106 Xsi Bottom End, 1.4 Xs Head

[drmo 5]

There's approximately 5cc between them though! You'll notice the XS pistons are dished slightly and don't reach the top of the bore, conversely the XSi pistons top the bore and have ~3cc dome.

Thanks for sharing the info on that. Didn't think that that was such a big difference.

I did my calculations and if you skim TU5 head for aprox. 1mm you get aprox. 9.4:1 CR. With xsi/rallye pistons the CR would jump to 11.3:1 aprox.