Difference between bad MAF housing design or too large MAF housing?

Hondanickx

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So today i tested a MAF housing i made .I know this isn't just a pipe and i covered all the ins and outs of the oem maf housing and designed something similar but a little bigger.Nothing extreme here.
I used a obd tool to monitor the Fuel trims and AFR values with the Torque app on my phone.
After installing the new MAF housing and starting up the car the car idles fine and initial STFT is 7-8%.LTFT is still in stock values and is -7% .( Oem Euro spec ecu's runs very rich) I played with the gas a little and let it sit for 10 minutes to see if the fuel trims where ok for a little test drive.In the test run i drove part throttle fuel trims where fine STFT 6-7% and LTFT where going down already -6%.After that i tried some quick full throttle runs of 2 seconds and noticed the STFT imidiatly jumped up to 16% sometimes even 20%.In part throttle the fuel trims did fine. LTFT where still dropping and by the time i was back home dropped to -3% .
I stopped testing the MAF housing after that .

Now my question is would the MAF design be bad and way off to cause the fuel trims to go that high in full throttle?Or is this just the increase in air that needs to be tuned for?
I think the MAF design is good because it runs fine in part throttle but i'm not a expert in this.
Is there a way to notice this ?Any experts have some info on this?

Ow yeah after i installed back the OEM airbox and started the car back up i got a christmas tree lights going on with engine light ,acc light ,brake hold ,traction control and several other lights coming on .The car runs and drives fine ,.Fault code gave a P0113 which is iat sensor too high.
I checked wiring and MAF sensor reads the temp just fine.Not sure if this has anything to do with the testing of the MAF housing ?
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Myx

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So today i tested a MAF housing i made .I know this isn't just a pipe and i covered all the ins and outs of the oem maf housing and designed something similar but a little bigger.Nothing extreme here.
I used a obd tool to monitor the Fuel trims and AFR values with the Torque app on my phone.
After installing the new MAF housing and starting up the car the car idles fine and initial STFT is 7-8%.LTFT is still in stock values and is -7% .( Oem Euro spec ecu's runs very rich) I played with the gas a little and let it sit for 10 minutes to see if the fuel trims where ok for a little test drive.In the test run i drove part throttle fuel trims where fine STFT 6-7% and LTFT where going down already -6%.After that i tried some quick full throttle runs of 2 seconds and noticed the STFT imidiatly jumped up to 16% sometimes even 20%.In part throttle the fuel trims did fine. LTFT where still dropping and by the time i was back home dropped to -3% .
I stopped testing the MAF housing after that .

Now my question is would the MAF design be bad and way off to cause the fuel trims to go that high in full throttle?Or is this just the increase in air that needs to be tuned for?
I think the MAF design is good because it runs fine in part throttle but i'm not a expert in this.
Is there a way to notice this ?Any experts have some info on this?

Ow yeah after i installed back the OEM airbox and started the car back up i got a christmas tree lights going on with engine light ,acc light ,brake hold ,traction control and several other lights coming on .The car runs and drives fine ,.Fault code gave a P0113 which is iat sensor too high.
I checked wiring and MAF sensor reads the temp just fine.Not sure if this has anything to do with the testing of the MAF housing ?
A race maf can be put on with the stock maf housing table and it will probably idle ok. I know on my 2015 Honda Fit, I had put on a larger 2014 Honda Civic maf housing and did just that. I drove around like this (NOT RECOMMENDED) for testing purposes.

You need a new maf table that reflects the larger maf diameter. Your car thinks the maf sensor tube diameter is a certain size (stock) so it's calculating the incoming air incorrectly. Tuners know how to do this or you can look online for tools that will help you accomplish this.


I don't think the maf housing design is 'bad' (You haven't provided pics though). It's just a tube with a sensor in it. Your car just doesn't know exactly what the diameter size is of the tube you are using.
 

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Without seeing the housing, it's hard to say. I'd wager that turbulence is probably the biggest thing that would throw off your trims and not even allow you to properly rescale.
 
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Hondanickx

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Well it's just a first test piece but without trowing all the details on the table i can say that it's very smooth in design,Smoother then prl for example.And slightly larger then a OEM Si housing .So aprox 8% larger then stock.
 

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I will describe the steps to recalibrate your MAF for the larger housing. I assume you have Hondata or Ktuner to reflash the ECU. I will use the Hondata terms below.

First do a rough computation of the percentage increase in MAF housing diameter. Next increase the Mass flow (g/s) by that percentage across the entire range.

Go for a drive in the low rpm range while datalogging. Get the average STFT at each MAF voltage and apply that to the calibration. + means the ECU is adding fuel and you need to increase the Mass flow in that cell. You'll more or less get a feel of how much you have to adjust the rest of the curve.

Hondata has an XY Graph feature for the above step.

Honda Civic 10th gen Difference between bad MAF housing design or too large MAF housing? 1610348573016


Once you finish adjustments, go for a drive again. STFT is +/- 5% should be good. Do the same for mid-rpms, then high rpms.

Rinse and repeat until you are satisfied. Go slowly to avoid running lean.

When you can't get it any better, check the MAF voltage vs Mass Flow graph. It should be a curve without big kinks and the car should drive smooth.

If you have kinks that can't be fixed or drivability is not good, then the MAF housing is not a good design.

I don't know how large you can make the MAF housing before:
1. Idling and low rpm range will be affected.
2. ECU will lose resolution and/or not drive properly.

HTH
 


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Hondanickx

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I will describe the steps to recalibrate your MAF for the larger housing. I assume you have Hondata or Ktuner to reflash the ECU. I will use the Hondata terms below.

First do a rough computation of the percentage increase in MAF housing diameter. Next increase the Mass flow (g/s) by that percentage across the entire range.

Go for a drive in the low rpm range while datalogging. Get the average STFT at each MAF voltage and apply that to the calibration. + means the ECU is adding fuel and you need to increase the Mass flow in that cell. You'll more or less get a feel of how much you have to adjust the rest of the curve.

Hondata has an XY Graph feature for the above step.

1610348573016.png


Once you finish adjustments, go for a drive again. STFT is +/- 5% should be good. Do the same for mid-rpms, then high rpms.

Rinse and repeat until you are satisfied. Go slowly to avoid running lean.

When you can't get it any better, check the MAF voltage vs Mass Flow graph. It should be a curve without big kinks and the car should drive smooth.

If you have kinks that can't be fixed or drivability is not good, then the MAF housing is not a good design.

I don't know how large you can make the MAF housing before:
1. Idling and low rpm range will be affected.
2. ECU will lose resolution and/or not drive properly.

HTH
Thanks ! This explains it better for me.So could you say that a good designed maf doesn't jump in fuel trims drasticly but goes up smoothly ?
 

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So today i tested a MAF housing i made .I know this isn't just a pipe and i covered all the ins and outs of the oem maf housing and designed something similar but a little bigger.Nothing extreme here.
I used a obd tool to monitor the Fuel trims and AFR values with the Torque app on my phone.
After installing the new MAF housing and starting up the car the car idles fine and initial STFT is 7-8%.LTFT is still in stock values and is -7% .( Oem Euro spec ecu's runs very rich) I played with the gas a little and let it sit for 10 minutes to see if the fuel trims where ok for a little test drive.In the test run i drove part throttle fuel trims where fine STFT 6-7% and LTFT where going down already -6%.After that i tried some quick full throttle runs of 2 seconds and noticed the STFT imidiatly jumped up to 16% sometimes even 20%.In part throttle the fuel trims did fine. LTFT where still dropping and by the time i was back home dropped to -3% .
I stopped testing the MAF housing after that .

Now my question is would the MAF design be bad and way off to cause the fuel trims to go that high in full throttle?Or is this just the increase in air that needs to be tuned for?
I think the MAF design is good because it runs fine in part throttle but i'm not a expert in this.
Is there a way to notice this ?Any experts have some info on this?

Ow yeah after i installed back the OEM airbox and started the car back up i got a christmas tree lights going on with engine light ,acc light ,brake hold ,traction control and several other lights coming on .The car runs and drives fine ,.Fault code gave a P0113 which is iat sensor too high.
I checked wiring and MAF sensor reads the temp just fine.Not sure if this has anything to do with the testing of the MAF housing ?
you (i think it was you?) asked me about my race maf & pictures but you did not provide yours.

some pics with description like above will help if you really wanna design or DIY your own street/race maf.

some have claimed that copied & reported me but without evidence but i do have documented evidence when i made my own with the blueprint after couple of revisions, failures, lots of testing on the road & of course on the dyno with dyno results & lots of logs of course at least 6 months ago.

gotta scale it right ;)

good luck with your tests & objectives. hope you will be successful :)
 
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you (i think it was you?) asked me about my race maf & pictures but you did not provide yours.

some pics with description like above will help if you really wanna design or DIY your own street/race maf.

some have claimed that copied & reported me but without evidence but i do have documented evidence when i made my own with the blueprint after couple of revisions, failures, lots of testing on the road & of course on the dyno with dyno results & lots of logs of course at least 6 months ago.

gotta scale it right ;)

good luck with your tests & objectives. hope you will be successful :)
Yes it was me.I looked around to see what everyone uses and they all use different shapes and they all seem to work.Some better then others .Mishimoto,PRL ,27won ,injen,CAPTS they all use different kind of sizes and shapes for their maf housing.
I did my own testing allready previously with a converted OEM SI airbox/MAF housing on a non SI (euro spec civic ) and that worked great and my own design is based on the Si maf housing.
I'm not trying to copy anyone ,i like to make my own airbox with a MAf housing that's perfect for the Euro spec model and in between a Race and street maf.

Here's a preview ;)

Honda Civic 10th gen Difference between bad MAF housing design or too large MAF housing? HN. intake


Honda Civic 10th gen Difference between bad MAF housing design or too large MAF housing? stack H.N
 
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Yes it was me.I looked around to see what everyone uses and they all use different shapes and they all seem to work.Some better then others .Mishimoto,PRL ,27won ,injen,CAPTS they all use different kind of sizes and shapes for their maf housing.
I did my own testing allready previously with a converted OEM SI airbox/MAF housing on a non SI (euro spec civic ) and that worked great and my own design is based on the Si maf housing.
I'm not trying to copy anyone ,i like to make my own airbox with a MAf housing that's perfect for the Euro spec model and in between a Race and street maf.

Here's a preview ;)

HN. intake.jpg
ah you're the CF guy eh ? now i remember !
that is FREAKING awesome work you did.
alot of tests are needed best if you can access to dyno to set it up properly then test it on the streets. took me about 2-3 months.
do keep us posted.
i send you 1 of my race maf then you send me 1 of your completed CF box when completed ?
 
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Hondanickx

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ah you're the CF guy eh ? now i remember !
that is FREAKING awesome work you did.
alot of tests are needed best if you can access to dyno to set it up properly then test it on the streets. took me about 2-3 months.
do keep us posted.
i send you 1 of my race maf then you send me 1 of your completed CF box when completed ?
I made a air scoop out of carbon fiber if that's what you mean ? That mold needs to be redone cause there are issues with the flimsy oem honda hood flexing so much under high speed that it touches the carbon .So needs more clearance and more testing after.
As for now i'm not even sure this airbox and maf housing will 100% fit in the engine bay cause it's really tight .I'm going to 3d print the first test pieces and go from there.
 


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I made a air scoop out of carbon fiber if that's what you mean ? That mold needs to be redone cause there are issues with the flimsy oem honda hood flexing so much under high speed that it touches the carbon .So needs more clearance and more testing after.
As for now i'm not even sure this airbox and maf housing will 100% fit in the engine bay cause it's really tight .
yeah i kinda looked into that & tight it is .. i have some CF stuffs & resins maybe just the mold if you don't mind but have to be very patient with CF stuffs still new with it but i had some fun learning a little here & there. i even had the idea to make CF TIP too but i think my skills are not there yet.
 

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I'm no air flow expert but I think that under boost, your wide entrance may cause turbulence and throw off your calculated values by a lot. Reducing the diameter through a path to increase velocity may be a good thing to try, but not that close to the maf sensor, where air flow should be steady and linear as much as possible.
 
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Hondanickx

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yeah i kinda looked into that & tight it is .. i have some CF stuffs & resins maybe just the mold if you don't mind but have to be very patient with CF stuffs still new with it but i had some fun learning a little here & there. i even had the idea to make CF TIP too but i think my skills are not there yet.
yeah i kinda looked into that & tight it is .. i have some CF stuffs & resins maybe just the mold if you don't mind but have to be very patient with CF stuffs still new with it but i had some fun learning a little here & there. i even had the idea to make CF TIP too but i think my skills are not there yet.
If you really want to make things like a Tip or intake tube out of carbon you're better off using out of autoclave prepreg carbon and have a 3d printer that can print ST130 or SR30 Soluble materials which are heat resistant .Then you could print the core wrap it with the prepreg carbon , vacuum bag it ,put in in a oven and its done.No mess with resin ,perfect results everytime .Only downside it's expensive.Companies like Eventuri and Sprint filter all use this but in a autoclave . ;)
 

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If you really want to make things like a Tip or intake tube out of carbon you're better off using out of autoclave prepreg carbon and have a 3d printer that can print ST130 or SR30 Soluble materials which are heat resistant .Then you could print the core wrap it with the prepreg carbon , vacuum bag it ,put in in a oven and its done.No mess with resin ,perfect results everytime .Only downside it's expensive.Companies like Eventuri and Sprint filter all use this but in a autoclave . ;)
too EXPENSIVE ! hard to find CF materials locally yes prepeg is awesome
 

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I'm no air flow expert but I think that under boost, your wide entrance may cause turbulence and throw off your calculated values by a lot. Reducing the diameter through a path to increase velocity may be a good thing to try, but not that close to the maf sensor, where air flow should be steady and linear as much as possible.
I just wrote a long response in agreement with you. Then I thought of PRL's race maf design and deleted my response. PRL's race maf entry is much more abrupt than his smooth funnel design but it works perfectly fine. Thoughts?

Honda Civic 10th gen Difference between bad MAF housing design or too large MAF housing? Race Maf
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