Stock ECU MAF replacement project

[A80Avant]

from what i can remember, the broken wire is very rarely the issue on the stock maf.
I had never had problems with a missing wire esp. on stock turbo/even the 3071. The problem was that either the maf was getting dirty,thus didnt read right, OR the maf itself failed after use to read correctly, but the wire was there.

would the HFM5 have similar issues with oil from the PCV system for example?

[s2_wot]

Can you quantify the maximum airflow you'd expect through the MAF and I'll check out a few suitable in line fans for you.

[prj]

Let's revive this slightly, and see what we can do for people who just have their MAF go bad.

So far my progress is as follows:
* Found a HFM5 housing that will bolt on to our cars without any mods.
* Have gathered enough knowledge and know which sensor to stick in the housing.
* Found a small uC to sit in between the HFM5 and the ECU and translate signals with 0.5 % precision, which should be plenty, as the HFM5 is specified to 2%.
* Wrote the code for this uC, to do the conversion.
* Designed parts of the surrounding board, where it will sit on.
* My friend has started work on the 6 pin stock MAF connector in CAD.
* Found the estimated cost to be around 200-220 EUR with VAT included for the finished product.

What I have the most issues with:
* Making up a nice connector that will mate to the stock MAF plug (can't buy these afaik).
* Rigging up something that can suck enough air, to put the two MAF's after another and calibrate the uC.

If I manage to overcome these two obstacles, I will be able to manufacture and sell a plug and play kit with a HFM5 MAF, to replace the stock MAF.
It will behave exactly like the stock MAF, no ECU modifications will be needed, car will drive like with a brand new stock MAF. This will fit AAN, ABY, 3B and ADU engines. Also the Porsche 968.
Because the kit will be made to exactly mimic the stock maf, it will max out exactly at the same time as the stock maf. If you want to go big power, you will still need the RS4 MAF, but with this one you will never have any problem with broken wires.

I will try to rig up a prototype without the connector and pretty casing, and if that works I can go into production with this.
The goal is to provide something that works just as well as a brand new stock MAF, but is more reliable and also cheaper.
Seeing how many people have bad MAF's, and how the price of the stock MAF is going up every year, this should be a good alternative.

[prj]

3.5" silicone couplers will fit on it.
It's around 92mm from memory.

If needed Pro-M can provide pretty much any configuration MAF though.
Also, I can map Motronic to pretty much any MAF as well, as long as it gives a 0-5V signal and reads high enough, no difference really.

The reason I used the RS4 MAF is because it is easily available, fairly cheap and reads up to 600hp (standard, without meth etc).

[Rocco]

What is the physical size of the RS4 Maf?

9.2cm i think

[Jamo]

What is the physical size of the RS4 Maf?

[EspenW]

Safe to say a large margin... Dyno sheet looks good!

Thanks Jason, and welcome to the forum

[orangepeel]

In That Case Dose Any One Need A Kidney Or A Liver So I Can Buy A New Maf

[prj]

In theory yes, in practice you will just have to buy a new maf.

[orangepeel]

prj is there anything for the 3b maf that can be done that dosent cost the earth or have to buy one

[prj]

going by the rule of thumb and repo's previous indications, injectors on a 5cyl are roughly making the amount of power in hp crank as their cc @ 3bar,

in other words, maxed out 630cc should give around 630crank.

to me GT35 is a bit optimistic for 700hp

If you look at picture you can see it's race octane. Jason's dyno is brutal - put that car onto any other dyno, and you will see higher numbers.

Good news Dmitri and well done, as this was a huge problem for those being on the limit of RS2 Maf of around 500ish hp. Now they can get a map done properly at least if they dont look to map themselves and get into it.

500?
MAF is maxed out on a 3071 car from 4000 rpm to redline.
Stock MAF can't even read 400hp.

[A80Avant]

going by the rule of thumb and repo's previous indications, injectors on a 5cyl are roughly making the amount of power in hp crank as their cc @ 3bar,

in other words, maxed out 630cc should give around 630crank.

to me GT35 is a bit optimistic for 700hp

nonetheless, the idea here is to prove that RS4 maf is more than enough for at least more than 600hp, so the ultimate problem with the RS2 motronic mapping is now gone!

Good news Dmitri and well done, as this was a huge problem for those being on the limit of RS2 Maf of around 500ish hp. Now they can get a map done properly at least if they dont look to map themselves and get into it.

[Thuppu]

Hmm, HX35 is a ~500 crank hp turbo, my CT should be that also, hopefully. Garretts are too expencive for me.

[prj]

Stock CR

[S2central.net]

The combination of cams and headwork shows nice result beyond 6000rpm... and the GT35 is clearly up for the flow requirements !!!
Any idea on compression ratio here for reference ?