MAFless Tune

[djwilk]

Hi,
Could anyone, please, point me in the direction where I would be able to read up a little about MAFless tunes and their pros and cons? It's for my LS3 VXR8.
Search engine on PH is what it is, and google sends me to different forums, with lots of followers and haters, but no solid basic knowledge to take in first.

Thanks.
Bart

[KMud]

If you search on google you'll probably end up back on here, Ringram vs. Monkfish in numerous threads.

[djwilk]

For that very reason, I am trying to get some independent knowledge myself first

[ARAF]

KMud said:

If you search on google you'll probably end up back on here, Ringram vs. Monkfish in numerous threads.

My basic understanding is that MAF does nothing at higher throttle openings, but adds an extra level of monitoring (and security) at lower openings. On the Monaro, the MAF was a lot smaller than on the VXR8, so restrictive when you were trying to extract additional power. Not such a problem on the VXR8, but still not liked by those trying to lose every last bottleneck in the gas flow.

[KMud]

djwilk said:

For that very reason, I am trying to get some independent knowledge myself first

Not sure if I qualify as independent, but here's why I'm MAFless...closed loop speed density to be precise.

• short OTRCAI pipework is not really long enough for a MAF, needs to be in the middle of a long straight pipe really for smooth air flow
• improved throttle response
• removed restriction
• no need to buy/tune bigger MAF when running more power than the stock MAF could deal with (loses resolution up top, I forget the actual airflow limit it can read)

There might have been other reasons I'm forgetting. I did appreciate Roger's arguments, but ended up on team Ringram on this one. If I remove the OTR I'll reconsider my position, but probably stick SD.

[djwilk]

I'm also running OTRCAI and the tract to the throttle body is fairly short.
Not huge spec over stock apart from full decat exhaust with headers and OTRCAI.
I was told about necessity for IAT to be installed. Would I have it installed on the intake pipe (before the throttle body)? And is there any UK place to source one from? I know there are plenty in the U.S.

[KMud]

Yep, if your IAT sensor is integrated into the MAF then it needs reinstating somewhere. This is where I step aside as mine was separate...but FWIW mine's in the OTR.

[stigmundfreud]

if you want to go mafless you need to go to the efilive forum and read read read their tuning sections.

You can retain the maf in situ and plugged in for IAT to get a decent SD map. You can trick the MAF into not having an input whilst not tripping an alert by adjusting the voltages from memory. Look on efi its years since I done it.

Once you have your SD map sorted you can then relocate the IAT into your OTR and remove the maf though it isn't really a restriction

[stigmundfreud]

oh saw you are looking for pro's and con's - pro's you don't have to worry about the maf going out of tune. Con's you don't have the maf helping the engine adjust for other failures or issues, fueling at altitude and well its a pain in the fking arse - the ls3 is a bloody good set up

[djwilk]

Thanks for the replies.
So no power gains resulting from MAF delete? No drivability improvement of the engine? Nada? So when you say about adjustment at altitude, does the engine become endangered especially when WOT?
You see, so many questions...

I was under the impression that MAF will give wrong reading because of its location in relation TB and OTRCAI and the fact it is such a short passage. No?

[KMud]

djwilk said:

Thanks for the replies.
So no power gains resulting from MAF delete?

Not sure on LS3, maybe smaller gains than LS1.

djwilk said:

No drivability improvement of the engine? Nada?

I think so...but again, LS1.

djwilk said:

So when you say about adjustment at altitude, does the engine become endangered especially when WOT?

The O2s will still sort the short/long term fuel trims (unless you disable them) won't they? Not given it much thought, haven't taken my Monaro up any mountains...

djwilk said:

You see, so many questions...

I was under the impression that MAF will give wrong reading because of its location in relation TB and OTRCAI and the fact it is such a short passage. No?

Not sure about wrong, but possibly a bit unstable.

Google around the terms 'MAFless' and 'speed density' to get more info from other (better!) sources...add 'LS3' too, to keep it more relevant to you.

[stigmundfreud]

you can rescale the maf if needed and I know ringram is reading this and going mad

Removing the MAF removes an element that can impede on overall performance and seriously removing the maf is not going to cause the engine to explode. Ringrams mantra is to extract every single last hp out of his car so for him it makes sense but you want to ask yourself why you want to remove your maf? LS1 it was a major restrictor, not so much on the 3.

If you have efilive and want to really improve throttle response immediately then disable your LTFTs (long term fuel trims) this will make the car feel like new every time you do your throttle. Cheap simple trick, used by unscrupulous tuners but it gives a shot in the arse that feels like an extra 30whp

[MyM8V8]

Mafless here.

The maf can be failed in the tune. I'd tale it out of the airflow too and re-site the IAT. Its not that hard and I think MF can make you a lead to remote mount it.

[Magic919]

I ran my LS3 and OTRCAI with a mafless tune. Left the maf in place for convenience of IAT. Might have been in the mind, but the car felt like it was more closely wired to the loud pedal.

[stigmundfreud]

it will feel it because no ltft's

[MyM8V8]

Magic919 said:

I ran my LS3 and OTRCAI with a mafless tune. Left the maf in place for convenience of IAT. Might have been in the mind, but the car felt like it was more closely wired to the loud pedal.

That's because the ecu is referencing the tables direct from the ecu and not reading from the maf first and then computing. Its this which gives better throttle response.

[KMud]

MyM8V8 said:

That's because the ecu is referencing the tables direct from the ecu and not reading from the maf first and then computing. Its this which gives better throttle response.

I thought it was because the MAF is slower to respond to changes in airflow than the MAP sensor

[MyM8V8]

stigmundfreud said:

Once you have your SD map sorted you can then relocate the IAT into your OTR and remove the maf though it isn't really a restriction

Well if you are running a 102mm intake pipe and TB and the maf is 85mm it will be.

[ARAF]

MyM8V8 said:

stigmundfreud said:

Once you have your SD map sorted you can then relocate the IAT into your OTR and remove the maf though it isn't really a restriction

Well if you are running a 102mm intake pipe and TB and the maf is 85mm it will be.

Only if you're required flow rate exceeds that of the maf.

[stigmundfreud]

MyM8V8 said:

stigmundfreud said:

Once you have your SD map sorted you can then relocate the IAT into your OTR and remove the maf though it isn't really a restriction

Well if you are running a 102mm intake pipe and TB and the maf is 85mm it will be.

whats the LS3 MAF like? I Thought it was built into the TB?