EGR Blockoff Discussion [Merged 8-8]

[Puller]

Before I speak my piece, this is directed to 'tuners' who are some what new and are somewhat impressionable. However there are many of you that never learned certain things the correct way. This also applies to stock or nearly stock vehicles. That said: Although many DSM followers are on the forums to help and provide insight, many fail to understand how or why certain components operate in the way they do. Even on this site's 'tech articles' there are modifications which do far more harm than good. I'm only going to refer to the articles posted in the free mods of this sites tech articles. First i'll start with the EGR block off. Whomever wrote this deposition clearly had no idea what they were talking about. The purpose of an EGR valve is to recirculate exhaust gas into the intake, as many know. What people fail to realize is that the EGR valve was designed to combat knock. Exhaust gases, on a normal running engine, are inert. They are recirculated to COOL combustion chambers by displacing usable air with inert air. Coincidentally that acts as an emissions device by lowering NOX (which is a product of heat). NOX is the EPA's main concern as far as emissions. Another point, it's operative under light cruise, not under heavy accel or WOT because it's vacuum is from ported vacuum. So that doesn't even bother most DSM drivers ;-) So if you blocked off your EGR i have only a couple things to say: congratulations you just increased the likelyhood of knock and the emission of NOX. Also you just found a quick way to fail an emissions test. If people would stop and think, they'd realize they aren't as smart as the Mitsu engineers and the thousands if not millions of dollars of R&D that went into that "stupid emissions device". Another note: under WOT emissions isn't a concern. You're vehicle goes into open loop and runs rich. a rich mixture emits HC into the exhaust. therefor most emissions devices are disregarded during WOT including your O2 sensor.

 

[Ultimatedsm]

I believe there isn't any gain from blocking off the EGR, I bet if you put it under a dyno you wouldn't even get 2HP. Now is it really worth it? You will never pass another emission test after this block off. If your going to get rid of the EGR, then get rid of all the emission devices on your car, then maybe you will gain 5HP. I am with you Puller on this one because I am against this particular free-mod that does more bad then good, there is no good actually, you make your car fail emissions really.

 

[sumenlo]

Starting in 1975 and up until about 1980 oxidizing catalytic converters (2 way cats using palladium and platinum) were used to help reduce the HC and CO. Catalytic Converters are pretty efficient (but not 99%- 75% efficient maybe on NOx, a little better for CO and HC- and that's with high quality cats) when the air/fuel mixture is balanced. TOO rich or TOO lean and the catalyst doesn't work very well at all.

So going off of this, it's basically useless to run a cat if your car is running too rich or too lean? Do I understand this correctly? And since the majority of DSM's run on the rich side of A/F mixture, wouldn't it be logical to not run a cat? Otherwise it's just a useless piece of metal that creates unwanted backpressure.

I'd actually like to see a tasteful debate on the elimination of catalytic converters. I have a few opinions of my own on that topic.

 

[BrassMonkeY]

My turd came from the factory without a EGR, and im
using a cam from a car that had a EGR.
I guess i will not be passing the emmisions any time soon.
haahahhahahah.

but i would get rid of the EGR system, and all emissions controll just to get out of the way.
that precious space is needed.and makes your engine bay look cleaner.
i got rid of all that stuff. my battery is now where the charcole canister used to be.
the earth? screw the earth, i want it to crash and burn with me.

 

[luvmygst]

I am soooo glad that this thread made a comeback. I think I will find a diesel motor to swap into my gst so I will have no egr. (or do they have it too?)

 

[NitrousPete]

I am soooo glad that this thread made a comeback. I think I will find a diesel motor to swap into my gst so I will have no egr. (or do they have it too?)

Yes, NOx emissions are a HUGE issue on diesel engines.

 

[MyBeatGSX]

That is because at an idle, the EGR is closed. EGR only opens under load. If an EGR opened at idle, you would have poor idle, rich smelling exhaust, possible stalling, etc.

Actually they test it at a 2,000rpm roll at like 30mph. Explain that.

 

[tstkl]

a cool 20 bucks will prevent that 2000 rpm test on rollers at most places. im sure if you brought enough money wiht you, you wouldnt even have to bring the right car and you could get it smogged

O NO, IM NOT GOING TO PASS EMISSIONS? REALLY? as the song that I happened to be listening to right now just said, "I don't give a fcuk, I'M AN AMERICAN"

 

[MyBeatGSX]

I wish it was that easy here. No one takes bribes anymore, this new system sucks. I guess its still not as bad as cali.

But I just realized that 99.9999% of stations only have a 2 roller dyno. So I'm set for life with only an idle test that it could probably pass without a cat if I lean it out enoug.

 

[90gst]

Here are my thoughts about why the producer of this post is wrong...Use common sensewhen talking about the egr...When driving, the car boost runs thru the intercooler to cool the air coming into the engine, so how would pumping 1000degree plus exhaust gas help cool usable air? its not gonna cool anything, quite the opposite, it doesnt take a rocket scientist to figure that one out...I agree it helps eliminate know tho, that's one of its primary purposes, for emissions

 

[xveganxcowboyx]

Here are my thoughts about why the producer of this post is wrong...Use common sensewhen talking about the egr...When driving, the car boost runs thru the intercooler to cool the air coming into the engine, so how would pumping 1000degree plus exhaust gas help cool usable air? its not gonna cool anything, quite the opposite, it doesnt take a rocket scientist to figure that one out...I agree it helps eliminate know tho, that's one of its primary purposes, for emissions

Seeing as how a reduction in temps is the purpose of the EGR I think it probably does that.

Exhaust gasses are nowhere near the temperatures that are actually reached durring combustion. They are comparitively cool. Even if that weren't the case, the displacement of O2 is what keeps the temps down, not the fact that the gasses themselves are cooler.

 

[Thomas91169]

who cares about its purpose. fact is it doesnt add horsepower nor does it take it away. unless youre a stickler about clean engine bays or for some reason love to increase the emissions in your vehicle, leave it on.

all cars that i have seen that can monitor knock through some sort of logging device still have some sort of part throttle knock. it usually nothing but road noise interfering with the sensor. and in todays cars, they run rich enough and low timing at part throttle anyways. hell, i disabled any knock under 2* with dsmlink, and thatll allieviate any part throttle phantom knock for good.

 

[Thomas91169]

I wish it was that easy here. No one takes bribes anymore, this new system sucks. I guess its still not as bad as cali.

But I just realized that 99.9999% of stations only have a 2 roller dyno. So I'm set for life with only an idle test that it could probably pass without a cat if I lean it out enoug.

leaning it out will only increase NOx, leaner burns hotter, thus the reason for a EGR in the first place to cool combustion temps with inert gas to lower emissions.

 

[Ultimatedsm]

a cool 20 bucks will prevent that 2000 rpm test on rollers at most places. im sure if you brought enough money wiht you, you wouldnt even have to bring the right car and you could get it smogged

O NO, IM NOT GOING TO PASS EMISSIONS? REALLY? as the song that I happened to be listening to right now just said, "I don't give a fcuk, I'M AN AMERICAN"

your an odd person, and you are an aermican, you don't give a ####? You are just making yourself look more stupid. Lot of americans give a #### about emissions or there would be no emission devices on cars today. Alright, so what is the benefits of blocking off the EGR honestly? What is the gain? I want hard facts and not stupid theories. If someone can find me ACTUAL facts about blocking off the EGR will do so and so for the better, until then, my shit is staying on. I like going to an emission place without any worries of failing, you get in then get out, your done.

 

[4pistons]

To address the issue of catalytic converters...

I have personally done testing on my 14B powered '91 GSX and have determined that mine is a huge restriction and power robber. I have a full 2-1/2" exhaust to a 2-1/2" turbo muffler.

I drilled and tapped a fitting on the exhaust pipe in front of the cat/con and connected some copper tubing to a 0-15 psi pressure gauge on my console. At any speed and any throttle position less than half there was absolutely no backpressure whatsoever. At full throttle however backpressure increased to about 6-1/2 psi, it didn't spool as quickly, and performance was lagging.

With the cat/con removed and a straight test pipe in place the backpressure at full throttle is less than 2 psi. Throttle response and spool is much quicker and performance was back.

The cat/con is a $65 aftermarket 2-1/2", straight-thru unit that uses a small-cell grid inside it rather than pellets. You can literally see through it but is obviously still quite a restriction. Would a Random Technologies High Performance cat/con work better? I don't know. I'm not shelling out $150 to try it.

The point is I did actual testing, got results and data, and found which way worked best for me without guessing or assuming.

Rick - '91 GSX

 

[TimG]

your an odd person, and you are an aermican, you don't give a ####? You are just making yourself look more stupid. Lot of americans give a #### about emissions or there would be no emission devices on cars today. Alright, so what is the benefits of blocking off the EGR honestly? What is the gain? I want hard facts and not stupid theories. If someone can find me ACTUAL facts about blocking off the EGR will do so and so for the better, until then, my shit is staying on. I like going to an emission place without any worries of failing, you get in then get out, your done.

The EGR blockoff myth is one used by old school v8 carb boys. Their EGR wasn't vacuum solenoid activated. It was activated by a cleverly positioned vacuum source slightly in front of a throttle plate so at idle their EGR was closed but at a regular slight open throttle, the egr had enough vacuum to open.

Right now, in todays day and age, EGRs are only open at a decent cruise. The ECU controls the EGR via a solenoid mounted on the firewall. It is mostly closed at idle, open under part throttle conditions and CLOSED DURING WOT conditions.

So to understand the EGR, it is designed to control the NOx levels of your emissions. It has very little to do with CO and HC.

At 2500 degrees F, Nitrogen in the air and Oxygen in the air combine to create harmful emissions called NOx. The EGR recirculates inert exhaust gases into the intake to lower the combustion temperatures. Everyone knows how impossible it is to burn already burnt gas.

I took out my EGR as a Canadian because of the room the EGR, solenoid and lines take up. I just hate the way they look. On a brighter note, my winter DSM has a fully functioning EGR system on it still.

 

[sumenlo]

To address the issue of catalytic converters...

I have personally done testing on my 14B powered '91 GSX and have determined that mine is a huge restriction and power robber. I have a full 2-1/2" exhaust to a 2-1/2" turbo muffler.

I drilled and tapped a fitting on the exhaust pipe in front of the cat/con and connected some copper tubing to a 0-15 psi pressure gauge on my console. At any speed and any throttle position less than half there was absolutely no backpressure whatsoever. At full throttle however backpressure increased to about 6-1/2 psi, it didn't spool as quickly, and performance was lagging.

With the cat/con removed and a straight test pipe in place the backpressure at full throttle is less than 2 psi. Throttle response and spool is much quicker and performance was back.

The cat/con is a $65 aftermarket 2-1/2", straight-thru unit that uses a small-cell grid inside it rather than pellets. You can literally see through it but is obviously still quite a restriction. Would a Random Technologies High Performance cat/con work better? I don't know. I'm not shelling out $150 to try it.

The point is I did actual testing, got results and data, and found which way worked best for me without guessing or assuming.

Rick - '91 GSX

I'm with you on this one. I didn't do any acutal testing like you with numbers and hard data, but I did it all by feel. I have full 3" exhaust from the turbo back with a pacesetter downpipe. The car originally had a high flow catco cat. Ran pretty good, but ran even better when I decided to take the cat out and go for a test pipe. The accelleration in the mid to high rpm range was drastically improved. Not to mention exhaust sound

I did run an open down pipe for a while, but that's a whole nother story. Needless to say, performance gains were huge. Overall, backpressure is a bad deal. Someone said something earlier about cat removal being another myth. I have to disagree with you 100% on this one. There's almost no application out there where backpressure is good for a motor. If you wanna compare N/A cars to force inducted, think of this: One of our old race cars was a dirt late model. It had a 700 hp, 15:1 compression N/A motor. That thing had straight headers and that's it. Not exhaust. Not the best example, but nonetheless, you see my point. With turbo cars especially, there is SO much exhaust pressure being generated by the turbo that any backpressure in the exhaust pipes is going to make the turbo work that much harder. Then you get into turbo life and efficiency. If I could, I would take my downpipe off and run straight off the turbo. Of course, engine fires aren't my favorite though.

You have to think about what backpressure does to a motor. Any kind of pressure in the back side of the exhaust is going to make the rest of the motor work harder to push those gasses out of the car. The more restrictive your exhaust is, the more inefficient and sluggish your motor will run. It's all physics.

Now, backpressure in a 2 stroke motor is actually good. I won't get into it here, but a 2 stroke motor is the only application where you do want backpressure.

 

[NitrousPete]

It's more about velocity than pressure, and matching the exhaust velocity to the RPM range desired.

On a NA motor, if the velocity is too low, it will leave combustion gasses in the cylinder. If you're running a cam with a lot of overlap as many performance cars do, too much velocity will actually draw out air/fuel mixture with it. The same can be said, however, that if the velocity is right, it will help draw in intake gasses and charge the cylinder. This is why you don't want to go slapping the 2 1/4" headers on your 350hp small block for example. There's simply not enough exhaust velocity to draw all of the combustion gasses from the cylinder in it's RPM range. The same can be said for a 600ci, 1,100hp big block; a 1 5/8" header, although it will be very high velocity for a motor that size, will not be able to flow enough gasses over a few thousand RPM to be effective and combustion gasses will be left behind, resulting in a smaller intake charge, and very reduced power.

Turbo cars are a different story alltogether, although velocity into the turbine is still a critical factor, everything between the turbine housing and valve is pretty much open season as the shape of the turbine housing itself is responsable for creating the correct flow.

 

[NitrousPete]

Actually they test it at a 2,000rpm roll at like 30mph. Explain that.

With an AWD car? How do they do that? The "old school" test is a static idle test, or a no-load test at around 2,000rpm in which the EGR is still generally not operating. When you said "old school" test, I thought that's what you meant.

 

[NoRider]

This forums arguements are way too long to read, but good job on posting this this info. I think that cars have these parts for a reason, and that if they weren't needed, then they wouldn't have been put on cuz it would have made the car cheaper for the company to make. Also, why would you want to release more emissions into the atmoshphere for 5 horse power you can't even feel? I mean if your THAT worried about hp, turn the boost up a little to make yourself happy.

 

[Ultimatedsm]

The EGR blockoff myth is one used by old school v8 carb boys. Their EGR wasn't vacuum solenoid activated. It was activated by a cleverly positioned vacuum source slightly in front of a throttle plate so at idle their EGR was closed but at a regular slight open throttle, the egr had enough vacuum to open.

Right now, in todays day and age, EGRs are only open at a decent cruise. The ECU controls the EGR via a solenoid mounted on the firewall. It is mostly closed at idle, open under part throttle conditions and CLOSED DURING WOT conditions.

So to understand the EGR, it is designed to control the NOx levels of your emissions. It has very little to do with CO and HC.

At 2500 degrees F, Nitrogen in the air and Oxygen in the air combine to create harmful emissions called NOx. The EGR recirculates inert exhaust gases into the intake to lower the combustion temperatures. Everyone knows how impossible it is to burn already burnt gas.

I took out my EGR as a Canadian because of the room the EGR, solenoid and lines take up. I just hate the way they look. On a brighter note, my winter DSM has a fully functioning EGR system on it still.

Hey theres a canadian on here we are rare. Anyway its up to people what they do and what they don't want to do with their cars. I just personally agree with the EGR being there because it just doesn't make sense to block it off. The way it looks? I don't even notice mine to tell you the truth. Anyway I think this thread is the same crap over and over with everyone . Its time for me to call it quits on this topic, I just agree with original creator of this post thats all.

 

[Attack Eagle]

I think this is one of those threads where it inspired lively debate, but the original poster mistitled it.

It's not about FREE MODS, it's about EGR blockoff, and no one has proven one way or the other that it is good or bad, but rather that it depends on the person and the CAR.
the original poster was completely conforntational about the topic, and did not know what an EGR's job is (emissions) and thought it was for knock (preignition/pinking/pinging for you international Tuners.) Once that was dealt with then there were lively discussions about what it was for and why IRL it can help, and why some people would do it and some would not.

I say lock the thread and change the title to "EGR blockoff debate" for the search records. There is nothing left to say or contribute in regards to this that has not already been said by someone.

 

[TheBoosted96GST]

probably not in the right forum but... Would it be bad to block of my EGR valve using a block off plate but leave the vac lines connected? thanks

 

[absolute_DSM]

How are you going to leave them connected to the valve when youll be replacing the valve with a plate?

If youre set on blockin your EGR for some reason, then just pull the vac lines to the valve all together. Leave the solenoid connected electronically.

 

[TheBoosted96GST]

what do you mean how? just by not changing anything but inserting a block off plate? all i'm asking is..... with the EGR blocked off using a block off plate...will it cause any harm or ill effect if vac. lines stay connected?

 

[absolute_DSM]

So are you trying to install a plate WITH the valve?

If you want to remove it for some reason you can remove the valve and the lines and replace it with the plate with no problems. Just leave the solenoid connected to the harness.