The Dodge Challenger SRT Trans-Am entry has performed well after its mid season introduction with a class top ten finish on its debut and a class 2nd next time out. The car is built to the TA2 regulations that see all cars using a Stockcar style tubular chassis from one of a number of suppliers (Howe being the most popular), and it is powered by an equally Stockcar V8 engine such as the LS3 or Ford Pushrod.
But according to chassis supplier Howe, the TA2 Challenger SRT is no converted circle track car ‘Unlike some new arrivals to this class ours is not a converted oval track car. The Howe TA2 is a variation of a proven design that we have produced for the European Camaro Cup / V8 Thunder Car Series since 2010. For the U.S. market the cars are configured to Trans Am 2, GT2 or GTA specs. New for 2015 is a version we call TD2 or “Track Day” which is the same chassis with lower cost components.’
TA2 is meant to be an All-American muscle car racing class – ‘They covered posters on your garage and bedroom walls and have been rolling off assembly lines in Detroit for decades. They’re the quintessential American cars, engrained in our culture and our hearts’ the literature claims.
All three brands of American muscle cars are represented with a choice of Generation 5 Camaro, Mustang and Challenger look bodies. The bodies are all fibreglass with a polypropylene nose currently only available on the Camaro.
The body dimensions are altered from stock enough to fit a common chassis. Each model has a common 104” wheelbase and 64” centre of tread width. The windows are polycarbonate with a replaceable tear off film applied to the windshield. Any chassis can be re branded by changing the bumper supports and body. 15” diameter x 10” wide,
5×5 painted steel Basset racing wheels are standard. A series spec aluminum wheel is also available but all wheels have the same minimum weight of 18lbs.
Stopping power
On the Howe chassis the standard master cylinders are Howe G3’s with remote fluid reservoirs. The standard calipers are Wilwood 6 piston front and 4 piston rear. Optional caliper choices include Performance Friction ZR34 and the new Stop Tech 4 piston . Standard Rotors are the AP “J-hook” in the front. The diameter is limited by rules to 12.19”. The rear rotors are 11.75” solid mounted. New for 2014 the front hubs have been upgraded to an independent hat and floated rotor mount for improved brake performance. High output SRS Brake Fans are now standard.
Suspension
The front suspension is a double wishbone type with low friction ball joints and a-frames. Hypercoil brand springs are standard and include tenders to maintain engagement when raised. The rear suspension is the three-link type with an adjustable panhard bar or an optional watts linkage. Cars are built to fit any 1/2” bearing mount coilover type racing shock. The Penske 7500 series aluminum body shocks are standard. You can upgrade the single adjustable 7500SA or a double adjustable 8300 series with remote canisters. Double adjustable RE Ohlins shock are another option that is approved for TA2.
The ‘Muscle’
The chassis will accept most V8 racing engines but if you intend on competing in the TA2 class the choices are restricted.
A Schwanke LS3 is currently our standard engine. For competing in TA2 with a Camaro body. In TA2 legal form a restrictor is installed to limit the power to 475 with a 6800 rpm limit. For open racing the restrictor may be removed and rpm limit raised to bump the power up to near 580 h.p. The engine is equipped with a 3 stage dry sump oil system with the 10 quart aluminum dry sump tank. A Wegner or Katech built Chevy LS3 are also available at a higher price. The
current Trans Am approved Ford engine is the sealed Phil Harper TA2 Ford. The works Challenger uses a new TA2 specific aluminum Hemi. Exhausts typically feature ceramic coated headers and a muffler to keep the sound below 100 db at 100 feet.
Really shifting
The class rules specify a stock car type non-sequential 4 speed with an H pattern shifter. In 2014 and on the Challenger Howe opted to switch from the well known Jerico 4 speed to a G-Force T101, though the Jerico is still available as an option. The standard clutch is a Quartermaster 7.25” three disc housing with two special thickness “Rally” discs to allow for taking off with high speed gearing. This clutch is part of a package that includes an aluminum bell housing with a reverse mounted starter.
The Challenger is fitted with a Tiger quick change rear end equipped with a Detroit locker. The rear end has an integral mechanical cooling pump with and external cooler. The Tiger rear end is assembled with high strength ARP ring bolts to improve durability for heavy down shifting.
The class is cost capped with a complete car costing less than $100,000 to produce and even less to operate for a season. The engines are restricted to just under 500 horsepower.
A full analysis of the TA2 class and Trans-Am will appear in a future issue of Racecar Engineering.
Stockcar Engineering does for NASCAR what Racecar Engineering does for Formula 1.
Covering the cutting edge technology of stock car racing, it is a highly targeted and hardcore technical publication read by those responsible for engineering and running stock cars at all levels.
Whilst other publications focus on Cup or circle track racing such as Modifieds and Late Models. Stockcar Engineering is only concerned with the application of advanced technology throughout oval racing.
From British Short tracks to Sprint Cup races at Talladega Stockcar Engineering covers it all, just as long as it is high tech!
You will not find set up tips or step by step how to guides, instead you will find the latest advance engineering solutions and their applications in racing. Often before they are even common knowledge in the Cup garage!
In the new issue we take a look at how the new rules change Sprint Cup, Mike Coughlan reveals how new rules in Formula 1 will change stock car racing. Some unfair advantages can be found in our products section and the failure of CFD to dominate NASCAR is explored.
