Effects of back pressure, other exhaust related questions
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Effects of back pressure, other exhaust related questions
1986 13B GLX
but this is a rotary in general related question
i know my fare share of piston, but im learning about rotary now
what would be best for an exhaust system? total free flow (straight pipes) or would a muffler (either straight thru design, or what have you) be more beneficial to a rotary engine?
basically what im getting as is how does back pressure effect rotary engines? is a small amount beneficial or...?
but this is a rotary in general related question
i know my fare share of piston, but im learning about rotary now
what would be best for an exhaust system? total free flow (straight pipes) or would a muffler (either straight thru design, or what have you) be more beneficial to a rotary engine?
basically what im getting as is how does back pressure effect rotary engines? is a small amount beneficial or...?
#2
if u go with something like straight pipes u get a lot of noise and a lot of gain in high RPM Hp. Apparently u loose low end torque though.
The more restrictive exhaust the more low end torque and less high end.
well at least this is what i've heard. I still have my stock exhaust cuz i have to go through emissions testing
The more restrictive exhaust the more low end torque and less high end.
well at least this is what i've heard. I still have my stock exhaust cuz i have to go through emissions testing
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how does back pressure effect rotary engines?
I don't think any back pressure is benefical from a preformance stand point, although some back pressure helps emissions.
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ok thanks..
im just considering my options..
i dont really mind if the police dont like it, but i WOULD try to keep it legal, in regards to noise
essentially around here it doesnt matter how loud it is unless you have something representing a muffler's function on the vehicle
would a general striaght through design muffler be able to take the heat from rotary? or is the temperature different not as much of an impact..
im just considering my options..
i dont really mind if the police dont like it, but i WOULD try to keep it legal, in regards to noise
essentially around here it doesnt matter how loud it is unless you have something representing a muffler's function on the vehicle
would a general striaght through design muffler be able to take the heat from rotary? or is the temperature different not as much of an impact..
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Re: Effects of back pressure, other exhaust related questions
Originally posted by Black13B
what would be best for an exhaust system? total free flow (straight pipes) or would a muffler (either straight thru design, or what have you) be more beneficial to a rotary engine?
what would be best for an exhaust system? total free flow (straight pipes) or would a muffler (either straight thru design, or what have you) be more beneficial to a rotary engine?
basically what im getting as is how does back pressure effect rotary engines? is a small amount beneficial or...?
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Diabolical,
It is desirable to have a high velocity exhaust gas flow because the velocity and momentum of that flow tends to help purge (or suck) the exhuast from the combustion chamber.
So, when folks put on overly big exhaust components, the exhuast gas goes into a bigger pipe, slowing it's velocity, and lessening the purge effect.
If more exhaust gas is left behind, that would lessen combustion effiency and torque fo a street car.
Is this the same thing you are saying or am I missing something relating to backpressure?
It is desirable to have a high velocity exhaust gas flow because the velocity and momentum of that flow tends to help purge (or suck) the exhuast from the combustion chamber.
So, when folks put on overly big exhaust components, the exhuast gas goes into a bigger pipe, slowing it's velocity, and lessening the purge effect.
If more exhaust gas is left behind, that would lessen combustion effiency and torque fo a street car.
Is this the same thing you are saying or am I missing something relating to backpressure?
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Originally posted by Stripgear
Is this the same thing you are saying or am I missing something relating to backpressure?
Is this the same thing you are saying or am I missing something relating to backpressure?
let me say this up front, i may be totally wrong on this - so please don't take this as me saying it's the way it is.
the reason why bigger pipes are bad for torque (on a N/A application) is simply because they shift the torque further up in the RPM range. it's not that you necessarily make LESS torque. the larger diameter will still promote the scavenging effect, it just takes more RPM before the effect gets to a point where the engine will be using less HP to expel the exhaust and, instead, allow you to put it to the rear wheels. i think it is the momentum of the gas that's changing not the velocity.
we seem to completely agree that bigger is not better when it comes to exhaust tuning, but i'm also saying that total freeflow is not that great for torque either. i believe you'd suffer the same torque shift (upward in the RPM band) if you ran two separate 2.0" pipes that never collect as you might experience running pipes that collect into 2.5 or 3.0 inch crotch that runs out a single inlet muffler.
again, in racing where absolute HP is needed and you're going to be shifting like mad, up and down, it won't matter, but it will make a noticeable difference on the street in terms of noise and low-end. it's true that one can live with it (i ran a 2.5 inch system for about 3 years) but the decreased low-end is very noticeable compared to tuned systems like the RB systems which use 2.0 inch. that was all i was saying.
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