SO apparently JWT is a pull through vs a blow by system so the HPX air flow meter cant read it right on all parameters. only way to combat this would be to convert the system to blowby or change out AFM.

Well I found out today the HPX closed down shop. SO I wanted to see what you other guys are running?? Any good alternatives??

... I may have the blowby Vs. pull through backwards if I do please correct me

 

just move your maf to after the intercooler, instead of between the filter and the turbo.

You can buy the MAF bung at GTM and just weld it onto the charge pipe going to the plenum (like stock)

 

thanks!

Now what about now that they arent made anymore?? I have a friend thinking about going FI on her Z any suggestions what she should get to use for tuning??

 

You could enlarge the MAF housing.

<=400whp just tune on the stock MAF.

Or go with a UTEC or standalone which doesn't use the MAF in boost (MAP instead).

 

but it was my understanding that the HPX allowed greater parameters higher then the stock MAF could read. When I was tuned on my stock MAF I would max out the AFM and it would go into limp mode. the HPX fixed this.

enlarging the housing wouldn't allow that would it??

 

You would need a new calibration curve but theoretically you may be able to bring the airflow into range of the stock MAF by reducing the airflow to it somehow, such as enlarging the housing. Or you could try to find a MAF from a different application - I seem to recall folks using a MAF from a Ford Lightning. All this trouble if you really insist on not moving to MAP...

 

MAP??

 

MAP sensor is the alternative to MAF sensor (pressure vs mass air). All the standalone's can use MAP - UTEC, FCON, Haltech, ProEFI, etc.

 

o ok thanks!! well I am gonna leave it as is since its working fine for now. Just wanted to see if there were other options out there!!

If I have any problems I will do what you suggested str8dum1 and relocated with the part from sam

 

So they don't make the HPX PMAS MAF's anymore?

 

Weird, I didn't know it would cause limp mode. Well Uprev better find another vendor/solution because that pretty much means no more Uprev FI tuning on the DE. I bought my HPX direct from Uprev.

I think an enlarged MAF housing would work for some but not everyone....for example my kit retains the stock MAF housing so it's no big deal, an enlarged one could pop right on. But for other kits where the MAF bung is welded right onto the intake pipe, that's gonna be a pain in the ****.

Luckily the HR doesn't need upgraded MAFs to the best of my knowledge.

 

from what was told to me one of the partners decided to leave and the other one who knows what he is doing.

Uprev is over 20 orders deep and no word if they will get any of them.

frank and frank at hills are working on a solution right now. I talked to him this morning. they found a MAF that fits and is the right wiring to work with our cars and they are trying to write there own ??schematics?? for it so they can plug it in flash it and it will work like stock then perform thier tuning from there... all in the works no results yet thats just there idea since they have not been able to find anyone else that makes one for our cars.

 

Interesting because when I set an HPX and stock MAF side by side, they look IDENTICAL with the exception of 'PMAS' engraved by hand into the HPX.

I also heard that Technosquare could modify the OEM MAF to handle more flow. I'm pretty sure it was some kind of wiring mod.

So putting 1 and 1 together, Shouldn't be too hard to reverse engineer the HPX or hack the OEM MAF... maybe Frank could hire an EE guy?? (hint, me!! LOL)

/Me hopes my HPX never fails...

 

why is your friend dead set on using Osirus? GTM doesnt have a stock of those MAFs anymore?

 

Location of the MAF has nothing to do with it's flow capability. Given the same diameter housing, the MAF sensor voltage will max out at the same mass flow rate whether it's before or after the turbos. In fact it's better to have it before the turbo's just like JWT designed it for several reasons:

• If there is any blowby from the PVC or the turbos, it won't coat the MAF in oil.
• It lets you have a proper PCV setup.
• It provides more even flow because the limited amount of pipe in front of the MAF does not create a fully developed (parabolic) flow cross section so the sensor readings are more accurate. A lot of times you will see a honeycomb or mesh screen in front of the MAF for this exact reason - to redistribute the flow in the pipe to make the air velocity more consistent across the entire cross-section of the pipe.

Look at every OEM system out there - the MAF is the first thing in the intake tract - before the turbos.

You could in theory put the stock MAF in a larger housing and then use Osiris to create a new MAF transfer function to predict airflow from MAF voltage, but that's not a very easy thing to tune without a flowbench I presume. And even if you doubled the cross section of the pipe, you would only double the flow capacity - so maybe it could handle 600 hp instead of 300. But then again there are probably other fluid dynamic factors to consider as tubing size gets larger, and at some point the airflow will be so low at low load/rpm that accuracy of the readings would suffer - maybe that's why you don't see people sticking the stock MAF sensor in a 5" housing LOL.

 

Some of what you are saying is not correct.

Compressed and pressurized air has a higher density and has a greater mass than the inlet air going into the compressor. So by defination the measured mass of air will be much greater if measure post turbo, vs pre turbo.

It's a common practice to run pull through setups to improve the range of an OEM sensor. Larger diameter MAF housing is another way.

 

We have four MAF sensors here in stock. Let me know if you are interested in one.

Thanks, Vince

 

You are correct, air becomes more dense when it is compressed.

But the air being drawn in the intake has a higher velocity so even though it is less dense, the mass flow rate will be the same. As long as no air is added to the system (i.e. a non-recirculated BOV) the mass of air entering the intake equals the amount of air entering the engine.

Correct me if am wrong but isn't mass flow rate exactly what hot wire MAF sensors are designed to do? In that case, it wouldn't matter what the density of the air is because that is one of the variables that determines mass flow rate.