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Michael's Speed Zone

25th June 2002

By Michael Knowling

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It's great when you come across someone who knows every last detail of an engine.

For me, meeting Mitsubishi Australia's engine development technician - Rod Campbell - was like striking it rich. At last, here was somebody who knew the answers to all those questions I had about piecing together a mumbo-rich Magna V6.

I suppose I'd better come clean. I've been contemplating powering-up a current-shape V6 Magna ever since I was stunned by the performance of a 163kW 3.5-litre TJ Magna VR-X equipped with a 5-speed 'box. Over the last few months, I've kept a keen eye out for cheap second-hand Magnas with plans of maybe 'VR-Xing' one.

But the big question is, which of the second-hand Magna models is the best platform for mods?

The Second-Hand Market...

The current shape Mitsubishi Magna kicked off in 1996 with the TE and TF model. Both series came powered by a choice of two engines - a 2.4-litre four-cylinder and a 3.0-litre V6. Of course, the 3.0-litre V6 is vastly quicker than the four, but why on earth would you bother looking at modifying one of these given the availability of the later 3.5-litre engine?

Building a quick Magna using the 3.0-litre V6 as the base is only making things hard for yourself.

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The next Magna series - the TH - started in 1999, bringing the availability of the 3.5-litre V6. The 3.5-litre engine was standard fitment to the Sport model and offered as an option on the rest of the range.

Oddly, though, the TH's 3.5-litre engine isn't as great to drive as you might believe. Sure, it had an extra 7kW and 45Nm (totalling 147kW and 300Nm), but the sweet-revving nature of the original 3.0-litre V6 had been lost. As we said in our contemporary new car test "The engine has been cammed to give that beloved Australian ignition-on instant torque, but don't expect high rpm performance to be strong..."

The TJ model Sport and VR-X were the first real performance Magnas.

Debuting in 2000, the TJ Sport (and the newly released VR-X) received a fair swag of extra power and torque over its predecessor - up to 163kW at 5250 rpm and 317Nm at 4000 rpm.

Surprisingly, the 16kW power hike over the TH's 3.5-litre engine came primarily from the fitment of a less restrictive rear muffler. The camshafts are also different to those found in the TH - the entire TJ range received the camshafts originally designed for the North American market.

Of course, accompanying these changes is revised engine management mapping.

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On the road, the 5-speed manual Magna Sport/VRX is a real flier - certainly, its low 7-second 0-100 km/h performance is more than capable of sinking a few egos at the traffic lights...

For me, the only 'problem' with the TJ Magna Sport and VR-X is they are still the current models - therefore secondhand examples are still quite expensive. I suppose the next best affordable option would be the TH Magna Sport. Of course, they aren't as impressive as the TJ Sport/VR-X in standard form, but - with essentially the same 3.5-litre engine - they've got the potential to be every bit as good.

The Search For Power...

A lot can be learnt from the Mitsubishi's new Ralliart Magna. Having spoken to Rod Campbell about its development, it's obvious this is the car anyone into hot Magnas should be taking notes from...

The Ralliart beastie pumps out a substantial 180kW at 5500 rpm and 333Nm at 4000 rpm.

So what sort of equipment is used to pick up this extra power and - secondly - can any of it be applied to a second-hand Magna?

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The Ralliart Magna uses heat-coated tubular extractors that will happily bolt to the heads of any TE-TJ Magna V6. On the other hand, Rod tells us the standard cast iron exhaust manifolds flow very well - the Ralliart extractors "are worth only a couple of kilowatts here or there".

Note that these extractors are longer than the standard cast manifolds, and - as a result - they require a new joining pipe. No performance advantage comes from the Ralliart's replacement front pipe - its only there to get gasses from A to B.

A 'bomb' style centre resonator is also fitted to improve the exhaust note.

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The rear section of exhaust is just as you'll find on a TJ Sport/VR-X. There's the same muffler that picked up a heap of kilowatts over the item used on the TH model 3.5. No changes here.

Interestingly, Rod says there's not much more to be picked up from further mods to the exhaust. "At one stage we tried a straight length of pipe with no mufflers and it made no more extra power." Exhaust backpressure in the Ralliart Magna is said to be less than 400mm of mercury (53 kPa).

And now we get into the guts of that 180kW 3.5-litre bent six.

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The only other components from the Ralliart Magna that are semi-easy to adapt to other models are the two camshafts (one for each bank). Rod says much of the Ralliart's power increase came from its camshafts, which have 10 percent more lift and an increased ramp rate compared to those used in the rest of the TJ line-up. "It's as big as we could fit through the bearing tunnels," admits Rod. Cam timing is set at 6 degrees retarded.

With the Ralliart's cam profile chosen, testing by the parent company in Japan later revealed that the standard valve springs had pretty marginal durability. As a result, the Ralliart uses nitrided versions of the standard springs. These can be fitted along with the bigger camshafts if you want the extra 'insurance'.

The rest of the Ralliart Magna's power comes from modifications that are not easy to adapt to an already built Magna.

Rod explains the Ralliart engine maintains excellent low rpm torque because it has reduced inlet and exhaust valve shrouding. The material right up against the side of the valve heads has been relieved, with the aim of increasing intake velocity particularly at small valve openings.

This handy gain is popular around the Mitsubishi camp because it came at zero cost. With all of the head machining performed 'next door', it's only a matter of changing the machining patterns. No new hardware.

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The Ralliart also boast an increased compression ratio thanks to its shallow-dish cast pistons. These pistons bump up the comp ratio to 9.4:1 (0.4 above the Sport), but it's still low enough to allow the use of normal 91-octane unleaded fuel. Rod says 10.0:1 compression would be "a walk in the park" using premium unleaded, but - again - different camshafts would be needed and that would most likely require altered gearing.

The Ralliart Magna pistons also feature anodised crowns and top ring lands to prevent wear and blow-by.

Of course, the Ralliart Magna's ECU is remapped to suit its mechanical changes but Rod says all the V6 Magnas end up running full load air-fuel ratios of around 11.3:1. "We don't like to go any leaner because of the negative effect on piston-to-bore clearance during endurance testing." Ignition timing is carefully optimised throughout the rev range and the speed limiter has been raised to 240 km/h.

So where does all this background info leave us?

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Well, without going through the hassle of modifying the heads and changing the pistons, Rod says it's easy to pick up power just by slipping in the Ralliart cams into any of the 3.5-litre V6s.

Note that the TJ Sport/VR-X's low restriction rear muffler is a prerequisite if you want decent exhaust flow.

During the development stages, Rod says they whacked a pair of the Ralliart camshafts into an otherwise stock TJ Sport and picked up around 5kW. The standard (non-nitrided) valve springs gave no trouble despite vigorous testing.

You can easily add the Ralliart extractors and front pipe as well. This, together with the camshafts, should give approximately 7kW total over the standard TJ Sport/VR-X - 170kW.

And that's without any expensive ECU changes or major engine teardowns!

Thankyou Mr Campbell, you've been more than helpful...

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