So from the start let me just say I have no intention to go big turbo this year or probably next year either, this is just to educate myself a bit more...
Question: Why do guys remove the MAF when doing a full on big turbo build? From what I understand the MAF measures airflow and then all tuning and fuel stuff gets done based on how much air the intake flows to the turbo?
Removing the MAF must make tuning a bastard unless there is another way to measure the amount of air flow in order to fine tune the map? One last thing, if its a case of size vs flow restriction, surely there must be a MAF sensor and housing big enough to accommodate for the added need for air flow?
If there is a thread explaining this..please point me that way
Ex:
White '07 Polo GTI 9n3 - Stock
Black '07 Polo GTI 9n3 - 113fkw 234nm stock -> 153kw 277nm chooned
Silver '07 Slowdi A4 B7 1.8t - w/ T3T4 powers
Current:
Green '16 Kawasaki Z300 - 28kw
Blue '15 Yamaha MT-07 - 55kw
Blue '13 B8.5 A4 2.0TDI - 130kw
MouseGTI wrote:So from the start let me just say I have no intention to go big turbo this year or probably next year either, this is just to educate myself a bit more...
Question: Why do guys remove the MAF when doing a full on big turbo build? From what I understand the MAF measures airflow and then all tuning and fuel stuff gets done based on how much air the intake flows to the turbo?
Removing the MAF must make tuning a bastard unless there is another way to measure the amount of air flow in order to fine tune the map? One last thing, if its a case of size vs flow restriction, surely there must be a MAF sensor and housing big enough to accommodate for the added need for air flow?
If there is a thread explaining this..please point me that way
The MAF is deleted on big turbo cars due to most of them requiring a 3.0" or larger intake diameter. stock MAF housings dont cut it, and to re-write maf scaling tables for the ecu to work with are a nightmare if you were to make a MAF to match.
fueling is then based on lambda values, the lambda value is set in the map (target AFR) and the ecu will try to meet that in respect to fueling.. boost control on BT cars in generally dealt with by an EBC
MouseGTI wrote:So from the start let me just say I have no intention to go big turbo this year or probably next year either, this is just to educate myself a bit more...
Question: Why do guys remove the MAF when doing a full on big turbo build? From what I understand the MAF measures airflow and then all tuning and fuel stuff gets done based on how much air the intake flows to the turbo?
Removing the MAF must make tuning a bastard unless there is another way to measure the amount of air flow in order to fine tune the map? One last thing, if its a case of size vs flow restriction, surely there must be a MAF sensor and housing big enough to accommodate for the added need for air flow?
If there is a thread explaining this..please point me that way
The MAF is deleted on big turbo cars due to most of them requiring a 3.0" or larger intake diameter. stock MAF housings dont cut it, and to re-write maf scaling tables for the ecu to work with are a nightmare if you were to make a MAF to match.
fueling is then based on lambda values, the lambda value is set in the map (target AFR) and the ecu will try to meet that in respect to fueling.. boost control on BT cars in generally dealt with by an EBC
This I've seen alot now...heard of another 2 stock 1.8t Polo GTIs using a boost controller in tandem with the N75 i think...not 100%
So should the intake system not flow enough for the turbo, how would you know without the MAF sensor there to show how much the car is flowing?
(sorry for the noob questions)
Ex:
White '07 Polo GTI 9n3 - Stock
Black '07 Polo GTI 9n3 - 113fkw 234nm stock -> 153kw 277nm chooned
Silver '07 Slowdi A4 B7 1.8t - w/ T3T4 powers
Current:
Green '16 Kawasaki Z300 - 28kw
Blue '15 Yamaha MT-07 - 55kw
Blue '13 B8.5 A4 2.0TDI - 130kw
MouseGTI wrote:
This I've seen alot now...heard of another 2 stock 1.8t Polo GTIs using a boost controller in tandem with the N75 i think...not 100%
So should the intake system not flow enough for the turbo, how would you know without the MAF sensor there to show how much the car is flowing?
(sorry for the noob questions)
In your conventional ecu, there are maps for sensors, each map has values you can configure and a map that defines a limiter. So as an example - a 1.8t maf limiter is set at 240g/s, should more than 240g/s flow past the maf, the limiter then it will throw a CEL and put the car in limp mode. (All this assuming you threw a BT on and used stock intake and MAF out of stupidity)
Also the MAF just shows air past the sensor - it has a physical limitation based on its dimensions - not how much the intake can support or not..
Based on the turbo you were going to install you would know what CFM it flows by looking at a compressor map.. or a general rule of thumb is to simply match the intake size to the actual turbo inlet.. BT usually 3.0 and up
MAF delete or better known as a Alpha-N tune is also done on naturally aspirated engines with huge increase in power on cars like high revving Honda Type R s2000 and bmw M cars. Evo tuning managed to squeeze another 63hp out of the E90 m5 by using alpha-n tune.
Down side is, it does make the car use more fuel than with a MAF
As I lay rubber down the street.
I pray for traction I can keep, but if I spin
and begin to slide, please dear God protect my ride.
MouseGTI wrote:
This I've seen alot now...heard of another 2 stock 1.8t Polo GTIs using a boost controller in tandem with the N75 i think...not 100%
So should the intake system not flow enough for the turbo, how would you know without the MAF sensor there to show how much the car is flowing?
(sorry for the noob questions)
In your conventional ecu, there are maps for sensors, each map has values you can configure and a map that defines a limiter. So as an example - a 1.8t maf limiter is set at 240g/s, should more than 240g/s flow past the maf, the limiter then it will throw a CEL and put the car in limp mode. (All this assuming you threw a BT on and used stock intake and MAF out of stupidity)
Also the MAF just shows air past the sensor - it has a physical limitation based on its dimensions - not how much the intake can support or not..
Based on the turbo you were going to install you would know what CFM it flows by looking at a compressor map.. or a general rule of thumb is to simply match the intake size to the actual turbo inlet.. BT usually 3.0 and up
Thanks for the explantion .
Its all making more sense to me now.
Ex:
White '07 Polo GTI 9n3 - Stock
Black '07 Polo GTI 9n3 - 113fkw 234nm stock -> 153kw 277nm chooned
Silver '07 Slowdi A4 B7 1.8t - w/ T3T4 powers
Current:
Green '16 Kawasaki Z300 - 28kw
Blue '15 Yamaha MT-07 - 55kw
Blue '13 B8.5 A4 2.0TDI - 130kw
For me its just lazyness to get over the max load in me7. Maf scalling is piss easy to change on me7 and me9.
However, if you go over a certain apecified load then alot of the look up tables require to be rescalled.
Just easier to drop the maf and fool the ecu into thinking its runing at a much lower load.
scaling is easy up to a point, but rewriting for a considerably larger maf is a challenge.
but then again, im looking at it from the perspective of the newer ecus as well
Stompie wrote:I would love getting rid of my MAF and using the MAP sensor. But i think its only available on Unitronic stage 2+ and involves alot of tuning.
CPi also does mafless files,yes it does need a lot of tuning, and believe me not one car is the same, we`ve tried it a couple of times, only custom tuning works for best performance results
I`m busy now with my Audi A3, you can email me and I can keep you update on the gains. on the moment the car run on a CPi file with MAF,with GT30 turbo, not a daily use friend, it just want to hol, I`m boosting 1.4bar with 630cc injectors 95oct pumpfuel and we got 300WKW, with fueling issues we kept the timing on 0 deg preventing detonation, think with the MAFless setup the fueling will be past tense.
I am running standard turbo - still using N75
and running a maffless tune and loving it!
but before you go maffless I suggest you drive a maffless setup first.
from my experience it takes some time getting used to, need to get used to the car again
driveability could change when traffic,, the way the car responds to throttle input
basically you going alpha N, at this throttle add this amount of fuel, based on map pressure add more fuel no cruise control when going maffless
there is a lot more to it, you change the size of throttle, you have to re-calibrate the map, change anything, need to recalibrate most likely
a maffless tune will be sure to show you all the other issues you car has that has been masked, most people assume its the maffless tune that's kak
its not, you are more than likely to spend quite some time fault finding to get things 100% when going maffless
a lot of other things to be aware of, car relies on other sensors, battery to supply enough power, not just the map sensor, other sensors play a role in the complete setup, water temp etc
need to have proper safeguards in place and tuning for all conditions need to be catered for.
if there is no need for maffless stay with maf.
that's my opinion
Just don't get caught in the dark and expect things to be how it was with a MAF
Ex:
2007 Polo GTI Eurodyne! 230WHP & 390NM @ KAR 2016 - without OB
2013 Honda Ballade Elegance
1996 Honda Ballade 150i
1994 Honda Ballade 150 Luxline
1991 Citi Golf 1.3
2009 Citi Rox 1.4i
2007 Polo 1.6 Comfortline
1989 Citi Sport 1.8
FrancoisMK2 wrote:MAF delete or better known as a Alpha-N tune is also done on naturally aspirated engines with huge increase in power on cars like high revving Honda Type R s2000 and bmw M cars. Evo tuning managed to squeeze another 63hp out of the E90 m5 by using alpha-n tune.
Down side is, it does make the car use more fuel than with a MAF
All the tuned Honda type R's still have a MAF sensor and they all can rev 9k easily
In some cases the MAF can become restrictive on higher revving NA motors and larger turbo setups.
In which case you can either go for a larger diameter MAF but will need to be re tuned or you can use a alpha-n tune.
Down side as mentioned is you tend to run slightly richer mixture through the rev range and use more fuel. If not mapped correctly throttle response is affected negatively.
If there are any vacuum leaks in the intake when using map sensor fueling becomes erratic as well.
Mafless has its advantages and disadvantages. The CSL E46 M3 uses a alpha-n intake which nets a few ponies over the stock setup but is quite a bit heavier on fuel.
That being said usually if you are exceeding the limits of your MAF then you are very near to the limits of your intake manifold as well, NA cars in particular. Removing a section of the intake pipe (MAF) will not achieve any more airflow through the same diameter of pipe and usually any power increases are only seen from fine tuning the engine, essentially the same as having your car chipped with the MAF in place.
So if you do go MAFLess then you should look at improving flow through the rest of the intake as well. Also look at head work and larger valves to see any significant increase.
As I lay rubber down the street.
I pray for traction I can keep, but if I spin
and begin to slide, please dear God protect my ride.
ok so i came across this post the correct time... i still have a stock intake and the car has a mad error so i checked it up and theres no power
going to the maf... any idea what could cause this? and would it be a issue if i leave it as it is when i want to do intake etc?
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