| Issue #2 - January 1999 |
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 Spitfire |
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This issue it's the Spitfires turn. A beginners guide to extracting some performance from the Spitfire's engine. It's not as simple as "let's whack some Weber's on it"... [more]
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| Peter Allott's Spit 6 Restoration |
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Peter Allott (based in Waterdown, Ontario, Canada) is in the middle of a frame up restoration on his Spitfire Mk4 with GT6 running gear. Well, actually the car is for his wife Lynn. [more]
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| Steve Smith's Racing GT6 |
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Steve Smith (based in Las Vegas, Nevada, USA) has been racing his MkII GT6 in Vintage races since 1990. The car is extensively modified, and really looks the biz. [more]
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| Your Stuff |
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Reader contributions - letters, photos, etc.[more]
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- [back to new format] -
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| Triumph GT6 Ezine |
Article - Modifying the Spitfire |
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Starting point
Once again you need to start with a healthy engine. I know it seems obvious, but it is worth stressing again how pointless it is to try and extract performance out of an engine with low compression and no oil pressure. Also, everyone repeat after me, if you are upgrading the engine you should upgrade the brakes & suspension as well (I should listen to my own advice, my Spit 6 remains as bought with the standard Spitfire Mk3 brakes/suspension & scary is an understatement).
If a lot of this article seems similar to the last article, that is because it is. The Triumph 4 cylinder responds to the same basic tweaks as the Triumph 6 cylinder.
Engine basics
The Triumph 4 cylinder responds best to the same set sequence of modifications that works for the 6 - extractors & sports exhaust system, improved carburation, attention to the cylinder head and then an uprated camshaft.
Exhaust
A good set of 4-into-2-into-1 extractors backed up with a straight-through silencer sports exhaust system should take care of the duties of removing spent gases. Make sure both extractors & system have been mandrel bent so that the pipe isn't crushed restricting flow.
Intake
Start by fitting 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 upgrade the HS2 SUs to HS4s with the appropriate manifold. Next up consider a single 45 Weber, or even better, a pair of 40s - these of course require appropriate manifolds.
Head Work
Your best bet is to get the head gas-flowed, fit larger inlet valves and get the combustion chambers modified to remove sharp edges. There are a number of firms now doing exchange heads, TriumphTune springs to mind.
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.
More cubic inches
OK, here is where you can start getting a bit more adventurous. The Spitfire had a number of different capacity engines. Does your car have an 1147cc engine? Why not fit a 1500cc! But the best swap in my books (I have to say this as I own one) is to put GT6 running gear into a Spitfire. I know the purists shriek with rage when they hear this, and I wouldn't recommend doing it on a good car, but if you have a couple of dogs why not make a GT6 convertible. They are a truly superb car to drive - the acceleration from standing start is guarenteed to give you a face splitting grin.
Conclusion & further reading
That is the bare basics for tuning. I'd highly recommend contacting Moss Europe and getting a copy of their TriumphTune manual. While being a parts catalogue it also has a lot of recommendations and suggestions to help tune your Spitfire. Go to the links section and check the racing Triumphs section - there are a lot of people out there with extensive experience at making Spitfire's go fast.
Most of the information in this article came from Ted Connolly's article "More fire for the Spit" in Issue 6 of Triumph World Magazine. Subscribe or miss out on a fantastic Triumph reference library.
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Next Issue - Suspension tweaks.
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