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Can't Boost Over .8 Bar After Engine Build Rb26

raceryan
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raceryan Newbie

raceryan

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Just dropped a newly built engine into my 89 GTR, and installed a new Innovate SCG-1 Boost controller wide band O2 at the same time. Put in Nistune ECU and went to start the tuning process. I've got it running, but pretty rich WOT and wanted to take the boost up to 1.2-1.4 bar and clean up the fuel trims thinking higher boost may even up the richness on WOT. The car will not push more than .8 bar regardless of gain, or duty cycle settings on the boost controller. I have tried everything, even tapped a line just after the turbines combine before the air enters the intercooler. Nothing over .8. I pulled of a line of the solonoid and it will boost like crazy, had to quickly let off throttle as it went up to 1.45bar on the pull, which tells me the actuators are working...Any ideas? What am I doing wrong? Actuators are T'd into each other and I was pulling the other source from the plenum right under the #6 throttle, also tried running a source from the "twin Turbo" collector?

HKS 2530's with oversized outlets, 264 poncams, NAPREC Port and polished head w/ 1mm over chamber, adjustable HKS cam gears, 1mm hks head gasket, N1 rods, n1 oil pump, n1 water pump, 680cc HKS injectors, 65mm downpipe, forged pistons.....should be putting out some decent power.

  • 3 weeks later...
raceryan Newbie

raceryan

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Yup, all that tried. With the innovate SGC-1 unit I discovered with twins you have to set the "spring pressure rate" setting well below the stock spring rate. My turbines are .8 bar, I had to tell the boost controller .22 bar to gain control. Any higher than that no matter what "waste gate duty cycle" or "gain" setting is used it will not do anything. Once you get control of boost you have to mess with the duty cycle and gain as normal. I have finally gained control but have not had luck achieving stable boost of of 1.5 bar. The closest I have been able to get is 1.3 spike to 1.1bar stable. I like the unit and features but it is PITA to dial in. Be aware of this issue for any one thinking about this unit.

Dyno tune now finally complete and put down 592ps @ 1.1 bar.....I really wanted to run 1.5bar. Still running the stock intercooler, fuel pump and a zietgen exhaust with premuffler.... Ended up using FCON-S as my tuning shop "STF" could not figure out NISTUNE mapping.

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