...what I know piece by piece.
Gen2 engines are worn, for a new engine you need new rings, bearings, gaskets, arp head studs, bc valve springs, valve seals, water hoses (stoney kit plus genuine), gates high performance timing belt (gen depends on oil pump/sump combination), water pump, highflow thermostat - and spend a few thousand) plus. Gen5 motor (2008 onwards) is a ten year old motor - not anywhere near new and cost you the same as all your new components above and you won’t know the condition and hoses / gaskets may need replacing sooner than you expect.
Block Gen2. There are many Gen2 blocks good available. I have one at a standard 86mm in good condition (not currently for sale), Falcon has some at varying bores (send down on e-go for cheap), many around. Machining cost ($1,000 depending on machine shop).
Block. Different design in the block is close non existent in a gen4/5 to gen2 (strength) - all only good for sub 400rwhp as a daily (yes there are exceptions to the rule). If anything a closed gen4/5 motor is worse than what you have in many aspects and known for exceptionally weak rods.
Oil flow. Gen5 has a majorly different oil pump (15mm gator vs 13mm)/ sump combination. You can use the 5s late model or ATS Racing high flow oil pump ($350 delivered) to achieve the same as the gen5 oil flow with a Gen2 sump. Or look for a gen3 sump (no crankshaft trigger, slightly less oil flow at pump than a gen4/5 however ample) or 4/5 sump (crankshaft trigger).
Oil Cooler. Oil cooler is different but can adapt different oil coolers. Oil cooler is different as the gen3-5 has the oil filter at the sump.
Ecu. You have a link ecu, far more customisable than a gen5 ecu. Adding a gen5 ct15 and it’s associated cams will be a bigger retune than rebuilding what you have.
COP. I have one spare COP plate adapter ($100) or their are RacerX plates for Gen2 head. Buy plate and smart coils ($200), you have a link ecu that can trigger COP.
Manifolds and turbos. Manifolds both intake and exhaust are different between gens. To use your turbo being better than the ct15, will require a gen3 exhaust manifold or custom cut and tap the ct15 manifold. Personally, use your Gen2 manifold, an ats straight throttle body inlet, tvis delete plate or phenolic spacer, gasket port match your exhaust manifold, your turbo, and you have the best flow at above stock boost pressure at best price.
Camshafts. Gen3-5 has a slightly higher lift and duration. Buy aftermarket camshafts ($450 second hand - $1000 new) or n/a camshafts ($200) for even better performance than gen5 or buy gen3 camshafts ($300) for same performance as gen5. Adjustable camgears ($300) will net a little more power again. Camshafts are necessary to put more fuel and air in the engine to achieve more hp - not just higher boost aka manifold pressure.
Overall, update your motor and you will spend all your money and have a new motor, more performance, COP if you really want them (ATS Racing own daily driven vehicles at 500 - 800rwhp cars use spark leads). Or buy a gen4/5, watch your spending and let us know how it goes.
Build it your way, your choices, my list is overkill, just hope my thoughts help ensure you get your Mr2 back on the road for the least cost and most enjoyment (reliability). :)
post edited by TonyMR2 - 2018/10/10 15:27:56