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

[Nbjeeptj]

So the 2023 season with NASA SE is done and looking to the 2024 season. The big debate I had all year was, is it better to reduce power to be able to run R7 or A7's, or just stay the course on Toyo RR's. The winner's at every event are always running R7, or A7,s, but this has never been a mustang. This has been a combo of c6 Corvettes, a CTSV, BMW's, and a supra. I keep hearing once you go purple crack its a hard habit to break, but I just wander if its worth the substantial power reduction to stay in TT3. The power reduction would be 49hp, current wheel HP is 439 and at current weight could only be 390hp with Hoosier. There are several events we have plenty of people to be able to get contingency tire money if I were able to win so that may help with the cost. Can anyone chime in to some realistic expectation of the Hoosier vs Toyo RR?

 

[flyhalf]

At least 2 or 3 seconds faster. A7 is the best TT tire.
If you want a compromise (but not contingency) you should consider some A052 yoko. It is -1 (vs 1.6 of RR)
A052 are similar in Lat G with hoosier slighty worst in braking G
But they ain't cheap and the real "hero lap " happens in the first 2 HC .
To be fair. A7 too are fast in the first 2 or 3 Hc then fall slowly but surely.

 

[Bill Pemberton]

Having run all the tires you are commenting on, I would dump the Toyos and switch to Bridgestone RE71RSs, Falken RT 660 , or Nankang CR-Ss. All will be faster than the SloYos and you will still get a 1.0 reduction. Would that still keep you in Class? I understand your issue as I will be in the same position in 24, but watching friends in various cars dropping to the slowest group of rubber with the 1.6 bonus factor is not always necessary. I would sure look into the super 200s before trying to drop such a large chunk of HP, and the only one I would skip would be the A052 Yokes -- too much one and done , they heat up quick but go greasy faster than you can say Athens!

 

[Nbjeeptj]

Would that 2-3 seconds be with the loss in power or 2-3 seconds if power was equal?

 

[Nbjeeptj]

Having run all the tires you are commenting on, I would dump the Toyos and switch to Bridgestone RE71RSs, Falken RT 660 , or Nankang CR-Ss. All will be faster than the SloYos and you will still get a 1.0 reduction. Would that still keep you in Class? I understand your issue as I will be in the same position in 24, but watching friends in various cars dropping to the slowest group of rubber with the 1.6 bonus factor is not always necessary. I would sure look into the super 200s before trying to drop such a large chunk of HP, and the only one I would skip would be the A052 Yokes -- too much one and done , they heat up quick but go greasy faster than you can say Athens!

I have tried the RT660's and in fact my PR at CMP was on a set of those but, for me they drop off fast. They only give me a few sessions at that speed. I switched to RR's since I could drop so much weight and still be on a reasonable tire but was never in the hunt for the contingency money. If Faulken had contingency I would probably go that way but, that's why I am looking to either Hoosier or Toyo, to hope to get some free tires to help with the expenses of this whole thing. I would not even be thinking I could get the contingency money other than with my current set up I am usually within 2 sec of the leader of TT3, so if that tire could put me with at least a chance it may be worth the switch.

 

[Bill Pemberton]

I understand your dilemma , but I think you are likely 1-2 seconds behind with the super 200s ( over an R7 ), but they come up fairly quickly and I think the RRs are 2-3 slower than an R7 at best. Pretty solid drop per weight on your car, so it makes it a toss up, but am I to assume you run tracks like Roebling Road , Road Atlanta ,etc. where you need HP for the long, fast sections?

Also what size tires are you running?

 

[Nbjeeptj]

Yes on Tracks. CMP, Roebling road, Road Atlanta, and new for 2024 is NOLA, and Watkins Glenn. I am running the 295 toyo on a 19" x 11" wheel, as this was the only size for a 19" wheel and the cost at $299 each made it attractive . The PR , I mentioned on the RT660 was on a 275 on a 10" wheel. My plan for 2024 was to get a set of 18" wheels and run 315 tires in either the toyo RR or the Hoosier.

 

[67GTA]

So the 2023 season with NASA SE is done and looking to the 2024 season. The big debate I had all year was, is it better to reduce power to be able to run R7 or A7's, or just stay the course on Toyo RR's. The winner's at every event are always running R7, or A7,s, but this has never been a mustang. This has been a combo of c6 Corvettes, a CTSV, BMW's, and a supra. I keep hearing once you go purple crack its a hard habit to break, but I just wander if its worth the substantial power reduction to stay in TT3. The power reduction would be 49hp, current wheel HP is 439 and at current weight could only be 390hp with Hoosier. There are several events we have plenty of people to be able to get contingency tire money if I were able to win so that may help with the cost. Can anyone chime in to some realistic expectation of the Hoosier vs Toyo RR?

What weight are you at?

 

[Nbjeeptj]

3750 is what I use on my tech sheet but I usually weigh in in the high 37's 3785 ish

 

[Bill Pemberton]

You and I are in a similar position and I would keep your HP , as you are close to the Max at your weight of 3750, but I would work on getting more weight out and getting closer to your weight when you run. I think your whole issue with the Falkens was their dinky size, get on a pair of 295 -315s and stay with the middle group. The RRs suck even when bigger and you will find the faster 200s will warm slower on bigger rubber race donuts. Apex 18x11s, sticky rubber , will get you a big improvement. I have looked like a Gumball Genius over the years finally getting some Road Course Racers to bump from 275 and 285s to especially 305s and 315s. 2 second jumps were common with the same tire and running with Vettes and such you need the HP. Honestly I think you solved your own problem, 315s with light wheels and an aggressive super 200 TWR tire.

PS- Plus you can lose a ton of weight with these tires and the bonus factor and loss of weight and more rubber also translates to better wear quite often. Granted with your current mods you likely can't get to your minimum weight but depending on how serious you are there is a 100 lbs. you might be able to get out. Every 100 lbs lost is 1 second improvement on a 2 mile track ( old, fairly accurate rule of thumb ).

 

[blacksheep-1]

the Hoosiers will rip the hearts out of any tire out there as of right now, that being said, you will also use more tires than you are now. Those 200TDW (and other like them) in Goodyear will run the same lap times at the end of the race as at the first lap,(in a 12 hour race). slicks won't do that. it really comes down to what you want to do and what you can afford.

 

[Vettel-ish]

the Hoosiers will rip the hearts out of any tire out there as of right now, that being said, you will also use more tires than you are now. Those 200TDW (and other like them) in Goodyear will run the same lap times at the end of the race as at the first lap,(in a 12 hour race). slicks won't do that. it really comes down to what you want to do and what you can afford.

Well said. How much is the 2-3 secs worth to you.

if it were me. I would get the best tire and learn to drive the car down a power a bit.

Can you confidently say your getting everything out of your power.. maybe but I bet you cant say that about the tire.

 

[Bill Pemberton]

Blacksheep, keep in mind he is running Time Trials so he will want to have something that is pretty damn quick but he won't need something to last a long session. The NASA rules for his car mean he will have to lose 50 plus HP and still carry plenty of weight so that is part of what makes this a difficult decision. He can lose weight , keep the power he has using a super 200, so it is a pretty difficult decision. There is no doubt the Hoosiers are the fastest but things can be determined by the tracks he runs and if there are lots of fast straights, the the Indiana Purple Drug of Choice may not override his speed down long sections.

The bonus matrix for using 200 TWR tires is quite large and over the past few years it is obvious NASA ( and SCCA ) want folks running street tires more than Hoosiers or Slicks. Frustrating for many, but it seems to be a trend that will continue since it is Hoosier against the rest. I love the Hoosiers, but the window keeps closing in Time Trial Circles and few are using them for an HPDE tire.

They ( Hoosiers ) will still be strong for racing and certain Classes in Autocrossing, but I fear the two main Sports Car groups will make them more and more difficult for many to use. If the OP drops HP , keeps his weight , a 315 Hoosier will be effective , it depends on the track and other items. Yet, his current HP and loss of weight may do all the same and if he stays on high mph tracks then that may be a better route.

 

[Bill Pemberton]

..........and we have to remember he will be going from bicycle tires to fat boys and that is worth a bunch of time too!!!

 

[Nbjeeptj]

I will have to look back at the car class form but I believe I would have to gain weight or drop HP to run the 315 RT660. If I remember right the reason the 275 rt660 was ok was there was a +.3 factor since it was a narrow tire. I ran some of the events on a Kumo V730 in a 305 size at more weight and it was pretty good but then ended the season on the RR and slightly reduced weight. I don't have my mind set on any direction, just trying to make the best choice out of the options I have at hand.

options I see at this point
1. Gain a little weight or drop a little HP and run super 200 (no new wheels to buy as long as 200tw choice is available in 19" only cost is possibly dyno tune unless I just add weight)
2. Run 315 toyo rr and drop a little weight (need to buy 18" wheels, and cost to buy reduced weight items)
3. Run 315 hoosier and drop HP to optimize power to weight allowed at current weight (cost for dyno tune and new 18" wheels)

 

[Bill Pemberton]

Rules for ST1TT1 to ST3/TT3 are confusing to me and others , but if one reads the actual rules it specifically states tire size and wheels are open, so I do believe you still apply N/A in that area of the configurator. So now you gain the - 0.3 factor back and you would be fine using a 315 tire. The way things are written it seems you have to select in the configurator , but since the written section the rule book says they are open I believe that is the reason you check N/A for any TT1-TT3 vehicle. The other tire modification data on width is for TT4 - TT6 I believe.

 

[RodS197]

@Bill Pemberton is spot on. Do what you can to run a 315 tire. Even if you run a -1.6 or -1 tire, you are building for the future when you will eventually run the R7/A7.

I ran my 2014 in TT3 for a year and a half. Prior to that a 2006 in TT4 and TT3 for 5 years. Never made the podium in 5 years of TT4 and TT3. Now I run in TT2 and get a few podiums per year. Not winning any tires, but running faster laps on the R7 now than ever.

Look at your competition in the TT3 and TT2 classes. How far away from the podium are you? For me I was 2.5 seconds out in each class (we have some very fast TT3 drivers). For me it was simple. Do I have a better chance of making up 2.5 seconds on the Hoosier or 2.5 seconds on the Toyo that I had been running for 3 years. I made up the 2.5 second on the first day of running Hoosiers and have made up another 1.5 since.

Your build is looking good. You have already taken the plunge by unbolting the things you can to save weight. (A/C Delete, going to cut holes in your trunk etc.) Put on the 315 Hoosiers, drop weight instead of HP and go to TT2.

 

[Bill Pemberton]

RodS197,

Perfect response and why I didn't say the exact thing I don't know as that is my exact dilemma. I keep wondering if I should just go to TT2 where I ran with some success and slap on Hoosiers, or go with Bridgestones so I can run in NASA and SCCA. They are faster that the Toyos, but not as quick as the Hoosiers. Great comment and now you have me wondering all over again, ha.

 

[67GTA]

This is what I like about NASA’s classing. There’s enough variables built into the classing form to get a diverse group of vehicles framed into a competitive format. But it forces tough decisions and compromise. Personally, I chose to add weight to stay in TT3, while still being able to run A7’s. There’s point modifiers for weight, on a tiered basis. Sometimes going up 20# gains you a -0.1 modifier, which is exactly what I found in my case. I was scaling at 3890ish, so I added a 25# lead ballast and gained -0.1 modifier by going over 3900#.

Average HP calculation is key as well. I couldn’t tell above if 439 was your peak or average. If your peak HP is 439, your average is likely 420ish. Study the dyno cert form, particularly how the average HP is calculated.

I’m on the ragged edge of both weight & HP, but what I would consider “optimized” for the class. My classing form is 3901# and 415 avg HP. Most times I hit the scales at 3915, so very thin margin of error, and one additional hot lap could put me under.

It proved effective, with 10 wins on 14 entries and class championship for the season. Goal in 2024 is to see how “optimized” the setup is against other regions, with Nationals in Utah. To be honest, I already feel like I’ll be bringing a knife to a gun fight with local TT3 Utah champ being a former National winner with a pro-built M3. Never know, maybe my girthy HP advantage can overcome some of the home-field advantage? Hope to find out.

 

[Nbjeeptj]

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.