Nistune Forums

in a 3" tubing, it can read to "700RWHP" as stated on VMP site. I'm at a peep more than half of that @ the wheels @ 16PSI. They said the resolution wasn't good enough for the MAF to be utilized perfectly.

ie: Problem was it being too rich in the higher rpm/load, but they scaled it enough to make it better. Any suggestions would be awesome though!

Like others I am very interested in this and it may be also worth some time trying to calibrate this on my vehicles and recalibrating the VQ map properly

The main issue is that Nissan has a 64 point VQ map which matches load to voltage. The VMP calibration tables provided contain less than half of these points, so there was not enough resolution provided

I took the provided table and doubled the size of it and then interpolated the mid points, but still left the table short of the full 64 points (by about 12 or so) so then filled points at the start. It may be that this table needs to be shifted left if you are reading lean

Really I should be expanding this table out further using some better method of filling out the interpolation points (say every 12 points adding an extra mid point rather than all at the start)

What this means is that at X voltage read, it is not reporting enough load to the ECU. The tuner should then adjust the VQ map by cutting from about say start 10 cells in and move that to the start and then fill in the end with max value (65535)

This will make the VQ map report more load for the read in voltage and then you will read further right in the fuel maps and get better AFRs

Yeah an exhaust leak will throw off the A/F #'s. Is it up stream or down stream of the 02 sensor?

Matt wrote:
Like others I am very interested in this and it may be also worth some time trying to calibrate this on my vehicles and recalibrating the VQ map properly

I hope that this will be high on Yours "to do" list.

thx for the further explanation Matt.

Ya, the provided "HPX" maf map was not good enough. Oh well, gotta pay to play. The tune right now is amazing anyways, I'm very happy w/ it.

BlueRB, the leak is definitely upstream from the O2 sensor. I would shit bricks if I hit 13-14 (sometimes 15's) on boost w/o the leak: my engine would be done by now.

I just needed a confirmation on if this tiny leak would alter AFR that much. Turbo spools just as great as it did w/o leak. The only issue is the slight exhaust smell in cabin and the wonky AFR.


cheers

Mike I've found someone cracked the original HPX spreadsheet and posted the polynomial for the 3" sensor

Attached is a sheet with an updated VQ map inside. I've taken the original 0 - 5.12 volt (0.08v increment) VQ map and transposed the polynomial over the top now I have the formula, so it is a lot better than the double points/average approach which had to be taken originally

Copy the VQ map from this sheet and paste over the existing VQ map inside nistune. I will update the map tonight in the install pack accordingly. Thinking of getting a HPX to try out on my R31 which was originally blow through:
http://www.vmptuning.com/store/index.ph ... &parent=29

Thanks a ton, Matt!

Matt wrote:Mike I've found someone cracked the original HPX spreadsheet and posted the polynomial for the 3" sensor

Attached is a sheet with an updated VQ map inside. I've taken the original 0 - 5.12 volt (0.08v increment) VQ map and transposed the polynomial over the top now I have the formula, so it is a lot better than the double points/average approach which had to be taken originally

Copy the VQ map from this sheet and paste over the existing VQ map inside nistune. I will update the map tonight in the install pack accordingly. Thinking of getting a HPX to try out on my R31 which was originally blow through:
http://www.vmptuning.com/store/index.ph ... &parent=29

Could we see a 95mm and 102mm version also?
I've modified the first 300HP worth of Air flow of the VQ map, should be finishing a bit more at WSID if it stops raining. Be nice to have a head start though ..

On their website they advise against larger piping due to the lowered quality in results (have a look at those links and they specifically mention this)

The polynomials for the sheet which were posted on the forum were only for the 3" size so I dont have the figures for the larger tubes

Is it possible to create a VQ map for 2.5 inch pipe? I'd be running two of these on a 300zx...

Need to crack their spreadsheet and get the polynomial for the 2.5 size pipe in this case

try to connect today ford lighting maf, but as soonest i try to re size maf in nistune to ford lighting and after ticking TP load and halve values car is starting like without maf, if i just load standard map without changing mafs engine is running ok, what can be reason ?
i have installed maf before intercooler into the piping , piping size is 3 inch

guricha wrote:try to connect today ford lighting maf, but as soonest i try to re size maf in nistune to ford lighting and after ticking TP load and halve values car is starting like without maf, if i just load standard map without changing mafs engine is running ok, what can be reason ?
i have installed maf before intercooler into the piping , piping size is 3 inch

Are you hitting the burn to rom button when your done changing the maf? try it again and before you start the car hit the burn to Rom button then save the map and start the car. Also if u have really big injectors you have to adjust the Kvalue, tick it on auto and start sliding it till you see the A/F lean out or the car start to idle normal.

ticking TP load and halve values

Dont tick the TP load for now... is this on a BNR32 ECU (R32 GTR)? This is the only ECU you use halve values on

Have you got both AFM inputs connected together into the Cobra MAF?

Matt wrote:

ticking TP load and halve values

Dont tick the TP load for now... is this on a BNR32 ECU (R32 GTR)? This is the only ECU you use halve values on

Have you got both AFM inputs connected together into the Cobra MAF?

Yes Matt connection is ok both of AFM in nistune is getting signal and there is no error, car is working fine unless i wont change afm with cobra one in nistune, so i need only halve values and dont tick TP load right ? i think need only calibration for VQ map

Sounds like it. If its runs better with the default map with your resized cobra, might be a better starting point. I'm in the middle of trying to calibrate my HPX and that is nowhere near the spreadsheet values resized for Nissan 64 point