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Neo Rb25 Valve Springs

R34GTFOUR

By R34GTFOUR,
in Engines & Forced Induction

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R34GTFOUR Mentor

R34GTFOUR

Posted
Posted

Hey everyone, just wondering if anyone that is knowledgable with the neo series rb25's can shed some light on this for me.

Im going to use my rb25de neo head on a rb30 conversion. I was intially going to change to valve springs since i was going to use a set of tomie pon cams (Duration: IN,EX 260 Lift: IN,EX 9.15mm) and after hearing all the people having trouble with r33 na heads with valves floating because of soft springs i thought it was a good idea. Anyway. i've since been lead to believe that unlike the r33's, the neo head uses the same valve springs for both the na and turbo setup, with only the cams themselves being different, so im asking myself will springs be needed?? So how far have people taken the stock neo valve springs? The 9.15 lift of the cams shouldnt be a problem, and the rpm limit will be at no more than 8000rpm so again that should be ok, but if i was running near on 1.8bar of boost with 500+awhp will the springs be upto the task?

Even if i wanted to stick some new valve springs in, im finding it hard to find springs for the neo head. The neo head as many of you know uses solid lifters, so the only springs i came across that might work at the r33 tomie spings rated to 10.25 lift but designed for solid lifter use. So im wondering if the springs are different between solid and hydrolic lifters, im wondering if r33 valve springs designed for solid lifter work with my setup?

:D

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R34GTFOUR Mentor

R34GTFOUR

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Performance Springs makes springs and retainers for NEO engine - I have them in my engine.

For the small outlay compared to the money you will be spending on the rest of the motor to make 500awhp - it isnt even worth considering whether to buy them or not.

cheers for the reply

i did a search and you recommended that mob in a few posts haha, which is good but a few people also said somethings that made me abit weary, I've still got about 6months up my sleeve before i start the build so i have a bit of time to sort it out. How much did they slug you for a set of springs if you dont mind me asking? I've seen anywhere from 300-600 for a set (tomie)

as soon as i sell my spare car i'll be msg you for some spool rods and cp pistons for the NEO :thumbsup:

Spoolup Mentor

Spoolup

Posted
Posted (edited)

I cant remember the price too be honest - maybe 300 - 400 for springs with the retainers to suit.

Depending on the comp ratio you are after, I can supply CP's and rods to suit the NEO with 30 bottom end.

Is this engine going in a R34GTFour ?

cheers for the reply

i did a search and you recommended that mob in a few posts haha, which is good but a few people also said somethings that made me abit weary, I've still got about 6months up my sleeve before i start the build so i have a bit of time to sort it out. How much did they slug you for a set of springs if you dont mind me asking? I've seen anywhere from 300-600 for a set (tomie)

as soon as i sell my spare car i'll be msg you for some spool rods and cp pistons for the NEO :thumbsup:

Edited by Spoolup
R34GTFOUR Mentor

R34GTFOUR

Posted
  • Author
Posted
I cant remember the price too be honest - maybe 300 - 400 for springs with the retainers to suit.

Depending on the comp ratio you are after, I can supply CP's and rods to suit the NEO with 30 bottom end.

Is this engine going in a R34GTFour ?

yep the gtfour :), i have a big lest of parts that i have written down to get, everything SHOULD slot in nicely. I'm getting a proengines 4wd adaptor, gt35r, already got the 6boost manifold, ported greddy copy plenum etc etc, the list is a long one :)

i'll definately be getting your rods and the low compression 8.2 CP pistons so with the less cc head that should bring it up to 9ish depending on hg (im waiting for you to do yours first to make sure its a-ok hahaha)

the only thing im uncertain on is the springs, i might give that mob a call this week and see what they can do.

:(

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