SuperHatch

iTrader: (23)

My thoughts for Evo's running large turbos at high HP levels that could potentially outflow the stock MAF. Is it possible to run a dual-MAF setup like the aftermarket supports for Z32 300ZX's, and if so, how would you accomplish this?

My idea...

Use two MAF sensors, split the intake pipe from the turbo to the two MAFs, only wire one of them, and use the scaling function in the Xede to essentially add double the fuel that is thinks it needs since theoretically half of the air would be passing through the one MAF that is connected to the Xede. The second MAF would simply be there to act as a flow balancer. The intake pipe and airbox would of course need to be set up in a way that promotes even flow through each sensor. I could see this setup with a large diameter inlet pipe and a larger airbox with a larger filter, combined with the SMART technology, helping to better meet the airflow demands of a stroker motor with a large turbo, such as a 35R.

Thoughts?

- Steve

shiv@vishnu

iTrader: (20)

Sure.. it's possible. We've been using larger MAFs on Subarus since they max out pretty early. On the EVO, we haven't seen this.. yet. But if the day does come, a larger diameter MAF is most certainly an option. Dual MAF might be tough to actually fit though. But who knows, you guys are crafty

Cheers,
shiv

MalibuJack

iTrader: (5)

From what I have read, the XEDE is flexible enough and from what I can tell that you probably have quite a few options, Shiv will need to elaborate on this, but I recall that with the XEDE inputs being configurable, you actually could use an analog MAF and IAT from another car (Ford Cobra, Z06 Corvette) calibrate them and use them.. Dont ask me how its done, I haven't had any opportunity to try one of my setups on an XEDE equipped car LOL..

SuperHatch

iTrader: (23)

Shiv & Jack,

Would it be possible then, to go to a different MAF without intermediate hardware? Jack, IIRC when you switched to your GM blow-through you needed a signal box to change the hotwire reading to a karman reading that the ECU could decipher, is this needed with the Xede?

shiv@vishnu

iTrader: (20)

The XEDE is capable of changing a Karman reading into a 0-5v reading, or visa versa in this case. You would have to calibrate this table, unfortunately. And it would take some time and effort to do right.

Shiv

SuperHatch

iTrader: (23)

Well, is there a table available that relates the Karman sensor output to CFM? If so, wouldn't cross referencing that table to the 0-5V output vrs. CFM tables for aftermarket hotwire sensors then give you a pretty good starting point?

Ludikraut

iTrader: (17)

Hmm, I would love to get MalibuJack's blowthrough MAF mated to a XEDE ... <wheels turning>

l8r)

SuperHatch

iTrader: (23)

^ my thoughts exactly

Ludikraut

iTrader: (17)

Alright, so now that I've taken a quick peek at MalibuJack's blowthrough MAF threads ( https://www.evolutionm.net/forums/sh...d.php?t=137212 , https://www.evolutionm.net/forums/sh...d.php?t=100437 ), the question would be if we can perhaps interest Shiv in taking this on as a future project for the XEDE: an upper IC pipe replacement with a blowthrough MAF sensor and a way to hook it into the XEDE.

IMO this would be great for not only the guys running big turbos, but would also, once and for all, end the intake and VTA BOV confusion/limitations/performance issues...

C'mon Shiv, ya wouldn't wanna get bored once you're done with all this SMART stuff.

l8r)

MalibuJack

iTrader: (5)

I'm sure I could build a calibration table that would work, unfortunately I'm not really in a position to buy an Xede and get it set up.. The two needed sensors are a Gates mustang IAT sensor, and a Ford Cobra MAF sensor (Granatelli sells nice all-in-one units). My past experience with GM MAF sensors (earlier L98, LT1 sensors) were less than optimal and my experiments on my corvette with supercharging was the GM sensors got damaged easier.

You are correct that my car is using a "Converter Box" and a "Calibrator" both of these things would not be necessary if its possible to map the analog sensors' output to the karmann value. Until someone offers an integrated solution, this was the best I could do that didn't require alot of cobbled together technology.

In reality, if the XEDE plugs in-line to the ECU (which it does) then besides configuration, all you would need to do is get the sensors, and wire them into a plug and play harness so its easy to swap back if necessary.

Overall, I've had really great results with the two generations of blowthrough sensors I've worked with, I honestly always felt a MAF sensor will always be superior to the speed density method on a street car (and in many forms of road racing) Given we could eliminate some of the shortcomings of the stock MAF.

Don't get me wrong, the blowthrough system isn't perfect, but I think I could address the quirks of the blowthrough if I had more control over how the signal is translated, and if I could control some level of tip-in compensation to the curves.

Just so you know, splitsecond engineering still makes a karmann converter to use on a DSM which will work, and it will work fine with anything that uses the stock MAF, its just the company I was using for my components is now defunct and I'd like to continue working with it, but its risky to keep tweaking on a unit that you cannot get replacement electronics for.

SuperHatch

iTrader: (23)

Jack, you're in NY, I'm in Jersey, I've got an Xede and the SMART stuff pre-ordered. I won't have the SMART hardware until august at the earliest (assuming Vishnu meets it's 7-23 ship date). I'm interested in trying this in the sept timeframe, would you be willing to help out?

shiv@vishnu

iTrader: (20)

What exactly is the advantage of running a blow-thru MAF besides more flexibility with VTA blow off valves?

Shiv

SuperHatch

iTrader: (23)

^ Jack can definately be much clearer on answering that than I can. And no, I'm not doing it for the VTA, I'd probably still recirc my BOV to keep things quiet.

MalibuJack

iTrader: (5)

Your not kidding, the setup I have now actually could relate the voltage to a karmann value, but in reality, I would build a table by installing both the blowthrough MAF and the stock MAF, and logging the voltage vs karmann value as both get airflow through it (obviously wiring the blowthrough unit as just a powered sensor)

Since the sensor I'm using doesnt have a intake temp sensor integrated into it (which is actually desirable since you mount the AIT sensor in the intake pipe, and not in the upper intercooler pipe anyway) you would also need to find a AIT sensor that is either close to the stock reading, or can be calibrated either digitally in the Xede or electronically with a resistor or whatever is needed to alter the value correctly.

I'm actually in a position where I can easily do this on my setup, so I have actually mapped my earlier sensor's data against karmann value, which is when I discovered I needed the calibrator device.

MalibuJack

iTrader: (5)

The biggest advantage is it eliminates the anomolous and inconsistent MAF readings when upgrading the intake pipe or airbox to a filter, also the stock MAF is prone to getting disrupted badly when recirculation airflow is enough to either flow into the sensor, or just cause turbulence in the pipe.

the readings definitely ramp more consistently, and is slightly more linear than the drawthrough stock MAF but realistically, its a much closer measure of the actual air demand of the motor since its measuring what actually is getting into the engine.

I agree with your assessment on the stock MAF not being very restrictive, but it does begin to read inconsistently beyond a particular airflow, this is where the blowthrough setup really made the biggest difference. Plus it eliminates any future possible issues with restrictions or finding that the stock MAF won't read above a certain point. Even a drawthrough unit would be an improvement when it comes to airflow disruption affecting the readings.