benefits of mafless
Discussion
As time goes on and I read more and more about going MAFLess just how good a mod is this?
Once the MAF is removed and you open the loop (or close which ever way) and rely on the tune map to be spot on - does it still check mixture etc to ensure it is running as good as possible?
What power gains, if any, are typical with removing the MAF or is it simply to allow for future big BHP upgrades and less things to go wrong?
Once the MAF is removed and you open the loop (or close which ever way) and rely on the tune map to be spot on - does it still check mixture etc to ensure it is running as good as possible?
What power gains, if any, are typical with removing the MAF or is it simply to allow for future big BHP upgrades and less things to go wrong?
I like SD mainly for the increased throttle response and in my car a MAF would be a physical restriction.
Thats the short answer, the long one is more complex.
Tuned right on a stock engine there wont be any power difference. Unless as you say you are into bigger power.
Fueling is kept bang on at 90% of the operating range by closed loop O2 function. I wouldnt run open loop unless you have a big scary monster.
It all comes down to the way in which the MAF works. In high power applications the MAF is both a physical and an airflow reading limitation. The MAF contains heated wires and the rate of the wires cooling determines airflow. This is deduced from the IAT temperature and the diameter of the MAF and the cooling of the wires.
Mafless is based on intake pressure, rpm and the volumetric efficiency of the engine.
The MAF by nature takes longer to feedback information. In the ECM it is merged with mafless data until 4000rpm at which point its airflow readings take precedence. So under 4000rpm you are running a mix of maf and mafless modes anyway. This is because at lower airflows the MAF is less accurate.
I believe a lot of the reason why a mafless tune works better is because most tuners do not attempt to correct the volumetric efficency table which is used as a base for fueling calculations. Especially under throttle. They just tweak timing and maybe the MAF table if you are lucky. A nicely tuned Mafless tune is required to do a fully tuned MAF tune. Its just due to time constraints etc some tuners just do some spark changes then check fueling under full throttle leaving the O2's to clean up the rest of the tune.
An open loop mafless tune requires a proper mapping of the engines efficency to be done to ensure fueling is accurate at all load points because you arnt relying on O2's or MAF's to fix up any short comings in the tunee. The MAF table I think has around 26 cells. The VE table has hundreds and hundreds. The same applies to tuning timing only under throttle as opposed to all load points.
Ask Smiler. he has done quite a few dyno tuning sessions with his SC car mapping a lot of this out, it takes time! But see what he says about the powergains to be had from a thorough tune.
But its all down to cost benefit. Would you pay £700 for a dyno full tune for example when max power with a £300 tune is within a few bhp? What of course you dont see is the better power and response under all throttle postitions and loads of the more expensive tune.
Thats the short answer, the long one is more complex.
Tuned right on a stock engine there wont be any power difference. Unless as you say you are into bigger power.
Fueling is kept bang on at 90% of the operating range by closed loop O2 function. I wouldnt run open loop unless you have a big scary monster.
It all comes down to the way in which the MAF works. In high power applications the MAF is both a physical and an airflow reading limitation. The MAF contains heated wires and the rate of the wires cooling determines airflow. This is deduced from the IAT temperature and the diameter of the MAF and the cooling of the wires.
Mafless is based on intake pressure, rpm and the volumetric efficiency of the engine.
The MAF by nature takes longer to feedback information. In the ECM it is merged with mafless data until 4000rpm at which point its airflow readings take precedence. So under 4000rpm you are running a mix of maf and mafless modes anyway. This is because at lower airflows the MAF is less accurate.
I believe a lot of the reason why a mafless tune works better is because most tuners do not attempt to correct the volumetric efficency table which is used as a base for fueling calculations. Especially under throttle. They just tweak timing and maybe the MAF table if you are lucky. A nicely tuned Mafless tune is required to do a fully tuned MAF tune. Its just due to time constraints etc some tuners just do some spark changes then check fueling under full throttle leaving the O2's to clean up the rest of the tune.
An open loop mafless tune requires a proper mapping of the engines efficency to be done to ensure fueling is accurate at all load points because you arnt relying on O2's or MAF's to fix up any short comings in the tunee. The MAF table I think has around 26 cells. The VE table has hundreds and hundreds. The same applies to tuning timing only under throttle as opposed to all load points.
Ask Smiler. he has done quite a few dyno tuning sessions with his SC car mapping a lot of this out, it takes time! But see what he says about the powergains to be had from a thorough tune.
But its all down to cost benefit. Would you pay £700 for a dyno full tune for example when max power with a £300 tune is within a few bhp? What of course you dont see is the better power and response under all throttle postitions and loads of the more expensive tune.
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