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Rolls

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Everything posted by Rolls

  1. Rolls
    Go look at a diagraph of a BOV, the 30psi is on both sides of the diaphram hence it doesn't open, you could put 100psi through it and assuming the piping itself could take it there is no reason why it would open either. The force holding it closed is identical to the force on the inside pipe. As both sides of the diaphram are the same size, and there is identical pressure on both sides the force is the same hence it doesn't open, doesn't matter how much boost you run, it will never open. The only reason it ever opens is as when you close the throttle there is a huge pressure spike near the bov, this spike is greater than the pressure at the intake manifold end, hence one pressure is greater than the other, hence the force allows the diaphram to open, there has to be quite a large pressure differential to open it though due to the spring. Depending on the design of the BOV you can get a pressure differential on vac conditions, this allows the bov to open on low throttle bypassing the turbo completely which imo is a good thing. There is a fantastic diagram here on wiki http://en.wikipedia....i/Blowoff_valve Have a look at the on throttle vs off throttle picture, it becomes blatantly obvious why it won't leak even with say 30psi.
  2. Rolls
    If it is working fine now there is no reason why it should stop working with the new turbo. The way the BOV diaphram works means more boost doesn't make it more likely to leak, as more boost means you have more boost on both sides of it, eg there's more boost in the intake, but there is also more boost in the vac tube holding it closed. You can mod them to change their behaviour on light throttle/going from full throttle to half throttle so they don't open as easily, but there isn't really any need imo.
  3. Rolls
    What spec is the turbo rated to ?
  4. Rolls
    How on earth is this not fixed yet, is there even a programmer that looks after the forum? It shouldn't be too much debugging to step through some code, look at logs and figure out why it isn't working. All the programmer needs is the login details of someone who is having issues. nismoid, who is looking after the forum software? If someone feels like making me an admin and giving me some information I'm sure I can figure it out, just need access to the server and information on who set it all up.
  5. Rolls
    The forces created by an identical stroke/bore motor revving to those speeds is identical if all the same parts are used, the torque is obviously different though. I guess what I was getting at is 8.5k is getting very close to the limit where stock rod bolts etc let go if held there for extended periods of time.
  6. Rolls
    Cool thanks for that, personally it looks a bit too laggy for myself, still looks like it goes hard though once on song.
  7. Rolls
    8500rpm is really stretching the limit of the rods/bearings limits though on a 25, if he dropped it to 7500 it would almost certainly double its life.
  8. Rolls
    If it withstands a year of this it will be a testament to the 25s reliability.
  9. Rolls
    How much did you sell it for in the end?
  10. Rolls
    Its a fantastic swap, night and day between the rb20 and the rb25 with VCT
  11. Rolls
    Full boost at 2400 on a 2.5L, is that thanks to the stall converter?
  12. Rolls
    Yeah it would be switched on just above idle and switched off at 4700.
  13. Rolls
    WUT please clarify
  14. Rolls
    Do you have VCT enabled?
  15. Rolls
    on my r33 intake I just simply put a screwdriver in it and turned it, what car/engine are you using ?
  16. Rolls
    Just remember to do it on a freeway lol, don't want anyone being arrested.
  17. Rolls
    Such is life, luck doesn't change for any reason, it is just how life plays out. I'm still getting immense enjoyment out of it when it drives so it will stay
  18. Rolls
    If anyone is interested in how my 240kw gcg turbo that comes on at ~3k and makes 240rwkw on 17psi with an average tune there are some videos here http://www.skylinesaustralia.com/forums/topic/371596-rollss-r32-in-the-processing-of-fitting-a-neo-25/page__st__20__gopid__6041779#entry6041779
  19. Rolls
    GOOD NEWS Took some videos of how it the motor is running now, tune is pretty shit and needs new diff and tyres as it is wheelspinning a lot, gives an idea of how crazily responsive it is though! BAD NEWS Some bad news, a dodly old 75yr old merged into me on south road last weekend, smashed the front left light, quarter, front bar, scratched up the rim and scratched the rear quarter. Was cruising along at 60 in the left hand lane and she pulled out in front of me, I quickly merged into the right hand lane to avoid her and she continued merging straight into me! Luckily insurance will cover it all with $0 excess as it was 100% her fault, I'm thinking I might ask the repair company to price up a GTR front bar and I will pay the difference so I get something out of this.
  20. Rolls
    In that case go to a workshop and pay them $40 to do it for you, worth checking imo.
  21. Rolls
    Could we get some footage of you flattening the throttle at 2k in 3rd gear until like 6k or something? I'f you could film the tacho that would be fantastic, love to get an idea of the transient response on the road.
  22. Rolls
    Just remember if a full tune does fix the issue it might have just covered it up. Eg my car had a big intake leak on cyl 3 and 4 from the wrong gasket, was bleeding boost down from 18psi to 14psi, the tune 'fixed' this and it ran much better, but obviously the leak was still there I just no longer noticed the issue. Just to humour me could you do a full intake system pressure test as well? It is fairly simple to do.
  23. Rolls
    lean popping isn't really an issue anyway, means you are running 15-16:1 at idle/really low load which is a good thing imo, better economy.
  24. Rolls
    Is it possible to compile something like what I said stao? I saw that you put quite a bit of effort into overlaying all your graphs in the past, would most likely be less work to do this.
  25. Rolls
    That is enough evidence for me. Agreed on the too many turbos thing zebra. Something like this would be fantastic turbo name, specs @ x psi, peak kw, peak nm, peak torque -25% from x-y rpm (eg 3500-6500rpm), cost, internal/external gate/housing type
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