Nistune Forums

Have a 1985 Nissan Z31 running nistune on a 87 N/A ECU. I bought a HPX about 4 years ago and now I'm getting around to tuning the car. Is there a programming difference between the standard HPX (designed for Ford motors) and HPX - N1 (small block engines)? I see there is support in Nistune for the N1 when you change the MAF but not the HPX. I have found in the VQ Transfer Generator there is support for the HPX, but I want to make sure I'm using the correct scale to start out with. I have gotten it to where the car rev's smoothly (slightly rich, but still dialing in K constant), but I can't get it to start on its own without feathering the gas pedal. It idles around 960 mV, where you can see the curve completely cuts off in the image below. We adjusted it upwards so it would scale in from 0-960 mV and are still having trouble. The car starts OK with the standard z31 MAF scale (still using the HPX), but obviously doesn't run through the revs smoothly. The MAF sits in a 3" tube with tons of straight pipe before and after.

Long story short:
1. Is the HPX and HPX - N1 programmed differently? Do I need to be programmed as the N1 - and is the HPX the same hardware but just programmed differently?
2. Does someone have a starting MAF translation curve they suggest starting out with for the HPX? Is there support for this in the NISTUNE software already? (We have tried using the HPX N1 MAF curves to start).
3. What adjustments are people making to this curve? Using the VQ Translation Function?

Here's my setup:
Nistune Type 1 Board
VG30ET - currently running on 87 address file (using the map you posted last year - need to hit no when it says map should be 86 address file from mismatch in ROM sync).
3" intercooler piping from outlet to 60mm throttle body
2.5" piping from turbo to intercooler
1985 mazda RX7 680cc injectors
Attached is the tune I'm currently running. Also do you know which feedback switch is for the o2 sensor?

I was just messing around with the HPX N1 Scaling and dialed it down to 30% and scaled in the 0-960 mV. The scale is much lower than the HPX set up.

I see there is support in Nistune for the N1 when you change the MAF but not the HPX

Officially I only support the HPX-N1 in the software, because that is all I could get running right on the dyno (and R35 GTR sensor)

I do have the original HPX sensor here but never could get it scaled properly and running right on my cars. That is why it is not in the MAF drop list. I did still add in the polynomials into the VQ generator for the HPX however since some people are running them

Thanks Matt, I went ahead and ordered the HPX N1