Like any passenger car, there are a various compromises that were made as the Spitfire made it's way to various markets around the world, and based on market demands/expectations and regulatory requirements.
For myself, I had a couple of issues I wanted to address:
Brakes. Everything else on the road today has ABS. I need my brakes to be the best they can be.
Engine. The EU cars has almost 2X the HP of the mid 70's US cars. I targeted 80-90 reliable HP so the car can get out of its own way. The stock US engine had terribly low power by the mid 1970s. (I am roughly stage 2 on Paul Geithner's chart)
Handling. The stock suspension is bit high to meet US bumper height requirements, and the suspension as a whole is a bit soft. The car has some nearly ideal physics in terms of ride height and mass. It can do a lot better without major surgery.
What did we do?
Brakes/Suspension. I kept the stock calipers and rear cylinders. I installed Earl's stainless steel flex lines. These don't expand under pressure so you get a much more solid feel on the pedal. Some like it, some don't. I also installed vented rotors and Mintex high performance pads. They are a bit noisy and dusty, but they work great. If money and time were no object I might swap in some GT6 uprights, hubs and brakes, but these work well enough for the street. Are vented rotors overkill on this car? Probably. It's light, and we're not going on a track any time soon. But it felt cool.
I wound up not painting the calipers, but got everything else updated
End state, with upgraded rotors, Spax adjustable shocks, 1" lowering sport springs (25% stiffer), Earl's stainless steel flex lines and a 1" front sway bar in poly bushings. The steering rack is in on Aluminum blocks. The alignment gave us -1 deg of negative camber up front and just a touch of toe-in. On 175/70R-13 tires it handles very respectfully.
One of the aluminum steering rack mounts. What a great modification! The steering rack with a good firm attachment and then a good alignment is really wonderful.
Spax & Earls lines out back.
ENGINE
Carbs and breathing are very important. These are EU spec HS4's. We're using ABT needles which are running fine even with the engine mods. The intake manifold for the SUs is much better than the Stromberg manifold. No 90 degree turns for cyl 1 & 4, just a nice straight shot into the engine.
This is the Moss 4-2-1 Stainless steel header. Even if you leave the intake alone and use a stock muffler, a header is a great way to get more power and actually keep the engine a bit cooler. They do not make it loud. The stock manifolds are heavy (cast iron) and they tend to crack. They also do not breath well.
Custom Lucas D22 distributor built by Jeff at Advanced Distributor (re-curved for carbs/header, etc), an oil cooler and we're cheating and using a Fram PH8A oil filter (Ford F series normally..) Bigger is better. And cooling is always key. I still use 2 fuel filters because the last thing you need is crud getting into the carbs. Those needles are your fuel map (an analog computer, more or less)
Big valve heads, the business side. Those marks are from getting shaved. This is after getting cleaned up during a head gasket job. The pits in the intake valves were earned.
A little detail on how we ran the oil cooler lines. I also had the radiator customized with a larger (thicker, denser) core which increases its capacity. Finally I also added a thermostatically controlled electric fan for those times I might get stuck in traffic on a very hot day. I also run cooler plugs since the comp is now 9.5:1. (BP6ES)
EU spec dual valve springs were fitted to the head
We bored the block .040 over and installed 9:1 pistons. We also shaved the head a smidge; (.063") the net compression is now about 9.5:1. Stock was 7.5:1. The "UE" suffix on the block indicates low compression and big valve heads. (This is during a head gasket repair years later. ) and of course, balanced it.
The Moss Europe dual exhaust is really very nice. Not too loud, just right, it fits well and it looks really nice.
For a while I replaced my radius rods with these racing bits. The handling got a lot nicer, but they do rattle a bit as they age. They needed spacers on both sides to fit the stock brackets too. (not pictured)
The final stance; down 1" up front and we used a 3/4" lowering block on the differential in the rear.
The last thing was a new set of 175/70-R13 tires and a 4 wheel alignment including caster, camber and front & rear toe. That makes a huge difference. Camber is set by shims under the lower front A-arm. Caster is set by using unequal numbers of shims in the front or rear of the lower A-arm. It sounds odd, but it works. I stick pretty close to factory specs there but with 1/16" toe in up front and rear, and about -1 of negative camber up front.
References:
Paul Geithner's amazing site: http://auskellian.com/paul/links_files/performance_enhancements.htm
The wonderful folks at the Triumph Experience forums
Dave Braun - SU carb rebuilds and great tuning advice! www.dbraun99.com
Comments