Chasing Reliable 300rwk

[bazr33]

i am chasing 300rwkw also

but in the middle of rebuilding a 25 to help with reliability

have most of the gear, just a matter of having the block bored and honed. Head lightly ported and polished and cleaned up.

then put in the acl 20 thou pistons, acl main and bigend bearings spool rods, and performance valve springs.

will be asking the dude i am taking my engine to, as to what cams he would recommend and go from there. As i would like to go past 300rwkw later on.

a gt30r will be hanging on the side of the engine, but will more than likely replacing it with something bigger later.

Will let ya know how i go.

[discopotato03]

Some very valid points of view here IMHO .

Nismoids experience shows how going for that bit more often makes unacceptable compromises overall , and yes the semi trailing arm IRS would make it - interesting .

First thing is budget because that dictates how good you can get the most critical areas to be .

You also have to ask yourself if your means and goals will allow you to remove

/strip/rebuild the engine itself before you bolt on externals . If you don't intend to remove the bottom end then lets hope for your sake that its in very good condition .

The path to making more power in most engines is to get more air and fuel in and then to vent the increased volume of exhaust gas . There is a cheap and a propper way to go about it , cheap being to raise the pressures and temperatures and propper to remove the restrictions in the system - and waste a bit more heat .

Most production heads just don't cut it when it comes to large power increases so getting it sorted will make the power lifting game much easier and more reliable later . Critical areas are exhaust porting and valves , the exhaust ports need improving and since you can buy slightly larger valves that go in on slightly modified std seats why not .

Tomei Poncams are supposed to fall in and you may get away with re shimed std springs if they are in good condition .

This sorts the head out and it can go back on if the bottom end is not being opened .

If I was spending money on an RB25 short for fast road I'd look seriously at factory RB26 bits like the crank/rods/pistons . These would be the best std Nissan bits and probably the most price friendly as well . Assuming that all std RB26 pistons are dimensionally the same the later/last evolutions would be worth considering to get the later technology . I'll assume they all have that oil cooling passage under the crown and run ~ 8.5:1 CR . If you seek the means to remove the engines breathing and venting restrictions generally temperatures and pressures drop so it gives more affordable components the ability to survive reasonably hard use . I can just about hear people say yeah cops mate but the cost and effort of fitting forged pistons is considerable . Forged pistons are good in two areas , firstly they are mechanically stronger so stand up to the innertial loads better . Secondly they'll generally cop a bit more detonation abuse before they fail . The thing is if your not going to rev beyond what RB26 pistons can reliably stand no problem here . If you tune the thing properly so it doesn't detonated it should cope fairly well .

For externals there's lots of choices . The std exhaust manifold seems to be able to cope with 300Kw worth of exhaust flow so thats a reasonable base option . Next up is probably the single low mount HKS cast manifold , it offers external wastegate (can blank it off) , its internal "bends" are a bit less abrupt than the std one and it angles the front of the turbo outwards slightly so the compressor cover is further away from the casting . After that there is a large range of fabbed manifolds but they are expensive and some have cracking issues , for 300Kw the above options are more cost effective and I believe long term reliable .

Turbos ? A real GT3071R could probably get there with the medium sized turbine housing in single scroll form . A GT3076R/GT3037 would easily get you there .

IMO the HKS manifold/ext gate with the twin scroll GT32 housing on a GT3071R or GT3076R would be very impressive .

Your bux your call .

[Devils_Advocate21]

WMI? anyone mention that yet