Stratocaster1422

has really tried to utilize one of these in a B5 A4 1.8T. Is there any reason why people haven't tried going down the route of getting turbos larger than a Stage III...then tune using a SAFC, MAF translator, lots of logging and properly sized injectors and FPR? Is the N75 valve and the need for its signal to not go into Limp Mode a reason?

Mat Indukts Lambos

I have a wideband o2 monitor, SAFC, 510cc injectors, and a 3" MAF housing, to work with the T3/T4E turbo setup. Hopefully this will be the trick to make it smooth enough to be able to use it for more than just 1/4 mile runs.

I still have the ATP chip though, want to change to the GIAC software some people have. Unfortunately I don't have the time I'd like to work on it, so it's a long, drawn out process.

Audi2ptzero

I will be running a set of 800cc PE high imp injecors but will be doing the tuning right thru the ecu. Actually the car is done, but the tuner cant work on the till the 22nd of this month.

Angry Alex

congrats man.

xr4tic

I've got a 2.0 with a T3/T4 that is currently running a 3" MAF housing and 440 injectors with PES/GIAC software.

It runs, but not well. The MAF is maxed out at 5000 RPM and the injectors seem to be maxed out as well, and thats only running 17-18psi of boost.

The stock MAF element is junk. Even in a 3" housing it doesn't provide enough signal resolution to be of any use above 5000 RPM. Once the MAF maxes out, the injectors open all the way.

An A/F controller will not help because the MAF doesn't have enough overhead.

So I contacted Pro-M to try and get a Ford MAF to work, they said no problem, until we found the voltage to airflow curves were completely different. Pro-M can modify the Ford curve, but they can't change the shape. I had bought a Split Second PSC1 to try and intrepret the Ford signal into the same shape as the stock, but I could never get it to run right. Then I found out that the ECU uses a signal up to 5.5V, but the Ford MAF is usually only based on a 5V max signal. They programmed the Ford MAF so it had a similar output above 5V, but the SS unit could only alter a signal below 5.1V (it can output much more than that)
Pro-M said they had something that would work better than the Split Second unit, so I returned the PSC1, then found out the Pro-M unit couldn't output a signal greater than 4.9V, so I couldn't use it.

So I was back to square one, stock MAF in 3" housing, and running way too rich down low, and too lean up high, and very frustrated

Sooooooo, the first thing we need to do is get rid of the stock MAF. Once we can do that, our options open up.

IMHO, the 440 injectors at 4 bar (comparable to 510cc injectors at 3 bar) should be capable of running close to 400 HP with proper tuning. My EGTs are hitting 1650F, but I don't know if that's because the timing is optimized, or if it's because it's too lean.

So I don't want to spend a bunch of $$$ on bigger injectors if the MAF is still limiting the amount of tuning I can do.

I've thought about it, and right now, I'm going to try and bump the fuel pressure up (using a new fuel rail and adjustable regulator) ~10psi or so. The re-order the PSC1, and have a Ford MAF recalibrated so that it outputs a voltage below 5V, so I can use the PSC1 to bring it up to what the ECU wants. I've got a WB on order (hopefully it will be in this week) With a WB, EGT, and RPM logging, I'm sure I can get this thing dialed in.

There is also one drawback to altering the MAF signal. Load is calculated using the MAF signal, and by reducing the MAF, the load is lower. This could result in more advanced timing. Since no one has tried it, we don't know exactly how much load will affect timing. If boost is controlled by the ECU, then you may have over/underboosting problems as well.

On the non-DBW cars, the N75 valve can be disconnected, in theory, a resistor would get rid of the CEL. For DBW cars, some electronic trickery would be needed to fool the boost sensor. I'm so glad I have nonDBW

xr4tic

So it's ready to be slapped on the dyno?

QGMika

and disable the MAF...guess all this would be done through custom programmer..

xr4tic

anytime you change something like the turbo, exhaust, cams, intake, whatever, it changes the VE table, throwing the values off.

Plus it's harder to modify the MAP signal.

Stratocaster1422

1.) What MAF kind of signal is our ecu looking for? karman signal or a hotwire signal? I know alot of DSM's that run a GM 3.5" MAF with a MAF Translator because their ECU is looking for a karman signal, but the GM is hotwire.

2.) Wouldn't the 510cc injectors at 3bar have a better duty cycle?

3.) How exactly does the ecu calculate load based on MAF? I didn't think that timing had a load variable in it? I thought that it was a combination of knock sensor and air flow.

4.) What T3/T4 setup are you using? I want to use something like a 35lb/min compressor wheel.

Stratocaster1422

so you are having your tuner do a custom program...