NOVELTY - Dimerization process comprises: (a) introducing at least one oligomer-based composition or feedstock; (b) introducing at least one solid acid catalyst to the feedstock for isomerization; (c) recovering and utilizing initial heat for isomerization; (d) maximizing concentration of olefin; (e) utilizing minimum reaction temperature; (f) decreasing trimer and oligomer formations; and (g) utilizing a first fractionation process to further produce a purer dimerized product having less than 2 wt.% total of dimers, trimers and oligomers combined.    USE - The process is useful for producing a dimer product having less than 1 wt.% but not more than 2 wt.% combined total mass of trimer, tetramer and oligomers and a fully saturated hydrocarbon gas, diesel, jet/turbine biofuel (all claimed).    ADVANTAGE - The improved unique and highly efficient process dimerizes terpenes, AOO and olefins using cost effective catalysts and low cost equipment that are ideally suited for commercialization of jet/turbine and diesel biofuel processes producing fuels with high flashpoints and superb cold flow properties.    DETAILED DESCRIPTION - Dimerization process comprises: (a) introducing at least one oligomer-based composition or feedstock consisting of terpene(s), ~ a-olefin oligomer(s) (AOO), and related olefins; (b) introducing at least one solid acid catalyst to the feedstock for isomerization; (c) recovering and utilizing the initial heat of the isomerization; (d) maximizing the concentration of reacting olefin during protonation; (e) utilizing a minimum reaction temperature zone to extend the catalyst lifetime; (f) decreasing trimer and oligomer formations via an active recycle protocol to produce dimerized products in the absence of trimers, tetramers, and up to octamers; and (g) utilizing a first fractionation process that mildly reduces pressure for the evaporation of unreacted feedstock to further produce a purer dimerized product having less than 2 wt.% total of dimers, trimers and oligomers combined. INDEPENDENT CLAIMS are included for:    (1) a dimer product having less than 1 wt.% but not more than 2 wt.% combined total mass of trimer, tetramer and oligomers produced by the above process; and    (2) a fully saturated hydrocarbon gas, diesel, jet/turbine biofuel produced by the above process.    DESCRIPTION OF DRAWING(S) - The figure shows a block diagram of a process for dimerization of terpenes, AOO or related olefins.    Isomerization/dimerization reactors (R1, R2)    Valve 1. (V1)