MAF or MAFLESS TUNE

[Harrismarine]

I have my own opinion on this but am keen to hear yours and why?

Mike

[5.7ute]

Mafless.


I need the maf to stop the papers from blowing off my desk.

[gmperformancecentre]

mafless all the way

[ringram]

Mafless. Allows better intake design, no upper airflow limit, zero restriction, better throttle response, handles larger cams better.

Maf. For people who cant be bothered tuning more than one table and performance isnt the number 1 priority.

Amen.

[Gordy M]

MAF Heavy autocrossing and High Speed time trials--after talking with Pratt and Miller PCM engineers, its the only way to go. They did hundreds of hours of testing MAF and MAFless on the C5R and C6R and MAF was consistently better. They did mention if you only drag race the MAFless might be better at a given strip.

[swingtan]

Hi Mike,

I'm going to take a guess that this is to do with your 6lt project. From memory you were going with the E38 controller so I'll tailor some info on that.

With the LS1 PCM, the majority of tuners would go with a MAF-less tune, but with the late model E38, there is no clear favorite. Some of the reasons for this ( in my opinion ) are...

• Tuning knowledge.
• Larger stock MAF size.
• Speed of the E38 PCM.
• Additional tables in the E38 PCM.

A good example of the differences in capability of the stock E38 controller is the fact that EFILive sees no compelling reason to offer full Custom Operating Systems for the E38. The usual response to requests for an E38 COS is "It's already in the stock calibration".

So I guess I should list some advantages of each type of tune.

MAF:

• The MAF will compensate for air density / IAT automatically.
• The E38 uses the MAF signal to operate certain tables directly.
• If you have a street car and EPA rules require the MAF to be "in place and operational", then there is less chance of trouble.
• The MAF can be tuned just like the VE table, so accurate fueling can be achieved.

MAFless:

• The MAF can be a restriction in the intake path and reduce max airflow at WOT. removing it also removes this restriction.
• There is no "delay" in air flow calculations from the MAF. Because the MAF is usually some distance from the TB, it takes time for air flow changes to reach it and then for the MAF sensors to react.
• For larger CAMs, if the MAF is too close to the TB, a "reversion" condition can occur where the airflow over the MAF sensors becomes unstable and the MAF reports incorrect data.

There are probably lots more, but those would be a few common traits of the two tunes.

Of the two, there is no doubt that a MAF tune is quicker and easier to set up, especially for a daily driver and more so if the car is an auto. One of the areas that seems to rely heavily on the MAF is the fuel dynamics. In a manual car you can get lean spikes on gear changes unless you do a lot of work when running MAFless. In the end though, I think MAF or MAFless will be a personal choice. To help that choice along, I'd think about the following...

[indent]

1. What is the vehicle going to be used for?
   
   
   

   • Daily driver, lean toward MAF
   • Weekend drag car, lean toward MAFless
   • Bit of both.... either.
2. How will the vehicle be used?
   
   
   

   • Lots of mid throttle work, gear changes, lean toward MAF.
   • Only really idle or WOT, MAFless.
   • Bit of both.... either.
3. What are your tuning skills like?
   
   
   

   • Bit of a beginner and not too sure, leave the MAF.
   • Tuning god and can convert lambda to AFR for any given fuel type in your head.... MAFless
   • Somewhere in between and want to learn, either.

Again from memory, I think you were setting up a boat, so it will probably respond pretty well to a MAFless setup, given you won't be on and off the throttle all the time ( unless we are talking jet boat racing ). I think the main reason for MAFless in drag racing, is the fact that the MAF can take longer to respond to changes, and when all the action can be over in less than 10 seconds, every millisecond counts. If on the other hand the action lasts for 10 minutes, the MAF response may be made up for in other areas ( like dynamics ) that may make it a better option.

Simon.

[JR-CRUZN-C5]

I know opinions are a "dime a dozen" but I would be curious to know if you guys quoting the opinions have any cars actually racing in the top levels of Drag, Road, or Autocross racing. My tuner a 2X National Muscle Car Dragracing Champion seems to think MAF tuning works just fine for top performing street/strip corvettes.

I tend to agree with him, as my 00 C5 Coupe runs consistantly in the 9.25 to 9.44 range @ 145 to 148 MPH. 60' times range from 1.32 to 1.39 off the foot brake launching at 1100 RPM. My car is a "blower" car and weather (DA) along with track prep seem to effect the "times" more than anything else. The tuneup is pretty mild on my C5R 427 motor which was built in 2003!

There has been a lot of "talk" about these two methods of tuning LS motors but I have yet to hear solid reasons why one method is "better" than the other. What is given up and what is gained by each method???

JR

[TuneMaster]

MAFLESS, Tuning with MAF is the lazy way, anybody can correct a poor VE via MAF. Get your fueling table spot on and throw the MAF in the Bin!

[5.7ute]

I know opinions are a "dime a dozen" but I would be curious to know if you guys quoting the opinions have any cars actually racing in the top levels of Drag, Road, or Autocross racing. My tuner a 2X National Muscle Car Dragracing Champion seems to think MAF tuning works just fine for top performing street/strip corvettes.

I tend to agree with him, as my 00 C5 Coupe runs consistantly in the 9.25 to 9.44 range @ 145 to 148 MPH. 60' times range from 1.32 to 1.39 off the foot brake launching at 1100 RPM. My car is a "blower" car and weather (DA) along with track prep seem to effect the "times" more than anything else. The tuneup is pretty mild on my C5R 427 motor which was built in 2003!

There has been a lot of "talk" about these two methods of tuning LS motors but I have yet to hear solid reasons why one method is "better" than the other. What is given up and what is gained by each method???

JR

Let me ask you a question. Have you ever run the car mafless & seen if there is a difference?
The reason I ask is I have seen a considerable increase in response in the NA cars I have tuned mafless compared to maffed. In every case I have had the owners drive it in both modes with the maf still in the air tract & they have noticed the same thing. My homemade OTRCAI will not allow for maf fitment so I have not tried it on my car.

[swingtan]

Tunemaster: When tuning the E38, it's not really fair to say that doing a MAF tune is "lazy". As I've mentioned, it's not the same as running a full COS in the LS1 PCM and there is a huge amount of work getting things acceptable for a daily driver when running MAFless, more so for the M6 guys. Another thing to remember is that a "proper" MAF tune takes more work than a MAFless tune as you should fist perform a MAFless tune, then re-enable the MAF to tune it.

JR-CRUZN-C5: Your MAF setup includes a blower, so some of the MAF negatives are covered by that fact. FI will reduce the restriction effects of the MAF as well as helping to reduce reversion. Go back to a NA setup and every little bit helps. As I mentioned in the earlier post, people should look at the entire setup before deciding on what will work best for them. It's no different to the rest of the engine build, all the components, including the tune should be decided upon for a complete package. Not a bunch of separate components thrown together in the hope they will work together.

5.7ute: Yes. I have tested my car in this way. Both MAFed and MAFless with the MAF sitting in place. All other factors have remained constant ( engine wise ) just the signal from the MAF has been removed. In the testing I found many of the issues already listed and I've worked around nearly all of them. It was not a simple process using the E38 but it is getting very close. Switching between MAF and MAFless now has minimal effect on the overall driving of the car, though the dyno may tell a different story. My current preference is to run MAFless only because When I go to the OTR I won't need to try and squeeze in a MAF.

Simon.