hpx maf

[fikemoo]

Ok hello guys so I've been doing some research for some time and following the progress of the builds of here especially the r34 rb25 neo running the hpx blow through and with my current set up the turbo size and where it is situated it's time to take the plunge and go blow through and get rid of the maf and the smaller pipework.

A couple of questions which hpx would you advise? Looking on pmas website the hpx n2 seems to be the one as it uses the Nissan connector the later +03 style connector

Does nistune now support the hpx may in the drop down menu?

And generally is there any more info you guys can share with me

Thanks mike

[Matt]

Hi Mike

Yes Nistune supports the HPX MAF

The drop down configuration can be used, but it is best advised to use the MAF Function Generation tool in the software at this time
http://nistune.com/docs/Nistune%20MAF%2 ... 0Notes.pdf

I will put some updated curves in the drop down for more realistic load situations

The main reason is that the MAF can measure a stupid amount of power, and I use the tool to rescale to the power levels that the vehicle can actually do. In my S14 for example I used about 30% of the total scale as to not throw out K constant too far in the vehicle.

[fikemoo]

Yes i saw the issues with the k constant but the calculator looks awsome being able to scale it looks like i will be going ahead with this, do you advise using the hpx n1 as it uses the nissan older style connector? And i will be using 3 inch tube so the hpx by default in the drop down will be correct i presume?

thanks Mike

[Matt]

HPX N1 uses the Ford style connector. I have a bunch of sensors and connectors here from Mass Air Direct

I would advise using the calculator and select 3" HPX from there. After this, adjust the MAF scaling. I use about 30% of the original scaling of the HPX MAF with my S14 so that there is no need to rescale the TP load scales on my fuel map

We will be doing some videos shortly on how we do the tuning for these

[fikemoo]

Ok well ive gone for it ive placed my order 1x hpxn1, 1x pigtail and 1x stainless steel flange is on its way, should be around 3 - 5 days when it will get to me due to me being in the uk, exciting times thanks for the info matt i shall let you know how i get on with it maybe upload some videos of the progress and the running of the car, i went for the N1 as it seems to be what you are using on the s14 and its the same price as the standard HPX

Mike

ps. as a quick side note what is the difference between the HPX and the HPX-N1?

[Matt]

The N1 is a newer model. Measures more airflow from what I can tell. Dont know the specifics through

[rick88ss]

I also see that there's an HPX-N2. What's the difference between the HPX-N1 and the HPX-N2?

[Matt]

Not sure. You have to check with PMAS (massairdirect.com). Probably different connector

[rick88ss]

I'm going with a 3" draw (suck through) setup and looking to make no more than 550-600 WHP on a VG30ET with a 6262 turbo and Z32 ecu with E85 fuel.

Looking at the info from PMAS.com website it shows the different power levels for the HPX MAF sensors

HPX : in 3″ housing 640 WHP

HPX-N1 : in 3″ housing 830 WHP

Which one should I go with for my power goals? Will both have the same idle and smooth low speed driveability? Are those WHP numbers close or actual numbers will be considerably lower?

[Matt]

The N1 is the model that PMAS is now selling us. It reads more power and I've had no drivability issues with these. ECU interpolates between the points so the decrease in resolution (due to reading more power over the same 64 points) is not noticable

[mastermechanic5]

Which HP figure should we use for the scaling? Like Rick said hpx website says the hpx-n1 in a 3" housing is good for 830whp, but in the nistune resize maf drop down it says 1570hp. Is pmas referring to whp and nistune crank hp? I'm going to be making around 450-500whp so would 60% load scaling on the transfer tool be appropriate?

btw.. Thanks for reactivating my account Matt

-Tom

[Matt]

The Nistune one was based on the adjustment required with K constant to use the new load. The figure is HP at the wheels (for example Z32 about 500rwhp = 370rwkw). This is theoretical based on our testing.

[mastermechanic5]

Its been awhile but I finally have time to work on my car again. I ended up using the z32 load hpx you added to the drop down. I'm having trouble getting the car to idle though, the car surges and stalls sometimes, the AFRs are all over the place. It maybe a hardware problem, I just don't know what. My car wasn't running quite right before I changed the maf, but I figured my old Q45 maf might be the problem. I don't have any vacuum leaks or anything. I tried adjusting the k constant, injector latency and the first 7 cells of the vq map but I just can't get it to run right. Do you have any suggestions? Thanks Matt!

[Matt]

What sized tube?

when I tried the 3" HPX MAF drop down on another vehicle, we had to increase K constant by about 20% to get the AFRs back to normal so I need to recheck the K offset adjustment

[mastermechanic5]

3" tube. I had the k constant all over the place and unless I set it so that the afr is around 17:1 it wont idle. I also tried disabling my o2 feedback and I filled in my fuel map raw values all to 0. I can get the k constant right at a certain rpm let's say 2k but than when I go up to 3-4k it goes lean.