MAF calibrations for bigger intakes

[Redline143]

Originally Posted by Lex I would not try and chase your tail with a 3.x LTFT. That is more than within spec - leave it as you will see more fluctuations from changes in weather. As for the WOT regions, did you modify the WOT region at all from the original MAF cal you started from?

Yes, I did. The MAF calibration ranges I adjusted carried all the way up into the 3.x voltage range. Remember, the first logs I took showed 8.x LTFT in the 40–150 grams/sec range (and the correlated voltages). Because of this, my curve no longer had the exponential smoothness to it. I had to smooth the upper range one more time today too. My final table looks like this:

0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.83	1.62	2.43	2.77	3.16	3.45	3.87	4.62	5.43	6.11	6.81	7.50	8.46	9.43	10.38	10.85	12.51	13.48	14.95	16.19	17.54	19.07	20.32	20.91	22.53	24.31	26.69	28.21	30.46	33.53	35.16	36.58	38.01	41.22	44.26	46.27	48.27	51.29	54.45	57.70	60.20	64.68	69.19	73.00	76.96	81.10	85.38	88.42	91.44	94.48	99.05	103.71	108.46	113.34	118.35	123.49	128.77	134.24	139.81	145.37	152.13	156.52	162.08	165.08	171.42	177.84	184.43	191.17	198.06	205.13	211.26	217.40	223.53	229.66	235.79	241.93	248.06	254.19	262.74	271.49	280.46	289.63	299.00	308.53	318.25	328.18	338.33	348.66	359.26	370.06	381.10	392.39	403.91	415.65	427.65	439.89	452.37	460.44	473.33	486.43	499.79	513.43	527.32	541.46	555.90	570.59	585.57

If you'd like, I'll reflash the original BETA calibration and send WOTs from that. It may take another day to do so.

[Lex]

Remember that your ECU compensates at WOT. So we are within +/- 12% at WOT but won't know for sure until we get this on a gen1 car or an MS6.

[Voltwings]

Originally Posted by Lex Remember that your ECU compensates at WOT. So we are within +/- 12% at WOT but won't know for sure until we get this on a gen1 car or an MS6.

will that compensation show up in Logs? When i tune Gen1's i can see their STFT's still active at WOT, but on my Gen2 its 0'd out the whole time. Do i need to be in FTCL for it to make those adjustments? Thanks.

[Lex]

Originally Posted by Voltwings will that compensation show up in Logs? When i tune Gen1's i can see their STFT's still active at WOT, but on my Gen2 its 0'd out the whole time. Do i need to be in FTCL for it to make those adjustments? Thanks.

No, it won't show up in logs. FTCL is allowing regular STFTs to be active, this gen2 compensation is not a parameter we can log.

[Redline143]

Alright, @Lex, here you go: 3 WOT logs from my E40-running car with your BETA calibration--no modifications to your 3.5 HTP BETA MAF table settings at all.

So, what's your analysis? Think I should stick with it, or smooth out the curve?

[Lex]

Some good reading on pressure drop for different sized piping with charts.

How to measure airflow in PVC piping requires careful measuring of airflow with a pitot tube or calibrtated anenometer to determine CFM

I am looking at difference in piping material and having a hard time locating equations for different materials. I think an interesting question is - does material make a difference in terms of flow (resistance to flow).

EDIT: Found it - the roughness coefficient. So pressure drops is calculated as the following:



Where f is the friction coefficient and it is directly proportional to pressure drop just like diameter (d) is.
However with laminar flow roughness has no effect.

With turbulent flow it does have an effect and here are some examples (no they don't have the materials that we generally use) of the friction factor. Our intakes do have turbulent flow, at 300 g/s we have a Reynolds number around 200 000.

[khopwood77]

@Lex;

Thank you for the great starting point! I tested out the HTP 3.5 beta curve with my new setup and it was spot on with no other tune changes. I only had time for idle and light throttle around the block but from what I saw it was within 2-3%.

100% E85, 17:1 part throttle AFR, JMF IM didn't seem to cause any driveability issues after the HTP intake swap.

[Lex]

Originally Posted by khopwood77 @Lex; Thank you for the great starting point! I tested out the HTP 3.5 beta curve with my new setup and it was spot on with no other tune changes. I only had time for idle and light throttle around the block but from what I saw it was within 2-3%. 100% E85, 17:1 part throttle AFR, JMF IM didn't seem to cause any driveability issues after the HTP intake swap.

Glad to hear it was close and helped out!

[Boosted Beluga]

I'll be testing the htp 3.5" map here soon also. Hope to get the same results.

[Redline143]

Originally Posted by khopwood77 @Lex; Thank you for the great starting point! I tested out the HTP 3.5 beta curve with my new setup and it was spot on with no other tune changes. I only had time for idle and light throttle around the block but from what I saw it was within 2-3%. 100% E85, 17:1 part throttle AFR, JMF IM didn't seem to cause any driveability issues after the HTP intake swap.

Interesting that with your 100% E85 you were within 2–3 LTFT. With my E40 blend, I had LTFTs in the +8 range. I thought it'd be the other way around since your fueling strategy requires much more fueling than mine (about 1.3 times over stock compare to my 1.15 or so). Perhaps it's the 17:1 that made the difference. I'm still running OTS AFRs in that range.

[khopwood77]

Originally Posted by Redline143 Interesting that with your 100% E85 you were within 2–3 LTFT. With my E40 blend, I had LTFTs in the +8 range. I thought it'd be the other way around since your fueling strategy requires much more fueling than mine (about 1.3 times over stock compare to my 1.15 or so). Perhaps it's the 17:1 that made the difference. I'm still running OTS AFRs in that range.

I was within 1-2% prior to the htp intake swap. My injector scalar and fuel gravity tweaks for e85 allow me to run pump gas MAF curves.

Sent from my SPH-L900 using Tapatalk 2

[Redline143]

Originally Posted by khopwood77 I was within 1-2% prior to the htp intake swap. My injector scalar and fuel gravity tweaks for e85 allow me to run pump gas MAF curves. Sent from my SPH-L900 using Tapatalk 2

Right. I also was within 1 or 2 LTFT having dialed-in my MAF cal after switching to ethanol. I, too, am running the appropriate scalar and fuel specific gravity for my E40 ratio.

Again, I don't understand why you wouldn't have more variance that me due to running a higher ethanol concentration. I was perfectly dialed-in too... I find that even when using the appropriate scalar and FSG, you still have to MAF cal because the ECU will be showing high positive value LTFTs before you calibrate after switching to ethanol.

[khopwood77]

Originally Posted by Redline143 Right. I also was within 1 or 2 LTFT having dialed-in my MAF cal after switching to ethanol. I, too, am running the appropriate scalar and fuel specific gravity for my E40 ratio. Again, I don't understand why you wouldn't have more variance that me due to running a higher ethanol concentration. I was perfectly dialed-in too... I find that even when using the appropriate scalar and FSG, you still have to MAF cal because the ECU will be showing high positive value LTFTs before you calibrate after switching to ethanol.

Thats the beauty of using a known maf curve all you need to change are the injector settings. Your usually off the same % throughout the curve. I only let the car warm and drove around the block. Its a great starting point and I wont have to do much work to dial it in.

Sent from my SPH-L900 using Tapatalk 2

[Redline143]

Originally Posted by khopwood77 Thats the beauty of using a known maf curve all you need to change are the injector settings. Your usually off the same % throughout the curve. I only let the car warm and drove around the block. Its a great starting point and I wont have to do much work to dial it in. Sent from my SPH-L900 using Tapatalk 2

I think you're not understanding me. I used the same BETA Maf curve as you. Your ethanol ratio should have put you at higher LTFTs compared to mine. We both had the correct FSG and Scalar in our tunes.

When I switched to ethanol, I did so after already perfectly dialing-in my MAF cal. When all I did was change the FSG and Scalar to run E40, immediately I was hitting + 6s or 8s. It was easy to fix through another revision or two, but in my experience, changing the FSG and Scalar isn't enough. A MAF cal is necessary too when running ethanol.

I observed the exact same phenomenon with Lex's BETA HTP 3.5 table. You know, it could just be that my car actually flows about 8% more, even with the same intake. Then, you were within +/- 2 right off the bat, but I was at +8 and needed to adjust my curve accordingly.

[Lex]

Originally Posted by Redline143 I think you're not understanding me. I used the same BETA Maf curve as you. Your ethanol ratio should have put you at higher LTFTs compared to mine. We both had the correct FSG and Scalar in our tunes. When I switched to ethanol, I did so after already perfectly dialing-in my MAF cal. When all I did was change the FSG and Scalar to run E40, immediately I was hitting + 6s or 8s. It was easy to fix through another revision or two, but in my experience, changing the FSG and Scalar isn't enough. A MAF cal is necessary too when running ethanol. I observed the exact same phenomenon with Lex's BETA HTP 3.5 table. You know, it could just be that my car actually flows about 8% more, even with the same intake. Then, you were within +/- 2 right off the bat, but I was at +8 and needed to adjust my curve accordingly.

If you don't have a leak, flow will be accurately measured by the MAF.

LTFTs are very sensitive to things like fuel, weather, and even small details such as air filters and even if the A/C is on. These intakes have the honeycombs glued in so there is some variance there as well. LTFTs that are within +/- 10% are not something I would tune on a MAF curve that is posted as a starting point. I see a variance of 5% in LTFTs during the same day. LTFTs are not bad thing - they are simply your ECU adjusting to the environment. They only become an issue if they are consistently too far from the mark.

[khopwood77]

Originally Posted by Redline143 I think you're not understanding me. I used the same BETA Maf curve as you. Your ethanol ratio should have put you at higher LTFTs compared to mine. We both had the correct FSG and Scalar in our tunes. When I switched to ethanol, I did so after already perfectly dialing-in my MAF cal. When all I did was change the FSG and Scalar to run E40, immediately I was hitting + 6s or 8s. It was easy to fix through another revision or two, but in my experience, changing the FSG and Scalar isn't enough. A MAF cal is necessary too when running ethanol. I observed the exact same phenomenon with Lex's BETA HTP 3.5 table. You know, it could just be that my car actually flows about 8% more, even with the same intake. Then, you were within +/- 2 right off the bat, but I was at +8 and needed to adjust my curve accordingly.

I knew exactly what you were saying. I was trying to give you hints that you might want to revisit your injector settings before jumping into a MAF cal. There is no way for you or I to know what mix content we run. If you were within 1-2% prior to swap then you probably built too much of the mix variance into your MAF curve. Now that you swapped intakes you need to dial in your injectors first before you touch the MAF.

I posted because with my setup I was really freakin' impressed I had no driveability issues with my first cold start.

3.5 BETA is a great starting point.

[Redline143]

Originally Posted by khopwood77 I knew exactly what you were saying. I was trying to give you hints that you might want to revisit your injector settings before jumping into a MAF cal. There is no way for you or I to know what mix content we run. If you were within 1-2% prior to swap then you probably built too much of the mix variance into your MAF curve. Now that you swapped intakes you need to dial in your injectors first before you touch the MAF. I posted because with my setup I was really freakin' impressed I had no driveability issues with my first cold start. 3.5 BETA is a great starting point.

I hear ya. I disagree, however, about not knowing our ratios. I'll grant that we cannot know to the exact point, but we can definitely be within +/- 5 of our exact mix by using the resources available to use on this forum:

Fuel mix cheat sheets

I simply cross reference my location and time of the year, and I know that when I put in 8 gallons of ethanol and 8 gallons of regular fuel during this time of year in North Texas, I'm at E40. Now, the question of whether or not the regular fuel does contain 10% ethanol is valid. I always assume it does, because most of the time that's true in my area. So, to be fair, knowing *exactly* the ratio is not feasible. But knowing within +/- 5 is completely feasible. And if you look at the difference between the scalar and FSG betwee E35 and E40, or E40 and E45, for instance, it's miniscule.

Of course, for this to work I can never top off my tank. I always have to put equal parts of each fuel (for my E40 ratio, this time of year). Some people still top off. I don't...

I agree that the HTP 3.5 BETA curve is a fantastic starting point. It worked better than the JBR one I used when I first installed the intake which required numerous revisions to dial-in.

[khopwood77]

I use that sheet as well but as a guide. I know we are "close" to knowing what is in our tanks but it's not 100%. Look for a pattern. If you are off the same amount throughout the curve even if you are 2-3% in the lows and 3-4% in the mids and 5% in the upper then adjust your injector settings to close the gap then do a MAF cal. That way if you swap intakes or MAF housings you will not have to mess with your control tables unless you get a different mix.

You asked why our results are so much different and I'm just trying to explain how I do MAF cals. Having a known pump gas MAF curve at least takes one unknown out of the equation. Maybe I just have an old school mentality as I have applied my tuning knowledge on my mustangs to this car.

[Redline143]

Originally Posted by khopwood77 I use that sheet as well but as a guide. I know we are "close" to knowing what is in our tanks but it's not 100%. Look for a pattern. If you are off the same amount throughout the curve even if you are 2-3% in the lows and 3-4% in the mids and 5% in the upper then adjust your injector settings to close the gap then do a MAF cal. That way if you swap intakes or MAF housings you will not have to mess with your control tables unless you get a different mix. You asked why our results are so much different and I'm just trying to explain how I do MAF cals. Having a known pump gas MAF curve at least takes one unknown out of the equation. Maybe I just have an old school mentality as I have applied my tuning knowledge on my mustangs to this car.

Yeah, could be. I appreciate you helping me to figure it out. In my tuning experience, every time I've got someone perfectly dialed-in (within +/- 2 LTFT) on their pump tune, when we switched to ethanol, they'd be up to about +8. Maybe it's just a coincidence, but it happened like clockwork. We would have already changed the FSG and Scalar. The MAF curve would be identical too. But all of a sudden, LTFTs that are much higher. I've always attributed it to the chemical properties of ethanol, which seem to cause higher LTFTs even with the proper FSG and scalar, everything else being equal.

[Awesomesauce]

@Lex; I didn't have a pair of calipers to measure the id properly on my SURE Full3 ID300 Aeros intake, but I've been using your SURE 3in maf cal and it's within 3+/-. It looks like they sent a 3.25in maf instead of a 3in. Should I try and scale it any?

Sorry for the crappy cell phone picture.

[Lex]

Originally Posted by Awesomesauce @Lex; I didn't have a pair of calipers to measure the id properly on my SURE Full3 ID300 Aeros intake, but I've been using your SURE 3in maf cal and it's within 3+/-. It looks like they sent a 3.25in maf instead of a 3in. Should I try and scale it any? Sorry for the crappy cell phone picture.

If you are using the 3" MAF I posted and it's within 3% then you have the 3" and the MAF calibration is correct.

[Lex]

Originally Posted by Tomas Dips all the way into the 10s and sometimes even mid 9s. You bet it causes driveability issues. It bogs like a bison. Only during shifts. Steady state is ok.

@Tomas;

Yes, let's move this here.

What I believe you are running into with the 4" intake is turbulence around the MAF sensor when the BPV vents. This is because the air velocity is much lower in the large intake and the pressure wave from the BPV venting doesn't get pulled towards the turbo quickly enough. This causes the MAF sensor to misread and you're riding a bronco.

You have a GA with the VTA feature I believe (with the new internals I sent out). As a quick test, plug up the recirc hose and VTA with the GA in VTA mode. See if the shifting is improved.

Also please post a log of the shifting/bucking.

[Tomas]

Alex, the bucking is only during very light load conditions. During WOT pulls everything is fine. Unless you disagree I'd say this is not BPV related. Besides, the BPV reciird tube into the intake is about 10" to 12" downstream from the MAF sensor.

Attached two logs. One with fairly horrible bucking and other less pronounced due to slower throttle modulation. Unfortunately I don't have LTFTs on it. Forgot to add that back on to the log list but will take another log with it today.

datalog2.csv

datalog3.csv

[Lex]

Originally Posted by Tomas Alex, the bucking is only during very light load conditions. During WOT pulls everything is fine. Unless you disagree I'd say this is not BPV related. Besides, the BPV reciird tube into the intake is about 10" to 12" downstream from the MAF sensor. Attached two logs. One with fairly horrible bucking and other less pronounced due to slower throttle modulation. Unfortunately I don't have LTFTs on it. Forgot to add that back on to the log list but will take another log with it today. Attachment 98934 Attachment 98935

The logs show some wild oscillations as you can see below. I went through a similar exercise with @dantes5823; and his 4" intake. In the end he said he was going to leave it since "race car"

Perhaps the turbulence is not from the BPV but rather from that pressure wave coming back through the turbo itself or the turbo speed changing abruptly.

In any case, the MAF sensor is not reading correctly with a 4" intake and you're not the only one. Not sure if there's an effective way of "shielding" it from this turbulence and I don't recommend an intake larger than 3.5" for this reason.

It's almost like you need an air straightener on both side of the MAF sensor if you're going to run an intake that size.

[Lex]

I would also look at a couple of other things although you can't really change some of these on the already built intake:

- The honeycomb pressed in there and glued is not the best installation.
- The air filter will have an effect. Remove it and add a temporary rag/screen and see if it improves.
- The sensor may be mounted too close to a bend (for the diameter of the pipe).

This stuff should have come out of the woodwork when the intake was being tested. I think a lot of people will have similar issues to yours.

[djuosnteisn]

Tomas, does your compressor have surge ports? That could be as much a contributor as a recirculated bpv.... maybe even more since you only have issues at light load (where a bpv may not even open fully).

[Voltwings]

A local Shop and I are going to try to adapt some 3v mustang MAF's they have laying around to our application to try and improve our resolution with larger intakes. Cant put a time frame on it, but am throwing the idea out and am open to suggestions.

[dantes5823]

@Lex; even with the hks i get the same behavior.

[Lex]

Originally Posted by dantes5823 @Lex; even with the hks i get the same behavior.

So you never got this sorted? Also back to Dustin's point do you have anti-surge ports on your compressor housing?

[dantes5823]

Originally Posted by Lex So you never got this sorted? Also back to Dustin's point do you have anti-surge ports on your compressor housing?

I do.

[Tomas]

Originally Posted by Lex I would also look at a couple of other things although you can't really change some of these on the already built intake: - The honeycomb pressed in there and glued is not the best installation. - The air filter will have an effect. Remove it and add a temporary rag/screen and see if it improves. - The sensor may be mounted too close to a bend (for the diameter of the pipe). This stuff should have come out of the woodwork when the intake was being tested. I think a lot of people will have similar issues to yours.

I'll try removing the filter and see what happens.
Sensor is about 3" from a bend.

Are you absolutely sure the "Null Type Adjustment" on the load based fuel compensation clutch in and out tables are directly related to fueling increase or decrease? is it possible that the null type adjustment is a time value? How about the load and RPM table? I am not sure the ATR help file can be trusted on this yet since I haven't really found anyone who has modified these tables and can say with certainty that modifying a certain value will lead to this or that.

Originally Posted by djuosnteisn Tomas, does your compressor have surge ports? That could be as much a contributor as a recirculated bpv.... maybe even more since you only have issues at light load (where a bpv may not even open fully).

Yes. It does have anti surge ports. But the air that exits through these should not disrupt the air flow all the way up to the MAF sensor. The air that exits through the surge ports does not go in a wave as when the turbo surges. It exits gradually the closer you get the surge line on the compressor map I believe.

EDIT: Dj, you also run a 4" inake right? You don't have any post shift enrichment issues at all???

Originally Posted by Voltwings A local Shop and I are going to try to adapt some 3v mustang MAF's they have laying around to our application to try and improve our resolution with larger intakes. Cant put a time frame on it, but am throwing the idea out and am open to suggestions.

Aren't you also running a 4" intake?
I thought you had worked out all the bogging issues? Or no?

[Lex]

WRT to the ATR helpfile I don't know if they are correct or incorrect nor how these tables are applied and when and neither does COBB - hence the BETA tag. I have used them to reduce afterfire successfully so either a time or a fueling value is correct but I have not zeroed them out - only reduced the values.

That being said, not sure if these are the answer to this problem seeing as you've modified them extensively with no observed changes. I would personally look at methods for creating a more laminar flow around the MAF sensor.

[dantes5823]

Post shift is perfect on my car. Moment i hit the clutch, afr's peg to 29. if i just go off throttle in gear, then it dips into the 9's.

[Voltwings]

@Tomas; when i first installed it, my base map was too rich, and i was bogging hard every shift, did about 3 maf cals that night and it gotten much better. Did lex's clutch table adjustments which to be honest im not even sure what they did but it seemed to help... I can post a picture of my set up since its custom, but im not sure this is a mechanical problem.

[Ziggo]

Good information. You can clearly see the fluctuations in the maf voltage that are causing the issue so I doubt there is anything in the tune that can really fix it.

Antisurge housings don't just back flow when you are near the surge line. They are actually comparable to intentionally adding a small boost leak back to the intake, they are aways going to back flow if the pressure in the hotpipe is above the intake pressure. It's not inconceivable that in certain conditions this could cause the flow around the maf to become unstable.

Zigatapatalka

[Voltwings]

Neither my old 3071 nor 3576 have the surge porting, could help explain my lack of issue.

[Lex]

Originally Posted by Voltwings Neither my old 3071 nor 3576 have the surge porting, could help explain my lack of issue.

Is your 4" an HTP intake or custom made?

[Voltwings]

Originally Posted by Lex Is your 4" an HTP intake or custom made?

Custom, just some 4" pipe and coupler from Intercooler Pipe Fabrication - Silicone Intake Systems Auto Parts and a 4" spectre filter. As soon as i find a way to make some more room in there im hoping to replace that with a larger filter. Recirc "bung" is just a brass fitting from ACE that fit inside the factory tube, i imagine the ID is a bit shy of where most normal intakes are, but im on a 50/50 valve so i really dont care that much.

Please ignore my ratty engine bay haha i spend every weekend working on other peoples cars!

[djuosnteisn]

Originally Posted by Tomas EDIT: Dj, you also run a 4" inake right? You don't have any post shift enrichment issues at all???

Indeed i do, and no substantial issues on the 6. My BW s300sx has surge ports too, but they are very very minimal. I'm currently installing a 35r on the 6 now, so we'll see if anything changes.

[rfinkle2]

Sorry to just barge in, but how stable is the intake itself? i.e. Maybe it is my imagination,

but when I secured my intake to a mounting point to keep it from flopping around, it

seemed to stabilize my afr's quite a bit.