2009 Cobalt SS TC (LNF) - Boost limited to 22.4 psi??

[metroplex]

ECaulk:

I started the pull around 2000 RPM because it was 3rd gear. I have another datalog from the same day where I started in 2nd gear, but the front tires lit up as soon as I went WOT. I had to modulate the throttle like crazy fighting the car as it jumped into the right shoulder of the road.


Yes, the original question was why am I not seeing more than 22.4 psi of boost - it was established that 22.4 psi is the limit of the Manifold MAP sensor, but using Boost Lo Res, basically I wasn't seeing more than 25 psi of boost (I saw a few 26.6 psi spikes).

Before I had to cut the throttle, I was seeing 30.39 lb/min of airflow around 4700 RPM. In the other datalog where I used 2nd gear, I was seeing 31.76 lb/min at 5300 RPM and 33.58 lb/min at 6500 RPM but the duration wasn't too long (but not a spike) due to how fast the engine was revving up.

[ECaulk]

If you want your transmission to live, I would recommend not going WOT in 3rd gear below 3500rpm.

The turbo will not push much more, you're getting near the limits of the wheel and defiantly falling off in efficiency. To extract more you need to really have multiple tables dialed in and you'll get maybe a little more airflow.

Upload your tune so people can check it out to see if there is anything glaring wrong with it. Screenshots are a royal pain to flip between and not everything has be screenshot

[metroplex]

Which tables have to be dialed in? DAL, MALT? Good to know about the F35. I may have to take it to a 1/4 mile track to get more data because 2nd gear with the torque limiter would undoubtedly skew the results.

[ECaulk]

Upload your tune. More boost is not always the answer to more power.

[metroplex]

This is what I found regarding DAL's:
http://www.hptuners.com/forum/showth...Air-Load-Table

So what Terminator2 said isn't true? I actually went back to my DAL worksheet and it looks like what I have for DAL converts to roughly 25.2 psi in the 90%-100% columns.

[TurboCobalt]

metroplex,

I believe some of the older threads that you are learning from were written very early on when HPTuners had only unlocked a limited number of tables. Later on they added more tables that we can change now. I believe that's why some of the older materials talk so much about the DAL tables because back then 2008 or so, they didn't have all the tables we have now. some of the newer ones are wastegate DC, max boost pressure, the boost PID controller values, not quite sure, i wasn't in the game back then either. Basically i am running almost stock DAL, and i have a steady 22 psi (with a slight dip to about 20 or 21 by 6500 rpm). My boost is steady at 22 not because that's all i can do, but because that's where i want it.

you can use different tables to control the boost to the value you want, there are various opinions on which to use, which is best bla bla bla. Personally i do not like the idea of using the Wastegate Duty Cycle Correction table to control boost, that's not what it was meant for and it defeats the purpose of having a boost PID closed loop controller. i control the ramp in (and yes, i had to slow down the ramp because the clutch would slip) with the Max Air Load Torque table. I then control the maximum boost i want with the Pressure Limit calibration, i don't think i've read of anybody else doing it that way, and im sure many on here would disagree.

I think you're pushing your car a little too far for what appears to be your level of understanding of the E69. Learn a little more before you boost to 25 psi maybe? Of course that's a matter of opinion, and feel free to ignore me.
Try reading this: http://www.hptuners.com/forum/showth...of-a-stock-LNF

A few posts ago i mentioned desired vs measured. Each control system has an input and an output. I said record fuel desired and fuel measured because then you know what the ECU WANTS, and what it MEASURES, this will tell you if your car is getting the pressure the ECU wants. You kind of dismissed it and i feel you didn't understand what i meant. (for instance a lower measured than desired may indicate a drop in pressure because you are asking for more fuel than the system can provide. The same idea holds true for other systems, for the LNF there's a Boost desired and a boost measured (Boost Low Res PID we keep talking about), use those to understand what your boost PID (Proportional Integrator Derivative) controller does. Same thing for the cam phasers, theres a desired and measured.

EDIT: I notice you're reluctant of sharing your tune, and that's fine, to each their own, just curious why not?

[metroplex]

Interesting read, I wasn't logging any knock retard at 25 psi and I'm running the stock timing tables with stale 93 octane fuel from last summer (mixed with Fuel Stabil). I'll back it down a bit after reading that thread.

[MikeM173]

I'm going to try and put this clear and nice. EVERYONE, not just you metroplex, needs to stop assuming that just because they do not see KR that they are good. When dealing with the stock turbo, HEAT is a huge factor. There are other things that come into play as well. Tuning isn't just about not having KR. And before anyone mentions the everyone thing, I don't literally mean everyone.

[ECaulk]

I'm going to try and put this clear and nice. EVERYONE, not just you metroplex, needs to stop assuming that just because they do not see KR that they are good. When dealing with the stock turbo, HEAT is a huge factor. There are other things that come into play as well. Tuning isn't just about not having KR. And before anyone mentions the everyone thing, I don't literally mean everyone.

Quoted for Emphasis.

[metroplex]

My SHO's stock tune for the EcoBoost 3.5L V6 pulls 6 degrees of timing at WOT in the high load / high RPM regions while using 93 octane fuel, and again it is the stock factory tune.

[ECaulk]

The LNF and the EcoBoost 3.5L are not the same engine. I would bet the control systems are also very different, even if it is a Bosch system in the EcoBoost. The stock LNF file has 0 KR in the high load, and most people can run 14-16* without KR, that doesnt mean you don't have high cylinder pressures from other things occurring, it's not all about KR.

[MikeM173]

Metroplex, no offense, but if you already know everything why are you here asking for advice? You aren't exactly taking what we are giving. Try to understand this, very few people understand the LNF. Looks like some more are starting to come around and that's good, but you nees to take some advice.

[cobaltssoverbooster]

Metroplex, no offense, but if you already know everything why are you here asking for advice? You aren't exactly taking what we are giving. Try to understand this, very few people understand the LNF. Looks like some more are starting to come around and that's good, but you need to take some advice.

such as (for like the 10th time now): post your tune file

also froget about the SHO tuning....its totally different than the GM tuning you are trying to tackle. Your comparing apples to a cat turd.
Its nice that you are active in multiple vehicles but none of the other ones will help you with the LNF coding.

[metroplex]

I'm just going to stick with the GMS1 settings for DAL and maybe add a few psi above that and call it a day, rather than deal with ring lands or anything else. I still firmly believe the problem with the SS/TC and LNF isn't the lack of power but the lack of traction. I do appreciate the additional insight into the LNF. All of the LNF tuning guides seem to need a lot of updating.

[metroplex]

Running a slightly modified version of GMS1, I was able to do some more testing and tuning at the dragstrip. Best today was 14.2 @ 108 mph with a best reaction time of 0.091 seconds (600' ASL, 55F ambient temps). I'm still running the OEM factory Conti's and the traction is terrible. Launch control makes it consistent at least, but its basically a 5000 RPM clutch dump and once it hooks - it just bogs.