MAF: Which to use for what application

[keo92stealth]

turbosincebirth is the man with them arc2s. if you go e85 750 or 850cc injectors would probably be good for your power levels you want.

[JasonY]

Todds car worked exactly the same wether it was 30* out or in the 90s with the arc2...my old 93 was the same....?

Jason

[MR2]

I don't see the point of buying any injectors less than ID1k's

according to my calculations the ID1k's will greatly loose efficiency and be maxed out on E85 up towards 700hp

[CoopKill]

There are peeps using the Montero Maf (unsure of the part #) in place of the Evo mafs, both of which have baro comp. This probably the way I am going.

[JasonY]

Im just not gonna run one...MEH!

If thats ever possible anyway with the flashed ecu's anyway...lol

*fingers crossed*

Jason

[heptone182]

turbosincebirth is the man with them arc2s. if you go e85 750 or 850cc injectors would probably be good for your power levels you want.

Yeah, I'm gonna have to talk to Michael more once I get this arc2 in. Also, as of today I've acquired the 90mm SVT Lightning MAF so I'm gonna experiment with that and the 87mm granatelli. I'll post results as soon as I test em.

[TurboSinceBirth]

There are peeps using the Montero Maf (unsure of the part #) in place of the Evo mafs, both of which have baro comp. This probably the way I am going.

482. It's actually what I have. I'm debating whether or not to run the Montero MAF at 500-550AWHP with the flashed ECU. I know it's accurate and the Evo guys have made 700AWHP with it but we don't know what that translates to on our cars. I'm just concerned about the turbos sucking in part of the maf ruining it. It's cheaper for me to run a $500 ARC-2 or $250 GM MAF/MAFT setup than shooting for 550+AWHP. I don't know how much power I will see on this motor depending on when it kicks the bucket.



I actually found out that some of the reasons I had to change the tune sometimes for a different temp or at startup was because of some miniscule boost/vacuum leaks that were creeping up. They were very small but now I never have to change the settings. If I do I know it's time to pressure test.

Steve, I replied to your PM about the settings. Let me know if you need any other help walking through it. The ARC-2 is really easy to use once you understand what's going on. I change fuel types all the time and it takes minutes before I'm done. It's definitely a breeze switching from pump to E85 or anything inbetween. I'm only switching to a flashed ECU because I want to be able to run 1000cc injectors on 91 or E85 plus have control over my IDC induced timing that comes with larger injectors and a piggyback. I'll get part throttle knock if I don't have it set right.

I'm confident I can run 1000cc injectors with E85 on the ARC-2 but I'm a little leery of it only because the computer uses IDC to calculate IPW. It will shift me to the left on the timing map running more timing because the low IDC makes the ECU think I'm at a lower load when in reality I need to run less timing going into WOT. This will cause knock at lower loads/throttle from what I have experienced and this is usually where the motor comes apart having seen it happen to at least half a dozen people. After overboosting to 26 psi at the track when I was only safe at 18 psi I'm going to switch engine managements to put more safety features in place. It's a personal choice and part of it comes down to riding out this stock motor for quite awhile. It'll pop eventually I'm sure. With a built bottom end it's much more forgiving.

[Greg E]

Few points:

*You can NOT leave the ARC2 unit zeroed out with the flash ECU. It's not like the MAFT which sends a calculated modulation based off the sensor voltage. You need to tune the frequency. Not sure why they set it up that way.

*You can tune the timing, injector scaling/latency tables and just use the ARC controller for real time tuning. You may not even want to touch the fuel map. In fact, I see most people going this route with the flash ECU because you can't tune the flash ECU live. This is how I tune all ARC2 and MAFT cars with the flash ECU. Works great. Check out Toni's dyno thread.

*Both the ARC and the MAFT give you consistent results with the simplicity of tuning with the 4 basic knobs. Set the mid to -7 and tune the others like you would with any other setup. With the MAFT, tune the base knob and leave the rest alone.

The trade off is the ECU won't know the exact airflow so this may cause headaches for ECU controlled boost/ fuel cut at first, but you can still tune it. It's all a matter of taking logs and adjusting the tables based on the airflow the ECU is seeing.

*If you tune the motor so that it all falls within the compensation range of closed loop, there should be absolutely no reason why your tune will drift. These Hotwire ford and GM MAFs are all relative sensors. NOT absolute like our Karmen Vortex meters. You really don't need air temp/ baro compensation because your base signal coming from those MAFs are already compensated.

IN FACT you don't even need to hook up the temp and baro signal wires from the MAFT or the ARC with the flash ECU. Just disable the CELs and the ECU won't adjust the load calculation for those factors. Two less wires under the dash you need to worry about!

[Greg E]

Well currently I'm running DR-16T's, FMIC, Walbro fuel pump, straight through borla exhaust with a stillen DP and gonna be swapping in those 750cc injectors. I do have a 87mm Granatelli MAF sitting in a box for a 96-98 Mustang GT, but not sure of my limitations with it. Plus since its calibrated for the GT at for 19lbs/hr injectors, not sure if it's a good idea since the SVT MAF's are set at 24lbs. That's another thing... what is the conversion from cc/min to lbs/hr? Not sure I understand that too much. Shooting for 500whp

Update: found the conversion on cc/min to lbs/hr plus the explanation on Jeff L's site here
Stealth 316 - Fuel Injectors

I like how you're cautiously approaching modifying your car and trying to understand how and why things work the way they do.

The ratings for the MAFs shouldn't be an issue because you're not sending accurate airflow information to the ECU anyway. The difference between a 19 and a 24lb MAF is the difference between an extra click or two to the base knob on the ARC2.

[Greg E]

482. It's actually what I have. I'm debating whether or not to run the Montero MAF at 500-550AWHP with the flashed ECU. I know it's accurate and the Evo guys have made 700AWHP with it but we don't know what that translates to on our cars. I'm just concerned about the turbos sucking in part of the maf ruining it.

This is why I gave up on it. There's literally nothing holding those delicate screens in place. It's very easy to pop them out. The metal is like tin foil.