Isn't running the exhaust down and out with large-bore long-tube headers with minimally restrictive mufflers accomplishing the same thing? Educate me. As an aside, I have just had my original ANSA units blasted and coated so they are going to be around for awhile. Is there a header upgrade I can use with my original heads and exhaust?
Original Post. I'm sure there is a connection to the Ford GT40 program with the degree headers. If the winning LeMans cars have it, then what would it do to a road car I guess that is the best answer that I can give.
I do not know of any dyno testing to support the hypothesis that it gives sufficiently more power -- so there you have it. If I recall correctly the 's optimize the exhaust pulse from the cylinders. The game is to get as much "dirty" atmosphere out of the cylinder and get more fresh air in as possible, the 's are a tool to do so.
It was by coincidence that physics gave us a bitch'in looking exhaust sytem with a distinctive tone. George P Admin. The "throws" of V8 crankshafts can be configured in either a "cross plane" design or a "flat plane" design.
The configuration of the crankshaft is what gives certain V8's a burbling exhaust tone, while others like the Ferrari V8's produce a smoother exhaust tone that has a "whine" to it. A "cross plane" crankshaft produces an exhaust tone that burbles, a "flat plane" crankshaft produces an exhaust tone that has a smooth whine. The firing order of the 4 cylinders in each bank of V8 engines with a "cross plane" crankshaft are not evenly spaced, so when the exhaust of all 4 cylinders in the common banks are connected in a common collector or header, the result is that uneven exhaust "burble" we all love so well.
However, that unevenly spaced firing order per bank results in uneven "pulses" within the exhaust system for each bank. That robs power. How much power you ask? About 30 to 40 bhp, depending upon the state of tune of the motor. That's too much bhp for a racer to give up. The purpose of the "bundle of snakes" is to even out the spacing of the firing order in each side of the two exhaust systems, evening out the pulses, and gaining that 30 to 40 bhp that would have otherwise been lost.
R 72red Guest. Ok, cool. What that tells me is that there is an optimum length and obviously order of the pipes that cross over.
I would be wary of making my own setup not that I could anyway, I am speaking theoretically but would want one that someone with an engineering degree had figured out. Are there setups that are considered historically correct when compared with the factory race cars? Anyone that knows also don't forget to chime in with answers to my more personally practical question above as well. The correct grouping of the exhaust primaries depends upon the firing order of the engine in question.
The Cleveland firing order is: To evenly space the exhaust pulses in each side of the bundle of snakes, you'll group the primaries so that every other cylinder in the firing order is in the same grouping. Collector A: Collector B: They are unusually quite at idle but start to scream at I love that little laugh as he gets passed. What a sweet, sweet sound! They include the theory of the principles behind the degree design. Here is where it has been discussed on the PIBB before.
Lots of pics of installations here. Even out the pulses from bank to bank. George explained it well. This involves making them correct in the materials used and the routing as based on the original race cars. I imagine that there is a magic number that would be your engines optimim primary length but I know of no way to determine this other than Dyno testing different lengths.
As a rule longer pipes boost mid range and shorter ones boost top end. The typical Pantera header is very short. I am going to push that limit when I build my under car set and see how long I can make them. I am building both the and undercar systems for my car and I will chassis dyno both to compare them but that is a long way off. Did I mention that 's look cool and I'm sure chics dig them.
D Derrick Guest. Just to add you will find it's the two middle cylinders that are crossed over on each bank. This all balances out the firing order as the next cylinder to fire exits out the opposite header as this is not the case with regular headers.
As mentioned this is eliminated with a cross over pipe yet it's not as efficient as a true cross over header. The back two cylinders get the extra pipe added to make all cylinders have an equal length tube. It's definitely a different sound.
This discussion could be taken deeper as you could get into the intake side of the engine and find that independent runner system would be the ultimate as a 4bbl intake has two short runners in the center and longer ones to the outside cylinders.
That's another story In the end you have a good pizza warmer. I just wanted to add a couple of points I didn't mention earlier. When I wrote earlier that a bundle of snakes exhaust system is worth 30 to 40 bhp, that's under racing conditions, i.
Mufflers alter the dynamic of an exhaust system tremendously, there's no guarantee a bundle of snakes will add anything, I'm not inferring they don't make more bhp, but exhausting through mufflers the gains will be less than 30 bhp.
But they do sound bitchen. The design shown in these pictures was developed that crossed the tubes under the engine. A special dry-sump oil pan was designed for the necessary clearance. The last photo shows a header we built for Caldwell Development for a Reynard chassis Lemans Prototype powered by a restricted Dodge V Because of the restrictor, the engine rpm was limited making it an ideal application for the degree header layout.
Though the use of degree headers is limited to a few mid-engine low-rpm cars, or high-budget builds with custom oil pans and bodywork, you can still maximize your exhaust systems by properly engineering your exhaust manifold for your engine and application. Properly engineered, an exhaust can be as, or even more effective , than these early degree designs.
Our completely custom engineered header collectors combine high flow and high velocity to increase and broaden an engine's torque curve all the way to the horsepower peak and beyond. Burns currently offers hand finished, high quality fabrication collectors , collectors , and even ,, merge collectors. The first step in this process is to complete the race engine specification form and send it to Burns Stainless for a custom exhaust design. Looking for a money saver and still end with a bundle of snakes set of headers.
All pipe cut to size, sbf flanges and collectors all in SS. Horsepower gains can be achieved elsewhere without much difficulty.
My phone e number is Jeep will have aforementioned 6. And later are to pull and stroke to To offer you the best selection of race quality parts. Relentless innovation in exhaust technology isn't just a tag line, we are always improving, advancing, and refining what we offer.
The shorter the connecting rods, the more severe the second harmonic vibration is and the low hood lines of '70s cars demanded both short strokes and short connecting rods in order for the engine to be compact enough to fit under the hood.
In less technical terms, most V8s fire I cylinder every 90 degrees. A flat plane or degree V8 fires two cylinders at the same time every degrees. This makes it sound and vibrate like two 4 cylinder engines intead of an 8 cylinder engine,. In Ford and Pontiac both came out with flathead V8 engines. The Ford was a 90 degree and was very successful and produced until in the US and through most of the 60s in some other markets. There are companies today that make flat plane crankshafts for your Ford or Chevy V8s.
I think the Chevy V8s that ran in the Indy many years ago when they allowed more displacement for stock block engines used flat plane cranks. Buick used a very odd firing crank to smooth out the vibration created by building a V6 with 90 degree separation cylinder banks.
All previous sixes were either inline, 60, or degree separation engines. A degree crank is stronger and is always forged. It is not counter-weighted and is lighter. That is one reason all-out fuel drag cars idle roughly. Scavenging is a more complete evacuation of exhaust gases. In order to fire two cylinders together every degrees, four cylinders would have to come to top dead center at the same time, two of them firing and two of them reloading.
With a 90 degree V angle of the cylinders, when either the two middle pistons or the two outer pistons of the left bank are at TDC, all the pistons on the right bank are at mid stroke. The piston acceleration at top dead center is much higher than the piston acceleration at bottom dead center.
The motion from mid stroke to tdc is not a mirror image of the piston motion from mid stroke to bdc. The asymmetrical motion of the pistons prevents the inner cylinders from perfectly balancing the inertial forces of the outer cylinders. This picture I drew illustrates what connecting rod length does to piston motion.
These are the kind of threads I really enjoy. The collective knowledge assembled on this site is impressive! The arrangement of plenums on intake manifolds of carburated V-8s is to take advantage of sequential spacing of cylinder intake events. If the intake sourced one bank from each side of the carburetor cylinders 7 and 4 GM firing order would run awfully lean.
Ahh praise be to sequential fuel injection to solve that problem! Runs smoother, sounds smoother but the exhaust note is definitely different.
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