Zappo Posted May 25, 2013 Report Share Posted May 25, 2013 4. The stock MAF is probably not big enough to handle the volume required. 5. The stock MAF is probably a bottleneck The stock MAF is not big enough for the stock turbo. It only gets worse with bigger turbos. Link to comment Share on other sites More sharing options...
DAYWALKER Posted May 25, 2013 Report Share Posted May 25, 2013 surprise you still have the stock air box. you should try to take the air box out and see if it still could collapse the hose. just curious. if the problem go away then you wouldn't need a big maf housing or hose for your 20g. Link to comment Share on other sites More sharing options...
boxpin Posted May 25, 2013 Author Report Share Posted May 25, 2013 surprise you still have the stock air box. you should try to take the air box out and see if it still could collapse the hose. just curious. if the problem go away then you wouldn't need a big maf housing or hose for your 20g. I have had both(stock and K&N). During all this testing I took out the air filter and propped the box open...no diff, it still did it. Which means the maf is the restricter . Link to comment Share on other sites More sharing options...
andyb5 Posted May 26, 2013 Report Share Posted May 26, 2013 Glad you gt the problem figured out. Looks like its time for an ME7 or Audi A8 MAF Link to comment Share on other sites More sharing options...
optimus prime Posted May 26, 2013 Report Share Posted May 26, 2013 Audi a8 maf fits? Link to comment Share on other sites More sharing options...
fwdGTP Posted May 26, 2013 Report Share Posted May 26, 2013 I have an A8 MAF, idle's kinda funky, rolling 1000-1100 stopped 1100-1400 lol. other than that works fine. My car gained a lot removing the factory box all together and running a cone filter even on stock MAF and intake tubing. My factory MAF maxed at around 12-14 psi on the 16T and around 10 psi on my 18G, leaving way too much of a dead spot where it runs super rich til it gets to full boost.I bet ur so far passed the max of the MAF that its causing that much of a bottle neck, but not 100% on that one although that's what it seems. glad you found out the issue, was bothering me that you weren't able to find it lol. Link to comment Share on other sites More sharing options...
lookforjoe Posted May 26, 2013 Report Share Posted May 26, 2013 late '90's A8 MAF housing (the Volvo sensor fits) is fine, but if you don't have TTusb or another way to rescale your maps, it's gonna suck. Good news that you found it! You can see the hose deflect in that video pretty clearly (I think it was 1:08, 1:12 I saw the shadow) You can also get this on eBay - sold for VW's Link to comment Share on other sites More sharing options...
RZT5 Posted May 26, 2013 Report Share Posted May 26, 2013 Glad you found the issue! I guess I should re-consider keeping my stock MAF even though my AFRs are spot in throughout the rev range (took some tuning to get there). I never guessed it would cause that much of a restriction, especially since the compressor inducer even on a 20G is significantly smaller than the MAF diameter. Link to comment Share on other sites More sharing options...
Über855R Posted May 26, 2013 Report Share Posted May 26, 2013 Glad you figured it out. That must have bugged you pretty bad. Just out of curiosity, what would indicate the stock MAF maxing out? I am running a M4.4 ARD black tune stock MAF with 3" j pipe and 3" intake filter. Doesn't seem to have any trouble pushing 20 psi. So I am curious what would be the giveaway of MAF reaching capacity? Link to comment Share on other sites More sharing options...
RZT5 Posted May 26, 2013 Report Share Posted May 26, 2013 Glad you figured it out. That must have bugged you pretty bad. Just out of curiosity, what would indicate the stock MAF maxing out? I am running a M4.4 ARD black tune stock MAF with 3" j pipe and 3" intake filter. Doesn't seem to have any trouble pushing 20 psi. So I am curious what would be the giveaway of MAF reaching capacity?The MAF signal is a voltage ranging from 0-5V. So once the MAF output hits 5V it has topped out and won't register any further increase in flow. I have my Innovate LMA-3 setup to monitor MAF voltage, so I can watch it real time or data log it, which is how I know it's topping out. M4.4 is designed to go into what is essentially open loop once the MAF tops out, which is why we are all able to flow much more air than the MAF will ever be able to measure. However, it would be ideal if we could somehow change this and keep the ECU in closed loop for longer. Link to comment Share on other sites More sharing options...
B Mac Posted May 26, 2013 Report Share Posted May 26, 2013 Nice job finding the problem, John. How does she feel now? Time for a 707? :P Link to comment Share on other sites More sharing options...
Simply Volvo Posted May 27, 2013 Report Share Posted May 27, 2013 The MAF signal is a voltage ranging from 0-5V. So once the MAF output hits 5V it has topped out and won't register any further increase in flow. I have my Innovate LMA-3 setup to monitor MAF voltage, so I can watch it real time or data log it, which is how I know it's topping out. M4.4 is designed to go into what is essentially open loop once the MAF tops out, which is why we are all able to flow much more air than the MAF will ever be able to measure. However, it would be ideal if we could somehow change this and keep the ECU in closed loop for longer. I would keep an eye on the Tuners Rejoice free tuning for m4.4 thread. We have dissected a large amount of the code already and have added true data logging. We may even be able to convert over a 3 bar map sensor and ditch the MAF all together. Unfortunately the MAF maxing is out is hardware realated not much in the software we can change and forcing the ecu to staying into closed loop would just result in the ecu seeing the same flow but actualy flow still increasing which would result in a lean mixture, aggresive ignition timing and a blown motor. Link to comment Share on other sites More sharing options...
piko Posted May 27, 2013 Report Share Posted May 27, 2013 What about removing the mesh before the sensor? It does take a bit of crossection area and shouldn't read any different exept for maybe having less laminar flow. Link to comment Share on other sites More sharing options...
Simply Volvo Posted May 27, 2013 Report Share Posted May 27, 2013 What about removing the mesh before the sensor? It does take a bit of crossection area and shouldn't read any different exept for maybe having less laminar flow. Leave the honeycomb on. You will get some messed up readings without it. Link to comment Share on other sites More sharing options...
fattmatt805 Posted May 28, 2013 Report Share Posted May 28, 2013 so i was right? first Link to comment Share on other sites More sharing options...
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