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hello, I am new to the car world and I’m starting a project which is a 91 mr2 turbo. The car is currently not running so my question is is investing in repairing a 30 year old 3sgte engine (estimated 150k miles) worth it or would I be saving myself a headache by swapping it? Some of my concerns about the 3sgte are reliability and the cost/availability of parts.
 

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gen2 3sgtes can be built to be strong engines making way more power than a MR2 should have. The most dated feature on the gen2 and 3 engines are the distributor, it can leak oil and cause problems with standalone ems. Telling us your power goal would give us a good starting point for which generation engine you should swap or keep the gen2. If all you care about is power a Honda K series is the best swap you can do but also the hardest and probably most expensive.

Most people with a dead gen2 or 5SFE swap a caldina gen4.
 

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Thanks for the response! Ultimately id like to be around 300 - 350 but nothing over that. My main concern honestly isn’t whether the 3sgte can make that power but if it can make that power reliably and won’t be breaking down on me all the time. I guess a better question would be whether a 30 year old 3sgte after being repaired and well maintained would be as reliable as a newer engine ( a Honda k series for example).
 

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I recently completed a gen 2 refresh. The motor has 150k on it. I only Have the head redone. I left the block alone. Replace all seals, gaskets and belts. Oh, I got the turbo rebuilt with billet wheel. I am not a horse power freak. I drove a 5fse for 27 yrs, so jumping up to a turbo is good enough for me. It’s been 11k miles now, I have no issues with the gen 2.
 

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hmm sounds like an engine swap might be overkill in that case since I’m just shooting for a fun weekend car that won’t be breaking down on me too often. Ill keep the 3sgte then and spend money getting it back in working order which in any case should be far cheaper than an all out swap.
 

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A billet ct20b would definitely get you there on a gen2 you just need to figure out what you want to do with the ECU. Gen2 ecus can be rom tuned by ATS for 550cc injectors vs the original 440cc or you would have to go with a standalone.

A gen4 or 5 swap with a billet ct15b or 20b would also get you there, they come with coil on plug and 540cc injectors factory but the rods aren't as strong as gen2 and gen3.
 

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hello, I am new to the car world and I’m starting a project which is a 91 mr2 turbo. The car is currently not running so my question is is investing in repairing a 30 year old 3sgte engine (estimated 150k miles) worth it or would I be saving myself a headache by swapping it? Some of my concerns about the 3sgte are reliability and the cost/availability of parts.
Check this video of my ride.
 

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A gen4 or 5 swap with a billet ct15b or 20b would also get you there, they come with coil on plug and 540cc injectors factory but the rods aren't as strong as gen2 and gen3.
Gen 3 also have 540s, what would it take to swap a gen3 to coils?
If you had the gen 4/5 ecu could you easily make the swap?
 

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I had the bottom end built with forged internals in 2005. I push 330 rwhp. I also had head work done at the same time. Things have obviously broken over the last 15 years but not that. I push 20lbs of boost and ran the 1/4 mile until 2009. The motor is very strong. Any more than 350hp is dangerous and will require a much more expensive build to keep it stable. I would build the stock motor and not worry about the headache and cost is a swap. My .02.
 

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Gen 3 also have 540s, what would it take to swap a gen3 to coils?
If you had the gen 4/5 ecu could you easily make the swap?
A standalone ecu and even then probably aftermarket crank and cam triggers, I think some can work with the factory distributor. If you could add the gen4 cam and crank sensor im sure you could use a gen4 ecu. But with that much work I think you'd be better starting with a gen4/5 and building that.
 

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hmm sounds like an engine swap might be overkill in that case since I’m just shooting for a fun weekend car that won’t be breaking down on me too often. Ill keep the 3sgte then and spend money getting it back in working order which in any case should be far cheaper than an all out swap.
Well.... define "far cheaper".. the cost of getting your car running depends on what your power goals are, who does the work, how messed up your current engine is..lots of different factors. You need to do some homework. There is a reason that many people have opted to swap Gen4 and Gen 5 engines when their original engine dies.
 

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If your aware of the common failure points and rectify these during a rebuild the 3sgte is a good platform to reliably meet your power goals. Besides for the engine mods also consider other components that need to be upgraded including clutch, brakes CV joints, etc. Do your homework and you will end up with a decent classic car that can contend with modern machinery.

jim
 
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