[Jeremy R.]

One of my long-term desires for my 1997 900 SE turbo has been to convert it to a 2.3, especially now that I own a pair of 9-5 Aeros and know what those engines are capable of. The easiest way to do that would be to drop in a 2.3 liter engine from a 9000, but those aren't exactly common anymore. Normally aspirated 900s show up from time to time at the local Pick and Pulls, though. Has anyone taken the engine block from a N/A 2.3 900, complete with crankshaft and pistons, and used that in a 2.0 turbo to convert it to a 2.3? Are there any ports or connections missing on a 2.3 block that would prevent me from swapping over all of the turbo parts? The plan would be to keep my existing head, manifolds, and any other external engine parts. I know that after doing this, I'd need to get a revised ECU, too.

 

[jakejm79]

If you use the pistons and rods you will end up with too high of a compression ratio to run any reasonable level of boost safely.

 

[Jeremy R.]

So the turbocharged B234 in the 9000 uses different rods and pistons than the N/A version in the 900? It was hard to tell from all of the different part number listings on the parts diagrams.

 

[jvanabra]

There are quite a few differences between NA and turbo in there. I would be a little concerned with boosting a non-turbo - even the NAs were known to break rods now and again. Not the stoutest engine Saab made.

 

[jakejm79]

So the turbocharged B234 in the 9000 uses different rods and pistons than the N/A version in the 900? It was hard to tell from all of the different part number listings on the parts diagrams.

Yes the NA B234 has a compression ratio of ~10.5:1 vs the turbo having one of ~9.25-8.5:1 depending on year and turbo level.