Little Power Gain with Headers.....I'm stumped
04-26-2013, 03:52 PM
#1
Burning Brakes
Thread Starter
Little Power Gain with Headers.....I'm stumped
I have a 2008 Z51 M6 with an LS3 engine (duh!), stock intake manifold, stock heads, stock cam. I have added a Halltech Killer Bee 2 intake with beehive and shroud mod, B&B bullet exhaust, and now recently B&B headers and new spark plug wires/plugs!
I know this is a detailed story, but I wanted to give background so I can hopefully get some help! I had the car on a dyno back in October with stock engine other than Halltech Killer Bee intake and B&B Bullet exhaust! It made 384 rwhp (some have said way too high for stock car, but thats what it made). Anyway I bought a set of B&B headers with a modified "x-pipe" to go on the car. The x-pipe was a stock LS3 x-pipe with high flow cats welded into it. And it actually was 2 completely individual pipes, i.e. not connected in the middle via an "x" or "h" (not sure to the reasoning of this, but it was free with the header purchase so I took it). After installing the headers and intermediate pipe to my car, I happily took it to the dyno. On the first few pulls it only made 386 hp!
Very disappointing. The dyno tuner, a very well respected individual in the corvette community who knows what he's doing, told me that it was possible that the cats were clogged, or the spark plugs were bad. So I had the spark plugs and wires changed to brand new ones and a re-dyno tune. It picked up 10 rwhp with just the spark plug change putting the car at 396 rwhp. Still not what I was expecting 
. The tuner said a manual LS3 with CAI and headers/exhaust should make about 420-430 rwhp (as he's tuned hundreds of cars identical to mine and had those results) So we talked about the options and came to a few possible conclusions:
1) I had messed up something internally in the engine, i.e. rod, piston, spring, rocker....whatever. But we debunked that myth mostly because I don't drive the vehicle hard, have never redlined it, and it was working great back in September with nothing out of the ordinary happening in the last 6-7 months. The engine is not making any funny noises or knocking sounds and the tuner said when he was running it through the gears on the dyno he did not notice anything out of the ordinary.
2) He next suggested taking off the modified intermediate pipe and either switching it back to the stock x-pipe with no cats (gotta love B&B for making a design that bolts to stock stuff) or buying B&Bs x-pipe for ~$450.........I switched out the modified pipe to the stock x-pipe but haven't had it re-dyno tuned yet! However, the high flow cats on the modified intermediate pipe were in perfect condition, not breaking up, not clogged. And I didn't feel that the individual pipes (not connected in middle) would cause a horsepower decrease as significant as 20 hp.
3) Final suggestion was a bad tank of gas......He said he was not able to dial in on the timing at all. Which after doing research and talking about it, I usually fill up wherever is closest. I have stopped that for the last 2 tanks and have run one tank of Texaco and one tank of Chevron through the system. And it will be Chevron from here on out, no exceptions!
So, that is where I am at now. Once I get paid again on the end of this month, I am going to take it back to the dyno with stock x-pipe and reliable tank of Chevron 93 octane gas to see if I can pick up the missing 20-30 rwhp.
What I want from you guys is any other suggestions of things I can fix myself or any ideas on another possible solution to why my car "didn't gain" any rwhp from a reliable header install without having to tear into the engine. It sounds great with the headers and bullets, I just want it to run like it.
Thanks in advance, Austin
I know this is a detailed story, but I wanted to give background so I can hopefully get some help! I had the car on a dyno back in October with stock engine other than Halltech Killer Bee intake and B&B Bullet exhaust! It made 384 rwhp (some have said way too high for stock car, but thats what it made). Anyway I bought a set of B&B headers with a modified "x-pipe" to go on the car. The x-pipe was a stock LS3 x-pipe with high flow cats welded into it. And it actually was 2 completely individual pipes, i.e. not connected in the middle via an "x" or "h" (not sure to the reasoning of this, but it was free with the header purchase so I took it). After installing the headers and intermediate pipe to my car, I happily took it to the dyno. On the first few pulls it only made 386 hp!
Very disappointing. The dyno tuner, a very well respected individual in the corvette community who knows what he's doing, told me that it was possible that the cats were clogged, or the spark plugs were bad. So I had the spark plugs and wires changed to brand new ones and a re-dyno tune. It picked up 10 rwhp with just the spark plug change putting the car at 396 rwhp. Still not what I was expecting . The tuner said a manual LS3 with CAI and headers/exhaust should make about 420-430 rwhp (as he's tuned hundreds of cars identical to mine and had those results) So we talked about the options and came to a few possible conclusions:1) I had messed up something internally in the engine, i.e. rod, piston, spring, rocker....whatever. But we debunked that myth mostly because I don't drive the vehicle hard, have never redlined it, and it was working great back in September with nothing out of the ordinary happening in the last 6-7 months. The engine is not making any funny noises or knocking sounds and the tuner said when he was running it through the gears on the dyno he did not notice anything out of the ordinary.
2) He next suggested taking off the modified intermediate pipe and either switching it back to the stock x-pipe with no cats (gotta love B&B for making a design that bolts to stock stuff) or buying B&Bs x-pipe for ~$450.........I switched out the modified pipe to the stock x-pipe but haven't had it re-dyno tuned yet! However, the high flow cats on the modified intermediate pipe were in perfect condition, not breaking up, not clogged. And I didn't feel that the individual pipes (not connected in middle) would cause a horsepower decrease as significant as 20 hp.
3) Final suggestion was a bad tank of gas......He said he was not able to dial in on the timing at all. Which after doing research and talking about it, I usually fill up wherever is closest. I have stopped that for the last 2 tanks and have run one tank of Texaco and one tank of Chevron through the system. And it will be Chevron from here on out, no exceptions!
So, that is where I am at now. Once I get paid again on the end of this month, I am going to take it back to the dyno with stock x-pipe and reliable tank of Chevron 93 octane gas to see if I can pick up the missing 20-30 rwhp.
What I want from you guys is any other suggestions of things I can fix myself or any ideas on another possible solution to why my car "didn't gain" any rwhp from a reliable header install without having to tear into the engine. It sounds great with the headers and bullets, I just want it to run like it.
Thanks in advance, Austin
Last edited by acscogginjr; 04-26-2013 at 03:56 PM.
04-26-2013, 04:29 PM
#3
Burning Brakes
Thread Starter
Different company but same dyno manufacturer. The company that did the dyno says these LS3 bolt on's consistently put down 420-430 rwhp all day long.
I don't know what you mean by actually check the cats. I shined a flashlight down in the cats and you can see straight through them and someone suggested shaking the pipe to listen for a rattle if the cat was breaking up and there was no rattle.
Austin
I don't know what you mean by actually check the cats. I shined a flashlight down in the cats and you can see straight through them and someone suggested shaking the pipe to listen for a rattle if the cat was breaking up and there was no rattle.
Austin
04-26-2013, 05:22 PM
#4
Drifting
I think you are losing power using the modified stock pipe. Also, not having an h or x pipe mating in the middle thus negating the scavenging effect that it would normally be provided.
So think about it this way, most headers have a 3" collector and you are narrowing it down to 2 1/2" with some unknown cat converters and no scavenging effect. IMO you're possibly losing another 10-15 rwhp.
So think about it this way, most headers have a 3" collector and you are narrowing it down to 2 1/2" with some unknown cat converters and no scavenging effect. IMO you're possibly losing another 10-15 rwhp.
04-26-2013, 05:26 PM
#5
Burning Brakes
Thread Starter
I think you are losing power using the modified stock pipe. Also, not having an h or x pipe mating in the middle thus negating the scavenging effect that it would normally be provided.
So think about it this way, most headers have a 3" collector and you are narrowing it down to 2 1/2" with some unknown cat converters and no scavenging effect. IMO you're possibly losing another 10-15 rwhp.
So think about it this way, most headers have a 3" collector and you are narrowing it down to 2 1/2" with some unknown cat converters and no scavenging effect. IMO you're possibly losing another 10-15 rwhp.
Austin
04-26-2013, 05:40 PM
#6
Can't compare them man IMO. It needs to be on the same dyno, with same correction factors, and same everything else to be comparative. Noticed I didn't say precise, but comparative; that's what you're really interested in: the difference.
As far as the X-pipe, you're losing power for sure; just don't know how much. When you dyno it again, post the results. By the way, '12s and up came with little cats on the X-pipe (I swapped mine with a catless '11 one), but they're not nearly enough to avoid a CEL if you removed the main ones. Good luck.
As far as the X-pipe, you're losing power for sure; just don't know how much. When you dyno it again, post the results. By the way, '12s and up came with little cats on the X-pipe (I swapped mine with a catless '11 one), but they're not nearly enough to avoid a CEL if you removed the main ones. Good luck.
04-26-2013, 08:55 PM
#8
Race Director
I have an LS2 with Kooks Headers, Ported stock intake manifold, 160 T Stat, and a GOOD TUNE by Cartek in NJ...& I'm only making 396 HP with my 2800 FTI converter I have been running mid 11 sec 1/4 mile times @ 118 mph...
04-28-2013, 08:05 PM
#11
Drifting
I have been chasing HP numbers on this forum for the past 2-3 weeks and have come to the conclusion that, mod for mod, you can't find a correlation between any of them HP wise even on the same dyno. Not sure which you installed, but some have suggested that the 1 3/4 size was a better power producer than larger on lightly modded cars.???
I think it's just time to do my own thing and don't worry about the numbers...and I will enjoy the new found power.
I think it's just time to do my own thing and don't worry about the numbers...and I will enjoy the new found power.
Last edited by ParisTNDude; 04-28-2013 at 08:11 PM.
04-29-2013, 10:29 AM
#15
Burning Brakes
Thread Starter
04-29-2013, 02:33 PM
#16
Tech Contributor
Need to see the data logs. What's the A/F ratio? What did he try regarding A/F ratio? Any timing retard / knock counts? What are the fuel trims? Other mods within the tune? Stock gears? What were the average values before the mods and after? Peak isn't everything.
04-30-2013, 01:02 PM
#17
I have a 2008 Z51 M6 with an LS3 engine (duh!), stock intake manifold, stock heads, stock cam. I have added a Halltech Killer Bee 2 intake with beehive and shroud mod, B&B bullet exhaust, and now recently B&B headers and new spark plug wires/plugs!
I know this is a detailed story, but I wanted to give background so I can hopefully get some help! I had the car on a dyno back in October with stock engine other than Halltech Killer Bee intake and B&B Bullet exhaust! It made 384 rwhp (some have said way too high for stock car, but thats what it made). Anyway I bought a set of B&B headers with a modified "x-pipe" to go on the car. The x-pipe was a stock LS3 x-pipe with high flow cats welded into it. And it actually was 2 completely individual pipes, i.e. not connected in the middle via an "x" or "h" (not sure to the reasoning of this, but it was free with the header purchase so I took it). After installing the headers and intermediate pipe to my car, I happily took it to the dyno. On the first few pulls it only made 386 hp! Very disappointing. The dyno tuner, a very well respected individual in the corvette community who knows what he's doing, told me that it was possible that the cats were clogged, or the spark plugs were bad. So I had the spark plugs and wires changed to brand new ones and a re-dyno tune. It picked up 10 rwhp with just the spark plug change putting the car at 396 rwhp. Still not what I was expecting . The tuner said a manual LS3 with CAI and headers/exhaust should make about 420-430 rwhp (as he's tuned hundreds of cars identical to mine and had those results) So we talked about the options and came to a few possible conclusions:
1) I had messed up something internally in the engine, i.e. rod, piston, spring, rocker....whatever. But we debunked that myth mostly because I don't drive the vehicle hard, have never redlined it, and it was working great back in September with nothing out of the ordinary happening in the last 6-7 months. The engine is not making any funny noises or knocking sounds and the tuner said when he was running it through the gears on the dyno he did not notice anything out of the ordinary.
2) He next suggested taking off the modified intermediate pipe and either switching it back to the stock x-pipe with no cats (gotta love B&B for making a design that bolts to stock stuff) or buying B&Bs x-pipe for ~$450.........I switched out the modified pipe to the stock x-pipe but haven't had it re-dyno tuned yet! However, the high flow cats on the modified intermediate pipe were in perfect condition, not breaking up, not clogged. And I didn't feel that the individual pipes (not connected in middle) would cause a horsepower decrease as significant as 20 hp.
3) Final suggestion was a bad tank of gas......He said he was not able to dial in on the timing at all. Which after doing research and talking about it, I usually fill up wherever is closest. I have stopped that for the last 2 tanks and have run one tank of Texaco and one tank of Chevron through the system. And it will be Chevron from here on out, no exceptions!
So, that is where I am at now. Once I get paid again on the end of this month, I am going to take it back to the dyno with stock x-pipe and reliable tank of Chevron 93 octane gas to see if I can pick up the missing 20-30 rwhp.
What I want from you guys is any other suggestions of things I can fix myself or any ideas on another possible solution to why my car "didn't gain" any rwhp from a reliable header install without having to tear into the engine. It sounds great with the headers and bullets, I just want it to run like it.
Thanks in advance, Austin
I know this is a detailed story, but I wanted to give background so I can hopefully get some help! I had the car on a dyno back in October with stock engine other than Halltech Killer Bee intake and B&B Bullet exhaust! It made 384 rwhp (some have said way too high for stock car, but thats what it made). Anyway I bought a set of B&B headers with a modified "x-pipe" to go on the car. The x-pipe was a stock LS3 x-pipe with high flow cats welded into it. And it actually was 2 completely individual pipes, i.e. not connected in the middle via an "x" or "h" (not sure to the reasoning of this, but it was free with the header purchase so I took it). After installing the headers and intermediate pipe to my car, I happily took it to the dyno. On the first few pulls it only made 386 hp!
Very disappointing. The dyno tuner, a very well respected individual in the corvette community who knows what he's doing, told me that it was possible that the cats were clogged, or the spark plugs were bad. So I had the spark plugs and wires changed to brand new ones and a re-dyno tune. It picked up 10 rwhp with just the spark plug change putting the car at 396 rwhp. Still not what I was expecting . The tuner said a manual LS3 with CAI and headers/exhaust should make about 420-430 rwhp (as he's tuned hundreds of cars identical to mine and had those results) So we talked about the options and came to a few possible conclusions:1) I had messed up something internally in the engine, i.e. rod, piston, spring, rocker....whatever. But we debunked that myth mostly because I don't drive the vehicle hard, have never redlined it, and it was working great back in September with nothing out of the ordinary happening in the last 6-7 months. The engine is not making any funny noises or knocking sounds and the tuner said when he was running it through the gears on the dyno he did not notice anything out of the ordinary.
2) He next suggested taking off the modified intermediate pipe and either switching it back to the stock x-pipe with no cats (gotta love B&B for making a design that bolts to stock stuff) or buying B&Bs x-pipe for ~$450.........I switched out the modified pipe to the stock x-pipe but haven't had it re-dyno tuned yet! However, the high flow cats on the modified intermediate pipe were in perfect condition, not breaking up, not clogged. And I didn't feel that the individual pipes (not connected in middle) would cause a horsepower decrease as significant as 20 hp.
3) Final suggestion was a bad tank of gas......He said he was not able to dial in on the timing at all. Which after doing research and talking about it, I usually fill up wherever is closest. I have stopped that for the last 2 tanks and have run one tank of Texaco and one tank of Chevron through the system. And it will be Chevron from here on out, no exceptions!
So, that is where I am at now. Once I get paid again on the end of this month, I am going to take it back to the dyno with stock x-pipe and reliable tank of Chevron 93 octane gas to see if I can pick up the missing 20-30 rwhp.
What I want from you guys is any other suggestions of things I can fix myself or any ideas on another possible solution to why my car "didn't gain" any rwhp from a reliable header install without having to tear into the engine. It sounds great with the headers and bullets, I just want it to run like it.
Thanks in advance, Austin
05-03-2013, 02:08 PM
#18
Tolero Apto Victum
I have been chasing HP numbers on this forum for the past 2-3 weeks and have come to the conclusion that, mod for mod, you can't find a correlation between any of them HP wise even on the same dyno. Not sure which you installed, but some have suggested that the 1 3/4 size was a better power producer than larger on lightly modded cars.???
I think it's just time to do my own thing and don't worry about the numbers...and I will enjoy the new found power.
I think it's just time to do my own thing and don't worry about the numbers...and I will enjoy the new found power.
