Newbie - SR20DET (mild build) S14

[BFLyth]

Hey all,
I am still in the process of reading through the documentation, so I'll restrict my stupid questions until I've done so.

Just wanted to introduce myself and my build.

I'm Banning with an SR20DET swapped USDM S14; she's got a Kouki facelift, and some spoilers. We're Mishimoto sponsored (for a car that doesn't run yet, yay), and have a mild build. I just recently finished rebuilding the motor with:

- JE Forged pistons (86.5mm)
- stock crank in a DE block (no oil squirters)
- .051 MLS HG from Cometic
- set of 260 degree Poncams
- 1 mm oversize intake and exhaust valves (Brian Crower)
- Z32 MAF
- stock turbo
- manual boost control set to absolute minimum (which I understand to be a 7psi diaphragm)
- some cheapo BOV that doesn't really seem to work so it's duct taped shut
- mishimoto S-Line universal IC
- stock FPR
- stock-size injectors from Deatschwerks (370cc)


I finally got the car to idle after a few weeks of headache when I noticed the MAF was frozen at 3.8 V regardless of actual airflow.
Unfortunately, the car still runs so rich (10.4 and below) that the spark plugs soak and foul nearly immediately.

I'm going to do a lot of reading into the documentation to learn how to actually tune, but for my first and hopefully only stupid questions:

Am I crazy to think that I should have a relatively decent running car off of the base maps supplied by Nistune?

Is it weird that the car still bogs itself down and dumps fuel or am I underthinking it and ignoring the fact that fuel needs to be tuned even from the beginning?

[my1path]

The small thing:
Did Deatschwerks provide a latency figure @ 14v. This mostly effects idle, cranking and anything else with a low duty cycle.

The bigger thing:
Did you use the "Change MAF" tool with "Adjust K" checked? Going Z32 MAF can be a big leap, Its HP rating is almost double what a lot of other cars came with. Usually lots of things need to be corrected after this. Feature Pack users may have it a little bit easier.

Can you still fit the stock MAF? Something that has helped me get going quickly is run a map trace on how it ran on stock electrical components using a VAC/Boost gauge and recording TP (load) numbers at 18-20 HG, 15 HG, 10 HG, 5 HG, 0, 4psi & 8 psi... After the injector and MAF changes your TP (load) will move to different cells under the same vac/boost conditions so all your numbers have to shift.

EXAMPLE: 2200 RPM at 10HG vac on a stock setup was 42* timing under the 66 TP coulum. But after upgrades 2200 RPM at 10HG vac only goes to 36 TP so you set that cell to 42*


Here is a sample of several map traces transcribed to a single spreadsheet. Once my new load scales are worked out, I can match the values in the colored vac/boost conditions to the vac/boost conditions with the new equipment

Map Trace results.jpg

4 Map traces in 1 spreadsheet

(209.24 KiB) Not downloaded yet

[BFLyth]

Deatschwerks says the minimum pulsewidth is 497 microseconds but it does not specify voltage with that. I can't attach the document, nor can I find the download link for it.

I did resize for MAF with Adjust K, and I don't have the original MAF.
Car came with a Z32 MAF, and I replaced it once last year when I first came into possession of the car, and once more this past month after the MAF crapped out from sitting on a shelf for 6 months during my rebuild.

I appreciate the traces! I'll definitely study that to get an idea.

EDIT:
I found the tuning data for the injectors
https://view.officeapps.live.com/op/vie ... BROWSELINK

[my1path]

Keep in mind, that is a visual sample. Your numbers will likely be very different.

[BFLyth]

So I've got this

74F0I FP wip.bin

(64 KiB) Downloaded 91 times

tune loaded on the board, and this

Startup and dies with current tune.csv

(30.2 KiB) Downloaded 93 times

is the log file from starting it up. It now will start, idle with an AFR around 14.5 for a few seconds, and then suddenly die.

[BFLyth]

After some reading, reviewing the tune, and experimentation I've figured out a few mistakes so far. I most likely was repeatedly making MAF/Inj adjustments which compounded. Obviously it's gonna run super rich if at all.

I started over with a fresh load of the ROM I intended to use (74F0I), adjusted the MAF once, made sure injectors were the right size, input known values for injector voltage latency offsets (interpolated below 9 volts if it's even necessary), and saved the file. I then uploaded that to the vehicle, and it started right up, albeit quite lean (14-17, erring on the 17 side).

To combat the new lean running condition I adjusted Total Injection Multiplier, aiming for 12.5-13.5. My TIM was 512 (default), and I adjusted it to 750 to get into the 13 range at idle. I'm not sure if adjusting the TIM this much is an indicator that some other settings are off/wrong, but if someone has insight there I'd appreciate it. My KConst is at 33106, and I have not touched that (per the documentation instructions on FeaturePack usage)

With the car warmed up and finally running fairly smoothly, I checked timing with a light. Using a coil pack attached to an old wire, and setting the active test to 15 degrees, I dialed in the base timing and locked down the CAS. I even used active tests to set the IACV to 50% with timing locked at 15, and adjusted my idle screw to achieve ~800 RPM.

The car is seemingly a lot more stable, and I might finally be able to drive it a few miles home, and get it out of my shop (it's been on a lift taking up space after the engine rebuild for just about 6 months).

Updates to come as I find a co-tuner to drive the car while I adjust cruising values in the fuel map.

EDIT: Drove it home, and logged some data in Stream mode until my laptop screen turned off about ten minutes in. I don't have a working speed sensor at this time, but seeing how much tuning can be related to and dependent on speed (gear) I will make that a priority purchase.

[Matt]

With those deutchworks (drilled OEM injectors) I would work around 800uS - 850uS starting latency

Usually we do the MAF adjustment first (to increase K constant, and that will adjust the maps for load upto the maximum range of that MAF ~350rwkw) and then resize injectors (in your case no changes here). If you go for 740CC later then you get more flow and K constant almost where you started

So yeah TIM ends up stock 512 until you adjust your load readings. Likely your trace cursor wont get halfway through the MAF on full load, so probably you can adjust K constant until you get full range (but will change fueling), but offset those changes with TIM (which put fueling to normal)

So for example, drop K constant by 10% and add 10% to TIM, check and measure

I finally got the car to idle after a few weeks of headache when I noticed the MAF was frozen at 3.8 V regardless of actual airflow.

This needs to be sorted. Measure the MAF with a multimeter and check it there. Might be a faulty or counterfeit MAF. It should be about 1V around idle or 0.5V with key on

Am I crazy to think that I should have a relatively decent running car off of the base maps supplied by Nistune?

It should at least start and run in most cases

Is it weird that the car still bogs itself down and dumps fuel or am I underthinking it and ignoring the fact that fuel needs to be tuned even from the beginning?

High MAF voltage = high load = high injection = rich

Also we advise against BOV as they cause issue on deceleration

[BFLyth]

As for the MAF, I didn't make it clear in the first post, but I replaced the Delphi with a new Delphi upon noticing the 3.8V freeze and managed to get the car to idle/start reliably.

As for the BOV, I have it taped up for now in an effort to keep that air in the system (and will work with my friend to replace the pipe from IC to TB, and the pipe from Turbo Outlet to IC with a recirc system)

If I'm understanding correctly, I should let Nistune send my KConst up to 62231 after the MAF rescale instead of 33106, and leave TIM at 512 while adjusting KConst until I can reach all load columns?

With the Injector latency and Feature Pack boards, I can't find a starting latency option anymore. I recall being able to set an initial value, but I can't find that in the FP tables. Screenshot of the table in Nistune

InjLatTable.png

(24.25 KiB) Not downloaded yet

and the table that Deatschwerks gives me for voltage offsets

InjVOffsets.png

(99.08 KiB) Not downloaded yet

[Matt]

Your board is feature pack 2.1 so uses a Latency Table instead of the single latency. You want about 800uS at 14v and then the rest of the table to reflect this. So not what is done in the last tune you posted, but raise the whole table up until 14V column shows 800uS

Also the TIM adjustment made your tune rich, and you still have S14 SR20DET MAF in that tune

So after resize to Z32 MAF, we have K almost double 55259 and with TIM=256 the car should run with this

Since you are still on factory injectors, we would normally recommend upgrading those, and this will then drop K after resizing for those (like I mentioned 740CC will halve K back to almost factory)

Otherwise to get full use of the load scales, I would recommend pulling K constant lower/TIM higher gradually in 10% increments until you get full use of the map

You are now mapped for Z32 MAF but if you don't use the full range of the MAF (say only 60% of it) then you wont use the full range of the ECU maps eiher

[BFLyth]

Had my friend drive the car while I looked at load values and adjusted K+TIM. I never quite got the car to run 0% trim, and was noticing that it would richen substantially (going from 14.4-14.9 AFR cruising to 13.2) when letting off throttle. Is this due to the injector latency being too large?

I also noticed that I would only reach TP index 56 when we were in boost transition around 3K rpm. The boost gauge read 0, but the load scales show that I'm still accessing cells of mild vacuum. Am I misunderstanding the fuel table? There was one moment where we had held the transition period for several seconds, and the cells moved up into the TP index 64 with the richer fuel numbers, but that was not a consistent experience.

I'm so far at K/Const 65535 and TIM 460

Attaching the log of the drive home (ignore when it dies a few times, it still is dying when coming down to idle out of gear) for reference.

I'm ordering an RS232 and associated supplies to start logging AFR in Nistune to help these logs make more sense in the big picture.

[Matt]

That is because the MAF is upgraded but the injectors are not. So 65535 is the most you can increase K constant, to get it to where you see in the fuel map

Your only option for now is to rescale all maps with load indexes to around 70-80 depending on full boost load figures, to get full usage of the map

I would suggest 740CC injectors and then your K almost goes back to factory and you wont run out of injector duty