![]() ![]() In a Chevy cylinders 5 and 7 fire sequentially. So we can forget wave mechanics, and look to fluid dynamics to make power. This gives the fluid that is the intake charge or the spent exhaust gas TIME to move. We use a long duration cam in a race engine to hold the valves open longer. Where there is less time to evacuate the cylinders. This is why headers do work better at high RPM. Since it is a physical plug of gas it takes time to move. This plug of hot gas seeks the lowest pressure gradient and follows that line out of the engine. Ignoring wave mechanics you can consider that when the exhaust valve pops open the pressure inside the cylinder falls to near atmospheric as the spent cylinder charge rushes out to fill the volume of the log manifold with high pressure gas. ![]() There is one other benefit a header performs that a cast iron log manifold can not and that is isolation of the cylinder pulses. The bigger the primary tube (to accommodate high RPM operation) the harder it is to fit the bag of snakes in the car.Ībove I mentioned the lack of scavenging with a street exhaust. So you had to do research (experiment in the old days) or run a computer program (I use Pipe Max 3.7) to calculate the length you want then fabricate that length so that it fits in the car chassis. The primary tubes of custom headers are of equal length and that length is tuned to scavenge at only one RPM. This means that if you want scavenging you custom build headers so that they fit your car body (off the rack headers fit every Chevy powered car that Chevy made, not just your car, which explains the poor fit that you read about). Run open pipes on the street and you will not only have a splitting headache by the time you arrive at your destination, but you will also attract the attention of the police. So a closed exhaust has no scavenging ability. You stick a tail pipe on it and you change the frequency (RPM affected), and if you install a muffler it is no longer an open pipe, and as such no waves to scavenge the gasses. If you have studied physics you know that the first thing about wave mechanics is you need an open ended pipe (think pipe organ). First of which is the concept of scavenging or using wave harmonics to improve performance. There are a lot of urban legends that are associated with headers. There are just a lot of options and am unsure of what to do. Thanks in advance to anyone that gives an advice. I know that you guys can only give suggestions if you have details. I would like to build an lt1 from the early 70s for the car eventually. Which muffler should i run? I was thinking a flowmaster but i really dont have much of an opinion on it so looking for suggestions What material is best for the exhaust i hear stainless steel is best but is also very expensive, I heard that aluminized metal works better and is far cheaper. With a motor that should never break 400hp i dont think 3 inch is really necessary, so should i settle for a 2.5? Next i want a car that sounds amazing, with good performance. It seems like every exhaust sytem you look at is headers back. This headers vs stock manifold is hard because stock manifold have way less options when it comes to exhaust systems. That would insure if i upgraded to headers or swapped motors that all i would need was for an exhaust shop to bend a pipe to the from the motor to the cross member. My first idea was to buy the best exhaust system that i possibly can from the cross member back. So if i already have a stock manifold on my car would it be worth the effort to install headers? I bought a CVR mini starter that has an adjustable solenoid so I can move it around. I know that some cars with those options had headers from stahl (I believe) installed and functioned perfectly. I hear that headers can be a nightmare for cars with power steering and a/c. So it would be mostly a daily driver but would like it to be fun to drive at a track occasionally.Īnyway i am going to be buying a complete exhaust system for my car this weekend. The car is going to be mainly a driver but there is a local track nearby that has track days so i think it would be fun to fine tune the car and try to get faster without upgradeing to super modern suspension components. I dont mind upgradeing the brakes to newer and better designs but dont want to overly modernize the car. My goal for this car is to build a car is to build a car that is a mostly original. It would probably be smart to include what i want to do with the car to help narrow down suggestions. I want to drive this car badly but would think that driving it as is for more than a few seconds could cause harm to the engine. I got the 350 that came with my camaro up and running, but all I have for an exhaust is the stock iron (ram horn?) exhaust manifold. I am nearing a critical time in my build. ![]()
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