Thread: 2.5 to 3.2 swap
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Old 10-14-2022, 06:41 PM   #1
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Join Date: Oct 2018
Location: North Cali
Posts: 727
2.5 to 3.2 swap

Dear All,

I`m still exploring the options of what I could do to my 1999 base Boxster with the blown engine. Now I could pick up a cheap basket case of a 3.2 engine from a local guy, so I gave it a thought.

I remember reading an old thread from someone who did this swap (I can`t find it any more), and if I remember correctly he:
- used the original 2.5 ECU that he reprogrammed
- he used the 3.2 intake plenum but combined with a manual 3.4 throttle body to overcome the egas issue

This is all I remember he did and allegedly it worked fine. Question is, whether reflashing the ECU would cause a fail at the smog test in California?

Also, 78F350 posted a picture of the 2.5 coolant tubes vs the 3.2, and they are very different in size. So I assume I would have to upgrade that together with adding a third radiator to match the cooling capacity of the 3.2. Anything else? Would the transmission fit the 3.2 engine? How about the clutch? Exhaust?

Now that I`ve got to the end of this post I`m already leaning toward not doing it, lol.. Anyways, has anyone done this? Thoughts?
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