Super Street Network

 |   |   |  1973 Triumph TR6 - Project Car

1973 Triumph TR6 - Project Car

Part 4: A triumphant return

Rob Mullner
Jul 30, 2008
Epcp_0808_01_z+triumph_tr6+side_view Photo 1/2   |   1973 Triumph TR6 - Project Car

It's been a while since my 1973 Triumph TR6 graced the pages of this fine magazine. I'm pleased to report the time away has been well spent. Since the last installment (ec, April 2006), I've fixed most of the TR's perennial problems. And of course, added more power.

One of the more unsettling IRS TR traits is rear torque steer, which occurs at the most inopportune times. As the car is wound up, usually shifting from second to third, the tail will lurch to the right. The combination of stock trailing arm bushings and open differential amplified this behavior. Fortunately, the Moss Motors catalog is chock-full of solutions, so I ordered upgraded Prothane bushings and mated them to Goodparts adjustable trailing arm bushings, allowing a greater range of camber adjustment than the standard frame shims. The final piece of the rear-steer dilemma was solved with a Quaife ATB differential, which distributes the brunt of the torque to both halfshafts, rather than shunting it to one unsuspecting and unprepared trailing arm.

Epcp_0808_02_z+triumph_tr6_engine+top_view Photo 2/2   |   1973 Triumph TR6 - Project Car

With rear steer under control, I went on the quest for more power. As luck would have it, Moss Motors had been developing a bolt-on supercharger kit. My car was used as the R&D mule and, over the course of a year, it was taken apart, measured, poked, prodded and fine-tuned. With an additional 40 hp and 35 lb-ft of torque at the wheels, the car is a newfound joy. Since then, I've driven thousands of miles of California back roads, hooning to my heart's content. Supercharging fits the straight six perfectly, with a broad and instantly accessible powerband. The only downside to all this project progress is the pile of accumulated parts waiting to go on, including a fresh set of GTS Classics seats. Since I'm already having so much fun, I'm reluctant to take it apart any time soon, but keep an eye out for future upgrades and more in-depth information on the supercharger.

By Rob Mullner
4 Articles

BROWSE CARS BY MARKET

MORE HOW TO

Our friends up in the Bay Area step up to help us get our EK hatch project back on track.
Sam DuApr 29, 2016
Paint matching Jofel's carbon fiber hood.
Jofel TolosaApr 26, 2016
For just under $2,000, we upgraded the iM three-fold, with better looks, more grip, and nicer handling.
Sam DuApr 20, 2016
CLICK TO PLAY WITH AUDIO
Adding some 19-inch VMR Wheels, Continental ExtremeContact DWS tires, an EBC brake upgrade, and a few winterizing bonuses
Michael FebboApr 14, 2016
Raceland brings moar low for the BMW E9X 3-Series with its coilover suspension kit
Bob HernandezApr 14, 2016

SEARCH ARTICLES BY MAKE/MODEL

Search
TO TOP