Snowflake Posted May 25, 2009 Report Share Posted May 25, 2009 I dont know much about what you guys are talking about but this is a great discussion. Learning FTW!! Quote Link to comment Share on other sites More sharing options...
Billiumss Posted May 25, 2009 Report Share Posted May 25, 2009 yes but when your racing and the MAF decides to go south on you and run your fuel trims at -25% then thats bad for my engine. which is what mine did when i was at nelson ledges last year. i wouldn't be surprised if that was a playing factor in my ring issue that started not long after that. What codes did you set? If you have a decent SD tune, then enable the MAF and dial that in, if the MAF does fail the VE table takes over and your tune is still pretty close anyways since your VE table was tuned and not "guessed tuned" If your are at -25% Ltrims that means your PCM is pulling up to 25% fuel out since your VE table is not correct and your still using your NB O2 sensors as inputs for closed loop mode. Depending on the car and mods I can spend anywhere from 3-6 hours tuning a car, its a very time consuming process. Quote Link to comment Share on other sites More sharing options...
AJ Posted May 26, 2009 Report Share Posted May 26, 2009 the MAF failed before i had it tuned. p0171 and p0174 IIRC were the two being set. was watching it on the tech 2 at work and unplugged the MAF and long term trims went to 2%. with there still being a junk MAF in my car for now just for the air temp sensor i'm not replacing it. i replace alot of MAF's that go out and don't feel like wasting money on one. Quote Link to comment Share on other sites More sharing options...
EricZ06 Posted May 26, 2009 Report Share Posted May 26, 2009 From a performance standpoint I would recommend to anyone to remove their MAF and go Speed Density. MAF: 1) Causes slower fuel/throttle response 2) Is a restriction to the engine 3) Cannot accurately and consistently meter airflow in high horsepower forced induction and large cam cars You bring up the point of why GM uses MAF's and spent x millions on them and here is your reason.... They have to make their vehicles operate perfectly in a wide range of elevation/temperature and still pass emissions in these conditions :-) How many true race cars use MAF's at the track??? Eric Quote Link to comment Share on other sites More sharing options...
thorne Posted May 26, 2009 Report Share Posted May 26, 2009 Hey brian, Hobby tuner question. How long does it take you to scale a maf? It seems to take me hours upon hours. I think I'm going about it the hard way. For anyone who's curious why a MAF is supoer important look up Hot Wire MAF. It will explain to you why simple changes such as a CAI will cause major problems if not calibrated for the car. Quote Link to comment Share on other sites More sharing options...
DTM Brian Posted May 26, 2009 Author Report Share Posted May 26, 2009 Hey brian, Hobby tuner question. How long does it take you to scale a maf? It seems to take me hours upon hours. I think I'm going about it the hard way Please be more specific Mr. Thorne. Why is it taking you hours? Quote Link to comment Share on other sites More sharing options...
thorne Posted May 26, 2009 Report Share Posted May 26, 2009 No MAF = BOV capable! Quote Link to comment Share on other sites More sharing options...
thorne Posted May 26, 2009 Report Share Posted May 26, 2009 Please be more specific Mr. Thorne. Why is taking you hours? Well what I end up doing. Log all fuel trims / Wideband / MAf Volts / Commanded AFR / RPM / Load(Calculated) I have to go into Drive X range lets say the Lower portion of the range. DRive around for a while get some logs go back in make corrections based on Fuel trims. Smooth out that portion and continue up the Range(Maf Volts) I've got a scaling tool in rom raider I've used but it requires me to drive around for a couple hours and it will get a pretty descent Rough calibration assuming you drive the car properly. When I dialed in my CAI I spent 2+hours. I'm sure its partialy due to lack of experiance scaling mafs. I've only scaled a total of 4. 2 of wich were diffrent intakes on my own car. the other 2 where a project car. I've done Big MAF rescaling (to get around 5v limit by using a larger maf housing) Quote Link to comment Share on other sites More sharing options...
DTM Brian Posted May 26, 2009 Author Report Share Posted May 26, 2009 Wish I could off load this 2 wheel drive dyno and go awd. Sounds like I would be right at home tuning subies. Quote Link to comment Share on other sites More sharing options...
thorne Posted May 26, 2009 Report Share Posted May 26, 2009 As long as you understand the IAM Portion of a subaru any tuner could tune one. That IAM portion seems to get allot of first time subaru tuners hung up. (1.0 * KC table) + MT = Total timing Initial is normally .5 or .7 so I've seen quite a few tuners who tune the timing wrong. Quote Link to comment Share on other sites More sharing options...
DTM Brian Posted May 26, 2009 Author Report Share Posted May 26, 2009 No MAF = BOV capable! My turbo cars have BOV's Maf sits in between the BOV an TB Quote Link to comment Share on other sites More sharing options...
Billiumss Posted May 26, 2009 Report Share Posted May 26, 2009 I guess I wasted a lot of money taking tuning classes then.... Quote Link to comment Share on other sites More sharing options...
Turbotrio Posted May 26, 2009 Report Share Posted May 26, 2009 I guess I wasted a lot of money taking tuning classes then.... If you are referencing SD tuning (Or lack-there-of) then yes you did Just out of curiosity when did you take the classes and who was teaching them? Jeff Quote Link to comment Share on other sites More sharing options...
MrMeanGreen Posted May 26, 2009 Report Share Posted May 26, 2009 I'd think every bit helps, personally. As for the MAF versus SD debate, it depends on the application. My green car is SD obviously because of the boost. My blue car is SD and sucks when there's a severe change in climate, which is what Ohio is known for. It's going back to a MAF here shortly. Quote Link to comment Share on other sites More sharing options...
Casper Posted May 26, 2009 Report Share Posted May 26, 2009 I'd think every bit helps, personally. As for the MAF versus SD debate, it depends on the application. My green car is SD obviously because of the boost. My blue car is SD and sucks when there's a severe change in climate, which is what Ohio is known for. It's going back to a MAF here shortly. For a street car in Ohio, MAF > *. Just my two cents. Quote Link to comment Share on other sites More sharing options...
bethel Posted May 26, 2009 Report Share Posted May 26, 2009 .... Quote Link to comment Share on other sites More sharing options...
gillbot Posted May 27, 2009 Report Share Posted May 27, 2009 I ran an SD tune for a while, I'll keep my MAF thanks. Quote Link to comment Share on other sites More sharing options...
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