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NASA TT Classing -- NA8 Miata with NB1 Head


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Retroffiting an NB1 head to an earlier 1.8 Miata is a pretty common mod, and my red car has it done.  My question is regarding classing for NASA TT.  If I'm reading TT rule 8.4.1(2) correctly, then I need to dyno reclass due to the head swap.  Is that right?  Anyone else out there done this?  Given how common this mod is, I can't be the first.

 

It really looks like a '99-'00 Miata is the ideal starting platform for TT.  Hmmmmm . . . .

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Yep, head swap means dyno reclass is mandatory, unless you want to run TTU

 

TTU . . . sounds fun!

 

I would expect that a 2001+ is a better starting platform. VVT can do fun things for power curves if you tune it.

 

robert

 

'99-'00 is base class TTE.  '01-'05 is base class TTE*, where (*) means a 7 point initial assessment.  Might be worth it.

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The VVTs were the TTE points car in '13 before the '14 rules added a star. The formula was suspension w/ stock sways (1000F/500R), IHE, aftermarket ECU and SM6s. They could keep the HP within the 16.5 weight/hp limit while maximizing the torque. Now the only way to get them in TTE is to dyno class them at 130 hp and 2405 lbs.

 

With the current rules a '99-00 can do about the same as the '13 VVTs except using aftermarket sways and RRs. But the '99-00 engine isn't as adjustable for HP to torque without the VVT.

A points RWD TTE car at 2400 lbs with 205s can have 145 hp. At 2480 lbs, 150 hp.

 

The standard Miata dyno reclass' at the end of the rules reduce the HP significantly over the points weight/hp limit.

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The standard Miata dyno reclass' at the end of the rules reduce the HP significantly over the points weight/hp limit.

 

All reclasses end up that way on purpose. No matter what car, there's always a power to weight line that Greenbaum uses, and that line is a good bit off from the class maximum ratio limits.

 

You are always better off with points if you can swing it. If your car is too light (meaning too many weight reduction points) or if the mods bust you out of class (too many modification points, or mods that require reclass like turbo, engine swap, etc) then reclass is where to go.

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Or it could be like me, I'd kill in TTC, but get my ass handed to me in TTB.  :laugh:

That's surprising. What are the details behind that? Tracks, cars and times? I figured if I somehow could get my 370z dyno reclassed and get into TTB that I could be competitive but if you aren't then I need to rethink that.

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Or it could be like me, I'd kill in TTC, but get my ass handed to me in TTB.  :laugh:

 

 

That's surprising. What are the details behind that? Tracks, cars and times? I figured if I somehow could get my 370z dyno reclassed and get into TTB that I could be competitive but if you aren't then I need to rethink that.

The TTB track record at MSR-C is 1:20. At ECR 1:57. If you are close to these times you should be ok in TTB.

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That's surprising. What are the details behind that? Tracks, cars and times? I figured if I somehow could get my 370z dyno reclassed and get into TTB that I could be competitive but if you aren't then I need to rethink that.

 

If you look at @@DTP525 laptimes, you'll see he's set a bunch of recent track records at different tracks. For instance his TTB record is 1:51 at TWS going CCW. It's going to be a long time before I get anywhere near that low. You're definitely a better driver than me and can probably challenge that, but if dtp525 decides to show up, I'm just gonna look like I'm standing still. I still have several points I can use in TTB, but I might get out there one day anyway to see how I do. 

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Looking at the 2014 track records for MSR-C 1.7CCW (http://www.nasa-tt.com/Texas_Track_Records), I would have set a record in TTD while getting outpaced in TTE.  A lot of times it's just a matter of how popular a class is and who shows up.  There are some really fast dudes out there.

 

As for me, looking to have fun and take on a new challenge.  Getting some timeslips to join Mazdaspeed and get a price break on parts doesn't hurt either.  :wink:  And, maybe, some contingency tires?  Every little bit . . . .

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The TTB track record at MSR-C is 1:20. At ECR 1:57. If you are close to these times you should be ok in TTB.

 

I haven't run MSRC 1.7 CCW with Z 2.0, but I think with some hoosiers and Z 2.0 I could come really close to that. 

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The standard Miata dyno reclass' at the end of the rules reduce the HP significantly over the points weight/hp limit.

These reclasses were added so that Spec Miatas could easily cross over into PT/TT.

 

hornetball,

You are much better of asking Greg G. for a reclass that is more specific to your car and prep level. To run TTE, you are best of asking for a TTE* reclass to maximise hp. Then add suspension +5 (Springs and shocks), 205 SM7 tires +2, LSD +3.  Still have 2 points left over for sway bars if you have already done them or use them for something else.

 

A TTE* reclass for an NA8 at 2400lbs will be around 140 whp if I remember correctly.  If you have a VVT head it will be slightly less hp at the same weight.

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