Bolt On's Increase Boost?

[reubone]

Hello all,
So I installed an Airaid intermediate pipe and a catless downpipe over the weekend and started doing some testing. I set the wastegate and canister tables to give me spring pressure only. Or at least that is what I thought. Turns out I still achieved 16lbs of boost. On a previous test without these items installed, I only got a tad over 9 lbs. Which is close to what the tune file says wastegate should be. My question is, Did the parts increase flow or something else that drove the boost this high, or was the testing not done in a repeatable way to know? Logs posted, New WasteGate.hpl
Wastegate Right.hpl

[IARLLC]

I'm sure that the reduction in backpressure affects some dynamics of the wastegate in addition to allowing the turbine to spin up noticeably faster. I've heard of EB folks getting codes related to turbine speed after a de-cat and/or catback so I'm sure it bumps up against the limiters related to supposed turbine speed more quickly in addition to hitting boost limits much more easily. Hopefully I will have some time to do similar back-pressure related testing on my Expedition soon.

A friend of mine installed a catless downpipe on his 18 Raptor a couple of years ago. He reported a decrease in fuel economy. I figured it was just because he was on it harder but this discussion brings up other possibilities. What if his stock throttle/torque request tables were being met more easily (boost comes up more easily) and the computer was requesting less timing? It has been in the back of my mind for a couple of years. Now the picture starts to have some possible reasons behind it.

[Seishuku]

On my setup, difference in fuel corrections for just a free flowing exhaust was about 7 to 10%.

But yes, opening up the exhaust changes the predicted behavior model the ECU is expecting, there are quadratic equation tables for that in the exhaust tabs. How to tune them? No idea.

In my case, just an aftermarket stock sized catback and stock downpipe we're enough to trigger over boost codes on the Ford Performance tune.

Though oddly enough, an open element air filter does nothing... But I suppose exhaust influences wastegate dynamics as well.

[reubone]

I'm sure that the reduction in backpressure affects some dynamics of the wastegate in addition to allowing the turbine to spin up noticeably faster. I've heard of EB folks getting codes related to turbine speed after a de-cat and/or catback so I'm sure it bumps up against the limiters related to supposed turbine speed more quickly in addition to hitting boost limits much more easily. Hopefully I will have some time to do similar back-pressure related testing on my Expedition soon.

A friend of mine installed a catless downpipe on his 18 Raptor a couple of years ago. He reported a decrease in fuel economy. I figured it was just because he was on it harder but this discussion brings up other possibilities. What if his stock throttle/torque request tables were being met more easily (boost comes up more easily) and the computer was requesting less timing? It has been in the back of my mind for a couple of years. Now the picture starts to have some possible reasons behind it.

Very interesting, because timing is used for tq modulation in some instances.... Ill keep an eye on that.

[reubone]

On my setup, difference in fuel corrections for just a free flowing exhaust was about 7 to 10%.

But yes, opening up the exhaust changes the predicted behavior model the ECU is expecting, there are quadratic equation tables for that in the exhaust tabs. How to tune them? No idea.

In my case, just an aftermarket stock sized catback and stock downpipe we're enough to trigger over boost codes on the Ford Performance tune.

Though oddly enough, an open element air filter does nothing... But I suppose exhaust influences wastegate dynamics as well.

Well sounds like the results are repeatable then. That is good to hear. Also leads me to believe that the wastegate is undersized with the results that I am getting. Boost creep from 9lbs to 15lbs by redline. That kind of flow problem is handled in the aftermarket with a larger wastegate. No real way to combat the issue here. Unless some porting could be done....hmmmm.

Tell me if I'm off track but this also re-enforces my Idea that the throttle body is not the way to control boost. If you have any mechanical sympathy for your turbo that is. On the stock tune, the wastgate is triggering higher boost levels than the throttle will allow past. That could only add to problems in my view. If the map is reading 22lbs with the throttle at 30%....How much pressure is in the intake track before the throttle body? How much does that effect the heat generated? If the turbo will build close to 16lbs on its own with the wastegate open, then there doesn't need to be much activity there to build more. Certainly it is worth a smidge of throttle response to keep the turbo happy. I could be way off base here so correct me where Im wrong.

[Seishuku]

Can't say I've noticed any boost creep issues with the stock turbo and wastegate actuator, most likely what you're seeing is just the various models in the ECU fighting each other.

I can hold about about 26psi to nearly the rev limit, but I don't know my throttle inlet pressures exactly, it maxes out the sensor currently (3 bar sensor, so 29+ psi)... Not sure how much high TIP really affects charge temp, but my temps are well controlled with the aftermarket intercooler I'm running, so 30+ psi TIP must not be generating too much heat.
I'm sure it's not great for turbo longevity. Lol

[reubone]

Can't say I've noticed any boost creep issues with the stock turbo and wastegate actuator, most likely what you're seeing is just the various models in the ECU fighting each other.

I can hold about about 26psi to nearly the rev limit, but I don't know my throttle inlet pressures exactly, it maxes out the sensor currently (3 bar sensor, so 29+ psi)... Not sure how much high TIP really affects charge temp, but my temps are well controlled with the aftermarket intercooler I'm running, so 30+ psi TIP must not be generating too much heat.
I'm sure it's not great for turbo longevity. Lol

Boost Creep.hpl

This is the boost creep I am referring to. 9lbs to 16lbs with zero wastegate activity. This is telling me that the wastegate cannot bypass enough flow to keep boost at spring pressure.

[IARLLC]

"Also leads me to believe that the wastegate is undersized with the results that I am getting. Boost creep from 9lbs to 15lbs by redline." Since my very restricted Expedition hits 17+ pounds of boost very easily from lower speeds but struggles to stay above 14 pounds to redline I'm clearly dealing with other issues....probably also a leaky BOV. But if you have adjusted your Pressure Ratio table to get more boost up at the big end (before freeing up the exhaust), the exhaust mods could certainly lead to higher boost numbers up top.

Of course if your wastegate is at 0 this must be as you expect. I have not had a chance to watch your scan yet, just considering possible reasons. The EB systems do like to overide our firmest desires from time to time.

[reubone]

I haven't adjusted anything for the turbo other than setting the wastegate to achieve the lowest boost possible. Full bypass in other words. to try and stay at spring pressure only. This will allow me to move other things around like lspi, driver demand and other tq limiters, without the worry of over boosting.

[reubone]

Your issue could most likely be a boost leak. I doubt that the turbos would be that undersized.

[Seishuku]

Boost Creep.hpl

This is the boost creep I am referring to. 9lbs to 16lbs with zero wastegate activity. This is telling me that the wastegate cannot bypass enough flow to keep boost at spring pressure.

Looking at the log, I think what might be happening is it might be underboost (or something else?) logic trying to force the air load up, because you're trying to force spring pressure.
Basically it's seeing actual load is far less than desired and isn't coming up at it would expect it to.

I wonder, if you were to make a very long pull at WOT, would it eventually fault out with an underboost code? I bet it would.

If you want to do this, you'll have to lower driver demand, or leverage LSPI load limiting and force a 1.5 to 1.7 load. Otherwise, the system just isn't really designed to run just spring pressure, except for under turbo FMEM fault or control solenoid fault.

Might actually be better to bypass the wastegate bleed solenoid and route pressure directly to the wastegate, the ECU *will* eventually toss an underboost code for that for sure. Unless you readjust underboost parameters to disable it first, I suppose.

[reubone]

Underboost is already bypassed as this would trigger an underboost code if not. The under boost situation is on purpose. As far as i can tell, the wastegate remains dormant. If the computer was trying to up the boost pressure through the PID parameters, wouldn't we see this reflected in wastegate duty cycle? The reason I am doin this is to be able to manipulate the driver demand table and LSPI tables to see what effect they have on desired load and desired TIP without raising actual power. Test mode if you will. This will help in understanding what tables need to be moved in what order without the risk of an over boost condition. Does that make sense?

[Seishuku]

Yeah, I get what you're trying to do.
In that case, I would just reroute lines around the wastegate solenoid, that way the ECU has no ability to increase boost at all.

Edit:
That reminds me, there's a parameter in I think the turbocharger tab that's listed as "manual mode" or "test mode", anyone know what that does?
I've never had time to try it, maybe it forces it to run wastegate spring pressure only?

[reubone]

Hmmmmm Good question. I wonder, may be worth a try. In the mean time, what do you think about this. I'm having the exhaust temp protection rear it's head at me again even though I am not anywhere near the protection temp and I have positive spark advance. Take a look. You'll see at the end of the pull, the desired tip and desired load take a nose dive. I must have missed something along the way
22-11-02 12-41-56.hpl

Sorry I posted wrong tune file. That is the file I hope to try next to see if its fixed

Swiper Test File2.hpt

This is the file used for the above datalog

[reubone]

Turns out that disabling exhaust temp protection with the drop down options triggered this I'm pretty sure. I have reenabled them and the problem went away.

[Seishuku]

That is *very* weird, no way that temp protection should be kicking in at those loads. I've had them disabled on my 2015 and it turned it off correctly...
I have no explanation for that behavior. lol

Though as for the "boost creep", I had a thought... Since the ECU is raising TIP desired, it might actually be the "Min vs. Turbo Airflow" table that's driving up TIP desired... So if you zero out that table, I'm thinking that will kill any creep issues.
Also "Expected TIP" table too, though that might be only used for modeling, I'm not sure.

[reubone]

Yeah I agree with the very weird statement. I'm gonna have to go back and verify but I'm sure that it was the enable/disable drop menu option that triggered this default protection. I hadn't thought about the TIP tables possibly having an effect on boost creep. I was hoping any tables doing that would show in wastegate activity but who knows. This is my latest iteration. This demonstrates how I have moved up the desired parameters and controlling boost with he wastegate. Now time to creep up on power. One question though, what is causing the commanded lambda to deviate from the wot lambda table
latest.hpl
Swiper Test File2.hpt

[Seishuku]

Looking at the log, I don't really see anything obvious that would cause it to slowly ramp in fuel like that, but if I had to guess... I'd say might be tip-in torque control of some kind?
I wouldn't worry too much about it, keep in mind that direct injection can handle boost at stoichiometric ratios, so if it runs a tad leaner than you expect, it's not so much of a worry as it was in the old port injection days.

The ecoboost strategy will actually have no issues with running 20PSI at stoich, as long as it's not in power enrich (obviously), there isn't any knock, and calculated EGTs are in "range".

[skylinedan]

Don't make this out to be a bigger deal that it is, you would have to get really stupid to do enough to get boost pressures much over 23 24 lbs. 20 lbs is fine, big thing is small adjustments and don't change a lot all at once. If something doesn't work, you wont know what you did to make it worse. As time goes by, you'll to watch things and understand what's going on. Also you'll gain a feel for the car, how the motor sounds and how the trans shifts. There's a lot going on, and a lot to learn. I've been tuning for ten years and still learn a new thing now n then.

[reubone]

Can't say I've noticed any boost creep issues with the stock turbo and wastegate actuator, most likely what you're seeing is just the various models in the ECU fighting each other.

I can hold about about 26psi to nearly the rev limit, but I don't know my throttle inlet pressures exactly, it maxes out the sensor currently (3 bar sensor, so 29+ psi)... Not sure how much high TIP really affects charge temp, but my temps are well controlled with the aftermarket intercooler I'm running, so 30+ psi TIP must not be generating too much heat.
I'm sure it's not great for turbo longevity. Lol

I have a couple of question if you dont mind too much. Are you really running over 29lbs on the stock turbo at redline or is that just a momentary deal? Also what does your timing look like at that level. I barley have 1* at 20lbs but I am still on the stock intercooler and temps quickly get out of control. Im going to start experimenting with timing here in a few.