Just wondering what is the benefit of headers? If a car has headers, what does it replace? Does it change the exhaust note significantly? Thanks so much for answering these questions from a guy who works on bodies but not cars!
From Wikipedia rather than rewriting something... Manifold or header... Aftermarket exhaust manifold In most production engines, the manifold is an assembly designed to collect the exhaust gas from two or more cylinders into one pipe. Manifolds are often made of cast iron in stock production cars, and may have material-saving design features such as to use the least metal, to occupy the least space necessary, or have the lowest production cost. These design restrictions often result in a design that is cost effective but that does not do the most efficient job of venting the gases from the engine. Inefficiencies generally occur due to the nature of the combustion engine and its cylinders. Since cylinders fire at different times, exhaust leaves them at different times, and pressure waves from gas emerging from one cylinder might not be completely vacated through the exhaust system when another comes. This creates a back pressure and restriction in the engine's exhaust system that can restrict the engine's true performance possibilities. A header is a manifold specifically designed for performance. During design, engineers create a manifold without regard to weight or cost but instead for optimal flow of the exhaust gases. This design results in a header that is more efficient at scavenging the exhaust from the cylinders. Headers are generally circular steel tubing with bends and folds calculated to make the paths from each cylinder's exhaust port to the common outlet all equal length, and joined at narrow angles to encourage pressure waves to flow through the outlet, and not back towards other cylinders. In a set of tuned headers the pipe lengths are carefully calculated to enhance exhaust flow in a particular engine revolutions per minute range. Generally, most car performance enthusiasts buy aftermarket headers made by companies solely focused on producing reliable, cost-effective well-designed headers specifically for their car. Headers can also be custom designed by a custom shop. Due to the advanced materials that some aftermarket headers are made of, this can be expensive.
Also, yes, the exhaust note can change and the goal is to gain a few HP for the investment. One of the easy "bolt-on" ways of gaining HP, especially when coupled with high-flow catalytic converters or "race pipes" connected then to a performance muffler system. A number of choices exist for our cars, and you'll find a lot of debate as to which is best if you do some searching here.
The exhaust your 360/430 has is already technically a header. The advantage you get by swapping it out is removing the pre-cat from the header's collector area which is arguably the most critical part of the header in regards to it's ability to make power. You will get greater exhaust flow(more power), more volume(the cat core works as a muffler) and a higher pitched exhaust note. The other end of the deal is that fairly often the cat breaks up and gets sucked into the engine causing damage. This is of course a situation that can be prevented with proper maintenance from someone knowledgable. The modified headers help reduce the likeliness of this happening. Unfortunately if your exhaust still has cats down stream as it should, this can still happen.
Josh, Where is your shop and are you open Saturday's? Looking to do some work to my 360 and want to speak with you. Thanks.
It will change the note of the car for sure, louder by the way. About power, it doesn't matter without test pipes/ high flow cats & exhaust and the most important the euc's needs to be reflashed.
How does the pre-cat in the header get sucked back into the motor? Is it with soemthing like 10% of the time the pre-cat fails on the header, or 50%? I think the Fabspeed rep who posts on here says they have seen pre-cats fail, but thus far the car's owners were lucky as no stuff got sucked back into the motor, which at least in that small sample seems to be more towards 10% vs. 50%. The next question I have is the cats that are down stream- how would that stuff get sucked into the motor? If there is a chance that the pre-cat breaks up and gets sucked in by some sort of vaccume wave backwards in some cases, it would seem to be that it would be very unlikley that material would get sucked backwards all the way from the main cats that are relatively far down stream and pulled all the way back up into the motor, but I'm not an expert thus my question... -Andrew
A well developed set of headers and exhaust and ECU tuning can dramatically improve performance and sound. watch this: http://www.veloceperformance.com/
Thanks for this link but I'm not impressed as there is absolutely no concrete technical information about their impovement solutions. Before I bite, I need serious data and no marketing blabla
Im pretty familiar with ECU tuning and I know the gains are solid and not marketing BS. Dino @ Veloce is a member here. David, you need to get your car running! BTW, your new avatar looks great!
