Improving performance from a series 2 4.2 roadster

[rtvet21]

Hi
CAn anyone point me in the right direction as to how one can start to look at improving engine peformance from the viewpoint of acceleration, top speed for a 4.2. Now I guess many will say why ? I guess I am interested in which order one would look at this. Is better ari filtration or no air filtration a good start, should I look at timing . Are there changes to needle size of SUs or is this a waste of time. Is gas flowing the heads, lighter flywheels etc the best way forward. The car has covered 50,000 miles, and runs well ( except for my early hassle of vaporisation) and now I am attacking the radiator etc for that problem, I wondered what else could be simply done

Hope nobodies offended

many thanks

[Heuer]

There are no simple fixes to increase the power of the XK engine. You could put ITG air filters on but this means the SU needles need to be changed to compensate. Better breathing works if you have uprated the engine but otherwise it will be purely cosmetic. You could consider electronic ignition but whilst it will possibly improve tick-over and simplify maintenance you are unlikely to see better acceleration. Lightweight flywheels will improve acceleration but make the car difficult to drive smoothly in traffic so best avoided. Classic Fab manifolds and exhaust will increase power output but you must fit their venturis to the silencers if you want to avoid a torque dip at 2,250 rpm.

So lots of 'but's' in there, there are consequences for every change. If you are in the UK you could send the engine to VSE and ask for their 02 spec re-build. This will give you about 280bhp and 350 lb/ft of torque which should bring a smile to your face but expect a lumpy tick-over. Their engine has been developed as a package so all the pieces work together something you are unlikely to achieve by doing it piecemeal.

[rtvet21]

Thanks , I need to look into the Buts more closely. Maybe from what you are saying this is not an easy option and a rethink is needed