Tremendous power

Totally equipping the TR6 to triumph

Take one Italian styled British sports car, add a touch of German modernisation, and you have the Triumph TR6. As butch as a TVR but without the kit-car image, there was nothing new about the TR6 when it finally hit the streets in January 1969. German designer Karmann did a fi ne job, giving the car a square-cut look that was right on the money for the start of the 1970s. Today, and with just under 8000 UK cars, there’s more than enough good ones around still to allow you to be picky when buying one to tune and improve.

BEFORE YOU START

Bear in mind that 80 per cent of all TRs were exported to America, but a good many have found their way back here and been converted to RHD. Generally, if the job has been done right it’s no problem, but remember US cars run on carbs and a detuned cylinder head (which at least already has unleaded valve seats fi tted) plus lower axle ratios. As with any classic, rust is the biggest concern. Whilst replacement chassis and body parts are easily obtainable from leading specialists, it’s a costly road to embark upon. Main rot spots are chassis frames and outriggers, front and rear suspension pick up points, steering rack brackets, inner sills, front and rear bulkheads, fl oors and around the window frame, particularly at its base. Make sure the doors shut properly, that the gaps are uniform and they don’t foul the body. They weren’t perfect when new, so if very bad, it’s probably because the shell has lost its rigidity due to excessive corrosion or been poorly rebuilt with new sills. Have a proper prod at the sills and B-post – and check that the mating seams are all evident. If not, there’s filler in it. Check the front and rear suspension pick up points. These rot and the diff mounting brackets (and trailing arm attachment points) can tear off due to age, rust – and too much throttle! Many re-plate these areas, but it must be done properly. While underneath, check the chassis for distortion due to past accidents and the inside of the valances.

HOTTING UP

While you can wring out close to 200bhp from this old but gold engine, for reliable road use there’s no need to go so extreme, especially if it negates all that lovely low speed torque this unit is famed for. The latest bolt on booster is just that – a supercharger from Moss that at £2640 ups the 2.5-litre engine by 40 per cent, meaning the 125bhp engine jumps by 50bhp to 175bhp. Dan Allen of Revington TR favours a more traditional approach. “A lot of these cars will see power gains simply by being set up properly in the fi rst place – they’re all around forty years old now and many will have been set up incorrectly at some stage. If all’s well, a bit of porting and polishing and blueprinting will give an excellent basis to work from.”

A lighter fl ywheel is recommended, and an improved throttle body will improve responsiveness. Never be tempted to fi t a hot cam if you’re keeping the PI system – the system takes its fuelling timing from the cam, and any alterations can mess it up. A hot cam could well decrease power output! “We’d rather stick with PI,” says Dan, “We tend not to convert to carbs. But it’s viable using Webers or SUs.” This should net in the region of a usable 175bhp in total – no more. By the time you’re done you may well spend more than the supercharger. But if the two are combined a power output of 200bhp is theoretically possible.

However, with a better fuel pressure relief valve and Tefl on lined fuel hoses it’s possible to make your 200bhp in a far more up-to-date manner. If you’re lucky enough to have £6000 to spend on uprating your TR6, Revington offer a choice of EFi kits. Fully remappable, these alleviate the issue of thinner air at altitude as found with the original PI system, without resorting to oft-diffi cult multiple carb setups. EFi won’t increase power without further work, though torque levels and the torque curve should improve. It also enables the use of things like hairier camshafts, which along with head work will help hit that 200bhp target. We should stress though that this is far from a cost effective method of increasing power, and is better suited to more extreme developments and cars intended for circuit use. If torque is your aim the engine can be taken out to 2.7-litres – useful and cost effective if a rebore is needed anyway.

HANDLING THE POWER

Start with the suspension as it’s the best way to make a TR6 faster point-to-point. Cheapest mods are a set of adjustable telescopic shox (Koni, Spax, Gaz) and polybushing, if you can stand a harsher feel. Lowering this already low slung car can work to your disadvantage for road use. If money is no object, a tailored kit from Revington TR of Somerset (01823 698437), comprising special alloy steering rack, harder suspension bushes, telescopic rear dampers, new front and rear springs and new meatier anti-roll bars will transform the TR6, but the cost is around £1700.

The brakes are usually suffi cient for road use if serviced okay. Mintex or Greenstuff pads help, though Revington suggests a set of DBA discs and standard pads are a better solution for cars which rarely see track action. Four pot calipers are the next step, but it gets expensive. In standard trim the TR6 rolls on skinny 165x15 rubber. A swap to 185/70s is the ideal as it fi ts the standard rims, six inch on later cars. Some go up to 205/60 but most experts reckon it’s best not to go too mad here as the standard steering is already on the weighty side!

The standard gearbox is a sturdy unit, but many have opted to uprate them to Stag specifi cation with beefi er bearings. Overdrive was a common option; the A-type being preferable owing to longevity. “Deep piston” derivatives of the A-type are most sought-after. For many, the manual/ overdrive combo is adequate and the o/d can be uprated, but now you can opt for a full fat five-speeder from TR Revington (http://www.revingtontr.com) which uses a modifi ed Toyota Supra gearbox costing £4400. Dear and these gearboxes are scarce now, but it’s a straight bolt on meaning it can be reversed to original without detection. Revington also does Ford (Sierra) Type 9 based conversions from £3300. Quaife or Salisbury offer limited slip differentials, but these are both costly and largely unnecessary for roadies.