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Need help with a Z32 using a BNR32 ECU for RB26DETT
Posted: Mon Jul 07, 2014 2:34 am
by Frontier
this Z32 has a swapped RB26DETT with upgraded Nismo R32 turbos and has a blow through single HPX MAF in 3" intake and siemens 660cc injectors. When I go under the change MAF after I change the injector size it blows up the K value from 155 to over 600?? I'm not sure where to start either with the Z32 maf or the HPX? Does anyone have any experience using this MAF to tune with Nistune on scaling for the injectors?
The HPX MAF shows 1460HP in Nistune??
Re: Need help with a Z32 using a BNR32 ECU for RB26DETT
Posted: Tue Jul 08, 2014 9:22 pm
by Matt
Yes that is the correct reading for the HPX. It can measure a massive amount of HP.
However with K constant, which gets used also for load calculations it throws a lot of things out. My R34 K constant went from 300 to 1300 which affected throttle and warm starts (once warm it was fine) due to TP affected
I'm adding a final injection multiplier adjustment to handle huge injectors and MAFs like this where moving K would not work correctly. Its in the feature pack firmware for limited models.
See how you go with the K at the moment, and make sure Halve values tickbox is used when resizing the MAFs on R32 GTR
Re: Need help with a Z32 using a BNR32 ECU for RB26DETT
Posted: Sat Jul 12, 2014 5:42 am
by Frontier
Hi Matt,
Well I have everything running and running pretty well, but its weird how this MAF reacts. If I adjust the K value to get close to 14.7 runs good and then if I blip the throttle or drive and come to a stop it will go up to 18-19afr?? start driving again back in the 13-14 range.
I have K value set at 255 for 660cc siemens injectors and runs 14.5-15 crusing and will start to dip in boost transisition. If I come to a stop afr goes to 18-19 again. If I increase K to bring down the afr to 14.7 then go for a cruise afr will be in the 12's. So I'm not sure whats going on at idle why it wants to lean out so much
When I did the maf change my K value was over 1000. The car wont even run at that. It will run good anywhere in the 250-350 range.
Re: Need help with a Z32 using a BNR32 ECU for RB26DETT
Posted: Mon Jul 14, 2014 12:31 am
by Matt
Time for some further investigation. Watch the HPX voltage in stream mode in the log recorder. Watch this against TP (load calculated from MAF) and resulting injection time and then your AFRs
See what the MAF voltage looks like compared to your AFRs. Would be interested if you could post the log here also. We are lining my s14 to run the HPX MAF using injection adjust constant instead of K on my S14 next dyno session