Rb25/30 Neo

[drgnball34]

98 Skyline GTT NEO with following mods

Rb30 block crack and pressure tested, honed etc

crank nitrided

Argo rods

Cp 20 thou pistons ceramic coated

ACL bearings

Fully balanced

main studs

Jun oil pump/crank collar

N1 water pump

H.E sump

ati balancer

NEO head

Fully recon

port/polished and matched to inlet/exhaust manifold

gtr tomei 260 poncams/cam gears

performance wise springs/retainers

1000cc sards

hks gtr rail

head studs

oil restrictors

greddy plenum

q45 tb

6boost manifold

t04z (1.00)

48mm progate

ARE intercooler

greddy radiator

splitfires

HKS twin ignition

NPC twin clutch

haltech e11

x2 044

NOS kit

braided fuel lines underneath car

etc

Will post more pics this week. Power goal of 620rwhp and 700 with nos

Edited August 4, 2008 by drgnball34

[Al]

Nice

What purpose is this package being built for? Drag Racing?

[drgnball34]

100% street driven! Although my gf will drive it more than i will. I will eventually do future drivetrain/suspension mods for alittle 1/4 mile times. Will be happy with 10's in the bag.

[R34GTFOUR]

bloody hell, that thing will be insane on the street...

620rwhp and only 2 wheels to put the power through, theres only going to be one thing happening... WHEELSPIN

[H@ME]

OMG...swing!! nice engine looks mint and sure will go i bet!

[drgnball34]

very good tyres and suspension tweaks...anything to help i guess but your right about spin city. Have you seen the 800rwhp+ supras going around in the usa on youtube? Hell they even got 1000hp beasts! I wont even bother launching the thing its pointless. Maybe roll ons on the freeway from 3rd gear

[R34GTFOUR]

did you by any chance cc your neo head? if so how many cc's was each combustion chamber?

[4drfts]

sounds like a mean build. What are the specs of your pistons? im using JE flat top pistons, but im worried about what the compression ratio is going to be. what is your dish/dome and deck clearance?

I just picked up my NEO head so ill be finding the CC of the chambers once i clean them and get a syringe and perspex but i had a rough measure using a CD and measuring spoons and they look around 56cc.

[Adriano]

CD and measuring spoon LOL, i love it. Im pretty sure thats about what i measures mine at. The flet top Pistons should work about right, thats what im using for my 25/30 NEO, and deending what the final measurements are, i could adjust the comp from about 8.4:1 to 9.2:1 depnding on th eheadgasket used

[4drfts]

yea well im hoping they will be sweet. I initially got them custom made to suit vg30 rods for a better rod/stroke ratio but i was going to use them with an R32 RB25DE head i had. they have a bit of deck clearance so i have room to deck the head if need be as well as play round with gasket thickness, so i dont think it will be a problem . also, since i got custom cams made (276 10.5mm lift) for the r32 head, i figured that to run them in the r34 head im going to need to run the r32 CAS, and im not going to run vvt, just block up the oil feed hole

also, just out of interest, i thort r34 heads had bigger valves but they look the same as my r32 head. again i dont have proper measuring tools on me im gona bring them home from work on the weekend to suss everythin out

[drgnball34]

I heard that the exhaust valves are bigger then the rb26's. They actually used r33 cp pistons which gave a higher comp ratio on the Neo head. But all technical aspects I would need to talk to the builder as my mechanical knowledge is little. It was pretty much drop my car off and let the workshop do their magic.

[Spoolup]

you wont be able to run those cams in the NEO head, the lift is too big.

yea well im hoping they will be sweet. I initially got them custom made to suit vg30 rods for a better rod/stroke ratio but i was going to use them with an R32 RB25DE head i had. they have a bit of deck clearance so i have room to deck the head if need be as well as play round with gasket thickness, so i dont think it will be a problem . also, since i got custom cams made (276 10.5mm lift) for the r32 head, i figured that to run them in the r34 head im going to need to run the r32 CAS, and im not going to run vvt, just block up the oil feed hole

also, just out of interest, i thort r34 heads had bigger valves but they look the same as my r32 head. again i dont have proper measuring tools on me im gona bring them home from work on the weekend to suss everythin out

[Spoolup]

Is that r33 rb25 or r33 rb26 pistons they have used ??

If it is either, youll need to run some serious race fuel as your comp is going to be over 10 to 1

I heard that the exhaust valves are bigger then the rb26's. They actually used r33 cp pistons which gave a higher comp ratio on the Neo head. But all technical aspects I would need to talk to the builder as my mechanical knowledge is little. It was pretty much drop my car off and let the workshop do their magic.

[drgnball34]

ill check and find out what piston specs etc was used. But i was told my comp is 8.4....Ill ring on monday and see what size headgasket was used also

[Spoolup]

Yeah I would just double check. It would want to be a pretty thick gasket.

Unless they are just mistaken on what piston they are using.

Im using RB30 ET pistons with a 4.5cc dish and have 8.5:1 , not a 11 cc dome like rb25 pistons.

[4drfts]

These NEO heads are really interesting and WAY different to any other rb25 head.

Hey Spoolup, do you mean I cant run the cams Ive got? I know they dont direct fit, ive had to grind a tiny bit off where the lobe catches the head around the edge of the lifter. BUT, in the R32 head i wuld have had to cut shitloads out but in this head i only had to cut a little bit. Maby this is partly because the Neo Buckets are wider diameter than r33 lifters, and a totally different design even to the gtr lifters. so far so good. the other thing is te shims in the Neo buckets are exactly the same diameter as Subaru shims, so thats a cheap alternative I used to get the clearance on my cams right coz theyre way more common to find

[Spoolup]

Yes they are a great head.

Just install your cams and turn the cam until you have a valve at maximum lift, then check your lifter and see if the oil gallery that runs along the lifters ( inside the head ) is exposed. If so you can not use them as you will never get oil pressure.

With my setup anything over 9.8mm lift exposed the oil gallery.

Im in the process of building a new head and trying to get around this my using small base cirlce cams and tipping the valves ( extending them )

Cheers

These NEO heads are really interesting and WAY different to any other rb25 head.

Hey Spoolup, do you mean I cant run the cams Ive got? I know they dont direct fit, ive had to grind a tiny bit off where the lobe catches the head around the edge of the lifter. BUT, in the R32 head i wuld have had to cut shitloads out but in this head i only had to cut a little bit. Maby this is partly because the Neo Buckets are wider diameter than r33 lifters, and a totally different design even to the gtr lifters. so far so good. the other thing is te shims in the Neo buckets are exactly the same diameter as Subaru shims, so thats a cheap alternative I used to get the clearance on my cams right coz theyre way more common to find

[4drfts]

O shit Ill have to check that out. how do you go about tipping the valves?

[Spoolup]

The tips of each valve is built up a little with weld - they are then ground to the determined length. Its cheaper than 24 custom valves.

With aftermarket springs there is enough room to run up to 12mm lift with out the springs binding - its just the oil gallery issue that needs to be resolved.

[4drfts]

ok, it seems your right but i think i have a plan. Im gona use gtr retainers and shims as they shim from underneath, so that will imitate the tipping your talking about. then, ill have to find some springs thatll be suitable or get some made, that shuldnt be too much of a prob. wat do ya think wise one?