[BlueM3Wagon]

Originally Posted by hassmaschine

Do you have headers? LTFT being that far off indicates to me a problem with the feedback loop (assuming nothing else like a vacuum leak, bad injectors, etc).

In true MAFless mode, you don't need to disconnect the MAF sensor either. It just ignores it. but the IAT is a better idea since it's so much smaller.

I had pulled the MAF signal wire because I was still using the tune that was using MAF signal but was stalling out the car on braking. We are now back on Alpha N. No headers on this. Still don't have the IAT relocation installed but working on it soon.

[hassmaschine]

I still don't think IAT location is worth anything. I just remembered last night actually, the DME already monitors the ambient temperature - so if the sensor is really heat soaking, the DME is already aware of it. It uses both the IAT and ambient temp sensor to correct for air density.

[BlueM3Wagon]

Originally Posted by hassmaschine

I still don't think IAT location is worth anything. I just remembered last night actually, the DME already monitors the ambient temperature - so if the sensor is really heat soaking, the DME is already aware of it. It uses both the IAT and ambient temp sensor to correct for air density.

But the reason for the relocation is to get an accurate temp post blower right? how does +30-40 unregistered degree temp increase effect the car, AFR and performance without receiving the actual temp that's going into the cylinders?

I've asked Bob a number of times if these issues could be hardware and not the tune. I've already had it into two shops that did smoke tests and looked over the car, no leaks and they both said it must be tuning issues. I just don't understand why the car acts great with no LTFT but when LTFT are calculated and adjusting the car can drive can drive fine, or go rich/lean during cruising, rich at idle or be perfectly fine. What condition is creating this is my question. I'm a dummy when it comes to tuning. I just need to know if something is fucked like O2 sensors that might be causing this, or there are things in the tune that could be causing it?

[BlueM3Wagon]

Bob is looking over the logs and seeing it we can disable LTFT all together. My question to him was, if that needed because my Wide Band O2 is bad, or the DME has issues sorting out fueling because of the SC kit?

[hassmaschine]

Originally Posted by Michaellcoates

But the reason for the relocation is to get an accurate temp post blower right? how does +30-40 unregistered degree temp increase effect the car, AFR and performance without receiving the actual temp that's going into the cylinders?

I've asked Bob a number of times if these issues could be hardware and not the tune. I've already had it into two shops that did smoke tests and looked over the car, no leaks and they both said it must be tuning issues. I just don't understand why the car acts great with no LTFT but when LTFT are calculated and adjusting the car can drive can drive fine, or go rich/lean during cruising, rich at idle or be perfectly fine. What condition is creating this is my question. I'm a dummy when it comes to tuning. I just need to know if something is fucked like O2 sensors that might be causing this, or there are things in the tune that could be causing it?

The high LTFT are a symptom, not the cause. Something is causing the feedback loop to go out of wack.

Makes sense if the sensor needs to be moved after the intercooler. I haven't looked at exactly what kind of temp delta the DME is expecting but I know that without the ambient temp the fuel trims go wacky.

[BlueM3Wagon]

Originally Posted by hassmaschine

The high LTFT are a symptom, not the cause. Something is causing the feedback loop to go out of wack.

Makes sense if the sensor needs to be moved after the intercooler. I haven't looked at exactly what kind of temp delta the DME is expecting but I know that without the ambient temp the fuel trims go wacky.

I was reading another forum that some turners tune out LTFT because ST is more responsive with aftermarket SC kits. They basically default LTFT to 0.00. Why does the car drive great with only STFT, but wack out when LTFTs are finally registering? I guess I'm still not understanding what conditions cause this.

My understanding that LTFT are adjustments made from ST feedback after that cars DME has adapted to conditions. Both LT and ST are based on feedback from the wideband O2 sensor. So my question is, if the O2 sensor is getting wacky numbers (even if it's faulty O2 or real numbers calculated by faulty conditions) why would the car act ok under ST and not under LT?

Pardon my ignorance I'm honestly just trying to understand and get that "ah-ha" moment.

[rjahl]

Originally Posted by Michaellcoates

I was reading another forum that some turners tune out LTFT because ST is more responsive with aftermarket SC kits. They basically default LTFT to 0.00. Why does the car drive great with only STFT, but wack out when LTFTs are finally registering? I guess I'm still not understanding what conditions cause this.

My understanding that LTFT are adjustments made from ST feedback after that cars DME has adapted to conditions. Both LT and ST are based on feedback from the wideband O2 sensor. So my question is, if the O2 sensor is getting wacky numbers (even if it's faulty O2 or real numbers calculated by faulty conditions) why would the car act ok under ST and not under LT?

Pardon my ignorance I'm honestly just trying to understand and get that "ah-ha" moment.

Just in case you don't already know, the DME logic for the n54 expects the IAT to be located after the intercooler. There must be a reason. The n54 also skips the MAF sensor completely.

[hassmaschine]

Originally Posted by Michaellcoates

I was reading another forum that some turners tune out LTFT because ST is more responsive with aftermarket SC kits. They basically default LTFT to 0.00. Why does the car drive great with only STFT, but wack out when LTFTs are finally registering? I guess I'm still not understanding what conditions cause this.

My understanding that LTFT are adjustments made from ST feedback after that cars DME has adapted to conditions. Both LT and ST are based on feedback from the wideband O2 sensor. So my question is, if the O2 sensor is getting wacky numbers (even if it's faulty O2 or real numbers calculated by faulty conditions) why would the car act ok under ST and not under LT?

Pardon my ignorance I'm honestly just trying to understand and get that "ah-ha" moment.

If they're turning off LTFT then I think they probably don't know what they're doing. It definitely can be done on these DMEs without disabling LTFT.

No, the car wouldn't act OK - because on the N52, the O2 feedback loop has a lot of control over fueling. With no MAF, it's like 80% of the algorithm.

The point of a LTFT adjustment is the STFT will never be very large, because it's only meant for minor transient changes - it needs to be able to respond quickly. If you need a 10% LTFT to have a 1% STFT, and then you disable the LTFT, you'll just end up with an 11% STFT (which it's not really meant to do).

[hassmaschine]

Originally Posted by rjahl

Just in case you don't already know, the DME logic for the n54 expects the IAT to be located after the intercooler. There must be a reason. The n54 also skips the MAF sensor completely.

N54 uses the MAP sensor though. The N52 has one but I'm not sure how much above 1 bar it will read - maybe 1.2?

[BlueM3Wagon]

Originally Posted by hassmaschine

If they're turning off LTFT then I think they probably don't know what they're doing. It definitely can be done on these DMEs without disabling LTFT.

No, the car wouldn't act OK - because on the N52, the O2 feedback loop has a lot of control over fueling. With no MAF, it's like 80% of the algorithm.

The point of a LTFT adjustment is the STFT will never be very large, because it's only meant for minor transient changes - it needs to be able to respond quickly. If you need a 10% LTFT to have a 1% STFT, and then you disable the LTFT, you'll just end up with an 11% STFT (which it's not really meant to do).

Thanks again. If you'd ever be open to taking a look at some logs let me know. I guess I might not do any good since you don't know how the tune is set up.

[hassmaschine]

I think probably your best course of action for now is to relocate the IAT to after the intercooler and see what happens from there.

[Biginboca]

I agree you need to supply the DME with as much accurate info as possible. Moving the IAT to a post boost area definitely makes sense. It can’t hurt... that’s for sure!

Also just thinking about what Hass posted... he said the N52 MAP sensor tops put around 1.2 bar. That’s 17.4psi. If you are running 6lbs of boost then you are around 21psi (1atm at sea level is about 15psi). I don’t see how running a MAP sensor which can’t read correctly can help.

Maybe the MAP sensor needs to be swapped for a N54 one and the ecu somehow calibrated for it?

I doubt it’s the O2 sensors. If they were working fine before the SC I don’t see why they would go bad so quickly. But then again, at this point maybe spend a few hundred and change them.

Once you can verify the DME is getting correct info from all sources (IAT is accurate, MAP reporting accurately, O2 are good) then the only thing left is tuning, right?

[rjahl]

Don't get Absolute and Relative/gauge pressures mixed up. The N52 is probably only going to read 1.2 bar absolute or about 3psi. While the N54 sensors read up 1.2 bar relative or about 18 PSI.

[hassmaschine]

1.2 bar was only a guess. But that is pretty typical for an N/A motor. I'm talking absolute pressure here, not relative.

an N54 sensor would read like 2 bars. You could probably retrofit it, but you'd have to figure out how to change the sensor curve - I don't think they're exposed in the parameter space either. Also I doubt that is the issue, as there are other ESS cars running without problems (not often on ESS tunes though, lol).

[matthewjmoser]

how come the ess supercharger doesn't say it works with the N51 ?

[rjahl]

Originally Posted by hassmaschine

1.2 bar was only a guess. But that is pretty typical for an N/A motor. I'm talking absolute pressure here, not relative.

an N54 sensor would read like 2 bars. You could probably retrofit it, but you'd have to figure out how to change the sensor curve - I don't think they're exposed in the parameter space either. Also I doubt that is the issue, as there are other ESS cars running without problems (not often on ESS tunes though, lol).

That's probably a good guess. N54s have two pressure sensors. One in the intake manifold like the n52 that reads a vacuum up to 1.2 bar and the second sensor reports charge pipe pressure up to 1.2 bar above ambient.

Data logging shows the first pegging out very rapidly under boost.

[hassmaschine]

That's cool. It's actually better than just having one sensor that reads ~2.4 bar - you only get a 0-5v signal, so the bigger your scale is the less resolution you end up with.

[BlueM3Wagon]

Thinking about placing the a 1/8 npt to 1/8 barb for the boost line and the m12x1.5 IAT probe a these locations. Seem ok?

[BlueM3Wagon]

Another question. Could my DISA valves be causing any of these issues if they were broken?

[Kubricks]

Originally Posted by Michaellcoates

Another question. Could my DISA valves be causing any of these issues if they were broken?

Unlikely.
I ran with a broken DISA for God knows how long, the only issue was that the car is down on low-mid range power. Idling and normal driving is not affected at all.

[Biginboca]

Originally Posted by Michaellcoates

Thinking about placing the a 1/8 npt to 1/8 barb for the boost line and the m12x1.5 IAT probe a these locations. Seem ok?

I feel like placing them in that spot would affect air delivery to the first cylinder and throw off the balance of flow between it and the others. I would not put them in that spot, but I suspect you want to add the sensors without removing the manifold from the motor?

I add ports to manifolds on the backside next to the oem pvc ports. There’s a large main chamber on the bottom of the manifolds in this area. This is a pic I had from a n54 manifold I was working on, but the n52 manifolds have a large chamber here also if I recall correctly. I suspect in this area the balance of flow to each cylinder isn’t affected, hence why the factory puts the PCV input here also.

[BlueM3Wagon]

Originally Posted by Biginboca

I feel like placing them in that spot would affect air delivery to the first cylinder and throw off the balance of flow between it and the others. I would not put them in that spot, but I suspect you want to add the sensors without removing the manifold from the motor?

I add ports to manifolds on the backside next to the oem pvc ports. There's a large main chamber on the bottom of the manifolds in this area. This is a pic I had from a n54 manifold I was working on, but the n52 manifolds have a large chamber here also if I recall correctly. I suspect in this area the balance of flow to each cylinder isn't affected, hence why the factory puts the PCV input here also.

[img]https://i.postimg.cc/P56tDhNh/83588-...3-DA186-F7.jpg[/img]

Right I was trying to not take the manifold out. Just really tired of wrenching on the car haha.

I know NYBulldog added his boost barb on the top of the manifold and hasn't had any issues. I assume we're mostly talking about the the IAT barb, but as you can see, I'm really limited to where this can go. The area you mentioned isn't wide enough to tap and allow the barb to seat.

I could secure it in the silicone charge pipe. It came with locking washer if that's what it comes down to.