NASA TT, Reduce power to stay in TT# and run Hoosier?

[Bill Pemberton]

If NASA lists the business as one of their approved Dyno Shops, they usually know how to do the average HP calculation. Most Regions recommend doing the Max HP , though, as if gives one more leeway if they require and on site testing.

 

[Nbjeeptj]

Our TT director said just use max HP, but that was when I was new to TT and was more worried about not breaking any rules and just trying to learn the game. I do need to find a shop that knows how to do the average HP if it will lower the HP I have to declare on the class form.

 

[Bill Pemberton]

My average and my Max were so close I just went with Max for safety if ever challenged.

 

[RodS197]

Definitely use the average HP. Here is my certification form. Start with the highest horsepower reading. Step up 250rpm and down 250 rpm. You are looking for the 6 or 7 lowest numbers 250rpm up or down from the max. My max is 413, my average is 400. I class it at 403 to give me some room. Makes a difference when classing for sure. Ask the dyno guy if you can have the tabular readout as it makes it very easy. It is hard to do it accurately off of the graph.

My car weighs 3407 with driver, so I class it at 3401 and make sure I have sufficient fuel to be about 3420. That way I can take the -.1 as mentioned by @67GTA . I can class it as low as 3375 if I choose to.

@67GTA it will be great to have you out to Utah! I am going to run there at the Nationals for sure. If you like I can send you a PM when Garages become available. I will let you know where all the Mustangs are if you like. The fastest in TT3 is the BMW you mention, he has the field by 3 to 4 seconds on the Outer Loop. Then the leaders are an MR2 and a GT350. The Outer is a horsepower layout. In TT2 I am contending with GT500s and ZO6 cars and a Porsche race car. But it sounds like you are a good bit faster than me, I am still working on it!

 

[Vettel-ish]

Definitely use the average HP. Here is my certification form. Start with the highest horsepower reading. Step up 250rpm and down 250 rpm. You are looking for the 6 or 7 lowest numbers 250rpm up or down from the max. My max is 413, my average is 400. I class it at 403 to give me some room. Makes a difference when classing for sure. Ask the dyno guy if you can have the tabular readout as it makes it very easy. It is hard to do it accurately off of the graph.

My car weighs 3407 with driver, so I class it at 3401 and make sure I have sufficient fuel to be about 3420. That way I can take the -.1 as mentioned by @67GTA . I can class it as low as 3375 if I choose to.

@67GTA it will be great to have you out to Utah! I am going to run there at the Nationals for sure. If you like I can send you a PM when Garages become available. I will let you know where all the Mustangs are if you like. The fastest in TT3 is the BMW you mention, he has the field by 3 to 4 seconds on the Outer Loop. Then the leaders are an MR2 and a GT350. The Outer is a horsepower layout. In TT2 I am contending with GT500s and ZO6 cars and a Porsche race car. But it sounds like you are a good bit faster than me, I am still working on it!View attachment 91828

Thank you for sending this. I will be running AIX next year it looks like.

 

[Fair]

It is hard to beat the performance of a fresh set of Hoosier A7 tires, if you are the sort of driver that can calmly throw down your best lap on hot lap 1 or 2. I have won a lot of NASA TT events (and free tires) with this method. The downside is the limited number of Heat Cycles and the high COST (and cost per lap).



The Toyo RR is a joke in NASA TT. Even with the 1.6 modifier bonus, its out of its league even with the 2nd tier 200TW tires that can get that bonus, and far behind the top tier 200TW tires (the 1.0 bonus tires). The Toyo should only be your choice when forced - like in the Spec Series that Toyo buys its way into. Yuck!



Lately I've been building around SCCA TT rules (Max1) and using the class required 200TW limitations. Then going to other events and wrecking havoc against Hoosier clad NASA TT cars.



The 200TW tire I've been using ALL SEASON is still cranking out Fastest Time of Day laps, after dozens and dozens of heat cycle. 8 events in, and they still have amazing grip.



If you can make a fast top tier 200TW tire (Yokohama A052 or Bridgestone RE71RS) work on your car, take that 1.0 bonus in TT and go for it. The cost per lap is VERY good, but you have to treat them like an A7... gentle out laps, take 1-3 hot laps, then come in. They fall off pretty fast after lap 2 or 3, so you are just burning up tires for no reason.

Cheers!

 

[Bill Pemberton]

Thanks Terry, coming from you and your extensive research I think this will help plenty of folks make that final decision on what to do tire wise. For those of us who are borderline, struggling to get to all the parameters to run a Hoosier, you evaluation notes will help some of us make that decision. Leaning towards RE71RSs so I can run a Class in SCCA and stay in my preferred Class in NASA, and your post has sure helped.

 

[Nbjeeptj]

Definitely use the average HP. Here is my certification form. Start with the highest horsepower reading. Step up 250rpm and down 250 rpm. You are looking for the 6 or 7 lowest numbers 250rpm up or down from the max. My max is 413, my average is 400. I class it at 403 to give me some room. Makes a difference when classing for sure. Ask the dyno guy if you can have the tabular readout as it makes it very easy. It is hard to do it accurately off of the graph.

My car weighs 3407 with driver, so I class it at 3401 and make sure I have sufficient fuel to be about 3420. That way I can take the -.1 as mentioned by @67GTA . I can class it as low as 3375 if I choose to.

@67GTA it will be great to have you out to Utah! I am going to run there at the Nationals for sure. If you like I can send you a PM when Garages become available. I will let you know where all the Mustangs are if you like. The fastest in TT3 is the BMW you mention, he has the field by 3 to 4 seconds on the Outer Loop. Then the leaders are an MR2 and a GT350. The Outer is a horsepower layout. In TT2 I am contending with GT500s and ZO6 cars and a Porsche race car. But it sounds like you are a good bit faster than me, I am still working on it!View attachment 91828

Thanks for you showing me your sheet. I think even if the average HP is only a few HP it will probably be worth taking the advantage. I will see if I can get someone to dyno it this time that knows what NASA is looking for. The shop I used is the most well known in my area but not for road racing, they are drag racers.

 

[Bill Pemberton]

Contact your NASA Region and ask for their approved Dynojet Shops? Many of those folks are also able to do your Annual Tech while you are there.

 

[SMGDHG]

It is hard to beat the performance of a fresh set of Hoosier A7 tires, if you are the sort of driver that can calmly throw down your best lap on hot lap 1 or 2. I have won a lot of NASA TT events (and free tires) with this method. The downside is the limited number of Heat Cycles and the high COST (and cost per lap).

View attachment 91831

The Toyo RR is a joke in NASA TT. Even with the 1.6 modifier bonus, its out of its league even with the 2nd tier 200TW tires that can get that bonus, and far behind the top tier 200TW tires (the 1.0 bonus tires). The Toyo should only be your choice when forced - like in the Spec Series that Toyo buys its way into. Yuck!

View attachment 91832

Lately I've been building around SCCA TT rules (Max1) and using the class required 200TW limitations. Then going to other events and wrecking havoc against Hoosier clad NASA TT cars.

View attachment 91833

The 200TW tire I've been using ALL SEASON is still cranking out Fastest Time of Day laps, after dozens and dozens of heat cycle. 8 events in, and they still have amazing grip.

View attachment 91834

If you can make a fast top tier 200TW tire (Yokohama A052 or Bridgestone RE71RS) work on your car, take that 1.0 bonus in TT and go for it. The cost per lap is VERY good, but you have to treat them like an A7... gentle out laps, take 1-3 hot laps, then come in. They fall off pretty fast after lap 2 or 3, so you are just burning up tires for no reason.

Cheers!

Terry, do you have cost per lap data comparing your A052 setup vs an A7/R7 setup if you win for the weekend? I have not done a deep dive on it but at first glance it seems difficult to beat the running costs of getting two free tires per weekend like you would on the A7/R7 (if you win, that is). My understanding is you can get a full set of tires in two weekends if you place well enough and a big enough group shows up to play. Not really sure how a $2.2k set of AO52's could compare to that.

 

[steveespo]

RodS197, I am reasonably close to the 1st place times, and all but neck and neck with the 2nd place times at most events. Every few events we have a few people come over from ST-2 and ST3 wheel to wheel to grab a set of free tires and usually they are the fastest by a few seconds. I ended up 3rd in our points but it was kinda by default since there were only 3 of us that did enough events to qualify for the points race. Had most of the people done more events I would have probably been able to keep third, based on where I would normally finish on weekends with 6 ish people in TT3. As for going up to TT2 there are usually only 2 cars in that class, so I would rather stay in TT3 to have more competition, but if I go the hoosier path I may end up in TT2.

67GTA, the 439 is my max HP. I dont understand the average HP and have yet had someone that can explain how to use it (probably since the people I have asked run TT3 ). I added the form below if anyone can take a stab at showing me how to get the average HP. Thanks.

I took a stab at your Average Horsepower and it is approximately 427.25. This is if 7250 is your max RPM. Would need the Win PEP file from your dyno operator to get the actual 50 rpm increments but I think I'm close using the chart posted. The process is to use the highest peak HP and 7 highest points (since redline is >7000) above and below in 250 RPM increments. You are supposed to use the 2 highest above peak, but since you shut off (limiter) at 7200 we only use that point and 6 below peak (@6750, 6500, 6250, 6000, 5750, and 5500) then divide by 8 to get the average. Hope that helps.