Thinking of going duals...
Founding Member
Joined: 11-23-2007
Posts: 8,210
From: Texas
I'm the kind of person that doesn't see a reason for this unless we are talking about HP gains. 4 banger from factory with duel is sometimes okay. Duel on a >200hp or economical car is retarded to me. I'd rather do in dash NAV and sync my smart phone than go duel exhaust.
BTW Capp's pic is what I would refer to as fart cans and ricing it out.
BTW Capp's pic is what I would refer to as fart cans and ricing it out.
Senior Member
Joined: 12-22-2010
Posts: 171
From: Bremen, IN
Just out of curiosity what is the maximum restriction allowable to be imposed by a full exhaust system, and what is the optimal backpressure from an exhaust system on these? The reason I ask is because of two things. The first is I have seen an exhaust system be too open, and that caused fuel economy loss. Also, the max backpressure thing is because I really want to know. I know working for Cummins and seeing datasheets on our engines every day that is one of the things specified on most engines we have.
In relation to the above questions, what would be an optimal exhaust size, whether duals or a larger single exhaust?
In relation to the above questions, what would be an optimal exhaust size, whether duals or a larger single exhaust?
Deceased
Joined: 06-30-2010
Posts: 25,739
From: Kannapolis NC
Interesting questions for sure, and I'm not positive that you'll find easy answers to them. The GMPP Exhaust is made by Borla and while the pipe diameter is the same as stock, the less restrictive muffler gives about a 3-5 horsepower gain, maybe a tiny bit more when combined with the GMPP CAI.
Yeah 3-5 hp, oh boy! Its the sound more than anything that you get from a performance exhaust on the HHR, if it sounds faster, it feels faster as they say.
You do need exhaust back pressure for proper cylinder scavenging, how much is optimal on the Ecotec, can't tell you. You'll see folks here running pipe diameters from 2 1/4" out to 3" with no real reason other than looks and perceived power gains(unless they spend the time and money to do some dyno pulls comparing different configurations). Can an exhaust be too open, you bet, especially when combined with a restrictive intake.
If I were to go the "Duals" route myself, I'd start with a good system from Borla, Magnaflow, etc. and split it with a custom fabricated "Y" pipe into another matching muffler. Would I do a "Dual" exhaust, probably not, I think the folks here with them have some pretty cool looking deals going on and I like them. But I'd rather not haul around another 50lbs of exhaust system and hangers on a four cylinder vehicle, not needed, unless you want it...and its a free country as they say.
Yeah 3-5 hp, oh boy! Its the sound more than anything that you get from a performance exhaust on the HHR, if it sounds faster, it feels faster as they say.
You do need exhaust back pressure for proper cylinder scavenging, how much is optimal on the Ecotec, can't tell you. You'll see folks here running pipe diameters from 2 1/4" out to 3" with no real reason other than looks and perceived power gains(unless they spend the time and money to do some dyno pulls comparing different configurations). Can an exhaust be too open, you bet, especially when combined with a restrictive intake.
If I were to go the "Duals" route myself, I'd start with a good system from Borla, Magnaflow, etc. and split it with a custom fabricated "Y" pipe into another matching muffler. Would I do a "Dual" exhaust, probably not, I think the folks here with them have some pretty cool looking deals going on and I like them. But I'd rather not haul around another 50lbs of exhaust system and hangers on a four cylinder vehicle, not needed, unless you want it...and its a free country as they say.
Senior Member
Joined: 12-20-2011
Posts: 102
From: Ohio
Just out of curiosity what is the maximum restriction allowable to be imposed by a full exhaust system, and what is the optimal backpressure from an exhaust system on these? The reason I ask is because of two things. The first is I have seen an exhaust system be too open, and that caused fuel economy loss. Also, the max backpressure thing is because I really want to know. I know working for Cummins and seeing datasheets on our engines every day that is one of the things specified on most engines we have.
In relation to the above questions, what would be an optimal exhaust size, whether duals or a larger single exhaust?
In relation to the above questions, what would be an optimal exhaust size, whether duals or a larger single exhaust?
Senior Member
Joined: 12-20-2011
Posts: 102
From: Ohio
Interesting questions for sure, and I'm not positive that you'll find easy answers to them. The GMPP Exhaust is made by Borla and while the pipe diameter is the same as stock, the less restrictive muffler gives about a 3-5 horsepower gain, maybe a tiny bit more when combined with the GMPP CAI.
Yeah 3-5 hp, oh boy! Its the sound more than anything that you get from a performance exhaust on the HHR, if it sounds faster, it feels faster as they say.
You do need exhaust back pressure for proper cylinder scavenging, how much is optimal on the Ecotec, can't tell you. You'll see folks here running pipe diameters from 2 1/4" out to 3" with no real reason other than looks and perceived power gains(unless they spend the time and money to do some dyno pulls comparing different configurations). Can an exhaust be too open, you bet, especially when combined with a restrictive intake.
If I were to go the "Duals" route myself, I'd start with a good system from Borla, Magnaflow, etc. and split it with a custom fabricated "Y" pipe into another matching muffler. Would I do a "Dual" exhaust, probably not, I think the folks here with them have some pretty cool looking deals going on and I like them. But I'd rather not haul around another 50lbs of exhaust system and hangers on a four cylinder vehicle, not needed, unless you want it...and its a free country as they say.
Yeah 3-5 hp, oh boy! Its the sound more than anything that you get from a performance exhaust on the HHR, if it sounds faster, it feels faster as they say.
You do need exhaust back pressure for proper cylinder scavenging, how much is optimal on the Ecotec, can't tell you. You'll see folks here running pipe diameters from 2 1/4" out to 3" with no real reason other than looks and perceived power gains(unless they spend the time and money to do some dyno pulls comparing different configurations). Can an exhaust be too open, you bet, especially when combined with a restrictive intake.
If I were to go the "Duals" route myself, I'd start with a good system from Borla, Magnaflow, etc. and split it with a custom fabricated "Y" pipe into another matching muffler. Would I do a "Dual" exhaust, probably not, I think the folks here with them have some pretty cool looking deals going on and I like them. But I'd rather not haul around another 50lbs of exhaust system and hangers on a four cylinder vehicle, not needed, unless you want it...and its a free country as they say.
Deceased
Joined: 06-30-2010
Posts: 25,739
From: Kannapolis NC
I knew going in that I wasn't going to be making "Monster Horsepower!!!!", heck just the GMPP exhaust on a Cobalt netted a whopping 1.2 hp gain on the dyno writeup that I read(yup 1.2 hp...big deal huh?).
I went into the exhaust/intake setup looking for a more aggressive yet decidedly non-ricey sound, the added little bit of extra "oomph" in the 3,500-5,000 rpm band is a nice bonus.
I went into the exhaust/intake setup looking for a more aggressive yet decidedly non-ricey sound, the added little bit of extra "oomph" in the 3,500-5,000 rpm band is a nice bonus.
Senior Member
Joined: 12-20-2011
Posts: 102
From: Ohio
I knew going in that I wasn't going to be making "Monster Horsepower!!!!", heck just the GMPP exhaust on a Cobalt netted a whopping 1.2 hp gain on the dyno writeup that I read(yup 1.2 hp...big deal huh?).
I went into the exhaust/intake setup looking for a more aggressive yet decidedly non-ricey sound, the added little bit of extra "oomph" in the 3,500-5,000 rpm band is a nice bonus.
I went into the exhaust/intake setup looking for a more aggressive yet decidedly non-ricey sound, the added little bit of extra "oomph" in the 3,500-5,000 rpm band is a nice bonus.
Deceased
Joined: 06-30-2010
Posts: 25,739
From: Kannapolis NC
Agreed, any gain in horsepower is a good thing, but some claims you read just stretch the realm of plausibility at times. Pick up one of the "Import Tuner" type magazines sometime, my doctor has a subscription to one of them and I love the "Get 900 hp from your Honda D16A1 1.6 with $50 worth of weekend mods!!!!!!" articles, sometimes you gotta wonder.
