will work and what will not to compete with the corvettes/vipers/porsche GT3 cup cars.

For example with my FFR challenge car in ST2, and with Pat's challenge car, we do pretty good against the corvettes. I won Saturday's NJMP race (7 in class), and Pat got 2nd on Sunday... I believe these are top running ST2 cars. Pat and I do share information freely on FFR setup, aero, etc.. to try to close the gap of the corvettes massive library of knowledge. That will be the same running FFR818R in any class, we need to build up that library of knowledge.

[Mitch Wright]

I couldn't agree more John, information is just starting to trickle in with a small hand full of 818R's on track at this point.

[Zach34]

Finally getting close to making a decision on turbo and also wheels/tires. I'm expecting to be a little on the heavy side (bigger STI spindles, dry sump, AWIC or custom remote A2A intercooler, passenger seat, large fuel tank, possibly sway bars). Playing around with the NASA ST class calculator at 2300 lbs, it looks like if I want to stay in ST2, the penalty for running 250-275 tires amounts to 24 hp. Hindsight fit 265/35/18 tires and from his pictures it looks like 275s are very possible width-wise, but that's on an 818S.

So my question, for those with some racing experience: Would you give up 24 hp for 30mm wider tires (just in the rear, probably can't get wider than 245 in the front)?

[C.Plavan]

Finally getting close to making a decision on turbo and also wheels/tires. I'm expecting to be a little on the heavy side (bigger STI spindles, dry sump, AWIC or custom remote A2A intercooler, passenger seat, large fuel tank, possibly sway bars). Playing around with the NASA ST class calculator at 2300 lbs, it looks like if I want to stay in ST2, the penalty for running 250-275 tires amounts to 24 hp. Hindsight fit 265/35/18 tires and from his pictures it looks like 275s are very possible width-wise, but that's on an 818S.

So my question, for those with some racing experience: Would you give up 24 hp for 30mm wider tires (just in the rear, probably can't get wider than 245 in the front)?

I would stick with the 245's in the rear. The Hoosiers are much wider than standard 245's and you are not penalized on it. You will need the extra HP to push the aero.

I highly doubt you can get hoosier 245's in the front. My 225's would rub with the old nose. I just let them self clearance.

[Mitch Wright]

I am running 235/40X17 BFG R1S's on the front and 265/35X18's on the rear, I get a very slight tire rub on the right front. Planning on ST2.

[johngeorge]

I strongly suggest to run max 245 as per ST2 rules its a nice add of +.7! I even switched to 245's from 275's in the cobra, raising my max HP from 325hp to 342hp.

[Zach34]

Thanks. I didn't think about the power vs aero as a factor.

Chad, I went digging through your build thread and found you initially had the following when you first got your wheels:

Front 235/40 R17 Toyo RR (17x8 +38 with 3mm spacer for now)
Rear 255/40 R17 Toyo RR (17x9 +40 with 5mm spacer)

I guess you eventually swapped to Hoosier 245s in the rear? How did you like how the 245s fit on the 9" wide wheel?

Mitch, thanks for the info. I have the new nose/fenders, so perhaps 18s are a possibility up front, but that might only be at S ride height. There are some wheel options I like that are 18+, so I'm tempted to try.

[C.Plavan]

Thanks. I didn't think about the power vs aero as a factor.

Chad, I went digging through your build thread and found you initially had the following when you first got your wheels:

Front 235/40 R17 Toyo RR (17x8 +38 with 3mm spacer for now)
Rear 255/40 R17 Toyo RR (17x9 +40 with 5mm spacer)

I guess you eventually swapped to Hoosier 245s in the rear? How did you like how the 245s fit on the 9" wide wheel?

Mitch, thanks for the info. I have the new nose/fenders, so perhaps 18s are a possibility up front, but that might only be at S ride height. There are some wheel options I like that are 18+, so I'm tempted to try.

I ditched the front spacers. You rub too much with the old nose. I went 225 in front and 245 in rear. Hoosier 245's were bigger than the Toyo 255's. Fit fine on the 9" rim. Keep in mind DOT R rubber is usually cheaper in 17"