SO WHAT VE HEAD SHOULD I USE?

NZ Performance Car - - Weekend Workshop -

What head you should use comes down to avail­abil­ity, fund­ing, and your power goals, as each of th­ese heads has their own unique ups and downs. By far the cheap­est head of them all is the P11 Primera head, or the Pul­sar VZ-R head, which are iden­ti­cal apart from the camshafts. The Pul­sar is more ag­gres­sive and bet­ter suited to nat­u­rally as­pi­rated set-ups. Although the P11 head is by far the cheap­est to buy from the get-go, it does need a lot more money spent for it to be suit­able for a rear-wheel-drive con­ver­sion. A Primera P12 CAS has to be pur­chased, and ex­tended ig­ni­tion coils have to be used or ex­ter­nal coils and leads, as the P11 still runs a dis­trib­u­tor. One rem­edy for this is us­ing the P12 rocker cover on the P11 head, which will al­low you to run S15 or P12 coil packs, and th­ese rocker cov­ers can be sourced through Bren­dan at Pten De­vel­op­ments. A Nis­san Primera/ VZ-R head will set you back around $400–$600 dol­lars depend­ing on the con­di­tion and mileage, plus the cost of the P12 CAS, ex­tended coil packs or ex­ter­nal coils and leads, and a so­le­noid re­lo­ca­tion kit.

By far the most su­pe­rior head is the later-model Primera head from the P12. This head is named the 20V in en­thu­si­ast cir­cles, and is by far the best to­tal pack­age. Firstly, there is no need to pur­chase the CAS as it comes in­stalled from the fac­tory. Se­condly, it comes fac­tory with the cor­rect coil packs, which are iden­ti­cal to that of an SR20DET from the Nis­san Sil­via S15. Thirdly, the cams in the 20V head are the best of the lot, how­ever, the ex­haust cam isn’t as good as the SR20VET ex­haust cam. Lastly, the 20V has one so­le­noid as op­posed to the P11’s two, this is im­por­tant be­cause the P11 so­le­noids hit the fire­wall in a rear-wheel-drive ap­pli­ca­tion, whereas the 20V sin­gle so­le­noid clears the fire­wall with a bit of an­gle-grinder work. An­other ben­e­fit of the 20V head is the in­jec­tors are top feed and, for ex­am­ple, In­jec­tor Dy­nam­ics ID1000cc are a di­rect fit with­out any mod­i­fi­ca­tion, yet again sav­ing you money as you don’t have to mod­ify the fuel rail on the P11 head. The SR20VET head found in the Nis­san X-Trail is iden­ti­cal to the P12 20V head, but it uses a dif­fer­ent ex­haust cam that is bet­ter suited for turbo ap­pli­ca­tions. The ex­haust cam doesn’t ac­tu­ally have VVL in the VET head, although both sets of cam lobes are present on the cam. By sim­ply in­stalling P11 or P12 rock­ers, this fan­tas­tic VET ex­haust cam can be used.

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