Whats stock boost for S13 S14 SR20DET - Page 3 - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

LoSt180 · 01-03-2017, 01:08 PM

Stock boost for both the S14 and S15 is the same. Approximately 10-11 lbs with the factory boost solenoid in place. With the solenoid unplugged it defaults to wastegate pressure of 7 lbs. It will also drop to 7 lbs if the ECU detects an error. I had an issue were it felt sluggish and wouldn't go past 7 lbs, after scanning with Consult port there was a knock sensor issue. Fixed problem, cleared code, bam 11 lbs and running strong again. The FSM also states the the boost solenoid responds differently based on speed; 'slow' turbo response at slow speeds and 'fast' response at high speeds.

If people have the boost solenoid hooked up and are still only getting 7 lbs, then they have another problem somewhere. For example, I noticed my auto-to-manual wiring specialties harness originally kept showing my car was in neutral. Car felt like a dog, after fixing the neutral sensor wiring, full boost and VCT started working like a champ.

Readings come from my stock Kouki DIN gauges and roughly converted to psi. The gauge reads up to 700 mmHg. Wastegate pressure is right at the middle line, or 350 mmHg (~6.7 psi). Full boost is a little before the 7 line. So I'm guessing ~550 mmHg (~10.6 psi).

I also upgraded to S15 injectors and S15 ECU and boost remained the same as S14 ECU.

Picture of my boost gauge for reference:

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01-03-2017, 01:08 PM	#61
LoSt180 Zilvia Addict Join Date: May 2013 Location: MD Posts: 966 Trader Rating: (18) Feedback Score: 18 reviews	Stock boost for both the S14 and S15 is the same. Approximately 10-11 lbs with the factory boost solenoid in place. With the solenoid unplugged it defaults to wastegate pressure of 7 lbs. It will also drop to 7 lbs if the ECU detects an error. I had an issue were it felt sluggish and wouldn't go past 7 lbs, after scanning with Consult port there was a knock sensor issue. Fixed problem, cleared code, bam 11 lbs and running strong again. The FSM also states the the boost solenoid responds differently based on speed; 'slow' turbo response at slow speeds and 'fast' response at high speeds. If people have the boost solenoid hooked up and are still only getting 7 lbs, then they have another problem somewhere. For example, I noticed my auto-to-manual wiring specialties harness originally kept showing my car was in neutral. Car felt like a dog, after fixing the neutral sensor wiring, full boost and VCT started working like a champ. Readings come from my stock Kouki DIN gauges and roughly converted to psi. The gauge reads up to 700 mmHg. Wastegate pressure is right at the middle line, or 350 mmHg (~6.7 psi). Full boost is a little before the 7 line. So I'm guessing ~550 mmHg (~10.6 psi). I also upgraded to S15 injectors and S15 ECU and boost remained the same as S14 ECU. Picture of my boost gauge for reference: