Whats your wideband solution?

[enthusiast]

Where would that be?

 

I just ordered a cat less DP and LC-1. Time for some serious tuning!

 

Come by and you can see where I put it. The muffler place on Broadway is cheap and they know what to do as well.

[SubieBlkOut]

Come by and you can see where I put it. The muffler place on Broadway is cheap and they know what to do as well.

 

I will be giving you a call soon!

[Drew888]

So that's it on the Wideband talk?

 

I'm running out of interesting threads to follow

[Boostin1657615274]

there's an entire thread on the stock wideband if you want to read it... you can skip over the posts about load calculation, that's just a sideshow

[cryo]

Bringing back a dead thread. I see there are pretty good results and feedback with the zeitronix zr2 setup and I am leaning twords that only because the software is pretty impressive, ease of installation *and uninstallation* as well as I found NO negative feedback about sensor life or issues plus GREAT customer service. My question is has anyone heard of cobb atr picking up zeitronix as a recognized afr sensor? I am using this for my own car as well as others but dont plan on permenently installing and would like to have rpm reference in my afr logs without running a lead to my own car. I plan on tracing a lead for any other cars if needed but I would be really interested in being able to incorporate the afr right into my atr logs for my personal car to compare afr directly to rpm instead of making an educated guess off live graphs vs rpm log and trying to overlay. sorry if I confused, just curious.

 

Dave

[RIPjeep2002]

Aem uego

[atc5]

I loved the zeitronix unit when i had it on my sti years ago.

 

now i simply use PLX WBo2....been on for 5 months with no problems.

[cryo]

Well I went with the Zeitronix ZT1 unit without guage. I use my laptop for tuning all the time anyway and dont have any other guages in the car. Should be fun.

 

Dave

[Infamous1]

I ran the Zeitronix unit on my leggy as well.

[cryo]

I ran the Zeitronix unit on my leggy as well.

 

Did you use the a/f function only or did you hook up rpm? All the other data is availible through the ecm but I would like to view rpm directly against afr in logs. Any downfalls/quirks/cool tricks I should know about the software? I want to play with the software but its hard with no data..lol

 

Dave

[Infamous1]

I had Afr, boost, rpm and EGT's all hooked up. As for the software, nothing special just does as advertised.

[Boostin1657615274]

relocated the stock front O2 post turbo. seems to be working well.

[NSFW]

relocated the stock front O2 post turbo. seems to be working well.

 

Gonna tune with that alone?

 

Somebody has to be the guinea pig...

[Boostin1657615274]

Gonna tune with that alone?

 

Of course I am. It ain't detonatin if you don't hear the marbles-in-a-tin-can sound

[Boostin1657615274]

retuned fuel after the installation of a Perrin TMIC. without any changes to the existing tune, the OEM wideband (post turbo) indicated a leaner mixture (in the low-mid 12's) due to the increased charge air density. No knock events showed up. Changed the target AFR's and all is well.

[LittleBlueGT]

retuned fuel after the installation of a Perrin TMIC. without any changes to the existing tune, the OEM wideband (post turbo) indicated a leaner mixture (in the low-mid 12's) due to the increased charge air density. No knock events showed up. Changed the target AFR's and all is well.

 

I still don't get how that happens to some people.

 

I went from TMIC to FMIC (just as big of a charge air density increase IMO), and my AFRs were spot on (+/- 1 or 2%, just like before)!

 

Wouldn't any actual increase in air entering the engine show up in increase MAF? And therefore result in ECU adding more fuel to keep the called for ratio correct?

[Boostin1657615274]

Wouldn't any actual increase in air entering the engine show up in increase MAF? And therefore result in ECU adding more fuel to keep the called for ratio correct?

 

I've thought about that and I'm not sure, but only because this is a MAF system. On the one hand, mass is mass right? But so many things depend where it's being measured. It'd be interesting test to have a volume airflow sensor mounted right before the TB at the same time as the draw through MAF. The sensor would have to be of the Karman vortex type (used in 90s Mitsus and some Toyotas) or the old vane/flapper type used in most mid 80s EFI cars.

 

My own experience with true speed density systems make me used to adding fuel after every little mod that would affect charging efficiency. The lower intake temps (measured at the throttlebody with a fast acting open element sensor) necessitates more fuel. On this car I know for sure that more air is entering the engine, although I can't be sure how much and I can't be sure how it should affect the MAF reading. This is a stock intake with a K&N panel filter. The calibration is stock except for some changes that have been made in the idle airflow range.

[LittleBlueGT]

You didn't do the K&N at the same time as the TMIC? Cause that does make a difference.

 

I just don't see it, and it doesn't make sense to me. I do 10+ WOT runs to scale OL MAF, and headers, TGVs, inlet, EWG, headers, etc..... did not make a difference in MAF scaling.

 

Are you sure the temps where the same?

[Boostin1657615274]

The K&N drop in filter has been on the car for months. The MAF scaling is stock, except up to like 5 grams/sec (around the idle area), and that wasn't even really necessary as the car was running fine before. After the intercooler I just changed the target open loop AFR table. It's still a stock intake in essence (all the trims were in line on stock calibration except at idle for whatever reason). I'm not going to do a "real" rescale on a stock intake when that calibration is based on airflow modeling by Subaru engineers. I think that would be counter productive. I'd rather play with the fuel tables. With the AP realtime capability and a two-man tuning operation it took less than 10 minutes to get the car dialed in for fuel around 11.4:1 AFR.

 

Are you sure the temps where the same?

which temps? of course the post intercooler temps are lower, although I don't know how much lower because there's no air temp sensor after the intercooler. As measured at the MAF I don't know. I didn't bother to look. Those temps don't seem to affect the measured AFR much on this car. Maybe that's because the stock intake and stock location intercooler mean that the ECU can compensate pretty well for changes in pre-IC temps.

 

Under WOT the cooler charge temps at the actual throttle body (post intercooler) are going to need more fuel. You'll see that on any speed density system. Right now it is more of a question of if and how the MAF and the rest of the engine management can account for the lower post IC temps without me having to change anything in the ECU. And apparently it can't. Whereas before the measured AFR was slightly richer than what the target AFR table commanded, the measured AFR is now actually leaner than what the AFR table specifies.

[LittleBlueGT]

The K&N drop in filter has been on the car for months. The MAF scaling is stock, except up to like 5 grams/sec (around the idle area), and that wasn't even really necessary as the car was running fine before. After the intercooler I just changed the target open loop AFR table. It's still a stock intake in essence (all the trims were in line on stock calibration except at idle for whatever reason). I'm not going to do a "real" rescale on a stock intake when that calibration is based on airflow modeling by Subaru engineers. I think that would be counter productive. I'd rather play with the fuel tables. With the AP realtime capability and a two-man tuning operation it took less than 10 minutes to get the car dialed in for fuel around 11.4:1 AFR.

 

which temps? of course the post intercooler temps are lower, although I don't know how much lower because there's no air temp sensor after the intercooler. As measured at the MAF I don't know. I didn't bother to look. Those temps don't seem to affect the measured AFR much on this car. Maybe that's because the stock intake and stock location intercooler mean that the ECU can compensate pretty well for changes in pre-IC temps.

 

Under WOT the cooler charge temps at the actual throttle body (post intercooler) are going to need more fuel. You'll see that on any speed density system. Right now it is more of a question of if and how the MAF and the rest of the engine management can account for the lower post IC temps without me having to change anything in the ECU. And apparently it can't. Whereas before the measured AFR was slightly richer than what the target AFR table commanded, the measured AFR is now actually leaner than what the AFR table specifies.

 

Just a couple mins now, will explain more tomorrow if required.

 

K&N filter is less restrictive, it changes the vacuum levels in the intake, thus affecting MAF scaling in the upper flow ranges. (will not show up in fuel trims, only at say 200+ g/s). Other tuners have noticed this as well.

 

I say temps, as different years have different MAF compensation (IAT) tables (thread on RR) even though they have the same actual MAF part number. So temp can make a difference.

 

I fully expected having to change things for fuel when I switched to FMIC, but my fuel trims are all within 1% and I anally (OCD like) scaled everything right up 347 g/s of airflow. I did not notice any difference at all! My called for AFRs on the pri fuel table are what I got before, and what I get now.

[Boostin1657615274]

Your zeal for keeping your car reliable is commendable. I put rescaling the MAF after a drop-in filter up there with panicking over feedback knock correction, freaking out about catch cans/hlowby on a stock engine, freaking out about closed loop/open loop transition points... you'd be amazed how many people don't have any idea that any of those potential problems even exist and never have major problems with their various cars. To each his own I guess.

 

For example: on old EEC-IV Mustangs, it's common to buy a new MAF sensor at the same time you install new injectors. Why, you ask? Because these MAF sensors are recalibrated to lean out the mixture... they account for bigger injectors by changing the MAF scaling. And all but the most hardcore tuners don't even see the potential problems from that (different load calculation, timing problems etc). Most DSM and 3000GT owners will install a crude piggyback like an SAFC or MAF translater and just turn knobs, not knowing anything about fuel trims. And a lot of those engines survive for a while, even though their tune does drift and the ignition timing is unpredictable.

 

There's a certain hypochondria among a segment of Subaru owners (not addressing you or anyone here specifically) that amuses me. Some of the rest are clueless and use Cobb OTS maps with catless exhausts, then wonder why they are overboosting. [/blog]

 

anyway, the factory wideband seems to be working fine at the front of the downpipe. Be happy you have one, most Evos don't even have a useable factory MAP sensor.

[LittleBlueGT]

I know I am anal about tuning. But I also lost an engine due to a tune that was not good for my gas, and was lucky enough to be in a place to get it fixed quick.

 

If I lost another engine now the expense and time w/o the car would be intolerable. I track my car, so I care very much about things running knock free. If we had smaller pistons, or even forged ones, perhaps I would not be so worried about things.

 

I also find it interesting, and like doing it. I also help a lot of locals out, and want to be ensure anything I do or suggest is safe.

 

FWIW I do 95+% of my logging while driving to and from work, so I am really not putting excessive wear on my car, nor really wasting gas, just making my time count. If you do have lots of logs in various situations, then you can also compare the difference a specific mod made, while being able to sort through any temperature or other skewing factors.

 

In this thread, I just would like to understand why more fuel is required, because all the evidence I have does not support it.

[NSFW]

For example: on old EEC-IV Mustangs, it's common to buy a new MAF sensor at the same time you install new injectors. Why, you ask? Because these MAF sensors are recalibrated to lean out the mixture... they account for bigger injectors by changing the MAF scaling. And all but the most hardcore tuners don't even see the potential problems from that [....]

 

There's a certain hypochondria among a segment of Subaru owners (not addressing you or anyone here specifically) that amuses me.

 

How often do Mustang owners post up about blown motors?

 

I wonder if Subaru motors are more prone to failure. I've seen enough pictures of cracked ring lands to make me pretty paranoid about detonation.

[LittleBlueGT]

How often do Mustang owners post up about blown motors?

 

I wonder if Subaru motors are more prone to failure. I've seen enough pictures of cracked ring lands to make me pretty paranoid about detonation.

 

Our 2.5 liter motors are not very resilient under detonation, anybody that says otherwise is wrong.

[Boostin1657615274]

In this thread, I just would like to understand why more fuel is required, because all the evidence I have does not support it.

 

are you wondering why more fuel is required, or are you wondering how or why a particular table in the ECU should be changed after an intercooler is upgraded? More fuel is required when the air entering the engine is more dense due to lower temperature (duh). And a more efficient intercooler results in lower temperatures. It's the principle of the ideal gas law.

 

You'll see it applied on any true speed density system. As the intake temps change, air temperature correction is applied and then fuel trims (in modern OEM applications) on top of that. Usually you have either a VE table (GM style speed density) or an injector pulsewidth table (many aftermarket speed density systems).

 

As for which tables may have to be changed after installing a different intercooler on a MAF system... maybe there isn't one answer to that. MAF based systems are complicated like that because of the way MAF scaling, injector scaling, etc work together as the ECU tries to hit the target AFR table. And it depends on the system. The Evo 8's for example use a volume airflow sensor (even though people still call it a MAF) so the sensor calibration and resulting load calculation don't work the same way as Subaru's. Nissan OEM applications (KA24, SR20, VG30, VQ35, VR38) are weird in that the 'load index' is actually called "Theoretical Pulsewidth." TP is how much fuel would be needed to reach Lambda=1. So your fuel maps are rpm vs TP, not rpm versus some normalized airflow (Subaru, GM) or a load % (Mitsu). And there are a bunch of functions that control how the Nissan ECU models this theoretical pulsewidth value. GM is unique in that it simultaneously uses speed density and MAF calculations on their Gen III (LS1) and later motors. That's some weird shit.

 

Any way you slice it though, if cooler air is actually entering the engine at the throttlebody it's going to need fuel. The question is how do you get there. I got there by changing the target AFR tables. You got there through another way somehow.

 

Our 2.5 liter motors are not very resilient under detonation, anybody that says otherwise is wrong.

 

It depends what you are comparing them to and what your expectations are