blackstang14

I recently bought a vortech kit that included a sniper bazooka m3000 MAF and new 42# injectors that are new and never installed. The seller states that the MAF is calibrated for 39# injectors that are still in his car.

My first question is with a ECU retune do we even need to have a calibrated MAF to our injector size? From what I have gathered so far I think the answer is no.

Then is it even possible for the sniper MAF to be calibrated in the first place or was it just made to work with an ECU tune to his 39# injectors.

So I guess i am wondering if I can use the injectors and MAF in my setup.

Thanks for the help.

vanquish

No you're right that MAF isn't calibrated for anything. The MAF transfer function is linked up to whatever injectors you're using when your tune is being made.

Are you using sniper to tune? I'd like to know how their MAF sensor works with their own software.

cliffyk

So-called "calibrated" MAFs are not calibrated for just a specific injector capacity, but rather for a specific injector AND a specific OEM tune.

Their output is adjusted so as to lie to the stock tune about how much air is flowing, telling it that the air flow is less than it really is--this makes the stock tune use a shorter injector pulse, which let's it work with the larger injectors. It also completely screws up load calculations which in turn really screws up timing.

The Bazooka MAF is not "calibrated", there would be no point in doing so as the transfer function is just loaded into the tune when you select it--I.e. it's done properly...

blackstang14

Right now I stil have to install my vortech kit, but I think I'll get my car dyno tuned. The sniper software seems convenient, but in the end isn't that just a canned tune. I guess I'm nervous that I will screw something up, lol.

That's good news though that I don't have to look for a new MAF or matching injectors (one less thing to buy

Thanks guys

cliffyk

A tune created with Special Forces is not a "canned" one-size-fits-all type of tune, it is a custom tune built according to your responses to the various questions and selections.

It is much the same as a mail-order tune except that you can tweak it yourself as your modifications/weather/etc. change.

I also thought this chart might be interesting to some, it compares the transfer functions of several MAFs commonly used on Mustangs. On thing to note is the EEC-V's internal 3830 lb/h (1740 kg/h, about 560 HP) limit. This means that without a custom tune the PCM will never use an air flow number greater than 1740 kg/h (1741.38 actually).



To use such a MAF the transfer function needs to be scaled so that the maximum value is 1740 kg/h, and then the injector slopes and air charge (the kg of STP air one cylinder can hold) need to be similarly scaled.

For example, let's say you were using the Bazooka MAF which is flowing 3180 kg/h at 5.0V output--1740/3180 = 0.55, so the injector slope and air charge values would also be scaled by 0.55.

Special Forces automatically performs this scaling whenever a MAF that flows more than 1740 kg/h is selected...

blackstang14

Thanks for the info, pretty interesting. Sorry, I meant "mail-order" not canned when I made that comment. I guess that beyond the initial paramaters for the ''safe" tune as Sniper states I am a little nervous to begin tweaking things on my own. Do you use a Sniper wideband with your set up for tuning? I was wondering if other brands (eg autometer) widebands would be able datalog for use on the sniper software. Or would you just drive the car to see what numbers your were getting and then tweak from there (trial and error?). Sorry just trying to learn more about this.

Thanks
James

cliffyk

Tuning is a "trial and error" process, the only thing experience brings to the game is knowledge of where to start and how to minimise the number of "errors" so as to faster zoom in on the goal.

A dynamometer is just one of many tools (a very convenient one) that can be used to perform the "trials", other than that it has nothing to do with the tuning process--also "dyno tunes" are themselves just starting points. If it were possible to achieve the perfect tune on a dyno you wouldn't see racer's in the pits tweaking things for track conditions/weather/etc. between runs.

As to wideband O2 systems, I use Innovate's LC-1 system although I do not recommend it any longer due to Innovate's lack of support, which has gotton worse since they were acquired by Performance Motorsports.

Innovate's logging software logs AFR only when used with the LC-1, a usable but not ideal situation. The LC-1 has two 0-5V analog output's and I use one to feed Delta Force Tuning's OBD2 Data Scout logger which let's me log up to 16 OBD2 PIDs and the 0-5V output of the LC-1.