1st Gen Haltech ECU Discussion

You'll find that if you switched to MAF based metering, completely negating a MAP sensor and speed density that the calculated load would deviate from the MAF reading as well because neither MAF or MAP are a direct 1:1 to engine load.

 

Actually that could be fun, but I forget how split systems work in Haltech, I think you can use a MAF and MAP together like a modern production boosted vehicle does but I forget how to setup the MAPs. Also finding calibrations for MAF sensors is a damn nightmare. I can see using the MAF out of boost for a possible efficiency bump or at least as an axis to help trim the speed density. I just wouldn't want it as another sensor to rely on. Simple has its benefits, and the stock sensor has a low total airflow measurement max and is an intake restriction. That also leaves where to place it? Pre or post turbo? My BMW had it post but my Nissan had it pre.

 

Right, I'd just be looking for error outliers around certain spots. It sounds like too much work for now, but it'll stay in the back of my mind unless I do it.

Probably wherever the most laminar flow is - mine's actually in an ideal location in the center of a straight pipe. But ya the calibration file too is an issue... not like I have the tools to create that profile myself either.

 

It's interesting too, it seems manufacturers nowadays are torn on whether MAF even has a place in performance vehicles as well. When I said modern I was referencing 2005-2014ish but it seems some now are preferring to spend the extra time in speed density modeling rather than trimming... That's actually a concern I'd have using a MAF as a trimming axis as well, it is susceptible to errors that speed density isn't from vacuum leaks (or planned leaks like a blowoff valve)

Not a particularly technical article but a good idea of what the OEs are trending toward and perhaps why
https://www.mishimoto.com/engineering/2021/05/maf-vs-speed-density

 

I'd say speed-density is a lot more favorable from a universal/drag & drop format perspective. Like you said, it will work regardless of what's in front of the intake. In fact, my intake tube blew off one time and it kept running just fine. MAF is the best measurement of true load, however, meaning you in theory have more precision by using both.

The T8 ECU on my Saab is a MAF format, and it's very different and hard to understand how all the tables work together (I mostly blame the organization of the tuning software) than even how we assume the OEM 5VZ ECU works. It's fascinating because it takes the base assumption that the MAF reading is the exact amount of airmass to add fuel for, and therefore (with other sensors) you can deliver a precise amount of fuel based on a torque request map, mapped from your pedal position map and current operating point, which translates to a real throttle position at any given condition. Then there are enrichment tables based on various criteria such as boost and fuel composition, on top of a MAF correction table (generally 1.00 +/-0.01) that I don't fully understand the purpose of. Then realtime error correction based on O2 sensor readings, which is typically surprisingly low. This is further complicated by the turbo maps, as you have to tell it ballpark how much a PR at each solenoid duty cycle changes mass airflow in order to get the PID correction a valid starting point. For timing, there is a whole MBT map(s?) from the factory that it is constantly trying to reach based on calculated octane and ozone-based knock sensing, which is exceedingly nice to have from a tuning perspective since you have a defined target for all conditions. Basically by starting with torque request + MAF it's able to predict the future, which results in an extremely tight response to changes.

 

Are you running a MAF? If not, how and where is the sensor placement and air intake temps on your setup?

2 psi at 9500' seems pretty good to me. What size pulley are you running currently?

 

Stock MAF in a airaid intake tube which is my IAT sensor too. Intake temps ranged from 80-115* ish on my this trip into the mountains. I may add a sensor to the SC for post compression temps.

I’m on a SNP 65mm now.

 

I've only dabbled with MAF tuning on HP Tuners for LS platforms (most just turn off the MAF but it can be good for somethings) and in NISTUNE. But man scaling is a bitch and the various corrections needed to make a MAF setup competent are probably more realistic on the OEM side where a whole research and development team can plot the engine behavior and generate various adders and modifiers since a MAF system really only has one solid piece of feedback in the form of O2 and really only recently has that become more useful since widebands are in everything. The tables in my E46 Bosch MS43 computer make my head hurt, so many revisions to counteract behavior... it makes for a really snappy closed system when it is all done but from the perspective of future tuning and tuning as a home gamer it is not as friendly as speed density since there are so many tables that have to be modified as a system to change a single value.

 

I haven't forgotten about you BTW, I just wanted to make sure you weren't cruising around with that heavily lean AFR target because some of those cells you had changed weren't low load.

 

Yeah, mine is after the SC. We did it to be able to eliminate the MAF restriction. There is a significant difference in readings from that location.

 

Imo you can't be as aggressive tuning without post SC temps measured. I still need to move my sensor post SC.

 

This is very likely true. Just have to be prepared to see +190° air temps on occasion.

 

What does your air temp correction table look like? How much timing do you pull out based on temp?

 

I only pulled a couple of degrees out over 160° IAT. His timing is pretty conservative. If he had meth I'd use it to trigger spray over 150

 

I went for a quick 40 mile ish trip today and the O2 sensor wasn't reading on the Innovate guage again. It kept cycling the O2 heater on and being it's regular dumb self
And then it came back but I don't know if I trust it at all. with that being said I did a small pull but stayed under 3psi of boost but while around 2 my AFR was showing around 14 still but it usually pretty good but being closer to 11 at that point. Maybe it's just not reading great.

Then while parked in a drive through staring at the setting sun waiting for a hamburger and an obligatory oreo milkshake this evening my Intake temp hit 123°f at the same time the AFR was bouncing back and forth between mid 13's and 16's shortly after a got home I was watching the AFR and it was still bouncing back and forth between high 12's and low 17's. But the motor sounded like it was following the AFR so the sensor still seems like it's reading half decent.

Don't the catalytic converter thrive from going rich and lean like that?

I got the Haltech WB1 ordered just wish I would have remembered to order it at the same time as the ECU, I forgotten the 2500 didn't have it built in because of all the day dreaming about the R3.

For those not following along my Little Red build the Boomslang harnesses arrived this afternoon



Im starting to wonder if I could get it up and running on the haltech before the next Trail Hero event in Sand Hollow (early October).
I've got a buddy who's been wanting to go for a couple years but it's not very wheelchair accessible so I'd like to take him and let the truck tires do the leg work

 

You'll have it up and running in no time!

I actually carried the stock ecu/piggy back with me on a couple trails incase I had any issue. Didn't need it thankfully.

 

That's a ways off, should be no problem. We usually get them going in 2-3 days, drivable in 1

 

Could I get recommendations on injectors? I meant to figure that out yesterday but got a bunch of other things done instead.

 

Ooh I like the idea of temp based spraying.
How low in the rpm range would you say you saw temps above 150 out of curiosity?
In the summer I have to be careful with how much boost I build down low and I imagine heat is a big part of that and resultant knock/ping.

 

Realistic power goals?

Is300 2jz-GE injectors will bolt in. I think they flow in the 310cc range. Not much bigger than stock, but better than nothing.

I got the ones listed above but they were redrilled to 440cc. They were second hand and I've had no issues in 4 plus years.

Snp sells 650ish cc. I have no 1st hand experience.