Valve Springs For Neo Rb25Det Head On Neo Rb25De Bottom End

[Sarumatix]

Hey Guys,

My intention is to put a T67 on a high compression RB25de motor and run E85. Sadly the de head's inlet manifold design was making things too difficult so i've picked up a cheap R34 RB25det head instead. My target is around 300rwkw give or take but really i'm doing this for the fun of it and am not particularly driven to an end point, therefore, i'm quite happy to do what's reasonable (good payoff for reliability or power) whilst trying to keep as much stock as possible. The bottom end is in excellent condition and I was going to leave it completely stock and find out what it is capable of. Before sending the head off to prepare it, it was suggested that I should replace the valve springs. I have found 2 options for NEO heads in Ferrea and Performance Springs. I have done a few searches which haven't really focused on what points really justify replacing the valve springs except that it's just a 'good idea'. Can anyone offer me advise on if it's worthwhile, and if worthwhile, which springs would make sense for my application?

Regards,

Saru

[GTSBoy]

I think you'll find that the question will be "staying with std cams?" in which case, if your answer is "yes" the response will then be "don't bother with the valve springs".

What it comes down to is that 300rwkW is nothing major. People are making that and a lot more on E85 on completely standard motors. You don't have to use a shit tonne of boost and you don't have to use a lot of revs and you don't have to use big cams to get to that sort of power. Therefore there isn't really any pressing drive to do valve springs.

If you have money to burn and/or would like to future proof your build against any urges to make the power levels go up a long way, then go right ahead. Ferrea have a good name for valves - you'd imagine their springs should be OK. And the other aspect of making a decision is that given that you don't need to use anything better than stock for your existing plans, then it probably doesn't matter if one brand of springs are effectively 5% better in some way than another if you're not likely to approach the limits of either anyway.

[Sarumatix]

That's an excellent answer, thanks.

I did find the following advice:

STATUS, on 29 Apr 2010, said: The rb25 will support mid 300's unopened all day everyday, there are however a handful that fall over valve spring wise.

I guess it begs the question, if I don't want to change cams, is there never a reason to go for after market valve springs?

e.g.

valve springs are a common failure point and should be replaced or

valve springs are the first weakest link in the RB25det neo head when making power

Edited October 23, 2013 by Sarumatix

[iruvyouskyrine]

From memory (this may be incorrect) S1 RB25's suffered from valve issues more so than S2 and Neos.

[WMDC35]

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