FACTS ABOUT EXHAUST HEADERS
Iperformance headers are the only headers available for Cavalier and Sunfire which are completely emissions compliant.
Only Iperformance publicly posts dyno tests of their products.Iperformance headers are completely and totally made in the United States of America.
Only Iperformance offers exclusively Tri-Y design headers.
Tri-Y designed headers outflow 4-1 designed headers.
Only Iperformance uses a flex joint in all of their headers.
Iperformance uses only Carsound / Magnaflow brand catalytic converters.
For the Ecotec engine, the Iperformance header is the clear choice over the RK Sport header.
Iperformance headers are the only completely and totally bolt on header available for Cavalier and Sunfire.No other header on the market for these vehicles is completely bolt in, including no catalytic converter and no down pipe, or at most, a stub pipe end that requires the owner of the vehicle to either fabricate or pay someone to fabricate a down pipe and catalytic converter assembly to connect their header to the rest of the exhaust system. Remember, General Motors designed and manufactured these vehicles with the catalytic converter welded to the OEM down pipe, and these other header manufacturers expect the vehicle owner to installer to cut the stock 1 7/8 inch exhaust pipe in front of the stock catalytic converter and weld their 2 1/4 inch stub to that used pipe. The owner of the vehicle must either have access to pipe bending, metal cutting, and welding equipment to use one of the headers from these other companies, or pay someone to bend, cut, and weld the pipe and catalytic converter into place under the vehicle to use their product. Most people do not have a fully equipped machine shop in their own home, and must pay to have a down pipe and catalytic converter welded onto their vehicle at a cost of $200-400 above and beyond the cost of one of these other company's incomplete headers.
Only the Iperformance header comes complete with the down pipe and catalytic converter assembly and ready to bolt onto the vehicle using only basic hand tools allowing easy and simple trouble free installation in the driveway of the vehicle owner. Once the cost of the down pipe and catalytic converter assembly and installation is taken into consideration, the Iperformance header is clearly less expensive in both dollars spent and provides a significant value in ease of installation.
Iperformance headers are the only headers available for Cavalier and Sunfire which are completely emissions compliant.
All of the other headers for these vehicles on the market are designated by their manufacturers as "For off road use only". This is because installing their product on your car is a violation of emissions laws. Only Iperformance headers are designated as "For on road use only", complete with all of the emissions fittings, EGR passages, O2 sensor fittings, and other features as the original equipment manifold and down pipe assembly, and the built in catalytic converter, making them the only fully emissions compliant header available for these vehicles.Only Iperformance publicly posts dyno tests of their products.
None of the other company's offering headers or exhaust systems for these vehicles posts any dyno tests at all, not dyno tests they have conducted themselves, and not dyno tests conducted independently by their customers. Meanwhile they will consistently make claims that their product "makes this much power" without ever providing any documentation to back up their claims.
Only Iperformance has the courage to put their money where their mouth is and post not only dyno testing done in house, but also dyno testing that has been submitted by our customers who have already paid for the products they purchased and have absolutely no alternate motivation or incentive to provide those tests to us. These are completely and totally independent and unbiased tests and provide the absolute highest level of genuineness.
Iperformance headers are completely and totally made in the United States of America.
Some other header manufacturers are making their products in Mexico while others are having their products made in South East Asia. There is nothing inherently wrong with Mexico or any of the countries in South East Asia, but none of those places are known as hot beds for performance parts manufacturing, for high technology manufacturing abilities, or for their high quality standards. These places are, however, known as the cheapest places available for manufacturing products which may or may not be of even the lowest acceptable quality level.
Iperformance headers and exhaust systems are completely and totally manufactured and assembled within the United States of America, with manufacturing facilities in Seattle, Washington and St. Louis, Missouri, both cities which are noted for their long history of commercial and aerospace manufacturing as is indicated by the fact that Boeing and the former McDonnell Douglas companies are based in these two cities. Iperformance takes advantage of the aerospace subcontractors in both these cities to provide raw materials and manufacturing quality that is second to none in the industry.Only Iperformance offers exclusively Tri-Y design headers.
Other manufacturers offer 4-1 headers, not because they provide better performance, but because these headers are cheaper to manufacture and offer much greater profit margins for the manufacturers of these products.
4-1 headers typically loose a lot of low end and mid range torque by their design. The 4-1 design will show a single peak in power improvement with a sharp decrease in power both above and below the single peak, when compared to the stock power level. Most header makers using this design will tune for peak horsepower at or above the engine's maximum speed, loosing power through the lower half of the power curve for a very small gain at maximum engine speed. However, the exact point in the RPM range at which that peak occurs is determined by the diameter and length of the primary pipes, and some makers will use longer and smaller diameter primary pipes which will result in a small peak in power in the mid to low RPM range with power loss at both very low RPM and across the upper half of the range of engine operating speed.
Tri-Y headers produce even power across the entire RPM range with very noticeable improvement in mid and low range torque. This is because the Tri-Y design produces two separate peaks in power gain which taper off more gradually below the first peak and above the second peak, most often not showing any dip below the stock power level. Where those peaks occur in the range of engine speed is determined by the diameter and length of both the primary pipes and also the secondary pipes. Most makers of headers with this design will tune for the first peak in power in the lower half of the engine's operating speed and the second peak in the upper half of the engine's operating speed, for an even and consistent improvement in power across the entire range of engine speed which will in all cases out perform the 4-1 design for both street and race use.
Iperformance uses only Tri-Y headers because this design offers the best performance, period. Tri-Y headers are more expensive to manufacture because they are more difficult to build with more labor hours per unit and more complicated assembly, but the difference in cost is more than outweighed by the difference in performance, and we offer only the best.Tri-Y designed headers outflow 4-1 designed headers.
Tri-Y headers are designed such that the opposing primary pipes are joined to make two secondary pipes and those opposing secondaries are joined at the final collector to form one pipe. By joining only two pipes together at each connection, and by making those connections between cylinders that are firing 180 degrees out of phase with each other, the Tri-Y design has the least turbulence and maximizes the affect of extraction, or drawing air out of the cylinders. Extraction is the suction caused by the exhaust pulse passing the connection of two pipes into one. This same affect can be seen if a straw is placed into a glass of liquid and air is blown over the upright end of the straw causing the liquid to be drawn up the straw above the water level in the glass. By connecting only the cylinders that fire opposite each other, this suction affect is exploited to maximum affect and exhaust gas from one cylinder is actually pulled out of the engine by the flow of exhaust gas from the opposing cylinder. This is why headers in some places are called "extractors".
4-1 headers reduce this affect because that suction is spread over all four cylinders, two of which are not firing at the time, and 2/3 of that suction affect is totally wasted. In addition to this, the large volume of a 4-1 collector is an enlarged chamber in the path of the exhaust flow. Because it does not maintain a consistent cross sectional area for the exhaust to flow evenly and orderly through, the exhaust expands, decelerates, and experiences a significant amount of turbulence when forced through this open chamber. All of this turbulence causes an increase in back pressure and a reduction of both flow and power output.
Tri-Y headers flow much more smoothly and with less turbulence and back pressure than 4-1 headers.
The smoother flow of Tri-Y headers also results in a more pleasant exhaust sound compared to 4-1 headers. Owners of cars with 4-1 headers frequently complain of raspy or obnoxious sounding exhaust. This is due to all of the turbulence at the large final collector which disrupts flow causing the exhaust sound to be unpleasant and often metallic sounding.Only Iperformance uses a flex joint in all of their headers.
Other manufacturers ignore the most significant issue of header design for front wheel drive vehicles, the fact that the engine moves fore and aft and that movement must be taken into consideration when designing anything that attaches to both the engine and the body of the car. The car manufacturer designed with this movement in mind by putting a flex joint in the down pipe to allow the engine to move independently of the exhaust system of the car, which is attached to the body of the car. Other header manufacturers sought to cut the costs of their products by simply ignoring engine movement and offering headers without any flex joints at all, making the exhaust system a rigidly attached extension of the engine which will in all cases seek to break between the engine and the catalytic converter. One of these other manufacturers even went so far as to manufacture and sell engine mount inserts which the offered to sell to people who bought their headers in order to prevent or rather postpone the breaking of that exhaust pipe between the engine and the catalytic converter.
Iperformance recognizes that for a header to work correctly, it must be designed and manufactured in a way that takes into consideration for this engine movement, which is why all of our headers for front wheel drive vehicles have a stainless steel flex joint in the down pipe.
Only Iperformance includes a high flow catalytic converter with all of the headers they offer for vehicles which have the OEM catalytic converter welded to the down pipe assembly.
The word "header" for most of the performance industry has come to mean a completely bolt in assembly to replace everything from the face of the engine head to the flange connection in front of the catalytic converter, a truly bolt on product. However, GM designed their small cars with the down pipe welded to the catalytic converter. Other companies resorted to making their products without flanges on the end of the pipe and expect you, the customer to either fabricate a down pipe and catalytic converter assembly by bending your own pipe, cutting it, and welding it to your OEM catalytic converter, or they expect you to pay someone to do that for you.
The Iperformance header is a complete bolt on product which includes a new catalytic converter as part of the three piece assembly, that is matched to the pipe diameter of the header collector and the cat back exhaust system. The overall performance of the exhaust system will only produce as much power improvement as the smallest part, and if the OEM catalytic converter is spliced between a new header and exhaust system, the overall performance of the system will be only as much as the OEM catalytic converter can flow. While OEM catalytic converters are typically decent quality with decent flow capacity, the hole on the inlet side and the hole on the outlet side is only 1 7/8 inch in diameter, and the OEM catalytic converter will not let any more exhaust flow than can fit through those 1 7/8 diameter holes.
The high flow catalytic converter used with the Iperformance header is 2 1/2 inch in diameter, and matches the header, down pipe, and cat back exhaust system for maximum flow and performance.
Iperformance uses only Carsound / Magnaflow brand catalytic converters.
Other companies are selling lower quality universal catalytic converters which are not bolt in and require the owner of the vehicle to weld them onto the car and fabricate O2 sensor fittings so that the car will run properly, or the owner of the vehicle must pay someone to do this. These lower quality catalytic converters frequently cause trouble with the OBD II computer control systems of these vehicles, often fracture and fall apart, and frequently degrade and fail emissions tests.
The Iperformance header uses only Carsound / Magnaflow brand catalytic converters which are the highest quality on the market and are the only catalytic converts we have found that do not cause any problems with the OBD II computer control systems of these vehicles. In addition, the inside of these catalytic converters is contoured to provide maximum flow without any of the ridges or structure extending into the passage of the exhaust flow, providing maximum flow and performance. And, as always, the Iperformance catalytic converter assembly is complete and ready to bolt on with all O2 sensor fittings and no welding required.
One further comment about catalytic converters, many people will state that the stock catalytic converter is a high flow catalytic converter and does not need to be replaced for this reason. While it is true that modern honey comb style catalytic converters are much less restrictive than the original pellet style converters used in the 1970's, the inlet and outlet of the stock catalytic converter is 1 7/8 inch in diameter and will allow only as much air as will fit through a 1 7/8 inch diameter hole to pass through it. All of the aftermarket headers on the market, even the ones that require the installer to cut the original down pipe and clamp to the front of the stock catalytic converter, have collectors or down pipe stubs that are 2 1/4 inch or larger in diameter. Certainly, even the manufacturers of those headers will readily admit that they chose that pipe size because they expect the header to flow more air than 1 7/8 inch pipe can. And it becomes very obvious that feeding the exhaust from that 2 1/4 inch diameter pipe through a catalytic converter with a 1 7/8 inch diameter inlet and outlet will be a bottleneck that will limit flow and increase back pressure. Based on these simple observations, it should be very obvious that maintaining the same diameter pipe throughout the exhaust system will result in the least back pressure, most consistent and unimpaired flow, and the best performance, and that connecting a 2 1/2 inch collector to a 2 1/2 inch catalytic converter and then a 2 1/2 inch exhaust system, will maintain this steady flow for optimum performance. So, yes, the stock catalytic converter does flow pretty good, but it will only flow as much as the 1 7/8 inch inlet and outlet will allow it to, and it represents a significant limit on the performance of the vehicle once the pipe in front of and behind it are increased in size for more exhaust flow.
The Iperformance header outflows every other header on the market, making it ideal for both naturally aspirated and supercharged applications.
Other header manufacturers are using primary and collector pipes that are on average 1/4 inch or more smaller than the primary pipes used in the Iperformance headers. The smaller pipes limit flow capacity of these other company's headers, limiting power output and rendering them totally unsuitable for use with supercharged engines, because of the increased exhaust flow produced by a supercharged engine.
Only the Iperformance header provides large enough primary, secondary, and collector pipes to allow maximum performance from stock engines while allowing enough flow capacity that they are also ideal for use on supercharged vehicles up to the 400 HP range without limiting the performance output of the engine.
It is not physically possible to port a stock manifold out with large enough exhaust passages to match the 1 1/2 inch diameter primary pipes of the Iperformance headers.
The outside diameter of the primary runners of the cast iron manifolds are 1.48 inches. The inside diameter of those same primary runners is .97 inches by 1.3 inches, oval in shape. Cast iron is a porous material without the tensile strength of steel and depends on thick walls to keep from breaking.
The Iperformance header has round primary pipes that are 1.50 inches in outside diameter and 1.36 inches in inside diameter. Steel has a much higher strength than cast iron and does not need thick 1/3 inch thick walls.
It is not physically possible to port the interior passages of a cast iron manifold large enough to match the interior area and flow capacity of a header. The stock manifolds just don't have enough material that can be removed without grinding through the walls of the manifold itself. In addition to this, GM cast iron manifolds typically collect cylinders one and two together and cylinders three and four together, which do not fire opposite each other. Above, in the description of Tri-Y headers, it was explained that Tri-Y headers collect cylinders 1 and 4 into one pipe and cylinders 2 and 3 into another, because these cylinders fire opposite each other, and collecting cylinders that fire opposite each other maximizes the scavenging affect of pulling exhaust gasses out of the cylinder. The cast iron manifolds to not pair opposite firing cylinders, and do not see any benefit of scavenging at all, causing increased turbulence and very poor exhaust flow.
These are the reasons that headers always out perform ported cast iron manifolds.
Some people are willing to accept lesser quality and lesser performance, because they have not ever experienced the quality and performance of a truly well built product.
Many people who have never used Iperformance products or have never driven a vehicle using out products will make bold statements that they believe there is no difference between what other companies offer and what Iperformance offers. These people are not basing their opinions on any experience at all and often go out of their way to avoid any discussion of the documentation of the clearly superior performance of the Iperformance product when compared to every other product on the market, namely the dyno tests.
While there is absolutely nothing wrong with accepting the quality and performance of lesser products than the Iperformance product, the question every person has to ask themselves is "Are you willing to accept second best?", and the answer to that question is in all cases a resounding "No.".
For the Ecotec engine, the Iperformance header is the clear choice over the RK Sport header.Customers of the RK Sport header have repeatedly complained about excessive under hood heat, incompatibility with intake systems, and the down pipe hitting the frame of the vehicle.
Heat and intake system incompatibility problems are due to the twisted pipe design of the small diameter RK Sport primary runners, where the runners are bent into 180-270 degree bends to fit those long runners within the small space between the fire wall and the engine. Exhaust flow is forced against the side of the pipe in a curve and transfers more heat to and through the pipe and into the engine compartment. In addition, forcing the exhaust flow against the side of the pipe increases friction, slows exhaust flow, and increases back pressure. All of these increase heat buildup and decrease power output by the engine.
Remember, exhaust runner tuning is determined by the combination of runner length and runner diameter, and the Iperformance header uses larger diameter exhaust primary runners, allowing for shorter length primary runners, that are straighter and are not need to be twisted around in 180-270 degree bends to fit between the fire wall and the engine to properly tune the power band of the engine. The straighter pipes reduce heat transfer to and through the pipe by keeping the flow from being forced against the side of the pipe, thereby reducing the under hood temperatures.
Furthering heat concerns, the RK Sport product uses only low temp 1200 degree ceramic coating, which offers minimal insulation and heat blocking quality when compared to the Iperformance header which uses the Tri-Coat ceramic coating system using seven layers of two different coating formulas that protects and insulates to over 2400 degrees, further reducing under hood heat.
But, multiple layers of coating and different coating formulas costs more money, which would cut into RK Sport's profit margin, so you won't see them offering any products with Tri-Coat finish.Fitment of a header is of primary concern, and numerous complaints from RK Sport customers of the down pipe resting and rattling against the underside of the car is most likely attributed to the fact that the RK Sport header does not have any hangers attached to it. General Motors graciously provided down pipe hangers on all of their 1996 through Current model J-body frames at the base of the fire wall. GM uses these hangers to hold up the down pipe of the 2.2 liter OHV engine and ignores them with the Quad Four and Ecotec engines.
When we designed the Iperformance header for the Quad Four and Ecotec engines, we made sure to use these hangers to make sure our product remains steady and lines up dead on for the best fitment on the vehicle. This adds further stability to the entire exhaust system, makes installation easier, and makes certain that the fitment is optimum.
But, adding hangers to a header costs money, and would reduce RK Sport's profit margin, so you won't see RK Sport putting hangers on any of their Quad Four or Ecotec headers.
