Davets

Here's another SR result from FB... seems pretty high for P11 cams and 25psi. link S15 SR20 VVL Head Using a Stock Head woth upgraded valve Springs std p11 Cams Garrett G25 660 Turbo .63 Housing Plazmaman intake manifold &INTERCOOLER Haltech Elite ecu on Board Making 565Hp@Hubs on 25psi

Here's two logs both with 4 port and 10 psi WG spring. Top one is with constant 20% DC, bottom one has 30%. The 30% DC run got another 4-5 psi at peak boost, but only 2 psi at the end of the run.

Duty cycle starts at 20% then tapers up with rpm. I've attached a log when I was using 4 port and 7 psi WG spring. Boost is 17 psi at peak (4200 rpm, 20% DC) then tapers down to 12.8psi (6500 rpm, 45% DC).

Both 3 port and 4 port soleniods are Turbosmart eBoost2 MAC valves, which don't seem to have full MAC part numbers on them... I'm driving both via a DPO on a Haltech IO expander box @20-30 Hz. Pretty sure this is the 4 port. Are turbosmart solenoids driven differently?

With 4 port control it can hit 30 psi with 70% DC but it's not controllable / consistent as small changes in DC results in massive changes in boost pressure (can't hit the pressures between 16 and 30 psi). I believe this instability is fairly standard behaviour for 4 ports. Sounds like an EMAP sensor should be the next move...

Yeah good call probably something I'll investigate in the future, but I'm a little worried about introducing a leak. From what I've read, unless something is seriously wrong, backpressure should not be an issue given this setup + boost level... BW MatchBot predicts an EMAP of 29psi@7000rpm with 20psi boost.

Yep, Turbosmart actuator was plumbed following the image below for 4 port testing. Boost control seems to work fine at lower RPMs... so I don't think its the plumbing. I'm using a Haltech Platinum Pro for the ECU. Its behaving like it has really high back pressure, I can use normal duty cycles (~20%) at lower RPMs (0-4000) but I have to quickly ramp in a lot of DC at rpm increases (e.g. 65%). If I use >65% DC at higher RPMs boost quickly jumps from ~16 psi to ~30 psi (probably maxing out turbo) as I move out of the linear range for the MAC valve.

Hey, I've had an issue with an IWG EFR turbo for about 1 year now ... I'm unable to hold anything much above spring pressure in the top end (above 6000 rpm). I've tried 3 port (with a variety of restrictors) and 4 port boost control ... 3 port gave spring pressure (@ max DC), 4 port I can manage another ~6 psi on top... nowhere near what I would expect. I've looked at WG actuator rod alignment, which is not perfect (had to machine some spacers) but seems to be an unlikely cause. Going a larger spring works (I've tried up to 24 psi) but it's for a S15 which struggles for traction in lower gears (needs boost by gear). Has anyone seen this before? Or can it be considered typical behaviour and I should just tune around it? Any advice would be much appreciated. Current Build: SR20 + VE head + EFR 7163 TS + Twin Port Turbosmart WG actuator + 3inch Exhaust

Thanks guys, no problem. SAU helped me out so many times it's good to be able to contribute. black bnr 32: Yeah, sure I’ve done some tuning with it. Set it up about a year back and it made a world of difference to my tuning accuracy. Best part was the ability to pull out timing in the hotter weather (although sometimes really cold weather can’t take as much timing as you may expect). To confirm the sensor was reading correctly I inserted a thermocouple into the intake pipe and compared the 2 measurement in a series of different operating conditions, at steady state they were within a degree over the range I checked (although the sensor doesn’t respond quite as fast as the thermocouple ofcourse). Recently I’ve changed to a vipec/link and still use the exact same sensor, just with the parallel resister removed, but still quite impressed with how well the power fc (mine was djetro) works and how easy it is to tune (with datalogit ofcourse, handcontroller’s a joke). .:::JAP TAXI:::. : I checked the excel file and it downloaded fine for me, possibly try a different browser. Between 5 – 60 degrees Celsius it was out from the RB26 Sensor by under 1 degree. I’m sure the repeatable accuracy of the factory sensor is over +/- 1 degree anyhow, so we might as well consider it spot on. Sure it can be used to display on a gauge, but for you to get the correct reading the resistance vs temperature curve must match.

Hi guys, After stumbling across this thread I remembered to post up an rb26 air temp sensor upgrade for the power fc I did a while back. Here's the link: http://www.skylinesaustralia.com/forums/topic/412248-rb26-air-temp-sensor-upgrade-for-power-fc/ Hope it helps some people out, Dave.

Hi all, This is something I’ve been meaning to post up for a while now to give something back to the hive of quality information that is SAU. Anyone who has tried to tune an RB26 engine is aware that the standard air temperature sensor is completely useless for measuring actual air temperature. No doubt it works great as a water temperature sensor (for which it is also used in the RB26) but why it was chosen to measure air temperature is beyond me. It responds extremely slowly and in the factory position measures nothing more than the temperature of the plenum. I’m sure the smart people at Nissan new what they were doing, but for the aftermarket street tuner it isn’t particularly useful. For those restricted to using the Power FC, even with the Datalogit, there is no ability to alter the resistance vs temperature curve for any of the measurements and, as such, cannot easily swap over to a modern sensor that responds at a reasonable rate. The method I propose involves the use of a Delphi Air Temperature Sensor (GM Part # 25036751). These are very common and used on a wide range of cars, hence they are cheap, reliable and easy to obtain. The resistance vs temperature curves don’t match but I have found with the addition of the correct resistor in parallel it is plenty good enough. Originally I was planning on adding another thermistor in parallel but found that this technique provided good results over the range I was concerned with and keeping things simple has its advantages. I measured the resistance of the factory RB26 sensor in 5 degree increments over the range of 0 to 90 degrees Celsius. These where graphed and compared to the known resistance vs temperature curve of the Delphi sensor. Attached is an Excel spreadsheet and also the supplied data sheet for the Delphi sensor. The majority of what is listed in this spreadsheet is self-explanatory, but the key part to pay attention to is the fair right hand column Temp Error, which shows the resulting error in the temperature measurement. The outlined box above, which currently is set to 14.2, represents the resistance in to be added in parallel. This 14.2 value can be changed and the effect shown numerically in the Temp Error column and visually on the graphed curve shown in purple. The value of 14.2k Ohms is the one that I used and it worked great for me. You can see from 5 to 60 degrees the error is less than 1, up to 80 degrees it is out less than 5. After that the error starts to run away a fair bit, but personally I haven’t measured intake temperatures of over 60 degrees C. It’s also important to move the sensor as to not be heat soaked by the plenum. I welded a mount into the steel piping, just after the intercooler. I know back when I was first trying to fix this problem I searched long and hard but didn’t come up with any answers. It annoyed the crap out of me while I was attempting to get a stable, consistent tune that performed well in both hot and cold conditions. I’m sure there are many other methods of addressing this issue, but this how I approached it and it worked just fine for what I required of it. Hopefully this info helps some people out. Cheers, Dave. GM Air Temp Sensor Calibration.pdf Standard RB26 vs Delphi Sensor.xlsx

Hi guys, I need an ACL Race Series piston for an rb26, 40thou oversize. I have one that is slightly damaged and don't want to reuse it in my current engine build. Part Number: RA9604X 1.00 If anyone has one spare they want to sell please let me know. Thanks, Dave.

Hi there, I am relatively new to this site as i have just recently purchased a beautiful R32 GTR. It has an extensive list of modifications, but it is being held back from unleasing it's true potential as it has standard injectors and air flow meters. I have a friend who is currently working at bosch and can get these parts for me at a substantial discount. I have sussed out the Bosch replacement for the nissan Z32 afm (Bosch part number F00E000202?) but i cannot really find any info on Bosch injectors. Is this because Bosch doesn't make any injectors that bolt straight into the RB26? If they do make some that fit, i'm after something in about the 700cc flow rate. Anyone got any idea of what the bosch part number for something in this range is? Any advise you guys can give will be greatly appreciated. Thanks in advance, Dave.