About exhaust Backpressure
#11
RE: About exhaust Backpressure
Back pressure will be fine on any car w/a midpipe and a catback you loose it when you get into big piping on a near stock motor and straight pipes which are a bad idea anyway they loose all of the 4.6 tone and sound like a truck.
#12
RE: About exhaust Backpressure
Backpressure is a M Y T H .
It does not help anything to have more backpressure in the system. When people think they are having a backpressure issue, whats really happening is a loss of the natural vaccum in the system, not a lack of backpressure.
The entire idea behind a H or X pipe is that the exhaust pulses from each cyilnder hit (your exhaust acutally pulses...only so fast you cannot tell) will create a tiny vaccum and help with cyilnder scavanging, that is, removing all the spent exhaust gases from the cylinder so that the next stroke only has clean air. LT headers also help with this, as since the tubes, being all the same length, help make sure the pulses are evenly spaced and don't run over each other in the system.
The myth of backpressure comes mostly from carberated setups, where people would try to run open headers (or none at all) and lost cylinder scavanging, not to mention throwing the tune way the hell off.
My exhaust consists of a set of LTs, a catless X pipe, a set of straight thru (well curved, but nothing in the tubes) magnaflow mufflers, and some dumps. There is literally nothing but straight open pipes in the system, and I did not loose any TQ down low, far from it, when I did my exhaust install.
The entire idea behind exhaust is to reduce backpressure. Any backpressure in the system is robbing power, because the engine must overcome the backpressure to get the exhaust out of the system. The less effort the engine has to use to push the exhaust out of the pipes, the more it can use to move the car.
It does not help anything to have more backpressure in the system. When people think they are having a backpressure issue, whats really happening is a loss of the natural vaccum in the system, not a lack of backpressure.
The entire idea behind a H or X pipe is that the exhaust pulses from each cyilnder hit (your exhaust acutally pulses...only so fast you cannot tell) will create a tiny vaccum and help with cyilnder scavanging, that is, removing all the spent exhaust gases from the cylinder so that the next stroke only has clean air. LT headers also help with this, as since the tubes, being all the same length, help make sure the pulses are evenly spaced and don't run over each other in the system.
The myth of backpressure comes mostly from carberated setups, where people would try to run open headers (or none at all) and lost cylinder scavanging, not to mention throwing the tune way the hell off.
My exhaust consists of a set of LTs, a catless X pipe, a set of straight thru (well curved, but nothing in the tubes) magnaflow mufflers, and some dumps. There is literally nothing but straight open pipes in the system, and I did not loose any TQ down low, far from it, when I did my exhaust install.
The entire idea behind exhaust is to reduce backpressure. Any backpressure in the system is robbing power, because the engine must overcome the backpressure to get the exhaust out of the system. The less effort the engine has to use to push the exhaust out of the pipes, the more it can use to move the car.
#14
RE: About exhaust Backpressure
Backpressure does not make low end torque.
Backpressure is a M Y T H. It does not do anything for a car whatsoever, nothing, nada, zip, zilch.
I really would like someone to explain to me the thinking on this (other than the problems with the carbd cars already described). The entire idea behind backpressure just lacks a general understanding of how the internal combustion engineworks.
Your engine is nothing more than an air pump. You open a valve, piston goes down sucking air in, close the valve, piston goes up compressing the air/fuel, detonate it (sparkplug), forces piston down, exhaust valve opens, piston comes back up, forcing exhaust out.
Exactly how is pressure holding the exhaust in (and thus causing resistance to the pistons upward movement, aka loss of power) going to help with low end torque? All it is doing is taking power away from the engine, not adding any.
The entire idea behind aftermarket exhaust is twofold... you remove restriction so that the engine uses less force (power) to expell the exhaust (which translates to more WHP) and you increase the scavanging effect via the suction cause by the previous exhaust pulse, which means less spent gas is still in the chamber, and more fresh air/fuel is, when you detonate the next time.
Backpressure is a M Y T H. It does not do anything for a car whatsoever, nothing, nada, zip, zilch.
I really would like someone to explain to me the thinking on this (other than the problems with the carbd cars already described). The entire idea behind backpressure just lacks a general understanding of how the internal combustion engineworks.
Your engine is nothing more than an air pump. You open a valve, piston goes down sucking air in, close the valve, piston goes up compressing the air/fuel, detonate it (sparkplug), forces piston down, exhaust valve opens, piston comes back up, forcing exhaust out.
Exactly how is pressure holding the exhaust in (and thus causing resistance to the pistons upward movement, aka loss of power) going to help with low end torque? All it is doing is taking power away from the engine, not adding any.
The entire idea behind aftermarket exhaust is twofold... you remove restriction so that the engine uses less force (power) to expell the exhaust (which translates to more WHP) and you increase the scavanging effect via the suction cause by the previous exhaust pulse, which means less spent gas is still in the chamber, and more fresh air/fuel is, when you detonate the next time.
#15
RE: About exhaust Backpressure
These threads crack me up. Optimal backpressure in your exhaust system is 0. Backpressure puts strain on your engine by the piston having to push against backpressure to get the gasses out of the combustion chamber. Backpressure does NOT create low end torque. That is the dumbest thing I have ever heard. When you go with a better flowing exhaust system it moves your powerband up where you need it in a performance car. If you go with to big of a pipe you slow the exhaust gasess too much and create backpressure.
#17
RE: About exhaust Backpressure
http://www.uucmotorwerks.com/html_pr...torquemyth.htm
so theoretically on some vehicles unless you have a tune for your new exhaust like many of us do (me thanx to brenspeed) it is possible to lose torque when changing an exhaust. so my earlier statement wasnt exactly false.but on the other side of the argument if backpressure was a good thing then why do many cars at the strip have cut outs.
so theoretically on some vehicles unless you have a tune for your new exhaust like many of us do (me thanx to brenspeed) it is possible to lose torque when changing an exhaust. so my earlier statement wasnt exactly false.but on the other side of the argument if backpressure was a good thing then why do many cars at the strip have cut outs.
Thread
Thread Starter
Forum
Replies
Last Post
junior04
4.6L (1996-2004 Modular) Mustang
1
09-28-2015 10:53 AM
tj@steeda
Steeda Autosports
0
09-24-2015 09:18 PM