Tech: The NHRA’s New Mandated Collector Tether Systems

Last year, the National Hot Rod Association issued a relatively controversial new mandate requiring the use of a tethering system for all vehicles in competition utilizing removable, slip-on header collectors or collector extensions, to prevent situations of an errant collector falling off a vehicle and onto the racing surface, which presents an interesting hazard. We’ve witnessed collectors and even mufflers that have gone unnoticed by track officials get run over at speed, and it’s never pretty.

The Lokar clamp-on collector tethers, in place on the Kooks Custom Headers exhaust system on our Project BlownZ Camaro.

The new requirement, effective as of the first of this year, is stated in Section 20 of the General Regulations in the NHRA Rulebook as: 

“All cars must be equipped with exhaust collectors, headers, or stacks installed to direct exhaust out of car body to rear of car, away from driver and fuel tank. Exhaust collectors/stacks must be securely fastened (i.e., metal connector straps, bolted, welded, etc.) to prevent loss of collector/stacks during competition. Flexible tubing or “flex pipe” prohibited in all categories. If mufflers are used, they must be securely attached to exhaust system and car body or frame. Consistent with its endeavors to maintain drag racing’s acceptance as a recognized sport and recreation, NHRA is enforcing maximum decibel levels for Super Street, Super Gas, and Super Comp vehicles competing at national events. NHRA may enforce the same or similar requirements on other categories in the future.”

Nobody wants to see anyone get hurt, whether it’s your own family on the starting line, a race official, or anyone else, and this rule just makes things a lot safer. – Rick Jones

The NHRA later clarified that ruling, adding the revision:

All removable multipiece exhaust collectors/stacks must be securely fastened with either an NHRA-accepted header tether or a minimum ½” (half-inch) stitch weld located on each primary tube to prevent loss of collector/stacks during competition.

The public reaction to the mandate has been mixed, with many seeing it as just one more extra cost to go racing. But at the end of the day, the intention is to create an even safer racing environment for racers, officials, and fans.

The clamp-on version of the Quarter-Max collector tether system, uses T-bolt clamps and tethers that are available in three different lengths to fit your specific needs.

“I truly believe the tethers improve the safety of our sport. I’ve seen collectors come off of cars before, and often, they come off during the burnout and they get underneath the rear tires and can fly back and really hurt someone, so I think it’s a needed rule, and they certainly don’t cost a lot of money,” chassis builder Rick Jones told us. “Nobody wants to see anyone get hurt, whether it’s your own family on the starting line, a race official, or anyone else, and this rule just makes things a lot safer.”

The complete Quarter-Max tether system, with the tethers and hardware for one set of headers.

Tim McAmis Race Cars’ Billy Johnston echoed that sentiment, stating, “I believe the collector tethers are a good idea from a safety standpoint for the driver and the innocent bystanders on the starting line. Anything extra to help contain a portion of the car that’s liable to come off at any given moment is a good thing. The tether system is made to keep the collector contained under the hood or connected to the car in a situation that it would break off from the primary tubes of the headers, so instead of coming off and shooting across the track and hitting your opponent, someone standing behind you, or someone standing against the wall, the collector will stay as one with your car and save the damage that could be done.”

Tethers From Quarter-Max, Lokar, And Tim McAmis

Whether you’re a fan of the new requirement (and the new expense) or not, with it there in black and white, if your exhaust system has removable collectors or stacks, you’ll have to get legal before you hit the track this season, and we’ve teamed up with a few of the manufacturers supplying the new collector tethers, including Lokar Performance Products, Tim McAmis Performance Parts, and Quarter-Max, to help educate you on the options out there and what you need to pass that first tech inspection.

Lokar’s NHRA-approved tether system, which is also sold through Tim McAmis Performance Parts.

In addition to the those companies we’re highlighting here, a number of manufacturers have begun offering tethering devices to meet the needs of the onslaught of NHRA-licensed racers who have and continue to seek them out, and each of them are relatively similar in design to one another.

The Lokar tether system is unique in that the length of the tether cable is customizable. The end user can cut the tether to their precise length, and then a supplied fitting eyelet, a ferrule, and a fitting nut lock the tether down, so it can then be anchored to the T-bolt clamp.

Lokar manufactures and markets their own device, and also produces the unit that’s sold through Tim McAmis Performance Parts’ catalog. The Lokar device is universal in nature and works with both merge and standard collectors, with a single cable length that can be cut down to size, and features high quality stainless steel hardware. Like others, Lokar’s tether uses a pair of clamps with T-bolts to provide an anchor for the tether. Theirs, however, has a combination of a fitting eyelet, a ferrule, and a fitting nut to fasten the custom-cut cable and connect to one clamp/T-bolt, while the opposite end is pre-crimped for the factory to another eye-end that anchors to the T-bolt of other clamp.

The headers on BlownZ are angled sharply down to the ground before turning out to the bullhorn just behind the front wheel. Our collector clamp is mounted around the collector primary and the large 4.5-inch pipe that leads to the bullhorn.

“We wanted to make the product as universal as possible, and we did so by designing it so you can cut the tether to fit. In other words, you can change the length of the tether yourself, rather than having to order a unit in incremental lengths. We give you a 36-inch cable and you can cut it to the length that works best for your application,” explained Lokar’s Brian Downard.

Jones and his Quarter-Max division offer both a weld-on and clamp-on version of their collector tethers, both utilizing a looped stainless steel cable in three different lengths: 11-1/2, 15-1/2, and  19-1/2 inches. The clamp-on version, like Lokar’s tether system, uses a pair of clamps (which are also available in arrange of diameters to fit your headers and collectors), the larger one for the collector and the smaller for the header primary, with a T-bolt and a locking nut, which the cable loop wraps around before being tightened down. The weld-on version comes with eight stainless steel brackets, that are welded onto the header primary and the collector, and use a 10-32” bolt and nut to secure the tether. 

Each of the products featured here are stamped with the manufacturer logo, per the NHRA ’s requirements as verification as an approved tethering system. Such steps show that the sports’ preeminent sanctioning body is serious about this added measure of safety at the race track — all part of a move that many believe is long overdue and a relatively minor cost for the peace of mind it provides.

About the author

Andrew Wolf

Andrew has been involved in motorsports from a very young age. Over the years, he has photographed several major auto racing events, sports, news journalism, portraiture, and everything in between. After working with the Power Automedia staff for some time on a freelance basis, Andrew joined the team in 2010.
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