Stew's Sonic

[Stew]

Time for a build thread. HP Tuners should be here tomorrow but I've already installed the newest version from their website and found an OEM 2012 Sonic tune to look at.

This is so cool.

Right off the bat I see some of the stuff that is so irritating that I'll be able to change, such as Launch Assist (the automatic raising of the idle as you let out the clutch), coolant temps (of course that is going to be there), rolling idle RPM for those times when I'm hypermiling and coasting, and so many more. Maybe instead of the cold start high idle lasting 40 seconds I only want it to last 37 seconds, just because I can.

I also have all the fixin's to finish up my custom dash mounted 3 gauge pod, and at some future point rear disc's are coming.

 

[Stew]

Custom Gauge Pod... coming soon!

 

[Stew]

Brake upgrades

Drum to RS rear disc conversion

My how-to thread:
http://www.sonicownersforum.com/forum/do-yourself-articles/17350-drum-rs-rear-disc-conversion.html

11.8" OEM Front Brake Upgrade mostly from this thread. CjCsonic's official how-to thread is here.

Original Sonic 12mm caliper bolts showing the grading and style

Original Sonic brakes

Mockup of the Buick Encore brakes on the Sonic

Shot of the hub and splash shield

Comparing rotor size

Drilling out the spindle hole

Finished drilling

Finished Encore brakes

 

[Stew]

Well there was a UPS delay so it won't be here until Monday. In the mean time, here are some fun facts from a 2012 Sonic OEM tune.

There is indeed a speed limiter configured in the OEM tune, it is factory set at 318 MPH so we shouldn't need to worry about that.

The speed limiter in reverse looks like 37 MPH, don't know if anyone's tested that out yet.

The factory RPM limiter steps in at 7000 RPM and then disengages when you fall back below 6900.

You can change the firing order, that's not useful for us but some V8's can use a couple different firing orders.

This is pretty interesting to me, while I'm not new to tuning, tuning a car using software is something I haven't done much. It seems weird that you can change things like the firing order by clicking a mouse instead of popping the hood and moving plug wires around, this seems so much easier!

 

[Eric Smit]

it's not often I need to go more than 2 in reverse.

 

[Stew]

I did my first flash, not upping power levels quite yet, just trying out some drivability settings.

I changed four settings for the first flash, lowered ECT from the factory 221* to a less scorching 198* (which is what another popular tuner does), disabled Launch Assist by making the RPMs for this table the same as the base idle which is 680 RPM, disabled the rolling RPM by making the RPMs for this table the same as base idle, and disabled torque shaping which is supposed to be doing you a favor by giving the torque request pedal (gas pedal) a weird non-linear relationship with the throttle body.

Everything seems to be working as expected except one thing. Now when you let your foot off the gas, sorry - I mean the torque request pedal, there is zero engine braking. I've confirmed this by slipping it in neutral without using the clutch and in fact the RPMs continue to hang wherever they were until you push the clutch in, then they'll drop to idle as expected. I'll have to re-enable torque shaping and take it for a spin because I just can't imagine the other changes would do this.

And, I'm making sure to follow the scientific method by changing all kinds of things at once so you don't know exactly what does what. Or was that change only one thing at a time... This is a blast!

 

[Stew]

It was torque shaping causing the odd coast down behavior, I re-enabled it and my first round of changes were good.

Next I started upping some driver demand and torque tables then going out for a spin to do some logging, then rinse and repeat. I'm still seeing how the different tables interact with each other, there is a lot you can change but I will say this... This car is feels like a whole new car, way more fun.

 

[Scot]

Check your PM inbox - I'll get you some of the things you need.

 

[ScarabEpic22]

Yep, welcome to the light!

As for the RPM limiter, yes that's the "official" hard limiter, but look at the commanded TQ table...it falls off over 6000rpms which is why these 1.4s fall flat on their face at 6k (not sure how much higher they can really rev due to restrictions anyway, but at least 6500).

 

[Stew]

Scot - Right on, thank you!

Erik - I did see that, also in my earlier post I was seeing the 7000/6900 RPM limiter in Engine -> Airflow -> Dynamic, but after I posted that I saw a lower 6700/6550 limiter in Engine -> Fuel -> Cutoff/DFCO.

Also interesting is that the settings for NLS are right there in Engine -> Fuel -> Cutoff/DFCO, I had assumed that was a custom feature exclusive to the other tuner. It is disabled by default by it's setting, which is active above 125% pedal position, which you can't ever achieve since the most you can depress the pedal is 100%. Sort of like the exercise in futility of trying to give 110% effort when the most a person can give is 100%.

 

[Stew]

Time for an update! I had hit a boost limit, I would get a peak of about 17.5 psi and then it would stabilize around 15.5 psi. Feeling pretty confident that I understand what most of the tables and values mean, but not yet knowing how they all interact with each other, I was going slow. You (well "I" at any rate) really need to put your thinking cap on when making sense of it all.

It got to the point where I had upped just about everything but still not getting to my goal of 235 kPa or about 19.4 psi. Logging was showing I wasn't near any dangerous conditions, in fact far from it. KR the whole time has been virtually non-existent, IDC was peaking at around 80% so still some room there, so what the heck? I know simply upping a bunch of driver demand and torque management tables willy nilly is bad practice, but for process of elimination it's ok temporarily.

Well I found the table causing my grief, it was the turbo base DC. Once I massaged this table and did some logging to verify my changes I went back to my base tune and started over; I increased the torque management, driver demand tables, etc to represent the actual limits I want rather than putting in max values.

Went out for some more logging and now I'm pulling a nice steady 235 kPa or 19.4-ish psi from approximately 2000 RPM to 6000 RPM. I didn't increase the boost much under 2000 RPM and 6000 RPM is buzzing along plenty fast enough for me, I normally shift way sooner.

Did a little more logging and things are looking good, there's a degree of KR here and there so I've started smoothing out the spark advance table. It's pretty slick, you look at your log to see where the KR occured then see what the RPM's and cylinder airmass were and then you simply go to that cell and remove a degree of timing.

Now I just need to schedule some dyno time to dial in the A/F and get some power numbers and I'm done! Trifecta is really close to me, I'll have to give them a call.

Sorry for the long post, and special thanks to SOF member Scot for helping with some logging and guidance.

 

[Stew]

I've got a dyno session scheduled this Saturday, we'll see what kind of numbers I'm putting down and maybe fine tune a bit.

Interesting little side story, I had stopped in at this shop and was chatting with the guy and he was familiar with Trifecta and in fact he seemed to know Vince and said that he occasionally will use their dyno.

 

[Stew]

Ok, Did a few pulls, played with timing and fuel a bit but they were really pretty spot on to start with. Tried adding a degree of advance but then started getting a little KR, it was a little on the rich side in the upper RPMs so I leaned it out a smidge but none of these things made a difference of more than a few HP and TQ.

So, I ended up with... Drumroll please... 151 HP and 201 TQ. I am happy with the torque but I was hoping the horsepower would've been a little higher, BUT I am stock except for porting the intake manifold. I suspect if I had an exhaust and intake to open up the breathing I would've seen higher numbers.

With how my car is, mostly stock, I don't know that I can get anymore power from it and still have a bit of a safety margin. IDC was around 90% so there is very little room for more fuel, which means I cannot really crank the boost up more; and the timing is about at it's limit. SO... with no more fuel, boost or timing available I think this is where I'll be for a while.

 

[Scot]

Hot damn!

Good Job Stewart!

 

[Stew]

Alright, time to start playing around again, kind of a long post.

So when I left off above, I had just been to the the dyno and all was looking good but I was at the limit of my injectors (above 90%) so that was as far as I could go.

Fast forward to last night, I pulled the trigger on a set of the Bosch 42 lb/hr 'green giant' injectors from ZZP and an Ultra-gauge to replace my Scangauge. The Scangauge is working just fine but I've tried to program the X-Gauges for STFT and LTFT and I'm not doing something right because I am not getting good data.

I believe (hope) that all you guys with the Ultra-gauge displaying STFT and LTFT are not having to do anything special to use those. After I get the injectors installed and update my tune I want to monitor those gauges to make sure all is well.

=====

Which brings me to updating my tune for the new injectors. Data out there on the interwebz on the Sonic OEM injectors is scarce, I've seen a couple of posts in this forum saying they are 28 lb/hr and I did find a fuel injector website which did list the OEM part number as 305 cc/min which using an online injector convertor, converts to 29 lb/hr which does jive with info on this forum and is probably a rounding error.

The Bosch injectors are 42 lb/hr which calculates to 441 cc/min, so we are going from 305 cc/min to 441 cc/min, an increase of around 44.8%. Now this is where I have to put my thinking cap on...

I've checked with another forum member who is very active here and who is using HP Tuners and who already has the Bosch injectors installed and he was gracious enough to share his Flow Rate vs Pressure table data. The data in his table is not 44.8% higher than the OEM injector data as I was expecting, it's actually a bit less and this is what I'm not fully understanding yet.

What I think is going on is that the nominal operating fuel pressure for the Bosch injectors is 39.15 psi according to the data sheet in the link below, but the target fuel pressure for our Sonic's is 58 psi. So presumably if operating the injector at a higher psi you would use a lower multiplier value in your tune. The problem is the percent reduction from 58 to 39.15 is not the same as the percent reduction from 44.8 to the multiplier used in the other users injector table.

http://www.boschdealer.com/specsheets/0280155968cs.jpg

If someone smarter than me (not hard, lol) can shed some light on the disconnect in the data, or my brain, that would be swell.

 

[Stew]

Alright, I think I may have a good starting point for the new injectors that makes sense with the math.

To summarize the above post, OEM 28 lb/hr injector to Bosch 42 lb/hr injector is a 50% increase in capacity.

The confusing part is: looking at another forum members Flow Rate vs Pressure data, his values are increased less than the 50% by enough of a margin that I needed to find out why.

The possible culprit is: The Bosch 42 lb/hr injectors are rated at a nominal fuel pressure of 39.15 psi according to a data sheet I found (link is in above post) but our Sonics run at 58 psi.

This is my plausible theory: The Bosch injector nominal fuel pressure of 39.15 psi is 67.5% of our Sonics 58 psi (58 x 0.675), so if you take the injector capacity increase of 50% and reduce it to 67.5%, you get 33.75% but we'll round to 34%.

So rather than add 50% to the values in your Flow Rate vs Pressure table, we're only increasing those values by 34% due to the difference in fuel pressure. This gets the values pretty close to the values in the other member's table and will be my starting point.

Not a lot of replies in this build thread but if anyone has something to add, please do so! Otherwise I'll continue to update as new info becomes available.

 

[Hulty]

Ok, Did a few pulls, played with timing and fuel a bit but they were really pretty spot on to start with. Tried adding a degree of advance but then started getting a little KR, it was a little on the rich side in the upper RPMs so I leaned it out a smidge but none of these things made a difference of more than a few HP and TQ.

So, I ended up with... Drumroll please... 151 HP and 201 TQ. I am happy with the torque but I was hoping the horsepower would've been a little higher, BUT I am stock except for porting the intake manifold. I suspect if I had an exhaust and intake to open up the breathing I would've seen higher numbers.

With how my car is, mostly stock, I don't know that I can get anymore power from it and still have a bit of a safety margin. IDC was around 90% so there is very little room for more fuel, which means I cannot really crank the boost up more; and the timing is about at it's limit. SO... with no more fuel, boost or timing available I think this is where I'll be for a while.

Stew, looking at your Dyno data, is your engine pulsing? My dyno looks similar and I've noticed pulsing off and on for some time now.

Any idea what or why that is?

 

[94383Z71]

I am following this as well, and was very interested in your injector flow information. I just didn't comment because I had no idea

 

[Stew]

Stew, looking at your Dyno data, is your engine pulsing? My dyno looks similar and I've noticed pulsing off and on for some time now.

Any idea what or why that is?

It does look like it from the graph but I was in the car during the pulls in the passenger seat looking at my laptop and monitoring data and I could not feel any minor differences that you see in the graph.

I was not given a printout, I got the files on my flash drive and downloaded the WinPEP software in order to view them. In this software you can smooth out the graph more or less depending on your preferences, scale the X and Y axis's however you want and more.

In fact I must have not scaled something right because the HP and TQ are supposed to always intersect at 5250 rpm and mine is closer to 4250, but those are my real numbers I swear!

I think the biggest thing that contributes to a pulsing that you are able to feel is when the ECM is intervening due to knock retard, it can retard timing and/or close the throttle to keep things safe.

 

[Stew]

They're here!

Going to wait to install until the Ultragauge gets here though.