Doesnt the knock sensor help reduce detonation as well? Maybe the designers figured the Knock sensor was good enough and left the EGR out.
Blocking Egr
- Thread starter snotboy
- Start date
That's what I meant. The Supra's ESA system handles spark control full time. Heck, I have a 1981 model year car that doesn't have EGR at all and yet always passes NOx with flying colors. It simply uses a another method. But that's a different story than yanking off an EGR that's supposed to be there. The 7M has no other method besides the cat and it depends on EGR to lower NOx to a level it was designed to handle. And I'm tallking about the stock cat, not those tiny aftermarket ones some people cheap out with.
What about the people that arent concerned with passing emissions? Im building My 88 CA model into a track car, so I dont see any benefit to me keeping the EGR on my car. Since track cars are almost constantly WOT or in heavy decel in High RPM. Both areas the EGR doesnt do anything correct?
Now If I were making a road car (Like my other MKIII) then Id of course keep the EGR for the benefits it gives as a daily driver. Especially for commuting.
Now If I were making a road car (Like my other MKIII) then Id of course keep the EGR for the benefits it gives as a daily driver. Especially for commuting.
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jetjock said:
LOL, I do remove the O2 sensor. I prefer to have control over fuel trims and be in open loop all the time. I'll be leaving the EGR in, though.
I'm assuming you're catless. Keep that baby a tad richer than stoich and you won't need EGR 
I also have a car I do something similair with. Stays in closed loop (with sensor installed) but I can bias the loop to control at other than stoich. It's "dial a mixture" so to speak. Gets outstanding fuel economy as long as the cruise is on and I don't forget to richen it up when needed
I also have a car I do something similair with. Stays in closed loop (with sensor installed) but I can bias the loop to control at other than stoich. It's "dial a mixture" so to speak. Gets outstanding fuel economy as long as the cruise is on and I don't forget to richen it up when needed
I tuned my sentra via boosted SAFC and full time open loop by removing the O2 sensor feedback signal. I simulated closed loop by tuning the SAFC for a 16:1 AFR while under small load conditions and cruising conditions. I got awesome gas mileage since the AFR was completely flat and it didn't hunt at all like it would with normal closed loop operation. Under load, the AFR dropped to a perfect 12:1(with alky) without the typical open loop transition spike.
i know i wont drop the subject and mostly cause i want to learn. Some people learn best by reading themseves others by what people sumurize to them.
either way still missing my point if the EGR help in crusing in general is it only to help pass emmisions testing or does it provide any other benifit. everything i have seem so far is just emmisions testing
And you can purchase very nice high flow aftermarket CAT's that will help as well with out killing to much performance.
I dont know everything yet so that is why i question people Jetjock i have seen you post on many subject and you seem to have a huge wealth of knowledge i am just trying to understand. why it was made, why its there now and what benifit it gives or doe snot give the engine.
I did enjoy your bit about engine oil choices and if you remeber i bugged you there as well to learn more from you
either way still missing my point if the EGR help in crusing in general is it only to help pass emmisions testing or does it provide any other benifit. everything i have seem so far is just emmisions testing
And you can purchase very nice high flow aftermarket CAT's that will help as well with out killing to much performance.
I dont know everything yet so that is why i question people Jetjock i have seen you post on many subject and you seem to have a huge wealth of knowledge i am just trying to understand. why it was made, why its there now and what benifit it gives or doe snot give the engine.
I did enjoy your bit about engine oil choices and if you remeber i bugged you there as well to learn more from you
http://www.fordscorpio.co.uk/egr.htm
I pulled this off of yahoo and looks to be good information. I didnt get to finish it since im leaving work. If you hate reading I'll put a summary up later.
I pulled this off of yahoo and looks to be good information. I didnt get to finish it since im leaving work. If you hate reading I'll put a summary up later.
Bobster, I'm hardly a wealth of information. I know a great deal about a handful of things. That leaves me pretty ignorant about the world in general.
You're correct in that EGR is there to reduce emissions of NOx. It serves no other purpose. The point is the car was designed for it. In the Supra's case it's removal is no big deal other than "just" emissions. I simply fail to see any benefit of removing something when there is no gain and when it does nothing but good. The bottom line, to me at least, is EGR removal is more a moral than technical issue.
Btw, the devil is in the details and if you really want to know your shit you won't get it from listening to me or anyone else. Take Yellow 13's excellent lead on the way to do things. After all you're connected to the greatest source of information the world has ever known.
Also a modern substrate cat cuts volumetric efficiency a tiny amount at best. Again, much of that myth comes from the pellet based cats of old. These days the only reason to buy another cat is to get a bigger one for handling the extra NOx your'e going to throw at it by removing the EGR.
*edit* I took a look at that site Yellow pointed to. It's a pretty good one in that unlike a lot of crap on the Net it's accurate. I suggest reading the cat converter and lambda sensor portions too.
You're correct in that EGR is there to reduce emissions of NOx. It serves no other purpose. The point is the car was designed for it. In the Supra's case it's removal is no big deal other than "just" emissions. I simply fail to see any benefit of removing something when there is no gain and when it does nothing but good. The bottom line, to me at least, is EGR removal is more a moral than technical issue.
Btw, the devil is in the details and if you really want to know your shit you won't get it from listening to me or anyone else. Take Yellow 13's excellent lead on the way to do things. After all you're connected to the greatest source of information the world has ever known.
Also a modern substrate cat cuts volumetric efficiency a tiny amount at best. Again, much of that myth comes from the pellet based cats of old. These days the only reason to buy another cat is to get a bigger one for handling the extra NOx your'e going to throw at it by removing the EGR.
*edit* I took a look at that site Yellow pointed to. It's a pretty good one in that unlike a lot of crap on the Net it's accurate. I suggest reading the cat converter and lambda sensor portions too.
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When you start reading things like car magazines, especially the import ones, there is a lot of bullshit, misinformation out there. The internet seems to be a better source for those wanting to read, but not buy a text book. A college store, if they let you buy one, will have all of this info in the mechanical and electrical engeering books. And the factory manuals will show you the protocol the manufacturere chose to use when building something.jetjock said:Nope, it doesn't. Thats why I said "it's interesting to note". The guy just refuses to give up but that's OK....it's how people learn
And I'm not saying you read shitty car magazines. I was only adding to the answer.
Yeah yeah im bring up an old thread but I think I can add a little more useful info.
For one its wasnt really explained how it reduces Nox so I'll fill that in(I just went over emission controls in class). Nox is formed when your combustion chamber exceeds 2500 degrees Fahrenheit. Your EGR mixes metered amount of exhaust gasses in with your air and fuel. This displaces some of the room the air and fuel would normally have taken up with non-flammable gas(exhaust) and causes a slower burn in your combustion chamber which in turn decreases your combustion temps reducing the formation of Nox.
It is only used when your cruising and not used at idle, WOT, and when your engine is cold.
The one thing not mentioned is that is HELPS gas milage when your cruising. Our teacher didn’t have a detailed explanation as to why but what it does is reduces your "Pumping loss" by lowering your compression and your pistons don’t have to fight as much to reach TDC. Im trying to find more about how it reduces pumping loss cause I know it also has to do with the your pistons having to fight less the air/fuel being pumped into your cylinder(there is more to it that less compression).
So I think taking off the EGR will hurt your wallet as well as creating smog.
For one its wasnt really explained how it reduces Nox so I'll fill that in(I just went over emission controls in class). Nox is formed when your combustion chamber exceeds 2500 degrees Fahrenheit. Your EGR mixes metered amount of exhaust gasses in with your air and fuel. This displaces some of the room the air and fuel would normally have taken up with non-flammable gas(exhaust) and causes a slower burn in your combustion chamber which in turn decreases your combustion temps reducing the formation of Nox.
It is only used when your cruising and not used at idle, WOT, and when your engine is cold.
The one thing not mentioned is that is HELPS gas milage when your cruising. Our teacher didn’t have a detailed explanation as to why but what it does is reduces your "Pumping loss" by lowering your compression and your pistons don’t have to fight as much to reach TDC. Im trying to find more about how it reduces pumping loss cause I know it also has to do with the your pistons having to fight less the air/fuel being pumped into your cylinder(there is more to it that less compression).
So I think taking off the EGR will hurt your wallet as well as creating smog.