TimMoffett

So I did the APR stage 2 - which I love. I am not so in love with the speed of the 1-2 and 2-3 shifts. I thought I read somewhere that there was a bypass valve upgrade that would speed up the release of boost pressure to make the shifting process not have to wait so long. I could be totally full of BS here...

Wondering what else I might do - if I am at the limit then that's cool, just didn't want to be missing anything.

I don't see exhaust or intake as a "performance" mod but I could be wrong?
Was thinking of trying out an aftermarket air intake for more sound quality but it's not a huge priority.

Definitely going to do the Eibach lowering springs as my C7 is not a sport model.

IknowHuhA6

Forgive the curiosity... I thought I read you had experience building mopars so wanted to learn from your experience. Why do you say that exhaust or intake is not a performance mod?

I can partially agree if not done correctly. Engines are basically air pumps where the increase and efficiency of intake and exhaust create additional power. I know I'm over-simplifying but curious about your view on the matter.

Thank you.

TimMoffett

I say that because I have not heard of or seen anyone that made notable gains in performance by replacing exhaust.

Doing it wrong? Yes that can have a dramatic effect - and I did spend much time designing the exhaust on my BB Mopar. Was faster with full exhaust than open headers.

I think Audi did their homework on exhaust - to the degree that it's not low hanging fruit, which is what I meant...

IknowHuhA6

Ah thank you for the explanation. I agree that an exhaust cat-back doesn't seem to give big improvements in power. The choke point remains the same if the exhaust manifolds/headers remain unchanged. We change the exhaust to bigger better designs but the air being pumped out is still limited by what the exhaust headers can provide. And even then the head port size, and valve size and rocker ratio also remain unchanged which doesn't improve airflow. This is where I find it fun in building horsepower as we put pieces together to build a system.

I'm looking forward to the day I can get an extra set of heads and start experimenting.

I found out the hard way about scavenging.. .so I understand completely getting better power from an installed exhaust system vs just running open headers.

Thank you for the reply = )

Regarding your bypass... wondering if you're talking about the Chipwerke chip system that tricks the bypass to open later than normal.

TimMoffett

The bypass comment was from something I read - but I think it must have been for turbo engines. Saw an aftermarket one that got rid of boost more quickly - and thus sped up shifting with auto transmissions. Like I said, I am way off on this for sure...

I am looking forward to the cooler air - got my car tuned recently and we've had nothing but 90 degree days since!

LiX

With auto transmission if you don't take off your foot from the gas pedal, the BOV should not discharge while the trans is shifting.
BOV discharges when there is a difference in pressure before and after the throttle body.