i dont think the thema ever had that kind of power 185 sounds about right,the intergrale(16v)started out with 205 and went up to 225 but im sure the thema never had that much...the engine is basicly the same its only the gearboxes and the bits'n'bobs like powersteering pump/alternator/aircon that are different.
also the inlet manifolds changed on the intergrale from the early model to the evo.
the series 2 was 185 bhp but the series 3 is 205 bhp and on the Intagrale they swop the cams around to give you more guts.The sump is steel/tin on the s2 and the s3 but the s3 has a pipe coming out the sum where as the s2 dosn't.I'm not sure it the Q4 engine has a alloy sump like the 16v or it is steel/tin.
Okay, so I think we've established that Peter's Thema is probably an S3 2.0 16V Turbo with somewhere in the region of 185-205bhp...
...but as FGN so succinctly put it...will it fit or not? Does anyone know?
This website explains that the Lancia Thema, Fiat Croma and Alfa 164 are based on a common platform.
I found another website that explains that the Fiat Tipo, Alfa 155/145 and Lancia Dedra are also built on a common platform, so if the Thema engine is the same as that in the Lancia Dedra Turbo, then there's a good chance it'll fit...I think.
I'm pretty sure the dedra turbo block will fit, you might have problems with anciliaries though - but I'm sure the 155 gear will fit on it. I'm also sure I've heard of it being done before too.. possibly one of the ARTC guys?
Just adding my 2p worth here, Basically the thema turbo engine is the same as the Q4/grale block, there are diffenences however with the ancillaries, makes sense really, on a grale the alternator is hidden away but on a Q4 its easily accessable. If you think about this logically why would Lancia/Alfa who weren't in the best of financial states back then bother to design another 2.0L 16v Turbo engine when they already had a cracking one sitting on the shelf. Making it fit could be fun, and not something that I would look forward to. Something else sticks in my mind about the thema Lump, and I may be wrong on this one, but doesn't it have larger exhaust valves than inlet? Something to do with improving torque. On the subject of torque curves, even though the EvoII and Q4 have almost identical engines the Evo makes 15bhp more, all to do with making the engine in the Q4 more economical, with better midrange.
BUT if this post is all to do with slotting a thema turbo engine into a 155, I would say that you are probably making work for yourself, the best way to go would be to get yourself a Dedra Turbo (about 25p is the going rate) and swap the complete engine/gearbox out of it. The advantage of this route is that the Dedra and 155 are almost identical. If you don't believe me go and sit in one, you will feel right at home. As it is tuned in the Dedra it makes 165 bhp (already 15 up on your 2.0L 155) But with relatively few mods you could coax that engine to produce 250bhp with more torque than you can ever want. And after all if it goes bang, just go out and get yourself another Dedra.
Just as a follow up, and cos I read some of the earlier posts, The Dedra turbo is an 8v and the Thema a 16v. Also I have been out on track with a Tipo that had an 8v turbo engine planted into it. Very rapid!
Just to add more sauce to the mix, here are some words of wisdom from Philip Day, a Lancia Thema officianado from the Thema/Dedra Consortium...
'The Dedra turbo in the UK used an 8v engine, the integrale after 1991 was 16v, the Thema LS turbo is a 16v turbo (actually any Thema turbo after 1990 is 16v), and I think the 155 used the 16v
turbo unit from the Integrale. Therefore the Dedra turbo will fit his car but is best not to be used, and yes the engines from the Thema and Integrale should do the job. The engine differ in
management and have various bolt-ons, so check which management system you want to use - integrale easily the better choice for performance and only uses one ECU so Eprom can be