Jump to content
SAU Community

Recommended Posts

Hello all,

Got my gtr tuned 2 days ago but i noticed that its actually very rarily running 1.2bar which i asked the tuner to set it to.

It initially hits 1.2bar, car makes a maximum of 275kw at 4800rpm which suprised me but then plataues off and bleeds off down to 1.0bar. I was expecting max power at around 6000rpm? Im sure if i got the boost to hold at 1.2bar it should make 300kw at 6000rpm.

Anywho, its running a pfc, profec b spec 2, -7 turbos, stock airbox with k&n panel filter, stock afms, stock injectors, tomei pumps and full 3.5" exhaust, rest is stock standard.

My injectors dont seem to be going over 94% atm but i do realise that if i am holding 1.2bar till redline i will need an injector upgrade to be on the safe side of things but i want to know what the best way of going about the boost control problem?

Will a pair of twin pods help or is my ebc just not setup correctly? im hoping my ebc can do the job if its setup differently.. the solenoid is currently in the spot where the stock solenoid used to be.

thanks in advance

Link to comment
https://www.sau.com.au/forums/topic/327080-boost-control-issue-on-rb26-with-7s/
Share on other sites

I don't have a boost controller at all - 1 bar HKS actuators that come with GT-SS's, or Garrett make an equivalent, hook up to the standard solenoid pipeing / hoses just run a little air bleed hole back over where the stock solenoid is to up the boost as desired. Has a perfect boost curve ~16/17psi.

I know it sounds really ghetto but believe me you will waste half your life trying to get an EBC to do exactly what you want.

Saying that- BWRGTR is right - try running your EBC as close to the actuators as possible and then tinker tinker tinker.

sigh, i left that part of the ebc install to the tuner thinking they know better than i do >.<

i havent played around with the ebc settings coz if i manage to get it to run 1.2bar to redline im sure it will lean out..

will pod filters help my case or is it mainly an ebc/solenoid position issue?

im running the standard actuators that come with the turbos when you buy them off garrett, ill have some pictures up tonight

thanks for all the input so far guys, ill search up for some diagrams of ebc setups that have been proven to work

write down all the settings in the profec so you can set it back anytime. then try running a little more gain, keeping an eye on inj duty obviously.

if your not sure how to use the profec i can probably help you out if your local

Ive been really busy with work lately but ive managed to find this thread; http://www.skylinesaustralia.com/forums/Si...;hl=rb26+profec

ive booked the car back in for a retune on wednesday so ill change the solenoid setup before then and let the tuner have another go and controlling the boost curve :blink:

i should bolt on some filters while im there too i think! ill try post up a dyno graph tonight and another one next week when shes tuned again

ahh silly me, upon reading the graph again with more attention to detail, it looks like im actually making 275kw at 6200rpm haha, max torque is at 4700 :whoops: , yeah ill ask tuner to include afrs/boost on next dyno graph if possible

Ok so i made an attempt to shift the solenoid to the other side but found that the metal actuator line that bolts into an adaptor with a 12mm fitting, above of the rear turbo, was completely loose!

I bolted that in, made the lines to and from the solenoid roughly 20cm shorter and thought id just give that a go. Couldnt be bothered taking off the intake piping etc.

Ive tried using a lower set gain value but a higher gain value and it has actually reduced the spiking and is now holding a stable 0.9 bar on the low boost setting, before it was spiking to 1.0bar for a split second then holding at 0.8bar.

I havent fiddled with the high setting yet, car is going in for a retune 2moro as ive been getting some high knock readings come through at high rpm on the hi setting >.<

With those power levels you really want to be doing those adjustments on a dyno as you can't tell if its leaning out or if you are maxing out the injectors.

Perhaps ask to stick around when he does it so you can have a play as well?

the dyno was occupied when i got there so sean plugged up the laptop to my car and we went for a drive, vin diesel paul walker styles, without changing any settings there was no more knock readings no matter wat i gave to it! sean rekons the knock wires were getting interference near the ecu so he put some insulation on it and tucked it away

as for the boost control im gonna leave it for now, im quite happy with the power as it is anyway, when i get some money for injectors and cam gears ill then worry about it wen it goes back on the dyno

thanks for all the input guys

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 plug the hole. The engine plant may not have known whether the car it was going into had a gauge or not. It was a long time ago and the integrations might not have been fully modern. Or they might not have cared because the extra inventory and processes to save a few cents on the sender might have cost more anyway. But please tell me you are not still confusing the idea of a pressure gauge sender, and an oil pressure light switch. The switch will be out there. In a separate hole. Probably with only one wire running to it. Running the light.
    • Blower needs to go low on the exhaust side, displacing the AC and PS, which you have to decide whether you want to keep and how and where to relocate if you do. Electric option for PS is, at least, helpful. Sadly, there is no workable 12V electric AC of any value. Whilst the blower is the last compression step before the throttle, and so it might seem a good idea to have it near the inlet manifold (as mentioned above), you probably want it to go through an intercooler first, so, having it on the opposite side of the car facilitates that air flow path. The turbo discharges into the blower, so proximity of the turbo's compressor outlet to the blower's inlet is nice. But then you might want to intercool that too, before boosting it again....which would probably be a ball ache. Routing pipes out to the front and back could be a bit shit. If there was room for (at least) a small (but preferably larger) water to air core on that side, then that would probably be the best approach. I guess a reasonable alternative would be to locate the blower where the alternator is (more or less, associated with the inlet manifold, per Matt's thought), and somehow incorporate a water to air core into the manifold, sort of like they do for modern blown V8s. The big difference here though is that those V8s have only the one throttle (upstream the blower) and only the one compression step (the blower) and no need for too much in the way of bypass/blowoff valves. Whereas in a twin charged 6, you do need to think about one or two bypass valves associated with the 2 compressors and you would prefer to have the intercooling done before the air has to pass through the throttle. You'd like the throttle to work approx the same no matter what the compression is doing. But if it is located in hot air stream before a cooler, then sometimes the air will be real hot, sometimes it will be quite cool, and the throttle mapping/response will be quite different between those two cases. The throttle, if sized for hot air, would be too large for cold conditions. It's all a ball ache.
    • Package SC on exhaust side. Remote mount turbo. Still a fair bit of room when you get creative on the inlet side of the motor too. Especially if you can get really creative with the welding, and effectively build it into the bottom of the inlet manifold. Would definitely take some design work, and some trial and error, to make sure flow works well still! Might be easier to just start with the Nissan March though... All the work is already done for you...
    • I'll sit down and get a post together 馃榿
    • The factory oil pressure sender is no longer in the car that's what is confusing me. In the Taarks adapter I have an aftermarket Bosch style pressure/temp sender and the factory temp sender only. Oil pressure is perfect. Where does the factory oil temp sender go to if there were never any gauges? Why was it there from the factory?
  • Create New...