MAF height on a FI system with piggy back ecu

jvanzyl · February 6, 2024, 13:47

Hi all,
I know the height of turn MAF is critical in the stock system (all of Corkys research showed that).

How critical is it on a turbo charged system with a piggy back ecu?

The MAF tube I'm using is 1.5 mm narrower than stock, and the height of the sensor is currently off by about 4mm (estimated).

Will the piggy back compensate accordingly? Or am I better off buying a stock maf housing and hacking it apart to make everything happy?

Thanks very much in advance!

Carolyn · February 6, 2024, 16:47

What sensor inputs will you be using?

jvanzyl · February 6, 2024, 16:58

The plan is to use the MAF, Wideband & boost level.
Closed loop will likely run off the standard narrow band O2 sensors.

My understanding is that I need all standard sensors that stock would use plus the boost and Wideband in order to make the Emanage ultimate work correctly.

Carolyn · February 6, 2024, 17:16

By boost level, I take it you mean Manifold Pressure? Does the emanage not want inlet air temp as well?

jvanzyl · February 7, 2024, 23:34

Sorry! I missed your response!
I think I do mean that.. I've got hopefully a working boost sensor:

Which plugs into an option port on the Emanage:

And I understand from reading the manual that by plugging boost I can do away with the maf sensor.

Now here comes the tricky bit, I've got another cable:

Which I had planned to wire into the Wideband controller to and so provide that input (via option port 2) to the Emanage..

Having read more, it seems like it CAN take air intake temp, but this would mean swapping this for one of the other inputs?

But which one? Or is there an order to this that I've missed? Is Wideband into a temporary thing just used for tuning (some how without the boost or the air intake temp sensor?) and then you unplug it and run just the boost and temp sensors long term?

Slightly unsure here.. but I've possibly gotten to an answer for original posts in that the maf can be ignored IF running boost sensor and using the airflow map

Oh and I've also got this sensor which I'm not sure MIGHT be a newer version of the boost sensor.. it is a greddy.

jvanzyl · February 7, 2024, 23:40

Wouldn't let me upload a pic to the previous post.

jvanzyl · February 8, 2024, 00:41

Just done more reading and the MAF should be producing IAT already and the Emanage can see a the stock sensor inputs (I believe), hoping that should answer the question you had about the Emanage needing temp?

In theory that means it should have boost, iat and Wideband all at the same time. Really hope I'm right...

shnazzle · February 8, 2024, 07:48

You want all stock sensors for closed loop and let the stock ecu do what it does best pre-boost.
As you've messed with the MAF setup, you'll likely have to play with the airflow map. Basically that's MAF calibration. Which is an absolute pig to tune. Once that is set, it sends the "correct" MAF voltages to the stock ecu for the airflow.

Then for boosting it up you need wideband, MAP ("boost" as you call it) and IAT.

IAT I would say is critical. It can read that from the stock MAF, and it does already I think... I'm sure I remember wiring in the IAT into the emanage.

Once you're in boost you can still do closed loop with the Ultimate. Based on the wideband. If you want. It's messy.

Let the stock ecu believe there is no turbo and do what it does until positive manifold pressure, then flick it into open loop (send it 11v to the throttle sensor via a relay... remember the box-of-tricks?) and then the emanage can take over using wideband, MAP and IAT.

Carolyn · February 8, 2024, 08:57

My understanding is that inlet air temp should be taken after the turbo and as close to the inlet manifold as possible to allow for heating via the turbo compression.

jvanzyl · February 8, 2024, 09:52

Quote from: shnazzle on February 8, 2024, 07:48You want all stock sensors for closed loop and let the stock ecu do what it does best pre-boost.
As you've messed with the MAF setup, you'll likely have to play with the airflow map. Basically that's MAF calibration. Which is an absolute pig to tune. Once that is set, it sends the "correct" MAF voltages to the stock ecu for the airflow.

Thank you @shnazzle !
This sounds like a very good reason to do everything possible to either use the stock MAF housing or search very hard for another MAF tube that is an exact replica of of OEM.

Quote from: shnazzle on February 8, 2024, 07:48Then for boosting it up you need wideband, MAP ("boost" as you call it) and IAT.

IAT I would say is critical. It can read that from the stock MAF, and it does already I think... I'm sure I remember wiring in the IAT into the emanage.

Once you're in boost you can still do closed loop with the Ultimate. Based on the wideband. If you want. It's messy.

Thanks for the clarification, I thought I remembered lots of people measuring IAT on their stock systems via OBD sensors ages ago.. makes sense now.

Quote from: shnazzle on February 8, 2024, 07:48Let the stock ecu believe there is no turbo and do what it does until positive manifold pressure, then flick it into open loop (send it 11v to the throttle sensor via a relay... remember the box-of-tricks?) and then the emanage can take over using wideband, MAP and IAT.

Yes I do remember the box of tricks but absolutely have forgotten the exact implementation of it. Trying not to freak out slightly.

Quote from: Carolyn on February 8, 2024, 08:57My understanding is that inlet air temp should be taken after the turbo and as close to the inlet manifold as possible to allow for heating via the turbo compression.

Thanks @Carolyn - if IAT is measured by the MAF sensor then it is after the charge cooler on my setup, I don't believe I could get it any closer to the throttle body, at least not easily.

I don't suppose anyone has an old MAF housing that they'd care to part with??

J88TEO · February 8, 2024, 10:18

Yes I have one

jvanzyl · February 8, 2024, 10:39

Quote from: J88TEO on February 8, 2024, 10:18Yes I have one

Thank you for the prompt response! @J88TEO I'll drop you a PM!

I have just re-measured the oem vs aftermarket tubes and they are within 0.5mm of each other (no idea what I was doing last time I measured..)

I also measured the distance between the top of the maf tube (exterior) to the bottom of the MAF sensor screw posts and found a 2.5 mm difference, with the thickness of the MAF tubes being about 0.5mm (aftermarket being thicker) this means that the MAF in the aftermarket housing is sitting almost 3mm higher in the tube vs stock.

so alllll I have to replicate stock is find a way of dropping the height of the sensor. Saying this.. I think I might need a better way of measuring the sensor height.. I don't want to start cutting the aluminium incorrectly.. argh..

Edit: I need a fat feeler gauge!