Questions about AFC and MAFT

I am looking to do some upgrades starting next year when I will finally have some money to put into my car but I have a question about using the AFC with a mass air flow translator. I was reading about the MAF translator and it say it has advanced features that eliminate the need for an AFC. I have heard some people explain that you can use the MAF-T for coarse adjustments and then AFC to fine tune it. I could see where this would be kind of confusing as far as tuning having to mess with both and consider how they play off of each other. Is there a better setup for air fuel tuning? Would it be easier to just get the ECU programmed for the new injectors and just run the MAF-T? I am planning to run a evo III big 16g with evo 560cc injectors.

 

[CutlassJim]

Then why go through all the trouble of running a MAF-T? A hacked 1G MAF or an unhacked 2G MAF will both handle a maxed out Evo16G, and there's not much chance you are going to even be maxing it out.

I just sold a MAF-T setup that was on one of the Galants I purchased because I'm not a huge fan and swapping to a 2G. It's cool I guess if your trying to go REALLY fast. My friend just went 10.9 on a 3052 and a GM MAF but he says it's very finicky to weather changes(temp and humidity) because it doesn't compensate for it and just spits out set values. Even then I have another friend who went 11.0 on a 3052 and a stock unhacked 2G MAF.

The only benefit to a GM MAF is the abitility to "blow off" to atmosphere, which is actually detrimental to performance, and if you pop and intercooler hose your care will still run. Not worth it IMHO.

 

[jepherz]

I don't fully understand the workings of the maf-t, but I think the GM maf outputs a value that takes temp and baro readings into account. This, not the fact that it doesn't output them, is what causes the problem because the compensation values are probably way off from what the ECU would be used to.

 

Alright thanks for the info fellas. I think I am just going to go with the 2G MAS and an AFC. Running that 3" GM unit doesn't sound necessary from what you are telling me and it seems to just create problems.

 

[belize1334]

Just get a keydiver chip to compensate for your 2g maf and 550s. It'll be just as driveable as stock (moreso in my case) and give you more room to play.

 

[Hertz]

Your best bet, for simplicity, without tuning:

Denso 660 Injectors.
2G MAS, with 1G adapter
Keydiver Chip.

No AFC or anything needed, really.

The MAFT does give you a high-flowing meter, it does have "fine grain" control (v2+) just like an AFC does. I got mine at a time when it was comparible in price to an AFC, 2G MAS were not used, and Keydiver hadn't started making chips. It was a great value for the time.

Now that more "factory" options are available, I would probably reconsider.

I've been running mine for about 3 years, daily, through -10 to 100+ F, 0 humidity to 99 percent and from a high pressure day at sea level to the top of Pike's Peak. ANYONE who says that the MAF has any problems with weather variations is wrong. I don't care how fast they run. The ECU doesn't do anything with those values individually, other than use them to guesstimate air volume anyhow.

That being said, I do have a big advantage: A Keydiver chip to correct the timing maps. (I don't need to run any compensation on the MAFT)

If you're running ANY airflow correction to compensate for larger injectors, your maps are f-ked and you will have problems depending on the conditions. I think that is where the MAFT poo-pooers are running into trouble.

 

[jepherz]

Quote:
I've been running mine for about 3 years, daily, through -10 to 100+ F, 0 humidity to 99 percent and from a high pressure day at sea level to the top of Pike's Peak. ANYONE who says that the MAF has any problems with weather variations is wrong. I don't care how fast they run. The ECU doesn't do anything with those values individually, other than use them to guesstimate air volume anyhow.



Can you clarify this, Hertz? Me confused!

 

[Galantvr41062]

Putting just a MAFT on a DSM is not a smart idea. MAFT and AFC combo plus a good wideband and a chassis dyno* will make the car work. The chip is the best way to tune the car(besides a stand alone ecu), or Link works good also. Just remeber that the MAFT and AFC are changing your Hz count the ECU sees, so getting the MAFT to spit out the proper Hz value for each area you can adjust: base, idle, mid, WOT is a lot of work, and you can not just set it up by the directions, each car is different so the wide band and a dyno* are needed.
* You can tune using knock count in place of a dyno if you know what you are doing *

~John

 

[Hertz]

Quote:
[Can you clarify this, Hertz? Me confused!



My understanding was that the ECU takes temperature, pressure and the Karman value together to calculate an air volume, then the air volume + rpm is used to look up a fuel and timing amount.

My point is that it doesn't matter what the values of those air components are as their product is used to deliver fuel and timing.

The fact that the translator returns the same temperature and pressure values is irrelevant becase it is already factored into the Karman value that it returns because of the nature of the hotwire MAF, it isn't measuring air velocity, it is measuring density. click

If you're having weather-related issues, it's not the MAF, it's the tune.

 

Quote:
That being said, I do have a big advantage: A Keydiver chip to correct the timing maps. (I don't need to run any compensation on the MAFT)

If you're running ANY airflow correction to compensate for larger injectors, your maps are f-ked and you will have problems depending on the conditions. I think that is where the MAFT poo-pooers are running into trouble.



I take it from that, a GM maf w/trans only used for blow through,550's and a Keydiver chip will run fine. Si? Im about to run that setup and hope its not going to suck to make it run.

 

[Hertz]

Yup, just remember that with the chip, you do not dial in any injector compensation into the MAF. Set it up like 450's. In fact, if your trims are already ~100s you can leave everything at the baseline default and it will fire right up.

 

[boostedinaz]

As already stated any car can run well if it is TUNED well. I had a few people tell me that the MAFT on my car was going to make it run horrible.

I went to my tuner and within about 30-45 minutes he had the idle and part throttle dialed in perfect with DSMlink. A total of two hours and my car runs awesome.

This weekend will be a good chance to see how it runs at different alltitudes and temps. I will be going on a cruise that starts at about 1000 FT and 70* and will going up to almost 7-8000 ft and mid 40* weather. I bet it still runs awesome.