suspension geometry

[Ryan S.]

I am currently weighing the options for rear geometry on a current build. It is a 1st generation RX7 with a live axle rear end I am putting together for ST2. In my contemplation the question of "tube frame conversion" comes up. The current definition in the rule book is "If a vehicle cannot be driven with any of the added tubes removed, it is considered a tube-frame chassis conversion." Does this rule apply if the main hoop of the roll cage is used to locate the suspension pick up points for the rear geometry?

 

Ryan

[wlfpkrcn1]

Connecting to the main hoop puts you in STR2

 

You can relocate suspension mounting points as long as the OEM frame rails and/or unibody, strut towers, floor pan, inner fender

wells, transmission tunnel, rocker panels, are not modified.

 

http://www.nasaproracing.com/rules/Super-Touring.pdf

 

STR1 and STR2 are for closed wheel/fendered monocoque sports racers,

tube-frame, tube-frame conversion, partial tube-frame, and other production and non-production

four wheel vehicles.

 

ST1 and ST2 only (not applicable for STR1 and STR2): Every vehicle must retain its

unmodified: OEM frame rails and/or unibody, strut towers, floor pan, inner fender

wells, transmission tunnel, rocker panels, windshield frame location, and subframes,

with the following exceptions: a) Frame rails and unibodies may have maximum

diameter 0.75 (3/4) inch holes drilled into them for purposes other than lightening,

such as for the attachment of ancillary parts. Cutting and channeling is not permitted.

b) Frame rails may have maximum diameter 1.25 (1-1/4) inch holes drilled solely for

the purpose of the placement of jacking lugs/plates. c) Modification of the OEM roof

line is permitted, but will be assessed via a Modification Factor in the “Adjusted”

Weight/Power Ratio. d) Modification of the floor pan for purposes of exhaust

clearance only is permitted and will be assessed via a Modification Factor in the

“Adjusted” Weight/Power Ratio. e) Additional permitted floor pan modifications are

listed in Appendix A. Floorpan modifications to include items such as subframe

connectors, roll cage bracing, and fuel cell placement may be approved on a case-bycase

basis by the National ST Director. Such modifications will be subject to approval

and possible Modification Factor assessments.

 

AAll ST1 and ST2 Vehicles—Floorpan Modifications:

1) Removal of the spare tire floor section of the rear hatch space and either replacement with a

sheet metal cover or placement of a fuel cell is permitted without an additional Modification

Factor.

2) The transmission tunnel may be modified for the purpose of installing a competition driver

seat. The floor pan must remain in its original position.