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Title: Low Maf readings -underscaled Maf Post by: Lost on December 06, 2014, 10:13:14 AM I have relatively low MAF Readings (g/s) compared to the cars Power output.
It is oem RS4 Maf, Reading max at 350g/s. I belive it is underscaled as my actual load is much lower than req. Act load at 200. Req 260. Now, this is no problem at all. The car runs just great. I am curious how could i scale this up?? Is this done by scaling up MLFM voltage vs air mass? Is there something else that needs attention itc? Or scaling up KFKHFM and equally scaling down KFLF. I understand that i need to recale axis in HFM and KFLF to match. Is this the case or is this done completely diff way? Title: Re: Low Maf readings -underscaled Maf Post by: nyet on December 06, 2014, 03:22:19 PM Leave it alone, nothing wrong with it being underscaled if stuff is running right.
Title: Re: Low Maf readings -underscaled Maf Post by: ddillenger on December 06, 2014, 04:07:41 PM Leave it alone, nothing wrong with it being underscaled if stuff is running right. He's got a stock RS4 MAF in a stock RS4 housing running an RS4 file. It's not underscaled. He also has a 16bit load axis so he doesn't need to underscale it. I think more likely he's just inputting ridiculous numbers into LDRXN and being limited elsewhere. Title: Re: Low Maf readings -underscaled Maf Post by: Lost on December 06, 2014, 04:23:07 PM He's got a stock RS4 MAF in a stock RS4 housing running an RS4 file. It's not underscaled. He also has a 16bit load axis so he doesn't need to underscale it. I think more likely he's just inputting ridiculous numbers into LDRXN and being limited elsewhere. I am not limited at all. I think you are misunderstanding my question. On my old MTM tune ( the same MAF) my readings were 315-320g/s. The car was dynoed on dynapack at 450whp. I thought it was too much so I dynoed the car on a mustang. Showed 413whp on e85 off course. This was more like it. Than I custom tuned my car (still the same MAF). It showed 350-355 g/s. The real power was around 450-460whp on mustang. I have helped several of my friends with same setup, and developing the same power but with much higher Maf readings 400-420g/s. So, my question is, can I scale up my MAF? Title: Re: Low Maf readings -underscaled Maf Post by: ddillenger on December 06, 2014, 04:26:36 PM I am not limited at all. I think you are misunderstanding my question. On my old MTM tune ( the same MAF) my readings were 315-320g/s. The car was dynoed on dynapack at 450whp. I thought it was too much so I dynoed the car on a mustang. Showed 413whp on e85 off course. This was more like it. Than I custom tuned my car (still the same MAF). It showed 350-355 g/s. The real power was around 450-460whp on mustang. I have helped several of my friends with same setup, and developing the same power but with much higher Maf readings 400-420g/s. So, my question is, can I scale up my MAF? Why would you scale up a MAF? Do you like early boost leak diagnosis? Redoing the ENTIRE timing table because the axis are no longer accurate? Title: Re: Low Maf readings -underscaled Maf Post by: nyet on December 06, 2014, 04:26:49 PM So, my question is, can I scale up my MAF? Why? You'll have to retune EVERYTHING if you do this. Title: Re: Low Maf readings -underscaled Maf Post by: Lost on December 06, 2014, 04:44:19 PM No, I certainly do not want to do it.
I asked BC I wanted to understand the reason and function. I was always wondering about having so low maf readings yet so much power. I have heard that old MAFs read low, but that can not be the case. I would not make power itc. I even bought new MAF not OEM, and that one was scaled differently. My readings was sky high, and I got intervention. So I switched back to my old OEM one. Shit the same. How is it done anyway? Title: Re: Low Maf readings -underscaled Maf Post by: nyet on December 06, 2014, 04:48:15 PM How is what done?
Title: Re: Low Maf readings -underscaled Maf Post by: ddillenger on December 06, 2014, 05:03:01 PM Did you change KFKHFM? Stock RS4 is 1.0234.
Setting this to 1 will have the unintended side effect of underscaling the MAF a couple percent..... Title: Re: Low Maf readings -underscaled Maf Post by: Lost on December 06, 2014, 05:12:25 PM Did you change KFKHFM? Stock RS4 is 1.0234. Setting this to 1 will have the unintended side effect of underscaling the MAF a couple percent..... Nope. It is stock 1.024 across the table. Title: Re: Low Maf readings -underscaled Maf Post by: Lost on December 06, 2014, 05:15:11 PM Title: Re: Low Maf readings -underscaled Maf Post by: ddillenger on December 06, 2014, 07:39:13 PM My original question. Is a terrible idea. Your MAF is properly scaled. There is nothing to be gain by changing that, unless you are looking for bragging rights. To answer (question that shouldn't be answered): You calculate the cross sectional area of the MAF housing you currently have. Calculate the cross sectional area of the new housing. Divide them to come up with the factor by which MLHFM is multiplied AFTER applying the offset contained at MLOFS. In your case, just apply the offset (MLOFS) to MLHFM, then multiply it by whatever factor you want to overscale (for whatever reason I can't fathom) your MAF. Title: Re: Low Maf readings -underscaled Maf Post by: Lost on December 07, 2014, 03:39:37 AM Is a terrible idea. Your MAF is properly scaled. There is nothing to be gain by changing that, unless you are looking for bragging rights. To answer (question that shouldn't be answered): You calculate the cross sectional area of the MAF housing you currently have. Calculate the cross sectional area of the new housing. Divide them to come up with the factor by which MLHFM is multiplied AFTER applying the offset contained at MLOFS. In your case, just apply the offset (MLOFS) to MLHFM, then multiply it by whatever factor you want to overscale (for whatever reason I can't fathom) your MAF. I see it as gaining knowledge :) Easiest way of Learning is testing things, isn`t it? Thanks for the answer!! Title: Re: Low Maf readings -underscaled Maf Post by: rnagy86 on December 07, 2014, 04:34:10 AM Just replace your MAF with a new one. It is most probably old or dirty and reading low.
Title: Re: Low Maf readings -underscaled Maf Post by: Lost on December 07, 2014, 07:09:06 AM Just replace your MAF with a new one. It is most probably old or dirty and reading low. Yes, it is an old Maf. I have had the car for 4 years - haven't changed it. You know what i mean?? We have similar setups, and your Readings are 400-420g/s and the Power output of our cars was in the same neighborhood - at least with old setup. Now is a diff story :) But if the reason is aging Maf sensor, and i buy a new one. It is gonna affect my tune considerably???? Title: Re: Low Maf readings -underscaled Maf Post by: rnagy86 on December 07, 2014, 07:16:19 AM Yes. Most likely you will have to fix your fueling because now you are tuned to your current MAF.
Title: Re: Low Maf readings -underscaled Maf Post by: Lost on December 07, 2014, 08:51:15 AM Yes. Most likely you will have to fix your fueling because now you are tuned to your current MAF. Mm, sounds about right. As I mentioned. I bought a new maf non-OEM. Scaling on that one was crazy. My readings and actual load was through the roof. The car was running piggrich AFR 9 on WB02. It was just to toast that shit and get back to my old one. Btw: tried scaling MAF. It was no brainer. Will not flash it in, but good to know how. Title: Re: Low Maf readings -underscaled Maf Post by: Westfarmracing on December 07, 2014, 02:23:51 PM Mm, sounds about right. As I mentioned. I bought a new maf non-OEM. Scaling on that one was crazy. My readings and actual load was through the roof. The car was running piggrich AFR 9 on WB02. It was just to toast that shit and get back to my old one. Btw: tried scaling MAF. It was no brainer. Will not flash it in, but good to know how. I think you are better off with the maf you have now, unless it starts to read even lower bc of age, then you will run lean.. If you change to a new oem one now, and get higher (correct) readings then you will have to redo the whole tune |