Are headers proven? Anybody with headers plz hlp
06-16-2010, 08:36 PM
#103
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Hey OP. It's me off Z28.
Like I said man don't worry. You wil see gains even with out the tune. As soon as you can retune. Bc with out your cats and O2's your cars going to not run the way it is SUPPOSED to run. I promise you you will love the difference in power once you get everything adjusted. At first I didn't feel a WHOLE LOT of a gain but I found out my exhaust was leaking from the Y pipe and all the way back to the tips. Had EVERYTHING welded shut and that helped a LOT. Just got to consider all variables when putting on aftermarket performance parts. The tune alone helps out a lot just like others have said.
Like I said man don't worry. You wil see gains even with out the tune. As soon as you can retune. Bc with out your cats and O2's your cars going to not run the way it is SUPPOSED to run. I promise you you will love the difference in power once you get everything adjusted. At first I didn't feel a WHOLE LOT of a gain but I found out my exhaust was leaking from the Y pipe and all the way back to the tips. Had EVERYTHING welded shut and that helped a LOT. Just got to consider all variables when putting on aftermarket performance parts. The tune alone helps out a lot just like others have said.
06-16-2010, 08:39 PM
#104
LTs are made to pick up peak power and not low end grunt, like shorties would.
More than anything it gives an "illusion" that you are losing power down low. Reason is is because say you pick up 20Rwhp up top and only 5Rwhp across the curve. It will seem like you don't have as much "get up" as you did before, even though you have more.
Hopefully I explained that in easy enough terms. Not exact on but gives you an idea of what they are talking about when they say this.
More than anything it gives an "illusion" that you are losing power down low. Reason is is because say you pick up 20Rwhp up top and only 5Rwhp across the curve. It will seem like you don't have as much "get up" as you did before, even though you have more.
Hopefully I explained that in easy enough terms. Not exact on but gives you an idea of what they are talking about when they say this.
06-16-2010, 09:04 PM
#107
http://www.dragtimes.com/da-density-...e=Calculate+DA
06-16-2010, 09:05 PM
#109
06-16-2010, 09:27 PM
#112
So you're not actually losing ANYTHING down low, at all? Not a big deal for a car that's meant for speed, but let's say you want to do a full exhaust to a truck. On a truck, you definitely don't want to lose any low end power because you need it for pulling/hauling, so are long tube headers still OK for a truck? If the primary size argument is true (in the LS1's case it's 1 3/4 vs 1 7/8), then I would think you'd want smaller primaries for a truck if you're worried about the low end.
06-16-2010, 09:45 PM
#113
You are losing down low. Put some headers on and drive up some big hills at part throttle at a lower rpm and tell me it didn't hurt you. Don't even go WOT so you won't have any sense of relativity. As far as the trucks go, I tuned an Avalanche recently before and after a header swap. It felt pretty strong for what it was but after the header swap it felt like ****. It's more exaggerated in that case because it's a 6000lbs truck with a 5.3 and not a 3600lbs f-body with a 5.7, but it's still a loss either way.
You're losing exhaust velocity (which some people confuse for back pressure). The bigger the primary the more you are hurting the exhaust velocity. You only want what you need and no more. The problem is that it's always changing. The higher rpm you go the more exhaust flow you need. In the lower rpms you need very little.
Kinda like how VTEC works in Hondas. You don't need it down low, but up high the VTEC kicks in and all hell breaks loose.
You're losing exhaust velocity (which some people confuse for back pressure). The bigger the primary the more you are hurting the exhaust velocity. You only want what you need and no more. The problem is that it's always changing. The higher rpm you go the more exhaust flow you need. In the lower rpms you need very little.
Kinda like how VTEC works in Hondas. You don't need it down low, but up high the VTEC kicks in and all hell breaks loose.
06-16-2010, 09:53 PM
#114
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Install them! I picked up headers/ORY/exhaust almost 2 months ago... big difference. Haven't had a chance to go to the track since headers/ory/exhaust/tune, but im hoping to go soon.
I was lucky enough to come across LT headers, ORY and exhaust for $125. You'll feel a difference without a doubt. Also, you'll love the sound of your exhaust after headers!!!
I was lucky enough to come across LT headers, ORY and exhaust for $125. You'll feel a difference without a doubt. Also, you'll love the sound of your exhaust after headers!!!
06-16-2010, 09:54 PM
#115
No problem.
Jon, would you happen to have any dyno graphs actually showing before/after header swaps and actually losing Rwhp down low? I am interested.. I would be surprised if you actually lost Rwhp throughout most under the curve. I am sure there might be a small dip or two, but nothing you would notice. 2-3Rwhp at most I would assume.
You are losing down low. Put some headers on and drive up some big hills at part throttle at a lower rpm and tell me it didn't hurt you. Don't even go WOT so you won't have any sense of relativity. As far as the trucks go, I tuned an Avalanche recently before and after a header swap. It felt pretty strong for what it was but after the header swap it felt like ****. It's more exaggerated in that case because it's a 6000lbs truck with a 5.3 and not a 3600lbs f-body with a 5.7, but it's still a loss either way.
You're losing exhaust velocity (which some people confuse for back pressure). The bigger the primary the more you are hurting the exhaust velocity. You only want what you need and no more. The problem is that it's always changing. The higher rpm you go the more exhaust flow you need. In the lower rpms you need very little.
Kinda like how VTEC works in Hondas. You don't need it down low, but up high the VTEC kicks in and all hell breaks loose.
You're losing exhaust velocity (which some people confuse for back pressure). The bigger the primary the more you are hurting the exhaust velocity. You only want what you need and no more. The problem is that it's always changing. The higher rpm you go the more exhaust flow you need. In the lower rpms you need very little.
Kinda like how VTEC works in Hondas. You don't need it down low, but up high the VTEC kicks in and all hell breaks loose.
06-16-2010, 10:30 PM
#116
No problem.
Jon, would you happen to have any dyno graphs actually showing before/after header swaps and actually losing Rwhp down low? I am interested.. I would be surprised if you actually lost Rwhp throughout most under the curve. I am sure there might be a small dip or two, but nothing you would notice. 2-3Rwhp at most I would assume.
Jon, would you happen to have any dyno graphs actually showing before/after header swaps and actually losing Rwhp down low? I am interested.. I would be surprised if you actually lost Rwhp throughout most under the curve. I am sure there might be a small dip or two, but nothing you would notice. 2-3Rwhp at most I would assume.
I was more talking about the loss during part throttle driving in the lower rpms (that you would normally be driving in). It's more apparent on an M6 car. I do think that stock stalls take more of a hurting at the track because they take so long to get up into the rpms and the first 60' is everything. You'll just about always notice stock stall A4 60's are slightly worse with headers, but they pull a little harder on the big end and sometimes make it up and have more MPH.
The exception is LS1Rook who gained .05 in the 60' and .4 in the 1/4 in worse weather, but to be honest his numbers are stellar by any stretch for what few mods he has. What all is done to your car LS1Rook? What's it weight and why do you not have a stall yet? Or do you have a small stall? I was running 8.1s/12.5s with draglites and not cutting those 60's.
06-16-2010, 10:55 PM
#117
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You are losing down low. Put some headers on and drive up some big hills at part throttle at a lower rpm and tell me it didn't hurt you. Don't even go WOT so you won't have any sense of relativity. As far as the trucks go, I tuned an Avalanche recently before and after a header swap. It felt pretty strong for what it was but after the header swap it felt like ****. It's more exaggerated in that case because it's a 6000lbs truck with a 5.3 and not a 3600lbs f-body with a 5.7, but it's still a loss either way.
You're losing exhaust velocity (which some people confuse for back pressure). The bigger the primary the more you are hurting the exhaust velocity. You only want what you need and no more. The problem is that it's always changing. The higher rpm you go the more exhaust flow you need. In the lower rpms you need very little.
Kinda like how VTEC works in Hondas. You don't need it down low, but up high the VTEC kicks in and all hell breaks loose.
You're losing exhaust velocity (which some people confuse for back pressure). The bigger the primary the more you are hurting the exhaust velocity. You only want what you need and no more. The problem is that it's always changing. The higher rpm you go the more exhaust flow you need. In the lower rpms you need very little.
Kinda like how VTEC works in Hondas. You don't need it down low, but up high the VTEC kicks in and all hell breaks loose.
Wow man I really thought you were smarter than this! Installing headers on any car/truck will increase the hp and torque output of the engine. Please people, if you are gonna post information on this site make sure that it is facts and not just your oppinion! The goal of performance exhaust headers is mainly to decrease flow resistance (back pressure), and to increase the volumetric efficiency of an engine, resulting in a gain in power output. The processes occurring can be explained by the gas laws, specifically the ideal gas law and the combined gas law. When an engine starts its exhaust stroke, the piston moves up the cylinder bore, decreasing the total chamber volume. With the exhaust valve opens, the high pressure exhaust gas escapes into the exhaust manifold or header, creating an exhaust pulse comprising three main parts: (factory manifolds do not utilize this effect) The high-pressure head is created by the large pressure difference between the exhaust in the combustion chamber and the atmospheric pressure outside of the exhaust system. As the exhaust gases equalize between the combustion chamber and the atmosphere, the difference in pressure decreases and the exhaust velocity decreases. This forms the medium-pressure body component of the exhaust pulse. The remaining exhaust gas forms the low-pressure tail component. This tail component may initially match ambient atmospheric pressure, but the momentum of the high- and medium- pressure components reduces the pressure in the combustion chamber to a lower-than-atmospheric level. This relatively low pressure helps to extract all the combustion products from the cylinder and induct the intake charge during the overlap period when both intake and exhaust valves are partially open. The effect is known as scavenging. Length, cross-sectional area, and shaping of the exhaust ports and pipeworks influences the degree of scavenging effect, and the engine speed range over which scavenging occurs. Headers work because of the savaging effect they have on an engine (this is also why having the correct ory merge collector like a mufflex or flowmaster is important). As the exhaust gases are being pushed out of the engine and pass through the collector they start to savage more air into the engine in turn creating more h.p. and torque. This affect it has on the engine is also the reason you would want to get the engine tuned after a header swap. You are pulling more air through the engine and causing it to run somewhat lean. Adding more fuel to compensate for the added air flow will again help the engine make more H.P. !!
Last edited by odarabla; 06-16-2010 at 11:11 PM.
06-16-2010, 11:09 PM
#118
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Here are a few links you can read to help you understand more about whats going on.
http://en.wikipedia.org/wiki/Volumetric_efficiency
http://en.wikipedia.org/wiki/Back_pressure
http://en.wikipedia.org/wiki/Gas_law
http://en.wikipedia.org/wiki/Ideal_gas_law
http://en.wikipedia.org/wiki/Combined_gas_law
http://en.wikipedia.org/wiki/Volumetric_efficiency
http://en.wikipedia.org/wiki/Back_pressure
http://en.wikipedia.org/wiki/Gas_law
http://en.wikipedia.org/wiki/Ideal_gas_law
http://en.wikipedia.org/wiki/Combined_gas_law
06-16-2010, 11:14 PM
#119
Wow man I really thought you were smarter than this! Installing headers on any car/truck will increase the hp and torque output of the engine. Please people, if you are gonna post information on this site make sure that it is facts and not just your oppinion! The goal of performance exhaust headers is mainly to decrease flow resistance (back pressure), and to increase the volumetric efficiency of an engine, resulting in a gain in power output. The processes occurring can be explained by the gas laws, specifically the ideal gas law and the combined gas law. When an engine starts its exhaust stroke, the piston moves up the cylinder bore, decreasing the total chamber volume. With the exhaust valve opens, the high pressure exhaust gas escapes into the exhaust manifold or header, creating an exhaust pulse comprising three main parts: The high-pressure head is created by the large pressure difference between the exhaust in the combustion chamber and the atmospheric pressure outside of the exhaust system. As the exhaust gases equalize between the combustion chamber and the atmosphere, the difference in pressure decreases and the exhaust velocity decreases. This forms the medium-pressure body component of the exhaust pulse. The remaining exhaust gas forms the low-pressure tail component. This tail component may initially match ambient atmospheric pressure, but the momentum of the high- and medium- pressure components reduces the pressure in the combustion chamber to a lower-than-atmospheric level. This relatively low pressure helps to extract all the combustion products from the cylinder and induct the intake charge during the overlap period when both intake and exhaust valves are partially open. The effect is known as scavenging. Length, cross-sectional area, and shaping of the exhaust ports and pipeworks influences the degree of scavenging effect, and the engine speed range over which scavenging occurs. Headers work because of the savaging effect they have on an engine (this is also why having the correct ory merge collector like a mufflex or flowmaster is important). As the exhaust gases are being pushed out of the engine and pass through the collector they start to savage more air into the engine in turn creating more h.p. and torque. This affect it has on the engine is also the reason you would want to get the engine tuned after a header swap. You are pulling more air through the engine and causing it to run somewhat lean. Adding more fuel to compensate for the added air flow will again help the engine make more H.P. !!
They will make more power, but at a certain rpm range. You just simply loose too much exhaust velocity and energy at low rpm to make power.
06-16-2010, 11:38 PM
#120
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Here is a comparison test write up you can read.
http://www.carcraft.com/techarticles...est/index.html