Nistune Forums

Good afternoon nistune boards,

I'm switching from a z32 Maf draw thru to a hpx-n1 blow thru Maf. Pretty sure this is a solid upgrade these days with how old the z32 maf's are getting. Does anyone have a decent tune for a sr20det running this Maf as blow thru?

Here is my set up
S13 blacktop sr20det with e5 ecu
555cc injectors
Brian crower stage 2 cams
Greedy intake mani
Garrett ball bearing t28
16 psi street cruisin
25psi drag racin lol

Any help would be greatly appreciated I've always struggled with a choppy idle on this thing and I think I have it diagnosed to a faulty Maf on its way out. Thanks again guys.

It is best to get the wideband and run through our tuning guide to make sure mixtures at cruise are around 14.7:1 with near zero trimming

Use the HPX (Z32 load) to get a good starting point with the HPX from the Operations > MAF resize

Thank you Matt,


Sorry for the late response but apparently a tuner put a lock on my ecu. so I had to have it sent off to get the base image wiped. I installed my new hpx maf (blow thru set up) and soldered everything in. I did manage to get the car running tho and adjusted k constant while in cruise/low load areas. I guess I have three questions for you (or anyone very knowledgeable). The first being can I tune this vehicle without the use of the 02 sensor??? I know it sounds hack Because it is but I always had this annoying unstable idle issue which I thought was the old z32 Maf being old and junky. It's not really that bad just kinda surges a lil bit going lean then back to stoich, but when you unplug the 02 it purrs like a kitten.my theory is the idle areas aren't that important when I wanna make a few passes. I know that's just dumpin a bit more fuel in and masking a problem but I'm tryin to get to the drag strip on the 15th. Believe me I really have checked all the basics on the idle issue. My next question is do you have any sr20det hpx Maf tunes with 555 injectors? It would help out a lot just to get me close and which method do you guys monitor knock on these things without being glued to a computer screen? Does anyone know of a decently priced knock monitoring system. I just wanna be safe.

Sorry for the lengthy post but specifics save time

1. You do not need the narrow band O2 sensor to tune. However you definitely need a wideband sensor and knock detection device as a minimum for any tuning

O2 sensor holds the ECU in closed loop. If the O2 sensor is trimming the tune leaner then unplugging it is just a band aid for not making any adjustment

2. We dont have a base tune for that setup. You will need to get it done properly. Perhaps stick with the Z32 for your drag strip with a known proper tune until you can get it retuned with the HPX

3. We have some details for building your own headphones in our 'general discussion' area

ok thanks matt I appreciate the help. I'm seeing
something called a knock warning panel in the
nistune is this something i can use? if not i might
pick up some knock detecting headphones or like
a light led set up.

Not for that ECU. Only some of the earlier ones with simple knock detection and count

mega bummer. i wonder if there was someway to get a
stand alone knock sensor and link it to the ecu
kind of like the wideband does. That would be the tits.

It would be great but knock detection is quick and sampling in the unit may be fast, but reporting it out (if possible) would not be

just a lil something to get around no biggie. I'm
diggin this software tho bud. It's a lot of bang for
your buck. Awesome job dude.

thanks