Sorry, I was confused. You said my desired air load is 2.2 and the actual is 2.2, where are you seeing 2.2? I am seeing 2.3?
Kris
Here for example:
So what I'm saying is the TIP Desired in that case (70 in.Hg) derives from this desired load. Your throttle is closed off a little in this case because your desired TIP is lower than actual, so the throttle has to restrict airflow to prevent from flowing more load than you desired.
You need to raise this load to get your TIP Desired to raise with it. This is because the desired load becomes a desired air mass, which goes through the VE equations to give desired pressure. Hopefully I'm making sense.
Bugasu, does the throttle always regulate boost at WOT with torque limiters removed or refined? Does the throttle ever stay open at WOT and the waste gate regulate boost?
I appreciate the sentiment. Making a book though is a lot of work, and I don't know if I currently have the time to do so.
The throttle regulates airflow. It is controlled directly from desired airmass. The factory tune often uses more TIP than is needed to achieve a desired airflow or rides it really close, so the throttle in this case regulates boost.
In order to keep the throttle open entirely, you'd want your desired load to always be out of reach of the actual load you can hit. Look at your log at the high RPMs for an example, desired load stays up, but actual load just simply can't reach it.
A way you can do this is to have your desired load request a TIP that would be quite high (say 25psig), but you only want say 22psig. You can set your TIP Desired Max to be 23psig in this case, actuate your wastegate to only hit 22psig, and the throttle should stay open because you're never going to hit your max as well. Take a look at Cobb's Ecoboost tuning guide for this.
I will add, you may not always want to do this. For example, on a car like mine with an upgraded turbocharger with much higher inertia, I actually allow the throttle to close down low and limit my airflow and let the turbo overshoot a little bit. This gives you a faster response than controlling the wastegate to just hit a set boost. Of course, you need to have headroom, and remember that power generated by the turbine at these higher airflows typically also comes with higher turbine inlet pressure, which means reduced VE and thus overall efficiency. Trade-offs for everything.
Ah okay, makes perfect sense. IMO the boost regulated by throttle is genius and as you stated, more responsive. I don't feel there is much benefit by changing it over. I feel more comfortable allowing the ecu to use the throttle to regulate boost based on load than trusting the waste gate to do its job as the primary source of boost regulation. I've seen many other vehicles suffer from overboost issues due to undersized or overworked wastegates. I just wanted your opinion on the matter.
I have found load limiters elsewhere that were not allowing me to hit my target boost of 22 psi. I have since adjusted them and I am comfortably hitting 21.9psi. I'll take that. Car pulls hard and strong. Next is e30.
I used the Max Desired TIP pressure to limit boost, I'd set it to the absolute boost level desired. For the Max TIP and Min TIP tables, I didn't really see any correlation with limiting boost. For example I set the max TIP tables to about 17 psi but can hit 18 psi if the Max Desired TIP Pressure was set to 32.5 psi
My issue was what I believe were three tables that play a role in torque calculation. I'll mess with them more to see if I can get the car to hit the TIP max desired limit.
Update, the car now rides between the LSPI max load I have set as well as a matched TIP Max desired. No more insufficient fuel and no more hidden torque limiters. I am running 22-22.5psi of boost hitting max load of 2.5 and quite a lot of torque.
I raised torque calculation, torque inverse, and IPC tables to allow more torque than I know the car will make. I now run the car off the LSPI tables and TIP Max Desired. I put E30 in it last night. The car is not adding timing as fast as I expected initially, that I am used to compared to coyotes. I will be increasing the knock advance rate limit to see if I can get it to add timing faster.
Kris
Under fuel sys > fuel pump you have fuel pressure that you can increase some. Seems like you found a better way around the fuel flow tho.
You are using the low speed pre ignition tables which the eco boost engines have a known serious problem with so be careful how far you take that in the lower RPMs with out considering upgrading your engine internals.
What's the serious problem with the LSPI tables? It seems a lot of tuners just increased those values across the board.
nothing wrong with changing them. Its necessary in order to increase boost and performance. I was just saying you do not want Low speed preignition. The ECO boost motors are prone to it being turbo charged and direct injected. So you dont want to be pushing it in the lower RPMS too much.
So we don't want to lug the engines (high load at low RPMs)?
tell that to the owner of the car you just tuned and it blew up.