Jump to content
SAU Community

Recommended Posts

Nah there is no feedback switch for th boost sensor on the neo ecu's. You can basically disable the sensor by setting all values in the TP Load Recovery table to max, 255. And then turn off the DTC flag to stop the check engine light from coming on, but I think you still need the sensor plugged in. I'm not sure if the ecu starts acting up if it can't detect the sensor is plugged in. I have also heard the you need to put a resistor in the line if you want to remove it.

Yeah the tables name is misleading, I don't know why it has been labeled as TP Load Recovery but it's function is definatley the boost cut limit. Most tuners will just max it out as well as the airflow cut, TP Load Limit, for obvious reasons.

But like I said, maxing out the values won't eliminate the sensor from the system, just stop the ecu from cutting once boost goes over its set point, roughly about 1 bar.

I've tried to work out how TP is calculated by using values logged with the data log, I've tried lots of combinations of MAF Lookup, rpm, injection multiplier, latency, number of cylinders, etc etc but can't seem to get the same TP value the ecu shows, there must be a bit going on in the background I can't see.

I didnt think the boost sensor has anything to do with TP calculations.

Rather TP is as GTSboy said, TP load (boost cut) doesnt limit the boost, it limits the TP, if TP exceeds set value eg 110 then the cut is activated, u can run as much boost as u want aslong as it doesnt exceed the set TP threshhold

Ah yeah right, jeez I'll never get my head around all this lol. Have read all the NIStune documentation 4 times now, still know nothing :P

I don't get any TP cut, the sensor doesn't seem to affect drive-ability at all. But neither did the TCS code. I just want to get rid of the code before I take it back in for a retune because I haven't actually ever had my car tuned without a DTC which is a big no-no in tuning 101 haha. Until I can get it tuned with absolutely no errors, I can't be sure that my setup is working properly.

good to hear you've got it sorted hanaldo, now for a proper dyno run to see if it cracks the 280-300rwkw that this turbo claims to make :thumbsup:

Haha well Stao made 320rwkw @23psi, so it should crack 300 on 20psi. Biggest thing for me is getting my VCT working, cos god damn this turbo is laggy without it...

I didnt think the boost sensor has anything to do with TP calculations.

Rather TP is as GTSboy said, TP load (boost cut) doesnt limit the boost, it limits the TP, if TP exceeds set value eg 110 then the cut is activated, u can run as much boost as u want aslong as it doesnt exceed the set TP threshhold

it doesn't, and what your saying is correct for the "Load Cut (TP Limit)" table. But on the Neo RB25 there is an additional Boost Cut, that will cut the engine when boost exceeds the set point (~1bar). The table this set point is in is labeled "TP Load Recovery" for some reason. I know when Matt is breaking down the image and locating the tables he compares them to other known images, so that part of the map may have looked like a TP Load Recovery table and adopted the name.

According to page 7 of Matt's mapping guide, TP = MAF Lookup * k / rpm

And MAF lookup is the output side of the VQ map.

yep, tried that. i have also tried the calcs from the nissan patents on TP. it just doesn't work out for the values i have, though i am running a Z32 MAF.

e.g.

RPM: 5162

VQ: 47544

K: 402

using the above formula 3702 (14)

Actual TP: 43900 (171)

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

    • Here's one I help build and tuned a decade ago, Garrett  GTX3071R Gen 1, T3 twin scroll 0.83 rear housing. Went from larger 272 cams down to smaller Tomei Poncams to help with the low end. S13 non VCT motor. Car was purpose built for the track, hence low down was the focus. Note the actual dyno chart shows lower boost, however the EBC and boost gauge showed 1.9Bar (Ignore the torque, I was young and didn't know how to set derived torque)  
    • I’m doing some side developments on SR20det S13 engines, its one my hobby cars used it to compare flow capacity of some smaller size wheels. SR20det is one of another JDM legendary engines I'm sure there are plenty of SR enthusiasts on this forum, I will share results some common turbo configurations here. a quick run down of what the car is: Wide body 180sx Type X with black top engine (blue). It has: Stock bottom end Haltech 1500 ECU 5-0 motorsports trigger kit Kelford SR20DET Beehive Spring with Titanium Retainers Kelford Cams SR20DET S13 188-B 268/272 Cams G25-660 Turbocharger in T2 .64 rear housing internally gated ARP Head studs MLS head gasket 1000CC ID injectors Walbro 450L Fuel pump Front mount cooler kit JJR’s 3 inches turbo back exhaust (its too short for the 180sx it had to be extended) Pump 98 fuel Hub Dyno tune So far made 270rwkws at 22psi full boost by 4500RPM. Engine is very knock limited hence a pretty bad looking top end. From previous experiences it seems like SR20dets are happier with bigger size turbine, some thing like a GT30 would make way better top end, but on same time response is lost. It won't be a problem with S15 VCT engines. I'll be testing alternative turbine housing, turbine wheel and possibly dump pipe options for extra flow to resolve the problem and of course E85 would resolve all the issues.            
    • Awesome writeup and details. Thanks for sharing the story so far. I can relate to parts of it with my previous car and some of the issues I had to deal with.
    • Wow the colour matched hard top completely transforms the car. Are there any nice front lip options for the car or is that off the table?
    • Generally yes but for some reason I've been ruthless this time around!  I might even need to do another tip run after the way I've finally been able to hit the delete button on shit I've stepped over, stepped around and tripped over for the past 10 years!
×
×
  • Create New...