JustinP Posted September 23, 2011 Share Posted September 23, 2011 I am just wondering - what would be the highest rev limit before valve float might become an issue for me with standard valve springs? The engine is an RB25DET Neo (solid lifters) with Tomei Type B cams (260deg and 9.15mm lift on IN/EX). The bottom end has lighter forged pistons / rods and is fully balanced, I am wondering what it will rev to when it is all put together Cheers Justin Link to comment https://www.sau.com.au/forums/topic/378057-standard-valve-springs-and-rev-limit/ Share on other sites More sharing options...
zebra Posted September 23, 2011 Share Posted September 23, 2011 7-7500rpmish, hard to say really Link to comment https://www.sau.com.au/forums/topic/378057-standard-valve-springs-and-rev-limit/#findComment-6029042 Share on other sites More sharing options...
GTSBoy Posted September 23, 2011 Share Posted September 23, 2011 Yuh, this is the catch 22 when you put bigger cams in. The cams make you able/want to use more revs from the point of view of breathing, but bigger lifts and longer durations = more aggressive ramp rates and makes it possible to float the valves at lower revs. It would be sensible to derate what you think you can get away with on stock cams in a Neo by at least 500rpm if you can't get solid advice from anyone. Link to comment https://www.sau.com.au/forums/topic/378057-standard-valve-springs-and-rev-limit/#findComment-6029081 Share on other sites More sharing options...
zebra Posted September 23, 2011 Share Posted September 23, 2011 For $300 I would through a set of supertech springs in, peace of mind, rather than getting it all together and find the standard springs have gone soft Link to comment https://www.sau.com.au/forums/topic/378057-standard-valve-springs-and-rev-limit/#findComment-6029093 Share on other sites More sharing options...
JustinP Posted September 23, 2011 Author Share Posted September 23, 2011 Thanks for the feedback everyone. If it is only going to cost me $300 for the Supertech springs I think I might as well get them too. I have come this far... why not!!! One question regarding the Supertech springs - I notice they do not have any springs listed in their catalog specifically for RB25DET Neo. The have 2 versions of RB25DET springs, one for hydralic lifters (R33) and one for heads with a solid lifter CONVERSION. I presume the second option will be OK with a Neo head, considering it comes with solid lifters as standard? Thanks For $300 I would through a set of supertech springs in, peace of mind, rather than getting it all together and find the standard springs have gone soft Link to comment https://www.sau.com.au/forums/topic/378057-standard-valve-springs-and-rev-limit/#findComment-6029150 Share on other sites More sharing options...
zebra Posted September 23, 2011 Share Posted September 23, 2011 hmmm not sure, I would call supertech and ask, if not there are a few other brands of springs around that money as well. Link to comment https://www.sau.com.au/forums/topic/378057-standard-valve-springs-and-rev-limit/#findComment-6029156 Share on other sites More sharing options...
JustinP Posted September 23, 2011 Author Share Posted September 23, 2011 In any case, I can't seem to find any sets of supertechs for around $300! I found these cheap ones though- miscellaneous brand! http://cgi.ebay.com.au/ws/eBayISAPI.dll?ViewItem&item=160489842337#ht_500wt_725 cheap though, i wonder if they are any good. they also sell with retainers: http://www.ebay.com.au/itm/Nissan-RB25-Neo-Valve-Springs-Retainer-kit-/160477165278?pt=Motors_Car_Truck_Parts_Accessories&hash=item255d2f36de#ht_500wt_725 very well priced, but i wonder if they are any good. hmmm not sure, I would call supertech and ask, if not there are a few other brands of springs around that money as well. Link to comment https://www.sau.com.au/forums/topic/378057-standard-valve-springs-and-rev-limit/#findComment-6029200 Share on other sites More sharing options...
zebra Posted September 23, 2011 Share Posted September 23, 2011 Performance Springs is the brand believe it or not, They are an Aussie mob, and supposedly pretty good, but I have never used them myself Link to comment https://www.sau.com.au/forums/topic/378057-standard-valve-springs-and-rev-limit/#findComment-6029205 Share on other sites More sharing options...
JustinP Posted September 23, 2011 Author Share Posted September 23, 2011 Makes sense!!! Maybe I will give them a go - cheers Performance Springs is the brand believe it or not, They are an Aussie mob, and supposedly pretty good, but I have never used them myself Link to comment https://www.sau.com.au/forums/topic/378057-standard-valve-springs-and-rev-limit/#findComment-6029215 Share on other sites More sharing options...
Kenna802 Posted September 23, 2011 Share Posted September 23, 2011 I have them in my car but only running standard lift, mechanic freaked out when trying to compress them lol Link to comment https://www.sau.com.au/forums/topic/378057-standard-valve-springs-and-rev-limit/#findComment-6029272 Share on other sites More sharing options...
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