Secretariat,

Your fine to add an intercooler, charging piping, and high flow catted DP to your car. The GMS1 tune will work with all of that. I dont think your car will make any more power than you already do though.

 

well the car does adjust boost to compensate airflow and density. This is true of the factory tune and I believe the GMS1 as well. Fuel trims being off are usually a sign of a leak, or the way a sensor measures has been altered (intake tube diameter is greater, parameters of MAF need to be adjusted as a result.)

 

Trims have to be adjusted when modding. Period i have already explained it well enough

 

Kmo has change intercooler is his own car more times than anyone lol

I was told the same from my previous tuner, that I would be fine with no tune after my intercooler swap but I got the bigger size zzp intercooler, my trims where pretty bad if you ask kmo

 

define pretty bad... Have you looked at the trims of an unmodified cobalt?

 

Ya 1 year i spent buying intercoolers each month it seemed. Going from ZZP back to stock was a huge difference

 

omg the intercooler is a sealed system!?! The air going in is already measured, it takes a fraction of a second to build to target boost with a larger intercooler vs the factory IC. Its not going to change your trims!

 

Idk my trims aren't the same and I upgraded charge piping and my intercooler. I got a tr10 so it's a very large intercooler. I've been needing a retune for some time and I'm finally getting HPTuners to be retuned by KMO43 instead of me having to drive a couple hours to get a tune every time I need a retune. But none the less my trims haven't been right since I upgraded.

 

A new wideband sensor will tell the true story though lol.

 

People are feeding a lot a miss information.

Throw bolt ons on the car, and enjoy it. Nothing is going break.

These forums are as bad as Facebook with BS propaganda.

 

He can put that parts on for sure nothing should brake, it just best to get it tuned to what mods you have instead of using a tune not made for them. I'm sure gm wasn't thinking let's do the tune and make it ready to go with a intake, high flow dp and another intercooler.
And bs on the Facebook comment

 

needing a tune because of fuel trims not being 0.0 at all times is a tuners selling tactic. Its been happening on this site since Ive been on here.

If your long term fuel trims are between +8 and -8, guess what, your car is fine and isnt going to explode. CEL trips at ~18 and up. if your CEL trips, its because you have a bigger problem than installed charge piping or intercooler..

The factory tune shifts anywhere from +8 to -8. I think Ive even seen it higher on a completely stock car.

Never in the history of css.net has anyone pointed to changing charge pipes and intercoolers as a cause to fuel trims shifting. This is a css.net first. You've heard it here first people!

 

I said that adding parts can lean out the fuel trims which is fine but in some cases when it gets bad it can knock. The Gm Stg1 and stock tune already run quite lean.

 

Here is a pic of a log from a Stg1 car with an intercooler and a DP. He had 0* knock but he was seling the car and he didn't like the idle. I told him I could get it to idle normal by tuning the trims and he wanted this so I cut him a deal and just did the trims and PE table (cause I hate it stock) with the MAF tuned it idled and he's happy with it.

If it was my car I prob would have left it and when I showed the car I would have it warmed up already but this is something he wanted to fix so I helped him out. In this case since there is 0* knock I would run the car it won't hurt anything.

 

The K&N intake runs 10-15% too lean in the upper RPMs/airflow with GMS1.

My long term fuel trims were +-3% which seemed good to me, but the upper RPMs were getting knock. Our computer loves to knock if the fuel trim is off.

But will an intake kill the engine on GMS1? No. I have about 75k miles on GMS1 and intake and intercooler.

Make sure to run good gas and take care of your car. GMS1 is very conservative.

Also, GMS1 has too much timing in the midrange and loves to pull timing. But I think GM did it for fuel mileage and knew the computer would compensate.

 

Nothing personally directed towards you, but you brought up a beef that I have with a lot of people's typical Cobalt parts recommendations.

Actually, one of the biggest bits of misinformation that gets passed around this forums is how you need "all these mods" to make power. Many of you guys just take other people's words for it and lack any of the real world experience with these cars to see how little, if any, of a difference most of these modifications make. In fact, some of the commonly recommended engine modifications will actually reduce the power output of the motor, sometimes even with a tune to calibrate for them.

Lots of you guys will buy intakes, and get all giddy over how loud the turbo sounds, and how much more noticeable your bypass valve sounds. You will claim up and down to your forum buddies to buy it, and show it off. But you fail to mention to them that you didn't dyno test these parts and didn't monitor the 30+ degree intake temperature increase that the new filter placement and intake elbow material caused at the MAF sensor. This then calculates into the airflow, the timing advance tables, etc. You can't necessarily make hotter air more powerful than cooler air, and many of you will just willingly pay a few hundred dollars for the intake to sound cool, you'll lose power, and you'll convince others to do it to.

Then the same goes on with a lot of the exhaust recommendations, Downpipes with or without cats, catback exhausts (only performance gain there would be potential weight savings if you bought a lighter system). GM Stage 1 sensors, while still running a stock K04.....lots of recommendations out there from lots of you guys sometimes with little to no valid reason other than adding expensive parts to your mods list for the sake of One Upping each other.

The reality is that you need a tune that calibrates the car and its trims to within very small tolerances. Then properly dialed in requested airflow, torque, timing, and other tables. With a proper tune you can virtually make the same power out of a bone stock showroom LNF, versus someone who added, Intake, Charge Pipes, Intercooler, Downpipe, Exhaust, etc.

I usually recommend the Charge Pipes to people who dont want to worry about breaking the stockers, or for Kappa cars where it looks like gorrillas bent them over brick walls in a factory. Intercoolers are iffy, sure having plastic end tanks sucks on the stocker but they are efficient and take a lot of abuse to heat soak on the road. Sure the intercooler will heatsoak sitting still on a dyno, but you aren't moving dragstrip volumes of air over it while spinning the rollers either.

 

Knock Retard shouldn't be viewed like a convenience for removing timing, it should be viewed as a warning sign of dangerous conditions. If the tune needs to pull timing, it is because the tune is impractical, or the driver is to blame for inducing way more load on the engine that at that RPM and load% than what the engineers predicted. (i.e. Flooring it in 5th gear from 2k RPMS uphill)

 

zzp charge pipe, treadstone tr8 intercooler are not going to throw fuel trims. Just saying..

I added brand names in case you guys are using something that routes charged air outside the car, through the passenger window, under the passengers butt, across the drivers dick, out the driver side window and connects to the exhaust.

That surely would throw fuel trims off.

 

They will. Many ppl just said so......

 

Modded stock intake FTW

 

So I did not need a catless DP? People were, and still are stating the stock is a bottleneck.

 

The stock downpipe is a bottleneck. 5-10hp gain when tuned.

I just gutted mine with a piece of pipe.

 

Catless Downpipes make some noticeable difference........but ONLY and I mean ONLY if you have a tune specifically for it. Otherwise you are wasting fuel and killing power. I have run across a lot of people with Catless DP and no specific tune for it, or just an O2 extender, etc.

Highflow DP are not generally a very good idea, just due to the typically inferior quality of the catalytic material used by aftermarket parts companies. I would say either go catless or stay stock.

 

And gains are very much in the single digit level. Gutting the stocker sure does save money ;-)

I usually suggest to people that if they want 3-5 more horsepower and don't mind paying a few hundred bucks for it, and want to take off their down pipe, then go for it. But otherwise keep the money in your pocket. These stock cats aren't the bane of existence, and $100 per horsepower is too steep for many people.

Worst is when they spend $500 - $1000 on exhaust and expect to be making more power because of it. Or a couple to a few hundred on intake and either gain nothing or lose power from it.

 

FOR GMTU(or GMS1 as you guys call it)

The tune was designed to deliver torque and HP at a certain value which means the ECM will do everything it's capable of doing to limit your TQ and HP output at xxxxrpm. Bolt ons for the purpose of adding power is a WASTE with GMTU if you are looking for dyno # improvements.
Any and all modifications in the intake tract that changes the way the air moves past the MAF can and will skew trims. The ECM/tune is adaptive and will compensate to a degree iirc.