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Mafless Tune Surprised and Disappointed!

davey g-force

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vn6pwr said:
Could anyone enlighten me as to what a mafless tune is, I know what a maf is so im guessing its a tune without the maf?

You're spot on!
 

klaw81

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You're dead right, the MAF is removed and the car re-tuned. Perhaps I could be more helpful by explaining why....

The MAF is the Mass Air Flow sensor - this measues the volume of air coming into the engine. Air flow into the engine is mainly governed by current engine speed (rpm), throttle setting & air temperature. The engine management uses this information to calculate the appropriate injector opening time, which in turn governs the amount of fuel that is mixed with the air that was measured. The idea is to always have near-perfect combustion efficiency, which is critical for power, emissions control and fuel economy.

The downside to having the MAF in the airflow is that it tends to cause a restriction. This means that only a certain amount of air can enter the engine to mix with the fuel, which tends to restrict power at high rpm when the engine is begging for as much air as it can get. The obvious solution is to get a bigger MAF to allow more air to flow in, or better still, ditch it altogether.

Since the engine managment is programmed to use the MAF to caculate injector cycles and regulate fuel supply, it spits the dummy when the MAF is removed. It reverts to TPS (Throttle Position Sensor) mode and cuts power to prevent engine damage. Re-tuning the engine management is necessary to allow the engine to run properly, and to take advantage of the reduced airflow restriction.

You might be wondering what happens to emissions control and fuel economy now the MAF is gone? Well theoretically it doesn't make much difference, seeing as the information the computer needs can be supplied by other sensors. The main factors (rpm, throttle setting & air temp) that govern correct tune have dedicated sensors, which are already installed and working fine...it's just that the MAF is slightly more accurate. So emissions and fuel consumptioon may be a little worse than before, but only very slightly. Some types of cars don't even HAVE a MAF sensor fitted from factory. And if you're spending that much money on mods to an Aussie V8, fuel economy and emissions are clearly not your highest priorities anyway.
 
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VYSS346

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Got my VY SS Series I run up on the dyno today.. 3 runs..

Im running mafless tune, otr cai and cat back 2.5 inch twin redback exhaust.. stock headers and cats... mines a manual too with 113,500k's on the clock

on the first run she pulled 277.8 rwhp
Second run pulled 280.5 rwhp and we noticed a nice hole in the timing map.. we temp adjusted that hole to make it straighter and netted 291.5rwhp, now from the graph/printout, i can see the tuner who did mine needs to adjust the tune somewhat in the 3000 - 4500 rpm range.. which should net me just over 300rwhp after being done..

Also want to get some pacemakers and hi flow cats done which should give me another small increase.. maybe 10rwhp..

so yeah more tuning to come for me! :D

oh and rough conversion of 291.5rwhp is 217.5 rwkw's

DR
 

davey g-force

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VYSS346 said:
Got my VY SS Series I run up on the dyno today.. 3 runs..

Im running mafless tune, otr cai and cat back 2.5 inch twin redback exhaust.. stock headers and cats... mines a manual too with 113,500k's on the clock

on the first run she pulled 277.8 rwhp
Second run pulled 280.5 rwhp and we noticed a nice hole in the timing map.. we temp adjusted that hole to make it straighter and netted 291.5rwhp, now from the graph/printout, i can see the tuner who did mine needs to adjust the tune somewhat in the 3000 - 4500 rpm range.. which should net me just over 300rwhp after being done..

Also want to get some pacemakers and hi flow cats done which should give me another small increase.. maybe 10rwhp..

so yeah more tuning to come for me! :D

oh and rough conversion of 291.5rwhp is 217.5 rwkw's

DR

Some good figures there Darkrayne. :thumbsup:

Just out of interest, when you say the tuner has to adjust your tune, is that part of the initial cost, or would you have to pay again for the re-adjustment?
 

VYSS346

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davey g-force said:
Some good figures there Darkrayne. :thumbsup:

Just out of interest, when you say the tuner has to adjust your tune, is that part of the initial cost, or would you have to pay again for the re-adjustment?

The tuner who did my mafless edit is my younger brothers best friend.. he works for Motec and does LS1 edits all over Perth.. I just rang him up after i got the dyno runs done and asked him whenever hes got time if he we can sit down and fine tune the maps.. said wasnt a prob so either be doing it this arvo or saturday!.. but yeah intial tune was loaded at his home, didnt have the use of a dyno so was a little trial and error.. but yeah should have it running sweet in no time! was happy to see with some fine tuning she jumped up quite a bit in the rwhp figure! :D... also running a bit rich in the top end so will adjust the fuel map to fix that too..

cheers

DR
 

davey g-force

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Aaah ok. So I take it a normal paying customer would get their tune done with the use of a dyno and there shouldn't be any 'holes' in the map or any need to adjust the tune.

Just curious as to whether they'll keep fiddling with it until I'm happy with it for when I get mine done.
e.g. If I was to get it dynoed elsewhere and discovered some problems.
 
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rousey

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coldasice

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My car ran 246.2 rwhp stock.

Then it ran 262.1 rwhp with Difilippo 1 7/8" extactors and a pod style airbox fitted (the larger extractors were put on for a purpose as the long term plan is forced induction).

Then it ran 272.1 rwhp (on a different dyno, so still has to be dynoed on the dyno that did the first 2 readings) with the above mods and an exhaust fitted (with high flow cats).

I am doing the dyno runs purely to keep a record of the increase at each modification, from stock. Over each run the torque curve has improved a lot. There are more things to read than just a number figure.
 

dynamytedave

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My '03 CV8R made 220rwkw (which equates to around 297rwhp) on Sureflo's dyno on a cranking hot day in October last year with 120,000k's on the clock. Mods are SS cai, mafless tune, headers and 2 1/2 inch system with no resonator. When sold new they were rated at 245kw at the engine. I was a little dissapointed at the result but with the k's and the temperature of the day and only having 95 octane caltex fuel, it's not so bad. I was hoping for around 240rwkw, but ditching the SS cai and opting for a OTRCAI should bring the figure a little closer. But when everythings said and done you can't really complain about the figures when you haven't even cracked the engine open. A nice cam, a little port work and some double valve springs would be nice.
 

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good reading, good reading... after a mild cam upgrade and mafless tune, pacemaker header's and 3 inch (no cats). the difference was very noticable all the way. a good job i reckoned. have now done 92mm throttle body, ported and polished head's, bigger valve's and "fast" inlet manifold. this brought the rwkw's up to 247.3.......but i gotta say....... i can't feel any difference down low at all. i feel completely ripped off.. $8,460.00 worth to be exact!! if i want to feel the extra power i will have to trot around the place at 140+kmh. this is an every day car so ya know..... going for a dif out of a manual so that should give me some joy apparantly.
 
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