Jump to content
SAU Community

Recommended Posts

Only when i first got it tuned, he wasn't to sure on why it was doing it. Told me to speak to Nistune, who told me to do the boost sensor.

I'll give him a call shortly, there is one tuner down this way, going to see if he happens to have Nistune software.

  • 1 month later...

Just thought i'd add some info to this for future reference and people searching.

I still have not fixed the limiter issue, i broke the gearbox so thats getting fixed now haha.

But i plumbed the sensor in as i posted, and fuel economy is WAY better, drove 120km return to and from the track (home with a g/box stuck in 3rd) and around 30-40 laps of the track and only used 1/2 a tank, i used to get 230klm's to a tank before i hooked the sensor up.

So it does not affect af/r under power, mainly under cruise. Massive difference.

Neo ECUs use a volumetric efficiency table in addition to the normal fuel map. Matt from Nistune has only recently worked out that the X axis for the VE isn't simply TP load like eveyone previously thought, and there seems to be a lot of logic around whether the VE map is activated to control mixtures or whether the ECU falls back to the fuel map. Closed loop flag is raised across the whole fuel map, you can't control whether it is on or off, but the ECU is clearly able to switch itself in and out of closed loop. It is therefore quite possible that the boost sensor might be part of the logic as to when and why it runs in closed loop (and hence why you're getting better economy with it connected).

I think if we are really forced to keep the boost sensor connected, we're going to end up running a bleeder T on them just like a boost controller. Bleed off some boost and limit how high the sensor reads. Still reads vacuum, job done. Having said that, the sensor is connected to the crossover pipe, so should never see vacuum. Should only ever see slight vacuum + boost.

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

    • I refreshed the OEM injectors with the kit and connected it up. It now ideals okay even with the IACV removed. Driving still has the same cutoff issue like the 550cc injectors so the issue is somewhere else. I bought FPG's Fuel Pump Hanger. I will be installing it next, but it is not as straightforward as I thought it was with my limited wiring knowledge and no instruction on the specific model I purchased (FPG-089). I also got the incorrect billet clamp as I could not find info on the OEM sizing.
    • Stop looking at the garage floor, and turn the radio up a bit louder if there's any strange noises...
    • No. Turbo shuffle and surge/flutter are not the same thing. Specifically, on a GTR, turbo shuffle has a definite meaning. On a GTR, the twin turbos are assumed to be the same thing and to operate the same way, exactly. In reality, they do not. Their exhaust sides are fed and exhaust a little differently, to each other. Their inlet sides are fed and exhausted a little differently, to each other. Consequently, when they are "working" they are often at slightly different points on the compressor map compared to each other. What this means, particularly when coming on boost, is that one of them will spool up and start producing extra flow compared to the other, which will put back pressure on that other compressor, which will push the operating point on that other compressor up (vertically). This will generally result in it bumping up against the surge line on the map, but even if it doesn't, it upsets the compressor and you get this surging shuffle back and forth between them That is "turbo shuffle" on a GTR. It is related to other flutter effects heard on other turbo systems, but it is a particular feature of the somewhat crappy outlet piping arrangement on RB26s. There are plenty of mods that have been attempted with varying levels of success. People have ground out and/or welded more material into the twin turbo pipe to try to prevent it. Extending the divider inside it works, removing material doesn't. There are aftermarket replacement twin turbo pipes available, and these exist pretty mush purely because of this shuffle problem.
    • You can temporarily* use lock collars to keep it in place until you can do the bushes, back the nuts off, slide them in, snug back up. *temporarily is often for ever
    • Thanks for the quick reply. To be clear, when you say turbo shuffle do you mean turbo flutter "stustustu" or referring to something else? I had thought they were the same thing. When I wrote the post my intention was to say it wasn't a flutter/compression surge sound. My understanding was that a flutter sound would be occurring when throttle is released, whereas I can keep the throttle in the same position for this noise
×
×
  • Create New...