Exhaust pipe

Is it better to make the exhaust salt of 4 to 1 or 4 to 2? What gives greater power and better performance?

The design and elaboration of escape collectors is quite complicated. To start we will have to stick to a mathematical formula that despite being something inaccurate, is quite easy to apply:

Lc = (13,000 x ge) / (rpm x 6).

LC = exhaust collector length in centimeters, measured from the exhaust valve.
GE = to the degrees that the exhaust valve remains open in each engine turn, that is, in the distribution diagram, apart from the 180º that in theory opens the exhaust valve, there are two dimensions that allow to maintain the valve more open time, the AAE progresses to the exhaust opening, which allows the valve Keep the valve more open degrees while the admission race begins.

So that ge = 180 + aae (35º) + rce (12º) = 227º (for example).

RPM is the number of revolutions to which the engine is turned on, or to which we want the exhaust to work in optimal conditions (sometimes we are interested that the engine has low and not high)

13,000 and 6 are always fixed values

​​to find out what is the optimal diameter of the tube, the following formula will have to be used:

diameter = 2 x square

root = to the unit volume of the cylinder (in case of being a 2,000 cc engine, and 4 cylinders as it will be = 500 cc)

Lc = exhaust length in centimeters, something that we have just found with the previous formula.
3,1416 is the PI number, it is fixed, as well as the 2.



This formula has been calculated for straight tubes

, so it will be necessary The exhaust collector (we are not going to put 4 outputs in the car) the diameter formula is used to calculate the main diameter of the exhaust pipe, only this time it is used with the total displacement (2000 cc) in the case of an output or with half of the displacement in the case of two outputs. With respect to the question of which of the two distributions it is better, if 4,2,1 or 4.1 or 4.2, I tell you, to get power based on turns the best is 4.1, the longer the individual and more parallel tubes go to reach the union, the better. (We talk about turn regimes of 7000, 9000, 10,000 rpm) (very prepared motorcycles or motors).

To remove the engine a quite elastic power curve and an elevated motor torque, the best distribution is 4,2,1, or 4.2, (double rear outlet).

This latest distribution is mounted by the majority of atmospheric gasoline engines, eight valves and gives very good result, BMW 318 not catalyzed, Opel Corsa A, Opel Kadett ... the longer the individual tubes are until reaching the secondary wongs, the faster the engine can turn (penalties the low) and the longer the secondary tubes are the secondary tubes until reaching the primary tubes until reaching the primary fork. (You penalize the high) although turning 5000 laps is already fine.

I hope I have solved your doubt, another world is the silencers ... but that, for another day.

All the best.

If it serves me, but it is not clear to me how to calculate the value of AAE and RCE, where do I take those values? And then if I did not understand me, I combine it from 4a2 and then I redus it at 1 exit at the end of the escape?