Air Pump ?
05-20-2005, 01:17 PM
#5
Senior Member
Join Date: Jul 2003
Posts: 1,850
[quote name='drftk1d' date='May 20 2005, 01:58 PM']why would you want to cool down the cat when it works off of heat?
why do you think startup emissions are worse than when the car is warmed?
[/quote]
the airpump is used to blow clean air into the cat to dilute the exhaust mixture, period.
oh btw, startup emissions are worse because the motor has been sitting and collected extra fuel and oil and such that has been sitting in the exhaust ports as well as the motor itself. When the car first starts, it blows all this smoke and extra stuff out into the atmosphere. I know my car smokes for a few seconds, but keep in mind the OMP also injects oil to prelube the seals for startup, which itself causes smoke.
why do you think startup emissions are worse than when the car is warmed?
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[/quote]
the airpump is used to blow clean air into the cat to dilute the exhaust mixture, period.
oh btw, startup emissions are worse because the motor has been sitting and collected extra fuel and oil and such that has been sitting in the exhaust ports as well as the motor itself. When the car first starts, it blows all this smoke and extra stuff out into the atmosphere. I know my car smokes for a few seconds, but keep in mind the OMP also injects oil to prelube the seals for startup, which itself causes smoke.
05-20-2005, 02:04 PM
#6
Super Moderator
Join Date: Sep 2002
Location: Tallahassee, FL
Posts: 5,425
The catalytic converter does a great job at reducing the pollution, but it can still be improved substantially. One of its biggest shortcomings is that it only works at a fairly high temperature. When you start your car cold, the catalytic converter does almost nothing to reduce the pollution in your exhaust.
Preheating the catalytic converter is a good way to reduce emissions. The easiest way to preheat the converter is to use electric resistance heaters. Unfortunately, the 12-volt electrical systems on most cars don't provide enough energy or power to heat the catalytic converter fast enough. Most people would not wait several minutes for the catalytic converter to heat up before starting their car. Hybrid cars that have big, high-voltage battery packs can provide enough power to heat up the catalytic converter very quickly.
Preheating the catalytic converter is a good way to reduce emissions. The easiest way to preheat the converter is to use electric resistance heaters. Unfortunately, the 12-volt electrical systems on most cars don't provide enough energy or power to heat the catalytic converter fast enough. Most people would not wait several minutes for the catalytic converter to heat up before starting their car. Hybrid cars that have big, high-voltage battery packs can provide enough power to heat up the catalytic converter very quickly.
05-20-2005, 07:17 PM
#8
Senior Member
Join Date: Mar 2005
Posts: 270
Thanks for the thorough explanation guys, I was too lazy to find out the info.
Anyways rx7man, are you sure you are feeling at the right hose?
I never even had an air pump on any of my cars, but it also might be because it's spinning to slow?
Take a supercharged vehicle for example, and think of the blower as some sort of air pump. Almost all supercharged vehicles produce vacuum at idle. You won't get any positive pressure, unless you have a load on the engine.
Taken from: http://www.victorylibrary.com
"Intake manifold vacuum is a very complex matter, affected by factors not readily apparent. Vacuum is caused by the ratio between 2 separate volumes, which are “connected” when the intake valve is open, and the piston passes TDC on the intake stroke."
Anyways rx7man, are you sure you are feeling at the right hose?
I never even had an air pump on any of my cars, but it also might be because it's spinning to slow?
Take a supercharged vehicle for example, and think of the blower as some sort of air pump. Almost all supercharged vehicles produce vacuum at idle. You won't get any positive pressure, unless you have a load on the engine.
Taken from: http://www.victorylibrary.com
"Intake manifold vacuum is a very complex matter, affected by factors not readily apparent. Vacuum is caused by the ratio between 2 separate volumes, which are “connected” when the intake valve is open, and the piston passes TDC on the intake stroke."
05-20-2005, 07:28 PM
#9
Senior Member
Join Date: Mar 2005
Posts: 270
[quote name='drftk1d' date='May 20 2005, 09:58 AM']why would you want to cool down the cat when it works off of heat?
[/quote]
Part of the answer to that would be because of the high TGT's that rotaries produce.
The site posted by baldy has a better in depth explanation as to how a catalytic converter works.
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Part of the answer to that would be because of the high TGT's that rotaries produce.
The site posted by baldy has a better in depth explanation as to how a catalytic converter works.
05-20-2005, 08:54 PM
#10
Senior Member
Join Date: Mar 2004
Location: A2, MI
Posts: 453
for something like an SC thats hooked up to the intake, it produces a vacuum at idle b/c the air is not pushed thru the intake very much (not much air is being gathered), so if it were stopped (ie not being sucked into the combustion chamber/rotor housing) it would be at or a tiny bit above atmospheric pressure. However since it is moving, from the SC to the engine, it has less pressure (bernoulli). the drop in pressure since it's moving more than compensates for the tiny pressure increase from the SC, creating a vacuum... I dont think a dedicated air pump would do this, espec from one of the output lines.