I've got a major update under way for my R33 GTST at the engines department
Im building a RB30 w. RB25DET head, CP Pistons, Tomei valvesprings, twinentry fuelrail, Bosch 1680cc's and so on but my mind is set on a certain problem, im going to run twin turbos, 2x Borg Warner 550hp a piece.
Im currently running the Z32 ECU w. nisTUNE and was thinking yesterday when i brushed my teeth... The Z32 has got TT stock so do you recon i could use 2 AFMs with this ECU without tricking it?
Other then that theres acouple of solutions but this one seems the easiest, if possible, and every other seems quite unnesseccary
Thanks for your answer, unfortunatly i realized that after some research that i could have done prior to asking it here. Looks like Ill be getting a SAFC/NEO to get it to work with 2 AFMs
Many of the Z32 guys use a "twin MAF" setup. I can't see why you couldn't run twin Z32 AFM's and only connect to one of them. Provided the plumbing isn't screwed up they should each measure the same. Taking this one step further, you wouldn't even need the second AFM - just fit a piece of 71mm ID pipe and save some $$$!
Idea number 2 is to pull the sensing element out of a Z32 AFM and graft it into a larger dia pipe. Wouldn't be hard to do. Cut out a section in a 100mm piece of ally pipe and glue the Z32 sensing element in. Not sure how much VQ map modification you'd need but if it was me I'd be going this way.
Please keep us informed of how you go. Sounds like a good "extreme" RB that could break some records for the NIStune setup.
Good thought there Have been looking at alot of solutions and that is on of them although after taking a look at this post i changed my mind heading for the AFC-solution instead
Just one thing - I've never run an R33 RB with the Z32 ECU but I have people ask me about the wiring mods all the time. I understand the need to:
1)Swap the injector wires around
2)Snip ABS wire (TPS WOT switch on Z32 ECU)
3)Join pins 29+55 as RB25 runs one O2 sensor and Z32 ECU runs 2
4)Move wire for PS switch
But what I don't understand is the Z32 ECU uses the old TPS setup with a switch for throttle closed and for WOT. RB25 doesn't.
So how does the Z32 ECU deal with the lack of throttle switches on the R33? I guess you could re-write the code (well, Eric could...) or fit your RB25 with a Z32 TPS?
I get a lot of people asking about running MAP sensors with Nissan ECU's so I thought I'd do a bit of research. Idea being that we should be able to just use a standard MAP sensor and as long as we could convert the output to be 0 to 5V like an AFM then it should basically function.
I'm sure there'd be a PIC out there with A>D and D>A stages that would do this for us with a bit of code in between. Theoretically we should integrate AIT into this too but I'm not sure what the function would be for that - or whether we really need it.
Anyway, after a bit of Googling I found that a heap of guys are actually converting their MAP based factory systems to AFM because of all the advantages AFM's offer! I lost interest pretty quickly after that!!
From what I understand HKS VPC is not as easy as install and it works. Takes some setting up due to IAT sensor, etc that affects the voltage that's sent to ECU.
Also from what I undertand, MAP is good if tuned correctly.
Stock BNR32, BCNR33, BNR34 ECU can run MAP sensor, as those ECU's have a IAT (Intake Air Temp) sensor as stock equipment.
These are the differences I see between AFM and MAP setups :-
AFM - Hotwire reacts to changes in air temp due to cooling (cold weather / colder intake air temperature) or not cooling enough (hot weather / hotter intake air temperature) the hotwire. Then reacts to changes in air pressure / altitude, as there is more air at sea level or less air at altitude that is cooling the hotwire. Then there's one input into ECU (voltage) via table that is converted to load.
MAP - MAP sensor does the job of the AFM (pressure only for load) but doesn't correct for intake air temperature (hot day and cold night or similar conditions). IAT (Intake Air Temp) sensor is linked to intake air temperature correction maps (ignition, fuel maps) on ECU that correct for the change in intake air temperature.
I gather the reason why MAP setup is not prefered, as it's harder to tune, as ECU moves between main fuel, ignition maps on stock ECU to intake air temperature correction maps (ignition, fuel). It's similar to switching between main maps, knock maps. I gather if it's tuned correctly between intake air temperature correction maps, main maps, shouldn't have any problems with driveability. But if not tuned correctly, could suffer drivability problems because of switching between the 2 sets of maps that have different values and make engine feel sluggish or alive. I guess the addition of more maps (more load, rpm cells to tune), is the reason behind why it takes longer (more than one day) to setup MAP properly which cost's more $$$.
I presume the BNR32, BCNR33, BNR34 ECU's have these intake air temperature correction maps due to having a stock IAT sensor, but don't see these intake air temperature correction maps in current BNR32 address file.
Look at aftermarket ECU's like Link, Motec, ViPEC, etc, as they have these intake air temperature correction maps and barometric compensation, etc.
A lot of people tend to place a lot of emphasis on the fact that AFM's represent an airflow restriction. In reality this is a few KW's worth at most.
While the advantages are largely overlooked. The biggy for me is that they make the system inherently flexible when it comes to engine mods. Change anything that affects the VE of your engine on a MAP based system and you'll be up for a re-tune. While AFM based systems will simply account for most changes because they're measuring the actual amount of air entering the engine.
I tuned an S14 once for the usual sort of stuff - more boost, bigger AFM and injectors. Then the guy decided to put aftermarket cams in it. So we got it back on the dyno for a tweak. I literally didn't have to touch a thing. It made another 20rwkw and required no additional tuning.
This guy sums it up nicely - sure it's a forum for Ford V8's but in the end they're all just engines..
any news on Z32 ecu TPS problem running RB25 with no Throttle valve switch ? Can you wire it manualy ?
Also my z32 ecu works without repining. When I use extended ecu harness repinned with injectors swapped as per ecu pinouts car runs rough, like misfiring. And it doesn't hold idle no matter what.
