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Maf Map

Road Tuning

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Discussion and questions related to the course Road Tuning

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Maf table - Map Load

i add 9% as start at all cel on the maf map at WOT

after i did that i went for a quick run to get some data login

i found that i have some rich & lean areas coz of the injectors plus weight changed.

so i would like to know, is it okey if i kept the 9% or more than 9% at maf map

and then change the value of the fuel map to get the target AFR ?

Im thinking to go more than 9% to get as close to 4.34 maf volt at high load and rpm.

also does the camshaft change the cfm of the engine ? if yes . can i go more than 9% and to try to get more air

Im using AEM FIC6 - NA Engine - bolt on - high performance camshaft

The MAF map is used to make adjustments to the MAF signal to the factory ECU. This map should only be necessary if you've fitted a different MAF sensor or modified the intake track so that the stock MAF calibration is now inaccurate. This is adjusted so that the factory closed loop system trims are close to zero. If you're getting close to the maximum voltage from the MAF sensor you need either a larger MAF sensor or to fit your current MAF sensor into a larger diameter tube.

If you've changed injectors then this needs to be dealt with in your MAP Load table. There is an option to automatically calculate the required percentage change based on old injector and new injector size. Beyond this you can then use the map to achieve your desired target AFR.

I hope the above helps answer your questions.

Thank you Andre for your reply.

actually im using 2.5' maf pipe which is bigger than the stock and im going to use 3" maf pipe to be as the same as the intake pipe diameter .

My question was : when i added 9% at WOT i got some rich & lean areas . in this case if i want to get the target afr do i dis crease the 9% or simply just go to fuel map and change the value of the same areas to get the target afr ?

If you change the MAF tube then the first task would be to adjust the MAF Map until your AFR is as close to target as you can get. To do this you would zero the MAP load table and do your initial tuning in the MAF map. Once you're as close to target as you can get, you can make further adjustments to the MAP load table. A good starting point is to calculate the difference in cross sectional area between the new MAF tube and the old one. If for instance the new MAF tube is 50% larger in area you can start by multiplying the entire MAF map by 1.5. This should get you pretty close right away.

Hi again,

I finally had the time to install the 3'' intake pipe with bigger maf housing but stock maf sensor.

I did calculate the difference btw the stock and the new one . it's around 30% bigger. I add 30% to the whole table of the maf table and then i left it alone because it was close to the target afr at some point. and i did all my work on fuel table to get the right AFR reading . as I dont know how to calculate the numbers at the maf table to get the right AFR .

Note : I did 2 things before i tuned

*Installed a bigger injectors and I did used the option to automatically calculate the difference btw the old inj & the new and then i fine tune it a lil bit.

*Installed a bigger intake 3" ( Short Ram Intake ).

My questions :

- Am i at the right way ?

- Also installing a bigger pipe should give me more Air G/S ? As i knew it should be but im only getting around 20 G/S from the bigger pipe @ full Wot (and still at 4.2v ) while the old pipe was 2.3''

- What do i have to do to make the maf reads more G/S with the 3" Maf Housing & pipe ?

- Is there a method for calculate the maf numbers to get the right AFR at close loop and open loop ?

- What if my wot already rich, can i simply lean out the fuel table at wot and then scale the maf to higher number to get more air ?

In short it's not usually recommended to change the injectors and the MAF housing/intake at the same time unless you're dealing with an ECU that offers complete characterisation of the injectors (such as late model GM/Ford). The reason is that any error between your target and measured AFR could be a result of a problem with your MAF scaling or injector scaling and it's not possible to know which is the issue.

You can either start with the stock injectors or the stock MAF and intake and then adjust the tune for just one element at a time. Once you've done that you can add the other element and complete the calibration.

Just adding a larger intake pipe doesn't necessarily result in additional flow unless there was a previous restriction. It's not a case of scaling the MAF to get more air, but rather scaling the MAF to ensure it's reporting the correct amount of air entering the engine.

You might find our Practical Reflash Tuning course valuable as it covers all your questions in detail and also shows you how to use data logging to help calibrate aspects like the MAF scaling and injector scaling.

Thank you Andre for the reply .

Is that mean i also need to start with stock intake manifold as well ? because im using aluminium one (a bit bigger ) and the stock was plastic.

or all i need is to start with stock maf and intake only ?

I'd probably start with stock injectors and all of the intake changes you intend to make. Then your calibration changes can be limited to just the MAF scaling initially.

As it's hard to get my old intake manifold back and the stock maf & intake

Shall i start with small diameter maf ( almost the same as stock ) WITH STOCK INJECTORS, and start calibration the maf table. ( STEP 1 )

and then install the bigger injectors and scale it. ( STEP 2 )

and then get back to the 3'' intake and rescale the maf table ( STEP 3 )

Is that will take me to the right way of tuning for the bigger injectors and MAF?

Up Up Up

Provided you can go back to stock injectors you will be able to rescale for your new MAF and intake from there. then swap the injectors and scale for those.

Thank you ..

actually i tried before to scale the new maf with the stock injectors but it could't handle. as the new maf is 30% bigger then the stock. that's why i wrote the steps which i found it better for me.


Im trying to scale the maf with the stock injectors but the maf mix out at around 5500 rpm so i had to decrees the number from 5500 to 6700 to try to make it flow until the redline and im still working on it.

I have one question:

If the flow of the mass does not want to go over 110 g\s is that mean i reach the limit of the engine VE??

I have this issue with both 3" & 2.3" maf housing

Im using short arm intake with V stack

Up Up Up

If your current MAF sensor is maxing out, you need a bigger housing.

Good info here! My previous tune was done with the injectors & intake already swapped. The tuner left the injector scaling alone & adjusted the MAF scaling only to tune the vehicle. Runs fine but since taking the classes I will be going to back to stock injectors and recalibrating my MAF scaling as I have a LOT of intake modifications. This way as the car progresses with future mods each injector or MAF rescale will be more accurate as they build on one another.

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