Exhaust bypass. Loud??
02-21-2008, 10:11 AM
#16
Rennlist Member
Is that a cat bypass? Looks the same as my 100 cell cat.
I am running a 100 cell cat (keep it legal) and magnaflow muffler, cup airbox. Not bad at all. It is quiet around town and growls when pushed hard. Haven't test db's yet but I am sure it is Lime rock friendly
I am running a 100 cell cat (keep it legal) and magnaflow muffler, cup airbox. Not bad at all. It is quiet around town and growls when pushed hard. Haven't test db's yet but I am sure it is Lime rock friendly
02-21-2008, 10:57 AM
#18
Rennlist Member
Tell me/us about the Magnaflow- I assume this is instead of the primary and you've deleted the secondary?
02-21-2008, 11:36 AM
#19
Rennlist Member
Yes Primary and secondary mufflers gone at a considerable weight savings and performance especially low and mid range increased.
02-21-2008, 12:24 PM
#20
Rennlist Member
What size did they use do you know? Single in and out?
This is the way I am going- I only have a HF cat but its too loud. A good light primary replacement is what I need. The Fabspeed muffler is an option but I think very pricey for what it is.
This is the way I am going- I only have a HF cat but its too loud. A good light primary replacement is what I need. The Fabspeed muffler is an option but I think very pricey for what it is.
02-21-2008, 12:32 PM
#21
Rennlist Member
Don't have specifics or pictures yet. Single in/out same dia as the adjacent piping weighs very little. IIRC the muffler including fabricating the piping in SS and installation of the 100cell cat (I supplied cat) was around $400. However we did use the existing G pipe I had and tail pipe.
02-21-2008, 12:41 PM
#22
Drifting
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Cobalt, is your setup going to be like the original in that you can still unbolt the custom primary and swap back to oem if you want? Or is it going to be all welded together?
02-21-2008, 12:52 PM
#23
Rennlist Member
02-22-2008, 10:08 PM
#24
Rennlist Member
My 2 cents
I have a highly modified car, incl a G-pipe/secondary by-pass. It is pretty loud. It satisfies my additction for external exhaust sound, but it is not very sophisticated sounding. It kinda sounds like a camaro. In some ways, I miss the stock sound that used to fill the cabin. Overall, I want to get a real, full performance exhaust system and try to maximize the sound quality, ASAP.
02-23-2008, 03:08 AM
#25
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How does the sound compare between a g-pipe and just not running a 2ndary exhaust at all (meaning no g-pipe to re-route the exhaust tip towards the back of the car again)
I have been running my car around like this, with just the secondary exhaust off and no g-pipe. However, it seems like it fills up the cabin with so much engine sound, it is almost hard to talk sometimes, at idle. While cruising, I don't have a problem with it. However, whenever I pull up to someone, it is hard to hold a conversation with anyone outside of the car.
I have been running my car around like this, with just the secondary exhaust off and no g-pipe. However, it seems like it fills up the cabin with so much engine sound, it is almost hard to talk sometimes, at idle. While cruising, I don't have a problem with it. However, whenever I pull up to someone, it is hard to hold a conversation with anyone outside of the car.
02-23-2008, 04:01 AM
#26
RL Technical Advisor
One should be aware of the engine's characteristics when making exhaust changes such as all these,.... 
All things being equal:
With the Cup (primary muffler bypass) pipe, the motor makes more HP but less low & mid-range torque.
With the G-pipe (secondary muffler bypass), the motor makes more low & mid-range but not as much HP as the Cup bypass pipe installed.
The Euro premuffler (cat bypass) adds power everythere in the RPM range.
Significant exhaust changes such as the cat bypass AND either primary or secondary muffler bypasses require different software for maximum gains since the AFR's are really changed.
Here's a dyno graph to look at. Both are 3.6's but one has RS cams (10HP), chip, cat bypass & secondary muffler bypass. The other is bone stock except for a chip.
All things being equal:
With the Cup (primary muffler bypass) pipe, the motor makes more HP but less low & mid-range torque.
With the G-pipe (secondary muffler bypass), the motor makes more low & mid-range but not as much HP as the Cup bypass pipe installed.
The Euro premuffler (cat bypass) adds power everythere in the RPM range.
Significant exhaust changes such as the cat bypass AND either primary or secondary muffler bypasses require different software for maximum gains since the AFR's are really changed.
Here's a dyno graph to look at. Both are 3.6's but one has RS cams (10HP), chip, cat bypass & secondary muffler bypass. The other is bone stock except for a chip.
02-23-2008, 10:07 PM
#27
Rennlist Member
I had my software then dyno done by Vitesse. I agree- when playing the Sorcerer's Apprentice you should measure what you're doing. With no cat, primary or secondary my car is +25hp/tq over stock but -25 vs. Derek's car which is similar but with no cat and primary bypass- we're still trying to figure that one out
BTW- with only a cat ( no primary or secondary) on the way home from the dyno a Cobra GT (with headers and exhaust I'd say) pulled up beside me and said "Niiiice sound- turbo??" Embarrassed I said, nope N/A. I was probably less than 1/2 his BHP.
Still, better I guess than him saying "Hey yer car sounds like ****".
BTW- with only a cat ( no primary or secondary) on the way home from the dyno a Cobra GT (with headers and exhaust I'd say) pulled up beside me and said "Niiiice sound- turbo??" Embarrassed I said, nope N/A. I was probably less than 1/2 his BHP.
Still, better I guess than him saying "Hey yer car sounds like ****".
