2.7 i conversion
- Thread starter smoat
- Start date
It is quite involved, but very possible. What block are you putting it on? It is more than just a straight swap of the heads.
If done properly, this is quite an awesome swap. Less of a noticeable gain on a 325, but if you use a 320 block, you'll really notice the difference from the old 320.
Total BMW magazine (UK) had a how-to with colour photos and all the info you need in the October 2004 issue available from the publishers here
It is the E30 birthday special issue and has a picture of a silver supercharged Z3 on the cover.
If done properly, this is quite an awesome swap. Less of a noticeable gain on a 325, but if you use a 320 block, you'll really notice the difference from the old 320.
Total BMW magazine (UK) had a how-to with colour photos and all the info you need in the October 2004 issue available from the publishers here
It is the E30 birthday special issue and has a picture of a silver supercharged Z3 on the cover.
Actually, the heads are very different, and the pistons are different as well.
The 325i 2.5 engines have domed pistons and large combustion chambers in the heads - so at TDC, the domed pistons protrude above the deck surface into the large combustion chambers. This technique produces more swirl/turbulence in the cylinder charge, and that equals more power.
The 325/325e 2.7 eta engine, on the other hand, has small combustion chambers in the heads and dished pistons. So, if you swap a 325i head onto a 2.7 eta short block, you will have large combustion chambers and dished pistons - the compression ratio will fall through the floor, the combustion will be inefficient, and there will be no power.
The cam is also different, but the differences between the 325i and eta engines is more than just the head, cam, and connecting rods.
The 2.7i swap therefore requires new pistons specifically made for the swap - building a 2.7i engine will necessitate a complete teardown and rebuild.
The 325i 2.5 engines have domed pistons and large combustion chambers in the heads - so at TDC, the domed pistons protrude above the deck surface into the large combustion chambers. This technique produces more swirl/turbulence in the cylinder charge, and that equals more power.
The 325/325e 2.7 eta engine, on the other hand, has small combustion chambers in the heads and dished pistons. So, if you swap a 325i head onto a 2.7 eta short block, you will have large combustion chambers and dished pistons - the compression ratio will fall through the floor, the combustion will be inefficient, and there will be no power.
The cam is also different, but the differences between the 325i and eta engines is more than just the head, cam, and connecting rods.
The 2.7i swap therefore requires new pistons specifically made for the swap - building a 2.7i engine will necessitate a complete teardown and rebuild.
