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Markus

Chassis update/backdate under PT/TT? IE '91 Miata->'95?

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Markus

Just curious....

 

Under SCCA IT rules, you can now take a '91 Miata tub and essentially make it a '95 by switching over all relevant performance parts.

 

I'm just wondering - can the same thing be done in NASA TT/PT without going the dyno reclass route? Say I have a '91 Miata, if I put in a '95 1.8l, switch to the larger brakes and different chassis bracing, switch ECU, etc - could I just run it under the '95 Miata line item in the PT/TT ruleset?

 

Thanks,

- Mark

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ILIKETODRIVE

Quote from TT rules:

 

Mazda Miata '94-‘97 1.8L (128 hp), using the 1.6L ECU, swapped into '90-‘93 Mazda Miata 1.6L

(116hp) body. The swap will result in the ’90-‘93 Miata moving to the TTE base class, with a base weight

listing of 2320 lbs. As well, the ’90-’93 Miata may update other non-ECU parts from the ’94-’97 Miata.

 

And this might be of help as well (don't know the Miata that well):

 

Replacement of the OEM '90-'93, '95 (with VIN's higher than 14193), '96-'97, and '99-'00 Mazda Miata

ECU 4.0MHz "clock" crystal, and the OEM '94 and '95 (with VIN's lower than 14193) Mazda Miata ECU

8.0MHz "clock" crystal with an aftermarket crystal of different frequency, sometimes referred to as

"overclocking" of the ECU, is permitted as a no-points modification.

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kbrew8991

I want to say that it's been done and was ok, but I can't find the thread(s) about it....

 

It isn't like we check VIN numbers

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Greg G.

The answer to the original question is "no". It is a motor swap, and then some, and requires reclassing.

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Markus

Thanks for the quick reply!

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gkmccready
The answer to the original question is "no". It is a motor swap, and then some, and requires reclassing.

 

The 1.8L into a 1.6L Miata seems really common. Is each instance going to require an individual request to re-class? The shop working on my 1.6L is already asking me about dropping a 1.8L in, which seems somewhat likely in the future so I'd like not to mod-up the 1.6L only to de-mod if/when a 1.8L goes in... making the updates seems like it just takes the '90-'93 and turns it in to a '94-'00 car?

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Markus

OK - so if Miata's can't update/backdate like this, how does it appear that the S2K guys are doing this between AP1 and AP2? Seems inconsistent - either all groups should be allowed to update/backdate or this should always be treated as an engine swap.

 

From this thread, makes it sound like AP1 guys are putting in an AP2 engine and taking the AP2 base class:

viewtopic.php?f=2&t=55865&start=30

I have an AP2 motor though, which are known to make more hp than AP1's.

(Thus we get stuck with the TTC base class rather than the TTD** base class).

 

For what it's worth, here is a quick comparison of base classes - both swaps involve jumps in base class.

1990-1993 1.6L Miata is TTF**, 1994-1997 1.8L Miata is TTE

AP1 S2k appears to be TTD**, AP2 S2k appears to be TTC

 

Sorry if I am misreading this, the NASA PT/TT policy on this is a little confusing!

- Mark

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