89' GTR RB26DETT hard crank

[RXXXII]

I have a mostly stock setup:

RB26DETT
Deatchwerks 800cc injectors
Deatchwerks 320lph fuel pump
Aeromotive Adjustable fuel pump (set @ approx. 43psi)
Dual ISIS N62 300ZX replacement AFMs

With Nistune loading a stock map then changing the MAF to Z32 mafs, it wants to try and fire up, but runs extremely rich so cranking is almost impossible.

Once it is running, adjusting the injector multiplier to compensate for the 800cc injectors almost seems impossible, it's like no matter which way we go, it's so touchy it just cuts off.

I keep hearing that changing the MAFs & Injector size in nistune doesn't work, you have to pick one or the other. Is that true?

Any way to setup NISTUNE for a good cranking situation?

We start with the 128 rom map for the BNR32...

[Matt]

Make sure you select 'halve' tickbox' when resizing to Z32 VQ map on this engine (it should only show upto 50% when using 0.12.5 Nistune in the VQ map graph)

Let me know how you go with this since I had another customer with 680CC injectors but having off throttle leanout issues to trying to diagnose this. I've had other people doing this setup no problems so I've got to look at their logs

[RXXXII]

Make sure you select 'halve' tickbox' when resizing to Z32 VQ map on this engine (it should only show upto 50% when using 0.12.5 Nistune in the VQ map graph)

Let me know how you go with this since I had another customer with 680CC injectors but having off throttle leanout issues to trying to diagnose this. I've had other people doing this setup no problems so I've got to look at their logs

Thanks I will try this, I did not know that I had to select the "halve values" tickbox.

From a stock RB26 BNR32 128 ROM file, I am going to apply these changes:

1. Operations > Change MAF > Z32 500hp > adjust TP tickbox checked > Halve Values tickbox checked

2. Operations > Resize Injectors > Current: 444 New: 800 > adjust TP tickbox checked > adjust TTP tickbox checked > adjust cranking tables tickbox checked

3. Injection Latency: 600 (for .6 millisecond latency for the new Deatchwerks 800cc injectors)

Does this look like a good start? Do I need to change any of the cold or warm enrichment tables?

[skylinegtrhr]

Did You try to modify VQ map as aparently these mafs are not same as oem z32, see this
http://forums.beyond.ca/showthread/t-287996.html

[RXXXII]

Did You try to modify VQ map as aparently these mafs are not same as oem z32, see this
http://forums.beyond.ca/showthread/t-287996.html

Interesting... this is the first time that I heart of this issue with the ISIS mafs. I could go back to my OEM mafs for the time being, but then that would limit my horsepower and I wouldn't be able to hit my goal of around 600hp.

Now I could talk to the tuner about the modding the VQ map to compensate, but when I tell him about the VQ map, is that the same as the fuel MAP? I don't actually mess with the nistune program itself. Where can I find access to the VQ map within the Nistune program?

[Matt]

When resizing for twin Z32 MAFs you need to double the K constant afterwards. Just spoke to a tuner here in Aus doing this yesterday. Once they doubled K (332 > 664 with 440CC stock GTR injectors for example) then car reved up okay after that