HPX N-1 Maf upgrade

[Ratsun815]

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.

[Matt]

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

[Ratsun815]

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

[Matt]

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

[Ratsun815]

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.

[Matt]

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

[Ratsun815]

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.

[Matt]

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

[Ratsun815]

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.

[Matt]

thanks