paul_dezod

Notice the inversely proportional relationship? As IAT climbs, ign timing decreases. Draw a best fit curve to see this happen.

paul_dezod

2) For easiest thing to do is to set your scan tool to metric and measure g/s^2 and compare to the X1 in the air tab of the real-time dash

ScionFred

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Quote:

Originally Posted by DezodDon

Sounds like you are experiencing heat soak as your MAF which contains the IAT sensor is located pre turbo

Heat soak it is then. What's the best way to compensate for this with the X1? I looked into using AfrIAT but the table starts at 60% load so it won't help. I assume the next best thing would be to add some fuel to the idle area of the InjADJ map (assuming that I keep a draw-thru MAF setup).

Set your MAF iD closest to what makes your setup run best. It thinks it has a 71 mm intake and you have made a 66mm intake, the velocity is going to be higher, however it is a hotwire sensor so it's going to read the amount of voltage it takes to keep that sensor at a steady temp. The most air flow the cooler it gets which translates into more voltage needed to warm it back up..... Same goes for velocity, if you change the ID of the pipe and the velocity goes higher then you are going to read the same change whether or not the airflow actually changed, which over all it wouldn't because the volume is down the velocity is up.

Right, since a hot-wire MAFS measures air velocity, reducing the tube size causes the MAF to read higher which the ECU then translates to greater air volume since it's calibrated for a larger tube. This is where I got confused with the X1 MafID because I thought you were supposed to enter the actual MafID which the X1 would then adjust to read as if the MAFS were in the oem tube. It doesn't work that way.

BTW, minor point but I don't want anyone to think that I actually made my intake tubing. That dubious honor belongs to CX Racing.

I suggest for your next setup making a blow through maf and the largest intake on front of the turbo you can make. You want as little restriction on the turbo as possible to prevent choking it which will send it into a free spin damaging the bearings. It's like a vacuum cleaner that has a clogged filter. The speed of the motor shoots up but it doesn't suck anything and if done for long enough the air gets hot and the bearings in the motor get wrecked........A turbo is no different. On an intake that small I'd be willing to bet even at 7 psi you are choking the turbo. Not even mentioning the large lip you have in your current intake which can add all kinds of variables to the equation as air passes by it and becomes turbulent or worse supersonic.

I have considered a blow-thru MAF for a long time now but adapting my existing setup to blow-thru is a PITA. I'd have to replace most of the tubing, re-locate the BOV somewhere and I'm unsure about how the MAFS would work in 2.5" (60mm ID) tubing with the X1 and my 71mm ECU programming.

I hear what you're saying about starving the turbo of air but actually my intake is 2.75" tube (66mm ID) vs the 2.5" tube (60mm ID) intake on your S1 kit. My Precision 5031E turbo is the same size as your S1 turbo but with a larger inlet (3" vs 2.75") and smaller compressor trim (50 vs 57). Even my air filter is the same size as the S1 filter. The only real difference is the intake tube length. Mine being a little more than twice as long. Does the extra length make enough difference to negate the 6mm larger diameter? I honestly don't know...



What does this tell you?

That the MafID setting works opposite to logical expectation. I was told that MafID was a setting designed to compensate for changes to the oem MAF tube ID. As such, when the actual MAF ID is reduced creating inflated MAFS signals, it should proportionately reduce the calculated air volume read by the X1 and send an equivalently reduced MAF signal to the ECU so that the X1 and ECU both see the same *corrected* air volume. In reality the MafID must be set much higher than actual to accurately compensate the ECU MAF signal and I'm concerned about how this affects the air volume read by the X1.

Of course running a different style MAFS in different ID tubes with ECUs programmed for different MAFS and tube IDs than what the X1 is calibrated for introduces a plethora of possibilities for air volume calculation error. Which is why (IMO) we have to search for the MafID that works best and then adjust cell by cell to compensate for the remaining error.

Thanks so much for your very informative and helpful reply. BTW, as you suggested, I did cut that BS 3" section off the end of my intake tube and it helped a lot. That abrupt transition was (presumably) producing enough pre-MAF turbulence to cause erratic MAFS signal problems. The car runs much smoother now.

ScionFred

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Check out Underdog Racing Development. They have the APR X1 and cam gears or a proven S/C kit with the X1, both pre-tuned. Any questions, talk to Gadget.

ScionFred

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I see what you're saying and agree... heatsoaked IAT = retarded timing = even leaner AFR = excessive positive fuel trims. Since I won't be installing those hideous rear hood lifts or adding a new IAT any time soon, what would you recommend to tune for this with the X1? InjADJ map? How many percent deviation between cells for a smooth transition?

Pity that the AfrIAT map doesn't allow for changes below 60% load.

Thanks, Paul.

BTW, after some more miles I can say that cutting that 3" section off my intake pipe helped a lot. I still have the problem of the tranny hanging in 1st gear at times and I would suspect mechanical issues more if not for the fact that this never occurred without the X1 installed. It never happened with the stock ECU or FIC installed, so...

ScionFred

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Thanks mang. At 76mm MafID the X1 and ECU match pretty closely. Although the X1 sees more air volume at idle than the ECU, they are within 2 g/s at WOT. I suppose I'll test 75mm next...

DezodDon

Awesome I'm glad to hear somethings are working out.

Our intake is 2.5" but if I'm not mistaken I think your filter is a little shorter than the one we use which would make for less filtering media causing restriction. However, I'm not sure I'm just going off the pic of your engine bay.

Tranny hanging in gear is most definitely a tuning issue via the MAF info. I wish I had an answer for that other than trial and error. Good luck.

ScionFred

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I think my engine bay pics are a bit deceiving. The air filter is tucked pretty far into the fender well but it doesn't show very well in the pics. It's not huge but it's a 6" x 5" x 5" AEM Dry Flow. I'm not sure how well AEM flows vs K&N but assuming 5cfm per sq inch vs K&N's 6cfm rating, it should still flow over 400cfm.

After cutting the end of my intake I can't fit a 6" filter anymore so I ordered a oval K&N that's 6.5" x 4" x 5" and flows almost 500cfm. I wanted something bigger but this was the 'best fit' compromise I could find. I'm not sure but my best guesstimate is that my engine needs ~400cfm. Does that sound about right?

Modifying my intake as you suggested made a big improvement but I'm still seeing some issues. I've found that a MafID of 75-76mm results in pretty even MAF readings between the X1 and ECU. However it also seems to be making both read a little too high. I think it would be pretty easy to tune around this small load error with a MT but I have to get the air load corrected, not just fuel. I'd like to try using the MafADJ map but it only extends to 100% and I'm not sure if that's 100% engine load or 100% MAF signal. My idea is to reduce the MAF signal by a small percentage across the map. If this doesn't work I may have no choice but to go to a 3" MAF tube. Do you think I could do a 3" blow-thru? What are the disadvantages (if any) to running such a large pipe from IC to TB? It seems to me that there would be a large pressure drop. My IC is 3" in/out but the pipes are 2" in and 2.5" out with reducer couplers.

Thanks again Don. I appreciate your help.

ScionFred

iTrader: (1)

Another question:

I logged a WOT 2nd gear pull with the X1 and my OBD scan tool. In comparing them I see that MAF readings are very close (176 vs 178 g/s) but air load % is not. While the ECU load maxed at 122% the X1 went over 150%. What is the relationship between ECU absolute load and X1 air load? I don't understand why air load is spiking where it is or why the cells are blank above 150%. I'm inclined to think that 76mm MafID is too high but the MAF g/s are so close. It also appears that VVT changes coincide with air load spikes.

What are other X1 users seeing for max air load?

paul_dezod

The injadj can be used to counter some of the heatsoak at idle, but understand it's a very course adjustment and global.

Max load I have seen on datalogs is 189 if I recall on a boosted tC.

As far as the trans hanging...is it only in 1st at WOT or all the time?

Also, load continues to read, but does not post in the software. All you have to do is click on the cell you want to see and it will flag a marker in the image to show what the load is. Example: it will read like this in the image: 2223.05.150.8255. The 150.8255 is the load value for that point.

ScionFred

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Just to be sure I understand how InjADJ works, if I want to add 10% fuel to a cell, I change the cell value from 1.000 to 0.900? Or is it 1.100? I don't want any drastic changes so I was planning to add 5% fuel in the idle range of 0-1000rpm, 0-40% load and let the ECU LTFT handle the rest. I just hate it when the STFT hits +20% and the engine stumbles lean before adjusting the AFR.

Wow, 189% eh? How much boost was that? I still remember David telling me that my 6psi load should be 120-125% load and haven't been able to confirm that with him. Thanks for that info.

I am still confused about why I'm seeing 2g/s at idle and 177 g/s max from both the X1 and ECU but 120% load from the ECU and 150% load from the X1 at the same MAF airflow reading. This is at 76mm MafID.

The tranny hangs in 1st gear at part throttle and WOT but only under certain conditions. It tends to happen in stop and go city driving when pulling out normally from a stop light or sign. Partial throttle lift doesn't help at all. I have to lift completely and then it will shift. Most of the time it shifts normally. 2-3 and 3-4 shifts are always fine.

Thanks for clarifying the blank cell load condition. It seemed rather odd to me as though the value exceeded the X1's expected range.

XPRTc

iTrader: (5)

^^^The hanging you experience may be from the increased IAT's when you idle. I just routed my charge pipe into the fender well and have seen improvements in the IAT, but I have to do more driving since it was only to the UPS Store and back home (2.0 miles total) and then to work (2.0miles).

In my experience in these couple of days the IAT's would increase at a traffic light and cause a lag in 1st (MT), but when IAT's weren't given the chance to build at a brief idle 1st took off as stock.

bdyer666

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.90 would be adding about 10% fuel and 1.10 would be taking out about 10% fuel. So lower than 1 is richer and higher than one is leaner

ScionFred

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I'm sure that large differences in IAT measurement vs actual can cause a host of problems and probably has a lot to do with my lean idle, but this really feels like a MAF issue. When I pull out the turbo spools fast, the engine pulls strong, no lag at all and AFRs are spot on. It just doesn't upshift from 1st when it should, given the actual medium load condition.

The big issue that I keep seeing is that when I set MafID so that idle and WOT airflow matches between the X1 and ECU, the ECU still reads as much as 20% higher at points in between. I've tried setting MafID from 65-80mm and none of them produce a matching airflow curve.

ScionFred

iTrader: (1)

Thanks. How about MafADJ? It appears that I'll have to use that table to address the shifting issue.

paul_dezod

Play around with it some and see what it would shift with the stock ECU wise in G/S^2. Try to manipulate that area on with the mafadj table. I have not had this problem with any autos to date, so this is purely experimental on your end. Dave from APR might be able to provide more insight on it.

ScionFred

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Would you be willing to send me some X1 logs from your shop XB so I can see what kind of airflow and load the ECU expects? I'm hoping that I can use the MafID to match airflow readings between the X1 and ECU and then use MafADJ to slightly reduce the airflow/load to compensate for the smaller ID MAF tube. TIA

paul_dezod

It probably won't do you much good considering it's a manual trans. Air flow will be the same for both N/A engines, but I feel that the auto trans has shift points which occur at very different points than anything I can show you.

ScionFred

iTrader: (1)

Thanks. I've recently discovered that the X1 has defeated the oem rev-limit but that the X1 rev-limit doesn't work on my car. I'm curious as to whether you have a working rev-limiter with the X1 installed. I can set the X1 rpmmax as low as possible in Xtune (5450) and still rev to and beyond 7000 rpm with no fuel cut.

Paul tells me that rpmmax works perfectly on their TCs and shop XB and I'm wondering if it works for you as well. This info might help nail down why the X1 doesn't have a working rev-limiter for my AT XB. APR is looking into this but hasn't found the problem yet. Obviously the trans hanging in 1st gear with no rev-limit is a serious problem. In one of my data logs my engine reached 7500rpm before I lifted. Had I known that I didn't have a working rev-limiter, I would have lifted sooner.

ScionFred

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Another dead APR/Dezod X1 thread... <sigh>