What's the most power engine fitted to a 105 from alfa?

[Colin Byrne]

Just throwing it out there, what was the most powerful engine ever fitted by Alfa to a 105, was it the GTA-SA super charged unit? or something in the latter GTAm's, or something else?

[LaStregaNera]

*probably* the narrow valve GTAm motors - 240hp claimed, all though there's evidence they wouldn't support more than about 220hp.
The later 16valve motors fitted to Autodelta works Alfettas allegedly made 290hp or so.

[Paul Byrne]

To get 240 BHP from 2 litres with normal fuel would need at least 8600 RPM. 290 BHP would require over 10,000 RPM.
Don't know what capacity these motors were however. The 240 figure looks plausible- dont know for how long though!

Figures above are based on the calculation that for a normally aspirated engine max BHP = Capacity (L) x RPM (1000s) x 14

This formula appears to be correct for all but the absolute ultimate engines produced for special purposes by the likes of Porsche, such as hill climb specials etc. Even with these engines the factor is no higher than 15.

"14" works for all the stuff we mortals do and is seems pretty close for V8 supercars, F1 (non blown), etc

So our trusty 2L at 7500 might produce around 200 BHP? (Theoretical max 210)

On the dyno mine got around 163 @ 6200 (vs 1.9 x 6.2 x 14 = 171). Seems pretty right?

[hammer]

That's a pretty solid calculation Paul and works out close enough to right for my race engine too.

Cheers,

Brent

[GTV6SA]

The GTA-SA was a 1600cc supercharged engine with twin oil driven compressors not a 2 litre. most Autodelta 2 litre GTAm engines produced around 210-220 Hp max with slide injection not carburettors i,e real HP not 240SAE as in most listings. Even a recent 16 valve 2 litre  Autodelta on 48 dellorhtos only  produced 230HP ATW.  Most NA 2 litre engines will not flow 200HP especially not on 45's according to Stuart Randall who did a lot of development on these engines. My own GTAm engine would flow 250 HP opn John Skolars flow bench! but that would be with slides where there is no impedence by the butterflies. In reality with Haltech and 50mm throttle bodies it put out 211 Hp. This same engine now rebuilt with  Siamese liners and Lucas injection now puts out 217 HP.There are so many variabes ie. atmospheric conditions , temp, oil viscosity etc, Even variables in Dyno readings.  In my Turbodelta GR.4 book a GTAm engine's  dyno sheets of 196 HP so there is quite a lot of difference depending on whose dyno figures you want to believe. As S.R. use to say "when the flag drops the B.S stops!"