Jump to content
SAU Community

Recommended Posts

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

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.

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

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.

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

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • To follow up a question from earlier too since I had the front bar off again (fking!) This is what is between the bumper and the drivers side wheel And this is the navigator side, only one thing but its a biggy! So basically....no putting coolers in the wheel arches without a lot of moving other stuff. Assuming I move to properly race prepping this car I'll take that job on and see how the computers respond to removing a whole bunch of ADAS modules
    • So I prepped the car for another track day on Wednesday (will be interesting to see coolant temps post flushing out and the larger reservoir, with a forecast of 3-14 being 20o cooler than last time I took it out). Couple of things to mention; since I am just driving the car and not taking a support vehicle, I took the rear seats out and just loaded the back up Team Trackday style. Look at all that space! To cover off removing the rear seat....it is weird (note the hybrid is probably different because it wouldn't have folding rear seats) Basically, you remove the lower seat base, very similar to a r series but it is a clip that pulls forward to release the base rather than it being bolted down. Easy Then, you need to remove the side section of the rear seat on each side. There is a 14mm head nut at the bottom of the side piece, the it slides upwards off a hook at the top to release; you also need to unhook the seatbelt from the loop at the top. Then the centre piece is weird. You need to release/fold the seats forward with the tab in the boot on each side From there, there are 2,x12mm headed bolts holding the rear of each seat to the folding bracket, under the trim between the rear seat and the boot (4x christmas tree clips there, they suck). The seat is out but you can see where the bolts attach to the bracket
    • As discussed in the previous post, the bushes in the 110 needed replacing. I took this opportunity to replace the castor bushes, the front lower control arm, lower the car and get the alignment dialled in with new tyres. I took it down to Alignment Motorsports on the GC to get this work done and also get more out of the Shockworks as I felt like I wasn't getting the full use out of them.  To cut a very long story short, it ended up being the case the passenger side castor arm wouldn't accept the brand new bush as the sleeve had worn badly enough to the point you could push the new bush in by hand and completely through. Trying a pair of TRD bushes didn't fix the issue either (I had originally gone with Hardrace bushes). We needed to urgently source another castor arm, and thankfully this was sourced and the guys at the shop worked on my car until 7pm on a Saturday to get everything done. The car rides a lot nicer now with the suspension dialled in properly. Lowered the car a little as well to suit the lower profile front tyres, and just bring the car down generally. Eternally thankful for the guys down at the shop to get the car sorted, we both pulled big favours from our contacts to get it done on the Saturday.  Also plugged in the new Stedi foglights into the S15, and even from a quick test in the garage I'm keen to see how they look out on the road. I had some concerns about the length of the LED body and whether it'd fit in the foglight housing but it's fine.  I've got a small window coming up next month where I'll likely get a little paint work done on the 110 to remove the rear wing, add a boot wing and roof wing, get the side skirt fixed up and colour match the little panel on the tail lights so that I can install some badges that I've kept in storage. I'm also tempted to put in a new pair of headlights on the 110.  Until then, here's some more pictures from Easter this year. 
    • I would put a fuel pressure gauge between the filter and the fuel rail, see if it's maintaining good fuel pressure at idle going up to the point when it stalls. Do you see any strange behavior in commanded fuel leading up to the point when it stalls? You might have to start going through the service manual and doing a long list of sensor tests if it's not the fuel system for whatever reason.
×
×
  • Create New...