Hi, I realise this has probably been asked a lot, but i can't for the life of me find any info regarding an engine swap, apart from a few silly comments like; buy a new car !

I have a 2005 mk2 focus 1.6lx with the sigma 100bhp engine

Is there any straight, bolt on swaps ? say to a 2l version

How hard would it be to go to with the 2.5L turbo ST engine ?

any info greatly appreciated !

Hi Jakub,

At the end of the day a straight swap works only as that - a swap of like for like. Now the issue you have is that you want to upgrade to a bigger engine, which will probably need new engine mounts, a loom that is catered for that particular size and shape engine (in which case you may find you need a new loom) the new engine may also have different connectors (again the reason you may need a new loom). The turbo may also need upgrading, depending on the number of miles and health condition as it may cause underboost and error codes on the ECU. You also have to bear in mind that the ECU will need to be tweaked to cater for the new engine, as too likely will the GEM.

These can all be relatively easily overcome, but engine swapping is a bit of an art, and upgrade is normally only done by those with a thorough understanding of the engine bay, electrics and parameters of each car in each model and engine, or has this information readily available.

You could probably easily overcome this, by visiting http://eucatparts.com/?action=cat_ford and browsing through the engine that you have and want to swap to, checking the part numbers of the looms, turbo's, brackets etc and if they are like for like, its achievable, alternatively, if they are different part numbers, you would need to compare the parts and their mounting options and upgrade as appropriate. But you still have to get someone (or if you have the knowledge do it yourself) to code the car and engine together, otherwise the ECU treats the 2.5 as a 1.6 and thats quite a jump which will cause errors at best, or a non runner at worst.

It would probably be cheaper and easier to just buy the car with the engine you want, that way you know it'll be working and fit, no worries with insurance and no worries with selling it on later.

Focus ST engines don't come cheaper either, a complete set up will cost a few K once you've bought the box, turbo, manifold and exhausts, you'd essentially need every component in the engine bay of one to make it run properly, and then the wheels that come with it otherwise smaller wheels will just spin.

True, that also leads me to remember as I forgot, that the gearbox and clutch would also need upgrading. These are in place for a level of torque and ratio, so although you have more power, you dont have the tools to cope with it, meaning you would likely shred the clutch very quickly and the gearbox ration would mean the power is in the wrong place and not getting the best out of it.

Also driveshafts, hubs and suspension, as it's all linked components, will be very very expensive, long gone are the days of dumping Saab turbo engines into Mk3 Astras and just requiring a loom adapter and a few other cheap mods.

The reason people say buy another car mate is youde be cheaper its not like the old days where you could swap engines over the wiring the ecu needs replaced the gearboxes are different i have the 115bhp ti vct 1.6 same gearbox on paper but it has subtle internal differences the ecu the mapping is different the engine sits differently in the bay

It can be done but as said ude need a whole car and if you had that whats the point