Exhaust note?
#2
The turbo acts like a muffler and quiets the exhaust down. Hopefully the HHR SS will get vendor support and you'll be able to go aftermarket on exhaust components, turbo, wga, suspension, etc.
#3
Last edited by c2vette; 02-10-2008 at 05:17 PM.
#4
I think the Chevy engineers did a great job on the design of the stock system. Large diameter, and fairly straight run with no kinks or flattened sections like you see in a lot of stock systems. For now I am sticking with the stock system as I like the sound quality and loudness, and prefer a good sound system to a loud exhaust. As you can see, there is not much to the stock silencer, so a "cat back" replacement might just be a straight pipe with the turbo and the cat providing all the sound suppression. Run the risk of it sounding "raspy" though.
Aw dude, you flipped your car on its side!
Last edited by HillsdaleHHR; 02-10-2008 at 10:31 AM. Reason: Removed pic from quote
#6
Doen't exactly apply, BUT I understand one of the exhaust manufacturers (name escapes me right now) claims a dyno run of 25 extra ponies on a Solstice GXP. If memory serves me correctly, the "system" was basically a different muffler and larger exhaust pipe from the rear of the turbo. Generally the thinking is the larger pipe allows the turbo to run faster/better/smoother.
#7
#9
Doen't exactly apply, BUT I understand one of the exhaust manufacturers (name escapes me right now) claims a dyno run of 25 extra ponies on a Solstice GXP. If memory serves me correctly, the "system" was basically a different muffler and larger exhaust pipe from the rear of the turbo. Generally the thinking is the larger pipe allows the turbo to run faster/better/smoother.
sound quality was much better and it was only slightly louder than stock.
Initial dyno tests some did show a hp increase but much of it is LEARNED
OUT by the new Bosch MD9 ecm that the GXP and HHR SS uses. It is different
from anything else US mfr are using. If you do a mod to increase HP and it
exceeds the torque limits programmed into the ecm, it will be reduced back
to close to stock. It has been shown many time by tests over on GXP forum.
There are ways to bypass including the BSR PPC tuner and some of the
software tuning in US are getting close to be able to modify boost tables
without getting LIMP mode. They can now change the PE tables to
increase fueling if you do the wastegate mod.
turbofreak
retired engineer on GM racing programs