Nice gains with the tune. I'm assuming this was an automatic?

 

I don't have experience with DI tuning yet.
Neither with Diesels.
Is it possible that the spray pattern / atomization suffers to a degree where it could have an adverse effect?
Meaning, 19% isn't really 19% capacity if you catch my drift?

 

Nice 21MC! Can I ask you a question, do you find the tunes are different based on the driving modes?

I posted a thread up earlier when me and my buddy pulled the tune off with hptuners last week and were looking at it. I did see the FI tables and was quite shocked.

Both him and me had FI/DI cars before this, so we are excited about throwing a tune on, any insight would be a help. He has tuned thousands of cars, but we just havent had the time to do a proper street tune followed up with a dyno test and logging.

In the turbo cobalt ss world (Direct injection stock turbo, in which the ats motor is an evolution of the LNF) injectors was never an issue, it was the high pressure fuel pump. Many guys were running 4-500whp on injectors that came stock for a 260 crank hp car.

 

What did they do to resolve the fuel pump issue?

 

Nothing to successful per se, some companies came out with cams that had a slightly bigger fuel pump lobe on it to increase duration and try to get the pump to just pump longer / harder / more etc. A friend of mine just put them on and we went to the dyno, due to other reasons, he didnt make any more power. The cobalt SS' dont have that big of an aftermarket support unfortunately, which is a shame because the motor is just awesome, and makes crazy power, and torque.

I routinely made 310whp/360wtrq out of the stock tiny k04 twinscroll turbo and ran high 12's on street tires on just an intake, catless downpipe, and a tune (thats 100whp and 140wtrq over stock out of basically just a tune). Its gone now though...

 

From what I remember didn't you Cobalt guys have issues holding the transaxle together?
(Unlike the SRT crowd).

 

Not particularly. My trans and stock clutch held that just fine. I was conscious not to beat on it down low though. It was really hit or miss, some people would blow the trans bone stock, and some people had serious power with no issue. Really it was more of an abuse or fluke thing. Realize most of the owners of the car are younger, and now that the turbo ones are entering the used market and getting even cheaper, there just gunna get flogged more.

I wish I could have kept mine and do the vette, I feel like some day Ill look back and see one in still decent condition and wish I still had mine / maybe itll be worth something (not crazy money, but some value)

 

I'll never sell my neon. These type of cars are dying out.
And the T850 usually handles up to 750 whp / trq.
Not sure what the tubo 'balts can do, I was turned off by their blown predecessors...

 

Then you do not understand it is not about MPG.

It is about emissions. It is about achieving and maintaining catalytic converter temperature. There are 20 other things they have to look at than MPG.

I know a lot of people say tuned cars drive like stock, they probably do 95 to 99 percent of the time but for an OEM it has to be 100 percent of the time.

I have my Regal GS tuned, 330hp from 270 stock, 65ft lbs over stock. It has a hair trigger gas pedal, its pretty jerky on the freeway because 22lbs of boost is about 1/8" of an inch away on the pedal.

It's much faster and I like it, but most would not and would complain. That is an extreme example but it rarely has much to do with MPG. Drive ability is a big thing. Especially on manual trans cars, they put a lot of work into on pedal/off pedal and slapping/slack in the drive train.

 

Your tuner should be able to adjust the pedal sensitivity, some of my first tunes had a hair trigger pedal like that. If they do it enough, they will figure it out. If not, I can hook you up with the one who did all of mine, he is very familiar with the systems. I should try to get him on the forum, as Direct injection is tricky business.

 

Nice work as always John Page!

 

Interesting... thanks for the info. Direct injection is new to many of us.

GM never said that. A troll posing as a GM engineeer Big_Gunzz on LS1 tech did. He had a whole flock of people riding his ***** before being outed.

 

OP, great results.

I love this platform as there are so many performance options.

Does your tune only operate in certain modes? Say the track mode only? Or does it work at all times?

Would you have the option of getting the full power program in track and maybe the best mpg program in 4 cylinder mode, or something like that?

On mpg & tunes, my previous car gained 50 rwhp with bolt ons and gained a solid 4-5 mpg. It was a pretty large improvement.

 

For most guys who develop and tune engines, there's a pretty big disconnect between what the aftermarket is doing and what they are doing. I said earlier the injectors can be "maxed out" from the perspective of impinging on the piston and cylinder wall. But we know that there are plenty of DI engines running around with much longer injection duration than stock in order to support a lot more horsepower. The owners of those cars probably wouldn't even know that their car is putting out way more smoke or diluting the oil more than necessary.

Considering most guys who mod their car take pride in changing the oil every 2500-3000 miles with expensive stuff, the mindset is going to be totally different from an engineer trying to tune the car specifically for max oil life. Also, the durability requirements are very different. When you run durability on an engine dyno, it's sitting there at a steady-state condition for what most would consider a very long period of time (it could be say anywhere from 5 minutes to an hour straight at WOT). In a car, you bang through the gears in a 1/4 mile and that's it. An engine dyno can't recreate that so easily, so something that shows up in a vehicle transient may be hard to catch during a tight development schedule. Look at the transient knock issue that the Subaru BRZ has had.

So when leaning out for power you might drop an exhaust valve in a manufacturer durability test but would never see that on the street unless you slap twin turbos on there or something. Or in the case of forced induction, the block may have been designed to withstand a low speed preignition event that you might never hit on the street, only an engine dyno. That's part of the reason why blocks designed for boost often hold up so much better than blocks not designed for it. The durability targets are set for a lab environment.

 

Outstanding! Great work and in an incredibly brief period of time. You guys don't mess around do you.

+35tq on top of a very favorable stock LT1 tq curve will give this car a huge "fun to drive factor". Gorgeous graph.

The car has only been out for a little over a week and the aftermarket has bumped the power in significant fashion. I can't wait till someone fabs up a set LTs and gets the numbers on that setup. This is going to be fun for sure.

 

Great work and my oh my, this was quick!

Could you post what the OEM A/F looks like vs your finished tune? Are these running rich from the Factory or Lean?

 

Maybe.

I think your example of tuning is a bit exaggerated especially being boosted. I'm sure the tuned C7 does not drive like what you are describing.

All I am saying is that when the car manufacturer, who has control over EVERYTHING (cam size, head design, displacement, pistons, injection type, tuning, fuel type, weight, CD, etc etc etc) can't give us better numbers than what they did, and then in the first few days of this car being out an independent tuner picks up 30rwhp and rwtq something is being held back

 

They give you a nice safe tune from the factory. A tune that allows for a multitude of variables including fuel, temp, etc. It makes perfect sense.

 

So in a few years when they pick up MPG and HP are you gonna buy that they "changed the intake runner" or "went with a less restrictive exhaust"?

 

Why are you so butthurt here? Go troll somewhere else.