Nistune Forums

Hey guys,

Im working with matt now on fixing the problem with the vh45 car but in the mean time , I'm gonna need to build a vq map for the vmp hpx maf in a 3.5 inch housing.

Does anyone have a link or instructions on how to do this? Ive searched all day and can't find anything on it. Or better yet if you have a scaled vq map that would even be better lol.

Any help on this would be appreciated..

Jerry

I built one based on the hpx in a 4" tube. I did call the guys who made them (pmas/vmp etc) but they only offered 16 or 32 point references and a spreadsheet that are nothing like that scalers nissan use. I supplied all the info to Matt months ago, stil waiting for a response for him to test'n'tune on his R31 (I think).

The quickest option is to pick a large VQ curve, set the fuel map lambda where you wanted it and adjusted the VQ to obtain the mixture commanded from the fuel map.
Accel enrichment can cause problems with this technique unless you can use steady state load (PAU dynomometer or brakes etc)

note: zero-ing accel enrichment, can cause engine stall for some reason not yet discoverd.

hope this helps,
please let me know if you get any further as I ran out resources to complete more than what was necessary at the time.

Can you post the vq map you built for the hpx in a 4inch tube just for comparison.

heres what I've been playing with, throughout just sheer trial and error.

This is a sheer guess on my part based on observed a/f against maf voltage and raising and vq look ups.

This got the car drivable n/a not on boost with the a/f all over the place from 12.3 to 16.1

voltage- vq
0.08 ----0
0.16 ----500
0.24 ----587
0.32 ----684
0.4 ----871
0.48 ----1768
0.56 ----2036
0.64 ----2058
0.72 ----2680
0.8 ----2814
0.88 ----2974
0.96 ----3380
1.04 ----3449
1.12 ----3965
1.2 ----4460
1.28 ----4670
1.36 ----4870
1.44 ----5048
1.52 ----5075
1.6 ----5198
1.68 ----5333
1.76 ----5520
1.84 ----5706
1.92 ----5937
2 ----6134
2.08 ----6350
2.16 ----6841
2.24 ----7070
2.32 ----7530
2.4 ----7875
2.48 ----8286
2.56 ----8551
2.64 ----9000
2.72 ----9498
2.8 ----10271
2.88 ----10903
2.96 ----11308
3.04 ----12262
3.12 ----13285
3.2 ----14354
3.28 ----15588
3.36 ----16823
3.44 ----18088
3.52 ----19504
3.6 ----21068
3.68 ----22831
3.76 ----24359
3.84 ----26056
3.92 ----27681
4 ----29417
4.08 ----31592
4.16 ----33690
4.24 ----35844
4.32 ----37650
4.4 ----40167
4.48 ----42907
4.56 ----45637
4.64 ----48368
4.72 ----51234
4.8 ----54674
4.88 ----57832
4.96 ----61525
5.04 ----65235
5.12 ----65535

just to update, i removed the hpx maf and installed a 90mm lightning maf, car is up and running like a champ. Thanks for the help guys.

The two lists are from different size tubes, 96mm and a 100mm. they are vastly different at low airflow metering due to the mounting choices & compensations for intake turbulence from ram induction.
The data in both is only good for the first 25% of values as a comparison.
87
124
153
182
168
202
248
412
488
550
627
704
797
921
1038
1156
1273
1390
1541
1692
1843
1994
2181
2367
2554
2741
2957
3173
3422
3671
3919
4168
4767
5365
6080
6795
7642
8488
9442
10511
11580
12814
14049
15465
16881
18445
20170
21895
23846
25797
27976
30155
32540
34925
37436
40044
42651
45381
48112
51117
54123
57974
61825
65535

8
8
55
84
126
167
209
250
320
382
459
536
629
599
742
857
973
1127
1408
1640
1791
1994
2181
2367
2554
2741
2957
3173
3422
3671
3919
4168
4767
5365
6080
6795
7642
8488
9442
10511
11580
12814
14049
15465
16881
18445
20170
21895
23846
25797
27976
30155
32540
34925
37436
40044
42651
45381
48112
51117
54123
57974
61825
65535

I supplied all the info to Matt months ago, stil waiting for a response for him to test'n'tune on his R31 (I think).

This one did not work well on my car. I think I have another issue with it since went back to baseline of RB30 AFM and still got running issues to been trying to sort that out last week

Another customer provided an update with 3" HPX sensor and ended up using that. Went better but problems with too lean at one end and too rich at the other. So I need to sort the car out and work from there

I've updated the 3" BIN file but will do 3.5" BIN when I get back next week and update the installer accordingly

Matt, what size tube were you using?

Did you change the maf when the R31 had an existing issue or just to illiminate when troubleshooting?

3" tube which HPX sell with their sensors

With my car I'm not sure what is going on. I had a problem with the Z32 MAF starting to run funny so going back to RB30 AFM (got three of them but not sure which ones are 'good')

Need more time on my car when I get back next week to sort out which ones are good and if there are any other issues with the car (shouldnt be)

I would think you could take an existing maf inline with the maf in question, and datalog voltages from both at the same time, then comparatively build at least a good section of the vq map. If you have a maf that is going to run out of steam, at least that builds the section up until it does?
I wondered this too, sometimes rehousing a maf is sufficient instead of spending the money on a z32 maf for example. Hell it might even scale higher.

tastyratz wrote:I would think you could take an existing maf inline with the maf in question, and datalog voltages from both at the same time, then comparatively build at least a good section of the vq map. If you have a maf that is going to run out of steam, at least that builds the section up until it does?
I wondered this too, sometimes rehousing a maf is sufficient instead of spending the money on a z32 maf for example. Hell it might even scale higher.

your are correct in that line of thinking, I've sucessfully rehoused the stock CR31 MAF that Matt is playing with and been able to scale past those terrible Z32/Q45 Mafs. the hot wire evens last longer in a larger tube.
Often simply adjusting 'K' and some low end tweaking will suffice.
As for measurement, you could perform your suggestion as a good starting point. I've been doing something similar with carby engines over the years to determine different breating characteristics of camshaft timing. building a vq map could be the next step but I've never really known what the numbers in nistune equate to in cfm without comparing to a known airflow measurement device.

Well the HPX is removed from the R31 and we are going to do the R34 instead, since I'm putting the R31 up for sale soon

I've got four different RB30 AFMs for the R31 and all are showing rust colour on one side of the hot wire. Doing bench readings on all of them, one showed higher figures than the others in terms of voltage reported with a fixed airflow - so others have gone in the bin (even after cleaning attempts) and car is running better now with the working one

Yes I thought about that also using the DLP A/D converter to record HPX voltage vs stock AFM voltage and use this to design a curve. However the HPX curve which one customer put together from the interpolation done correctly went really well and required minimal tweaking on the dyno so will try that on the R34 instead... time to cut some intercooler pipe

Hi guys,

If anyone needs working HPX VQ maps let me know. So far I have 3" confirmed working and also 3.5" but not tested. I can calculate other tube sizes upon request.

Cheers

Hey guys

Attached is an updated sheet using the VMP transfer function polynomials. I've taken the original sheet of matts which used his 6 order function and replaced with the VMP 9 order

The 6 order one has been tried and tested, and the 9 order output matches the final tested VQ map figures. So you can cut/paste from this sheet into your VQ map table

I'll update the existing VQ maps for HPX into 2.5", 3", 3.5" as drop down items for the next version based on this updated sheet

Matt wrote:Well the HPX is removed from the R31 and we are going to do the R34 instead, since I'm putting the R31 up for sale soon

I've got four different RB30 AFMs for the R31 and all are showing rust colour on one side of the hot wire. Doing bench readings on all of them, one showed higher figures than the others in terms of voltage reported with a fixed airflow - so others have gone in the bin (even after cleaning attempts) and car is running better now with the working one

Yes I thought about that also using the DLP A/D converter to record HPX voltage vs stock AFM voltage and use this to design a curve. However the HPX curve which one customer put together from the interpolation done correctly went really well and required minimal tweaking on the dyno so will try that on the R34 instead... time to cut some intercooler pipe

If its not too late, can I have all the faulty units please.
Thanks

Too late... I did a clean out and those ones ended up going. I couldnt get them running okay again. If only we could get hold of the hot wire element