| Issue #1 - October 1998 |
In this issue |
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| Page 1 |
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The lastest rantings from the editor. [more]
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| Modifying the GT6 |
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So you want to make your GT6 go faster. Who doesn't? This article covers the basics of getting the most out of your GT6, and points you in the direction of the right resources if you need to find out more. [more]
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| My Spitfire/GT6 Restoration |
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OK, so this isn't a full restoration, more just a quick road-worthiness fix, but this is the first issue and I didn't have any reader contributions of the trials & tribulations of restoring a GT6/Spitfire. Watch this space. [more]
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| Again - My Spitfire/GT6 Hybrid |
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The first feature car has to be mine of course. It is a real bitsa, a Spitfire Mk3 body, GT6 Mk2 bonnet, seats and instrumentation and a 2000 engine. Not to mention the bodges that have been done to it over the years - but I have plans for the beastie. [more]
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- [back to new format] -
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| Triumph GT6 Ezine |
Article - Modifying the GT6 |
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Building a fast road car
OK, where do you start. Well first of all you need a healthy engine. It is pointless to try and extract performance out of an engine with low compression and no oil pressure. Might as well just set fire to your wallet. As with any car, if you are upgrading the engine, you should upgrade the brakes & suspension as well. I'll cover the engine first, as that is what everyone wants to know about.
Tuning the lump
The Triumph 6 cylinder responds well to a set order of performance modifications - extractors & sports exhaust system, improved carburation, attention to the cylinder head and then an uprated camshaft.
Exhaust
Starting with a good set of 6-into-2 or 6-into-2-into-1 extractors helps to improve midrange power. I have also heard of 6-into-3-into-1 system that improves top end power with some sacrfices to low end power.
Back this up with a twin silencer sports exhaust system (make sure both extractors & system have been mandrel bent so that the pipe isn't crushed restricting flow).
Intake
As a bare minimum, fit some free-flowing sports air filters, such as K&N, and surround them with a cold-air box which gets air from in front of the radiator. The next step is to ditch the Strombergs and fit twin 1.75 HS6 SUs, which will require adaptor plates, the right needles will need to be fitted and some additional modifications. If you have a reasonable amount of money, invest in a set of triple Weber or Dellorto 40s (45s are too big for the road) and the appropriate manifold. If you really want the ultimate setup, there are fuel injection systems available for the GT6 (SAH used to produce a system) and undoubtedly you could have an EFI system made up.
Head Work
If you have a Mk 1, the head will need considerable amount of work on ports and chambers, the best bet being to go for a flowed head with larger inlet valves. The later heads are better material to start with, and carefully porting and flowing the head will give you reasonable gains, but go to bigger valves for more gain.
The rocker gear can be worked on, the rockers can be lightened and polished, the spacer springs can be replaced with solid spacers and Tuftrided rocker shafts are available. The ultimate conversion though (for those with deep pockets) is a roller-rocker conversion (I know that Triumphtune have this kit available).
Cam
With camshafts, there are a lot of options. Most suppliers have a fast road cam and that would be your best bet. The best thing to do is go to your (hopefully reputable) supplier with your engine details and what you want the engine to do and let them recommend a cam for your car.
It is highly recommended that you fit the duplex timing gear from the 2.5 engine.
Conclusion & further reading
That is the bare basics for tuning. I'd highly recommend that you head to Egil Kvaleberg's 2000/2500/2.5 page and go to his excellent tuning page. It contains a lot of great information, and further reading.
If you want to race your GT6, I suggest you get hold of "Kas" Kastner's "Triumph Competition Preparation Manual Part 1 GT-6 and 2000", Brooklands-Heritage, ISBN 1 88520 0678.
Most of the information in this article came from Ted Connolly's article "GT6 Power Tune" in Issue 1 of Triumph World Magazine. Subscribe or miss out on a fantastic Triumph reference library.
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Next Issue - Modifying the Spitfire.
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