3" Stainless Steel Cat-less downpipes
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I am starting to think about mods for my FS. Had the car over 2 years now.
1. Are DPs a good first mod? Seems like opening up the flow coming right out of this engine is logical, plus the HP gains calculated by darkstar. I think a tune is where I will go next.
2. I saw the video that darkstar posted regarding the sound. Even with videos though I still think that it is tricky to REALLY tell what the true sound is. I am not looking to significantly alter the factory sound. I drive a lot on the highway. I don't want any "drone". I don't mind a little extra acknowledgement when I am accelerating. Can anyone give me some feedback on what they have experienced here?
I would do the "catted" option.
Thanks!
Tom
1. Are DPs a good first mod? Seems like opening up the flow coming right out of this engine is logical, plus the HP gains calculated by darkstar. I think a tune is where I will go next.
2. I saw the video that darkstar posted regarding the sound. Even with videos though I still think that it is tricky to REALLY tell what the true sound is. I am not looking to significantly alter the factory sound. I drive a lot on the highway. I don't want any "drone". I don't mind a little extra acknowledgement when I am accelerating. Can anyone give me some feedback on what they have experienced here?
I would do the "catted" option.
Thanks!
Tom
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Tuner first for sure. Everything thereafter is built on that.
I have Darkstar catted DPs - The sound is absolutely a great growl on start up and is especially noticeable when cold. But it isn’t even perceptible to my ears from inside the car when out on the road. I don’t know if it’s a true fact that the catalytic converters need to “light off” but the way mine sounds on cold start until it warms up, it seems like the cats are “bypassing” (?) exhaust until they get up to temp. The quality of the Darkstar pipes are like a work of art. I didn’t know whether to put them on the car or hang them in my living room - (my wife helped me decide!)
I have Darkstar catted DPs - The sound is absolutely a great growl on start up and is especially noticeable when cold. But it isn’t even perceptible to my ears from inside the car when out on the road. I don’t know if it’s a true fact that the catalytic converters need to “light off” but the way mine sounds on cold start until it warms up, it seems like the cats are “bypassing” (?) exhaust until they get up to temp. The quality of the Darkstar pipes are like a work of art. I didn’t know whether to put them on the car or hang them in my living room - (my wife helped me decide!)
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Tune-only should get you into 12s easily. An aftermarket FMIC is about the only worthwhile mod from what I have seen here on the forums and based on my research. When you max out the stock turbos, the charge air temp rises to 100F over ambient, which is too much. The FMIC is supposed to drop that by 70F, or about 40-70 hp "gains". I believe Twin Force Fusion saw the most gains because his tune wasn't really that aggressive.
I've yet to hear a single EcoBoost (except for the Ford GT) that sounded anywhere decent with an aftermarket exhaust system. It mostly sounds like a cross between a diesel pickup with the turbo wind-down or a Japanese import with the fart can BRRRRRRRRRPpppp sound. The OEM exhaust systems attenuate that sound to prevent hearing the wind-down and the fart can sound.
I've yet to hear a single EcoBoost (except for the Ford GT) that sounded anywhere decent with an aftermarket exhaust system. It mostly sounds like a cross between a diesel pickup with the turbo wind-down or a Japanese import with the fart can BRRRRRRRRRPpppp sound. The OEM exhaust systems attenuate that sound to prevent hearing the wind-down and the fart can sound.
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Yup.
The only non V8 car I owned that had a great sounding exhaust from the factory was a new 2004 SRT-4.
It came form Dodge without a muffler, and didn't need an aftermarket exhaust!
https://youtu.be/pgEKptQtA2I?t=161
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YES!
The Fiat 500's stock exhaust actually sounds nice too, like a very growly and aggressive 4-banger almost on-par with a Subaru boxer sound (but not too much like a lawnmower).
My Cobalt SS Turbo from the factory has cats, a resonator, and a "muffler" which is a box with a straight tube inside (non-perforated). It idles like a Japanese sport bike, but is very docile at WOT. I heard people that removed the resonator and muffler on the Cobalt LNF and it caused it to sound like a ricer, so I never touched the exhaust on it.
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Seems like we have something else in common besides Fusion Sports, Cobalt SS's!
I owned a new '07 Cobalt SS Supercharged and had the dealer install the factory GMPP Stage 2 kit (pulley/injectors/tune).
In 2008 I did a same day/same dyno test vs. a bone stock '08 Cobalt SS Turbo:
'07 Stage 2 GMPP Supercharged - 227 hp/203 lb ft torque
'08 Cobalt SS Turbo - 237 hp/ 258 lb ft.
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The Cobalt SS is a fun car to drive! The Stage 2 kit for the SS/SC really bumped up the power! GM pretty much killed most of the stage kits and development for the SS Turbo with the 2008-2009 subprime mortgage crisis, but they did release a Stage Kit that was comprised of a weak ECU reflash and 3-bar MAP sensors. I bought the plug-n-play harness kit and the 3-bar MAPs separately, then reflashed the ECU with HPTuners (which got me hooked into using HPTuners for Fords) with a more aggressive E40 tune. The stock intercooler is amazing, it's like an aftermarket FMIC for the Fusion Sport. I run 20-21 psi on the Cobalt and the stock FMIC barely rises in temperature (stock turbo is a K04). Rumor was that GM was going to release a Stage 2 kit that had a special ram air intake, but cancelled it due to the disbanding of GM Performance division.
I have the rotated trans mounts because the stock F35 trans/driveline wasn't angled right from the factory, resulting in really excessive wheelhop (my rear mirror would droop during a launch). I tried the K&N ram air, but went back to stock due to the hot air the K&N was ingesting. I saw a performance increase with the stock airbox due to the cold air going in. I also installed some adjustable front sway bar endlinks.
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So wait, there was a supercharged and a turbocharged version of the Cobalt SS?
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I replaced my exhaust 2 years ago and I love it. It's not raspy and has never popped. When I drive next to a fart can there's a huge difference. My exhaust is much lower and smoother. Of course it's not a V8 but it still sounds great. The key is the Magnaflow Tru-x resonator. It's what makes the sound. I then added two round mufflers and kept the stock tips. You can use more restrictive mufflers for a quieter sound. I paid around $500 installed. After 35000 miles I have no desire to go back.
Plus loosing that giant, heavy, water heater of a muffler that it came with saves weight. Stick your head under the back. This thing would be huge on a truck.
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Yes, 05-07 SS was the Supercharged (SS/SC). 08-10 SS was the Turbocharged. The SS Sedan was available for 2009 as well. Easiest way to spot the differences is to look at the wheels. The smaller spoiler was standard on the turbo SS's, and I paid extra for the larger wing that was stock on the 05-07 SS. I also added the USB drive and Reprogrammable Performance Display, and the Quaife Limited Slip Differential.
The Turbo engine was designated LNF, and is a GTDI engine with a water/oil cooled K04 turbo: 260 hp / 260 ft-lb. Basically the grand-daddy to the LTG 2.0L GTDI used in the modern Cadillac ATS / Malibu 2.0 / Camaro 2.0 engines. My girlfriend has the LTG in her 2015 Malibu Turbo, and they are very different engines but I can spot a few similarities in its DNA.
The LNF was first developed for the 2006 Opel GT, which eventually arrived to the US as the Saturn Sky Redline / Pontiac Solstice GXP. They then put the LNF in the HHR SS and Cobalt SS/TC. I believe the Fisker Karma got the LNF for a few years as well. VW/Audi had some of the first GTDI engines (FSI) and the LNF arrived later on. Basically these were Ecoboost engines before Ford ever coined the term Ecoboost.
The GM Stage Kit brings the 260 hp to 290 hp, and it is a very very mild tune with only a few extra psi of boost at WOT. GM tested the Cobalt SS Turbo at Nurburgring and John Heinricy ran it out to 160+ mph, basically pegged out the throttle/RPM in 5th gear. I believe it set a lap time only slightly slower than the 2010 Camaro SS at Nurburgring at the time.
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My apologies to the OP, promise this is my last post on the thread regarding the Cobalt SS.
Pic of my SS/SC when she was new ...
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Hey DAS
Wondering if you have the parts numbers by any chance?
And do you have a video with soundclip?
Thanks
Wondering if you have the parts numbers by any chance?
And do you have a video with soundclip?
Thanks
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The thing is, the stock "restrictive" exhaust isn't restrictive. There are those with catless downpipes and cat-back exhaust systems that yielded minimal gains on the dyno and the track. The weight reduction isn't worth much on the dragstrip either. I've messed with cat-back systems for over 20 years and the lessons learned is to just keep it stock unless there's some kind of factory/Ford Racing kit available and even then it is only for sound.
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On the FFS? Yes and no. The stock exhaust is indeed restrictive, but most folks running catless downpipes are already tuned, and most tunes available push our tiny stock turbos close to their effective limit. That is why guys are seeing minimal gains when they open up exhaust after.
As was already mentioned, the upgraded FMIC is the better mod since these ecoboost engines run very hot and are prone to heatsoak. High IATs will cause the ecu to aggressively pull timing which robs us of considerable power
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Of course it's for sound. Stock is like an electric car with horrible, fake sound coming through the speakers. It's like putting a card in your spokes so it "sounds" like a motorcycle. Weight and flow gains are just a plus if anything. Not a reason.
Another big reason is when paddle shifting. You can keep your eyes on the road and hear when to shift. The stock exhaust is a lot harder and you spend too much time looking at the dashboard.
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Agreed. I was in the first group with Darkstar's intercooler. I really noticed a difference.
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The stock turbos max out at 43-44 lb/min with a tune, so the stock cats/piping aren't a restriction. I wouldn't use the paddles to up-shift because it is a lot slower than letting the ECU do its thing. This isn't a twin-clutch automated manual tuned by Michael Schumacher. It's a transmission designed for soccer mom Traverses and Explorers also doing double duty on some performance models.
The aftermarket FMIC is about the only mod I'd recommend, as the stock FMIC has a temp rise of about 100F over ambient at full boost. Any reduction would help as cooler air is more dense. It's not just about the timing, as I can still run about 17* advance at WOT with a lot of boost using the right fuel.
To me, the aftermarket exhaust systems for GTDI/Ecoboost sound like a ricer fart can mod with a diesel pickup truck turbo wind-down, something a high schooler would be interested in. The stock exhaust system is just quiet from the outside. The fake engine noise isn't my favorite but there's no drone and it is quiet. I've messed with catbacks and downpipes for over 20 years and the lesson I learned is to just stick with stock, especially as I got older.
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