Rb25Det Rebuild Questions

[RB26_Zoli]

Hi,

I'm rebuilding a blowned RB25DET engine basically for drift use with the following main components:

86.5mm CP forged kit

ACL bearings

Cometic gaskets

OEM oil pump

HKS 264 cams 9.0mm lift

HKS GT2540

740cc injectors

Splitfire coil packs

APEXi Power FC

My wanted hp range is nothing serious just reliable ~350-400 @ crank and don't want to rev above 7500rpm.

I read very different opinions about oil control modifications.

The most common advices are:

- use the aftermarket crank collar.

- use 1.25mm restrictor with OEM pump

- block off rear oil feeds

- drill out oil return galleries in head&block about ~1mm each

- use a head to sump oil drain kit

Lots of other ppl says it's all just stupid things, there isn't any trouble with the RBs oil control, and these mods maybe leave the head without oil ... Modifications needed only on seriously modified engines that will get high amount of G forces.

So what's your opinion, what are the mods that definitely need to be done in ~400hp RB25DET?

I had a 430hp RB26DETT (N1 turbos, HKS cams, Nismo bearings, IMPUL ecu) before in my JDM import PS13, and never had any troubles with the oil control. I used MOTUL300V oil overfill ~0.5-1.0L .To tell the truth I didn't open it while I owned, so I don't know It had wider crank collar or not, but there wasn't any oil drain uprated pump or smtg. Oil pressure was 6.5bar at WOT, and never seen under 2 bar at idle after drift use.

Regards,

Z

[GravyGarage]

Also keen to see opinions on this