3.9mpi completely stock boost limits
Posted:
May 24th, 2008, 9:50 pmby ford_drift
I have a 3.9 litre mpi motor with 190 k's that i wish to boost. With no engine/ecu mods (but adequate fuel reg upgrade and extra injector) will these motors handle boost as well as the later 4 litres. I ask this because of the 3.9's head design- walls between valves are sharp and susceptable to glowing causing detonation. 10 psi will be my limit. 450*300*75 intercooler.
Re: 3.9mpi completely stock boost limits
Posted:
May 31st, 2008, 10:50 pmby XG95
not the best, the 3.9 have a higher compression than later 4.0's(i think) but the heads flow very well, although even in standard form they tend to warp and buckle
but obviously if you slap on an 4.0l EBII or ED head it'll drop the compression ratio a little bit and you will have better head for future port and flow improvements
otherwise try water(andd/or methanol) injection at high revs/loads, not as crap as everyone thinks