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LIGHTWEIGHT K3 PROJECT (TALON GTM K3R)
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In late 2006 we acquired a part built GTM K3 kit. The car was intended by its original owner to be a standard road going 1.4 K3, but we had other ideas! We are converting this car into a lightweight trackday toy. In keeping with our traditional ethos regarding such cars, we still intend this car to be fully road legal and fully reliable, but to convert it we intend to remove all unnecessary weight, fit a 1.8 VVC engine and change the rear subframe to MGF. Other modifications will include a PG1 gearbox, 14" wheels, cable gearchange etc. The engine will be totally standard, ensuring maximum reliability, but in a lightweight car the 143BHP delivered by the MEMS2J system should be more than entertaining.
Key to the success of this car will be the 6 point rollcage. As the K3 is an open top composite monocoque design, cutting large chunks of it out to save weight is guaranteed to reduce torsional stiffness, which the rollcage needs to compensate for. To that end it will be tied in to the cross braces at both the front and rear of the monocoque, and into the rear subframe mountings.
You can follow the progress of this project here .....
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DECEMBER 2006
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Strengthened Rollcage Mountings
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Main Rollcage Hoops Fitted
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Roof Test Fitted
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Reconditioned Rear Subframe
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We started by stripping the car back to almost a bare monocoque. The only thing we left fitted was the front subframe, which had been re-conditioned by the original owner and was in perfectly serviceable condition. Having stripped the car we then cut out the dashboard moulding and the rear cross box section. The dashboard moulding is an extremely heavy item just to house a few instruments and a pair of sunglasses so it's completely pointless in a track car. The rear cross box just gets in the way and takes up valuable leg room and the strength lost by removing it will more than be replaced by the rollcage.
Having removed the rear cross box we quickly realised that the floor below it was nowhere near strong enough to support the roll-cage adequately so we laminated in approx 1/2" thick matting to provide a positive location.
In order to fully weld the rollcage we had to make it as two side hoops with the cross bars fitted afterwards, otherwise it would have been impossible to get the welder into the foot sections. Even then we had to make the side hoops in two halves and sleeve weld them at the top, but we ended up with a 100% welded cage. The rear brace bars were a challenging shape but we're very pleased with the final result.
The only other job completed in December was reconditioning of the MGF rear subframe we intend to fit. The standard K3 uses a modified Metro front sub-frame in the back, which leads to some 'interesting' handling characteristics, so we've opted for an MGF rear subframe instead. This should not only improve the rear stability of the car, but it also enables us to use MGF rear brake calipers, complete with a working handbrake. We've also fitted new bushes and bearings and made solid bushes to bolt the whole thing to the monocoque with as we considered the original rubber bushes to give too much flex.
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JANUARY 2007
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1.8VVC Engine Being Rebuilt
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Rear Subframe Fitted
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Fuel Tank Recess Removed
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Engine/Gearbox Fitted
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The engine we had lined up for this project wasn't one we had had the opportunity to test run, so we opted to strip it down and rebuild it, replacing whatever parts were necessary. As it turned out it was in virtually perfect condition internally so all we had to do was re-seal the liners and fit new gaskets.
We've fitted the rear subframe mainly so that we can get the car onto its wheels to move it about. When the time comes it will get new disks, calipers, pads etc. Because we're going to use a PG1 gearbox from an MGF, as opposed to the Metro gearbox originally intended for the car, we had to sligtly re-shape the nearside gearbox mounting bracket as it fouled on the rear bulkhead in its original form.
When fitting the engine and gearbox assembly we discovered that the VVC top hose outlet fouled on the fuel tank recess moulded into the rear bulkhead. All we really needed to do was remove a small section of that recess, but since we're not going to fit the fuel tank there anyway we've opted to remove the whole recess and later we'll laminate in a new flat panel.
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AUGUST 2007
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Well, its now the start of August, and having shelved this project for 7 months due to other commitments we've resurrected it again because we need a car for the VAB Autohappening in Zolder, Belgium, in 7 weeks time!
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Custom Pedal Box
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Rover 200 Front Brake Upgrade
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The original K3 design utilise a standard Rover Metro pedal box, complete with cable clutch and servo assisted brakes, and both are a weakspot on the car. We already sell a hydraulic clutch conversion for the K3, and since our gearbox was from an MGF and was already hydraulic we fitted the conversion to this car as well. In addition we manufactured our own pedal box, using a Rover 200 master cylinder but without the servo. To compensate for the lack of a servo we lifted the fulcrum considerably and manufactered a brake pedal with a 4.2:1 lever ratio. This should make the braking considerably easier than on the original design yet retain a consistent feel.
The front brakes have been upgraded to Rover 200 calipers using our Metro upgrade kit whilst the rear retains the standard MGF setup. New discs and calipers have been fitted all round, complete with EBC Greenstuff pads and new handbrake cables. The Rover 200 handbrake has been grafted onto the inner steelwork.
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Rear Brakes Complete
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Gearchange and Handbrake Fitted
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We've also incorporated the MGF cable gearchange setup into the inner steelwork, and relocated the fuseboard, which used to reside in a part of the dashboard that we've now removed. This entailed considerable lengthening and relocating of dozens of wires in the wiring loom, but it makes for a very neat installation.
On the subject of wiring, a standard K3 has an engine extension loom that runs from the multi-plug at the front of the car that used to go to the engine, all the way through the car to the back, where the engine now resides. This loom contains 10 wires, and doesn't allow for an electronic speedo, which requires another cable to be pulled in. We thought we could improve upon this and investigated the standard loom and discovered a lot of wires that go to the back of the car that aren't used. In fact, on our loom there were 14 wires that ran the length of the car that weren't used, so these have now been re-allocated to run the engine, which means we don't need the two extra looms. This not only makes the installation a lot neater but it also saves more weight.
To be continued .......
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