When tuning your 121 it is important that you get it right so follow our 121 tuning overview and see which the best modifications are.
Available in standard form with power of upto 77bhp (depending on the year), so this goes to show the tuning potential of the 121. From this you can increase the power from anywhere between 84.7bhp to 130.9bhp with modifications varying from a few DIY mods to some pretty major engine work. The higher you go the more unreliable the car will be and you should expect to have to rebuild the engine regularly if you want to extract silly power. A big forced induction upgrade would be needed to push beyond the 100bhp per 1000cc limit.
An engine swap with that from the 77bhp 121 Hatchback will give a massive power gain and provide a better base to work from. Lighter cars respond very well to tuning, if your car is heavy then your first job should include weight reduction. Car Tuning Guide have been impressed with the addition of fuel pressure boost valves on the 121s , if you want to improve your throttle response get one fitted! The Car Tuning Guide recommend that on the 121s , you get a fast road cam.
NOTE: POWER GAINS ARE PROPORTIONAL TO YOUR BASE POWER. The more you start with the better your gain will be. Doing an engine swap will give a better result than modding a small engine. Turn your attention next to the 121s engine head. With a good gas flowed ported engine you will see much better mid and peak range power and some owners have reported more economy. The 121s handling can be dramatically improved with some choice suspension modifications. A drop of 35mm will work well on most cars, any lower and you will hit other problems.
Check back frequently for updates as we will be adding more detailed tuning guides to this site.
Here are some motoring links who provide some excellent resources on all aspects of car tuning and modifications:
Car Tuning Forums A really friendly chat forum aimed at car modders.