TOPDRIFT – LIMITED 2017 Season
TOPDRIFT Limited is a 3 round competition series, focusing on “street legal cars” with minimum
modification. This is a separate series from TOPDRIFT FD Proam. TOPDRIFT Limited has no affiliation
with Formula Drift Pro2 licensing. TOPDRIFT Limited rules are different than the TOPDRIFT FD Pro Am
and are as follows:
● The following engine swaps are allowed:
○ Same manufacture engine swaps
■ i.e. RB/VQ/VK in Schassis, 2JZ/3UR/5UR in SC300, S54 in E36, etc…
○ Any manufacturer 4 cylinder engine swap
■ i.e. K20A2 in an AE86 )
○ Rotory engines must remain manufacture specific or follow 4 cylinder rule
● Modification of engine is allowed (Turbo Charger, Super Chargers, Internal modifications, including stroker kits, variable valve timing etc.)
● Use of nitrous oxide system is prohibited.
● Firewall modification is prohibited. Slight clearance modifications for engine fitment must be
approved by tech.
● Transmission tunnel modification is prohibited. Slight clearance modifications for transmission
fitment must be approved by tech.
● Transmission swaps are open to any transmission that was offered in a factory roadgoing car. (i.e. R154, CD009, W58, T56.)
● Examples of transmissions prohibited are Holinger sequentials, Gforce GSR, HKS sequential, Sadev sequential, anything baller AF.
● Transmission internals are open to modification .
● No fuel cell allowed.
● Surge tanks are allowed but must be enclosed from the cabin of the vehicle.
● Roll cage minimum requirements:
○ 4point bolt in roll cage with door bars welded in
○ 6point fully welded roll cage with door bars welded in recommended
○ Roll cage material should be SAE 1020 or 1025 Mild steel tubing or DOM, 1.5”x0.120” or comparable. Check with email@example.com if you are unsure
*Roll cage is not required for qualifying but competitor cannot proceed to top 16 tandem rounds (not including convertibles).
● SFI or FIA rated roll cage
door bar padding required in exposed impact areas.
○ Door bar, main hoop bear helmet, etc…
● Fire extinguisher required. Must be mounted inside the cabin, positioned within driver’s reach.
● Front windshield must be glass with no cracks larger than a quarter. No polycarbonate windshields allowed.
● Aftermarket bash bar are OK (must fit bumper properly).
● Functional tow hooks required in front and rear. Factory tow points OK but not recommended.
● Seat belt / harness
○ OEM seat belts allowed with factory seat.
○ 4point harness with with SFI or FIA rating required for any aftermarket seat.
■ Harness must be properly secure using proper hardware and anchors.
■ Shoulder harnesses cannot be 10° above shoulder height or 20° below shoulder height.
■ Single anchor point style shoulder harnesses must be installed in conjunction with a crossbar that orients the harness as described above.
■ Harness anchors must be a 7/1620 eyebolt
○ Use of OEM seat belt with aftermarket seat must be preapproved by tech
● SA2010 or newer helmet required. Motorcycle helmets regardless of Snell rating are strictly prohibited.
● Cover positive battery terminal.
● Batteries must be secured properly using steel/aluminum tie downs. Zipties and ratchet straps are not suitable.
● No routing of oil, fuel or water lines inside cabin.
● Minimal firewall modifications allowed (check with tech)
● Bumper, Fender, Hood and complete panels required at all times – CAN’T BE REMOVED DUE TO OVERHEATING OR TO MAKE UP FOR LACK OF COOLING.
● Aftermarket hood and vents allowed.
● Lexan allowed except for front windshield.
● Complete OEM style headlight must be in place and working
● Complete OEM style tail light must be in place and working
● Front end conversion is allowed but fenders/hood/bumper must line up properly (When in doubt, have tech preapprove your modification)
● Wheels must not protrude more then one inch pass the fender or quarter panel.
● Factory dash and factory door panel required. Dash and door panel may be “trimmed” to allow roll bar pass through only.
● Treadwear rating cannot be lower than 240.
● Tread width cannot be wider than 235. Suspension
● Factory pick up points location.
● Modifications to the subframes must be preapproved.
● No driver restriction.
FYI: This is a new series and we are in developmental stage. Please visit this page frequently for
updates/changes/additions to the rule book. We want to level out the field to keep it fair for all
Contact us if you have any questions. Thanks!