Observations With The Egr System

[Slater]

15G was replaced in 96?  Wouldn't that be 98?  Otherwise I have a 16T in my 97?  That doesn't sound right.

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Ah yeah, you're right. Brain fart. 15G straight flange was 96-97.

So yeah, swapping to the 96-97 ECU with no other changes MAY show somethign on the dyno, assuming Volvo made ZERO changes to the ECU fuel and timing tables (which I doubt as manufacturers are always tweaking).

Don't forget - the EGR does not open while in boost and WOT. So on the dyno the results may be a little misleading or confusing.

Also, even when the EGR valve is closed, there is still 200+F exhaust gas inside the pipe and valve body, which is bolted to your manifold heating it up.

So the BEST test on the dyno would be to dyno a stock 95 car with EGR intact, then repeat the test with a 96-97 ECU, the EGR pipe removed from the manifold and plugged, and the EGR removed from the intake manifold and the blockoff plate installed. That will be the only way to truely see the effects of the EGR - be it EGR temps, A/F, or the effects of the EGR system heating the intake air.

[thelostartof]

Ah yeah, you're right. Brain fart. 15G straight flange was 96-97.

actually 96' was conical flange 15g .... ask me how i know ... i've only sold 3 of them ... pulled them off cars ... checked the vin plate along w/ date code on head/door

and there is so much i wanna add to thread but no time need to go to work

every car that has EGR only works @ part throttle/cruise .. no EGR work @ w0t ... along w/ yes it does stop combustion temps as reusing that exhaust gas DOES help the mixture

reason they stopped using it is because they found another way to make the engine run clean enough that they do NOT need it ... EGR is/was a temp/quick fix for a motor that didn't run clean enough

if 99% of those 93-95 cars w/ EGR had them clogged then every one of those cars would NOT pass smog and throw a check engine light ... if the car passes smog then the system is working

and yes EGR and that rear 02 are only in the US because its for emissions which yes is lower power usually ...

and as bad as egr is .... unless youve had a car running on the dyno(smog) .. and pulled power/vac to the EGR and seen the readings jump it really does more for an engine than you think(but its all smog related)

[Slater]

it really does more for an engine than you think(but its all smog related)

Exactly. That was my whole point. It's all for emmissions and smog.

If you want to make more power the EGR has to go. Been that way since the 60s and 70s when EGR was one of the ONLY emmissions controls before catalytic converters were even invented.

Anyone remember downdraft tubes?

[billr99]

If it is so good then I have two questions for you.

(1.) Why does Slater's engine temps drop by about 50f and thereby inrease timing for more power when the EGR is disabled?

(2.) Why did Volvo remove it from models later then '95?

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In regard to Question 2, according to VADIS the EGR valve was removed when it was no longer necessary due to changes in the design and function of the cat. converter amde in MY '96

Cheers,

[thelostartof]

Exactly. That was my whole point. It's all for emmissions and smog.

If you want to make more power the EGR has to go. Been that way since the 60s and 70s when EGR was one of the ONLY emmissions controls before catalytic converters were even invented.

Anyone remember downdraft tubes?

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yes so if you remove it ... then come smog time the car will NOT pass as it is designed to work w/ it ... if anything go to a smog shop .. pay the $30 to test the car on a 5 gas machine(anything less is pointless) ... and then remove the EGR .. and test again ... see how readings change .. as that's just as important as making more power

[Slater]

yes so if you remove it ... then come smog time the car will NOT pass as it is designed to work w/ it ... if anything go to a smog shop .. pay the $30 to test the car on a 5 gas machine(anything less is pointless) ... and then remove the EGR .. and test again ... see how readings change .. as that's just as important as making more power

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Are you just speculating, or have you tested this for yourself? Uness you have tested it yourself, you can't say the above with absolute certainty.

For example, on my last car I had NO CAT - that supposedly is GUARENTEED to fail emmissions, right? Wrong. When I tested, my numbers were CLEANER than my wife's 98 Civic LX ULEV vehicle!

There are many more variables that contribute to a pass/fail on an emmissions test. Sludge in the intake/tb/manifold, gas octane, operation of 02, ecu tune, ignition timing, camshaft timing, EGR, etc. If you know how to make an engine run "clean" by adjusting the other variables, you can remove many of the emmissions controls and still pass emmissions in most states. The exception is NAZI California.

So for example, VADIS says for 96 they redesigned the cat, and by doing so eliminated the EGR. So there ya go. Install a more effiecient cat and rip that EGR out. Also, the ECU tune and cam timing has a hell of a lot to do with emmissions. Dialing out overlap and adjusting fueling and timing at idle, as well as part throttle low-rpm operation goes a long way in passing emmissions tests.

Personally, I'll bet all Volvo did was move the cat closer by a few inches to heat it quicker and keep it a little hotter than 93-95. Also, it would not suprise me if they made some fuel/ignition changes in the ECU, which is even more reason why I say the "right" way to disbale the EGR is to get a 96-97 ECU and plug everything up. If you still fail, adjust the cam timing a tiny bit until you pass.

So it's not as simple as saying "if you disconnect X you will fail", because most of the emmissions controls on cars overlap each other.

[PorBleemo]

So basically all that is needed to disable the EGR is:

1. A corresponding 96-97 850 ECU for your car.

2. A new, more efficient catalytic converter. (Optional?)

This is significantly easier then I was hoping for! Perhaps that's why FCP-Groton has two cats, one for 94-95 and one for 96-97 models. But the big question is if their cats are more efficient then the stock cat so I could get away with a direct fit 94-95 with a 96-97 ECU. Otherwise would the 96-97 cat fit directly onto my '95 Turbo without any issues (space, O2, etc)?

And would it be okay to leave the EGR installed with a new ECU and cat? Or would it be better to pull the entire system and reroute the hoses?

[Slater]

So basically all that is needed to disable the EGR is:

1. A corresponding 96-97 850 ECU for your car.

2. A new, more efficient catalytic converter.  (Optional?)

This is significantly easier then I was hoping for!  Perhaps that's why FCP-Groton has two cats, one for 94-95 and one for 96-97 models.  But the big question is if their cats are more efficient then the stock cat so I could get away with a direct fit 94-95 with a 96-97 ECU.  Otherwise would the 96-97 cat fit directly onto my '95 Turbo without any issues (space, O2, etc)?

And would it be okay to leave the EGR installed with a new ECU and cat?  Or would it be better to pull the entire system and reroute the hoses?

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It's BEST to pull the hoses as there is just extra exhaust gas filling up the pipe and hitting a "wall" (i.e. the valve never opening). But honestly if you just run the 96-97 ECU it will be fine as it just never opens the valve.

Stay tuned though. I may have the ultimate solution where an ECU upgrade is not required...

[PorBleemo]

It's BEST to pull the hoses as there is just extra exhaust gas filling up the pipe and hitting a "wall" (i.e. the valve never opening). But honestly if you just run the 96-97 ECU it will be fine as it just never opens the valve.

Stay tuned though. I may have the ultimate solution where an ECU upgrade is not required...

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I will do so as this really intrigues me. Thanks for your advice.

[thelostartof]

Are you just speculating, or have you tested this for yourself? Uness you have tested it yourself, you can't say the above with absolute certainty.

actually i used to do smog work .. and yes when you remove it it does fail .. the fact that you passed w/o a cat just means your state is one of those ones run by the fcking retards that don't give a stuff causing cali and the rest of the states to have such tight aholes when it comes to smog ... i know of more than a few cars that passed smog w/o cats or even w/ v8 swaps w/ no emissions devices .. but that's just because those smog regs are so lax it doesn't take much to pass. if ALL states had SOME smog regulations then others wouldn't need to be so tight as it would all even out to one point

and when i say it will fail i mean it will fail cali smog which is pretty much going to be the norm in a few years ... so just wait and see ... in 5 years when all of these mod'd cars that pass fine now have to meet up to cali smog specs they are gonna be in for a world of hurt. and the fact that my car passed cali smog w/ all of my little tweaks and mods just because i still have a cat and EGR makes me happy.

and hey go ahead and remove it ... but for everyone who's gonna do it ... if you ever sell your car or it ends up in a state w/ smog and they find out the federal emission part has been removed they will go back to the last owner who knowing sold an illegally modified car and your jerk will be grass ... seen it happen to way to many shops ... most of them deserve it but i've also had friends lose thier shops from some f tard who worked there who did that and caused the gov to come down on them

if you want that extra 3-10 hp you'll gain from it go ahead but it can be made up in other ways

and remember this is is coming from a person who ran w/o a cat for 8 months and will build his next exhaust system w/ a test pipe(gutted) cat to run around on as i hate hot exhaust gasses and w/o a cat i love how the entire system is ice cool after 3+ hours of driving

[lax01]

how would they know which owner illegally modified the car? and do you really think they look for an EGR system on your car? Do you think most state inspectiors know what an EGR system is? My car passed state inspection when I bought it and it had a 2.5" downpipe and high-flow cat....then when I got my exhaust ticket (with NO CAT, ticket for my ricey exhaust tip, not the no cat) two different shops signed off on it...they didn't even look under the car...I don't know what its like in CA, but I know they won't look to hard at a Volvo, unless its heavily modified

anyways, Slater I await your solution as I would love to remove that rusted piece of junk

[Slater]

actually i used to do smog work .. and yes when you remove it it does fail .. the fact that you passed w/o a cat just means your state is one of those ones run by the fcking retards that don't give a stuff causing cali and the rest of the states to have such tight aholes when it comes to smog ... i know of more than a few cars that passed smog w/o cats or even w/ v8 swaps w/ no emissions devices .. but that's just because those smog regs are so lax it doesn't take much to pass.   if ALL states had SOME smog regulations then others wouldn't need to be so tight as it would all even out to one point

and when i say it will fail i mean it will fail cali smog which is pretty much going to be the norm in a few years ... so just wait and see ... in 5 years when all of these mod'd cars that pass fine now have to meet up to cali smog specs they are gonna be in for a world of hurt.    and the fact that my car passed cali smog w/ all of my little tweaks and mods just because i still have a cat and EGR makes me happy. 

and hey go ahead and remove it ... but for everyone who's gonna do it ... if you ever sell your car or it ends up in a state w/ smog and they find out the federal emission part has been removed they will go back to the last owner who knowing sold an illegally modified car and your jerk will be grass ... seen it happen to way to many shops ... most of them deserve it but i've also had friends lose thier shops from some f tard who worked there who did that and caused the gov to come down on them

if you want that extra 3-10 hp you'll gain from it go ahead but it can be made up in other ways

and remember this is is coming from a person who ran w/o a cat for 8 months and will build his next exhaust system w/ a test pipe(gutted) cat to run around on as i hate hot exhaust gasses and w/o a cat i love how the entire system is ice cool after 3+ hours of driving

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Dude you have to be kidding me. Just because you worked for SMOG doesn't mean you can make some generalization that ANY car with EGR disabled will fail. That's BS and you know it. Unless you've tested a Volvo 5-cyl with and without EGR then I don't buy your opinion. I don't see you on a high horse every time someone asks about a rear 02 sim...

Half the people on here are running no cat and e-cutouts and stuff. And what about the 99% of the chips everyone on here use that run PIG RICH, dumping all those unburnt HCs out the tailpipe? Where do you think all that excess fuel goes? You think it all gets squeazed through the 1/4" EGR pipe? Riiight.

Also, if you want to get technical, NONE of the aftermarket parts for our cars are CARB legal that I know of, including the dps and exhausts you and everyone else makes. So anything you're making yourself including the down pipe on you own car is technically "illegal" and will "fail smog" just by being installed on a car in CA.

I don't see what the big deal is with EGR. If you disable it, and PASS emmissions because you ran a better cat, or retuned your cams, or adjusted your ECU tables, what the hell is the problem? So the people with straight pipes, rear 02 eliminators, and pig rich ECU tones are A-OK because boy they sure do have their EGR system working as designed allowing us all to breathe better. Give me a break.

Besides, you know as well as I do that ALL emmissions tests are flawed, and do not represent REAL world conditions. Why? Because they only test @ idle or part throttle low speeds. Not @ WOT or high rpms when most cars run excessively rich. They also do not test cold starts, which is when LARGE quantaties of pollutants are released - some condsider that's the time when MOST pollutents are released on modern "clean" engines - ULEV and up. So you can have a car that is a true gross pollutor - billows black smoke (i.e. unburnt fuel) @ WOT and a terrible cat that does not heat up quickly at all, but when they get on the gas analyzer it will pass according to the flawed emmissions "test".

Also, some people keep forgetting that on a bone stock 93-95 the egr IS 100% DISABLED AT WOT AND UNDER ANY BOOST AT ALL.. So a car that may possibly add 0.0005% more unwanted emmissions by having it's EGR disabled is only doing so at IDLE and part throttle with no boost. The minute you hit the gas EGR is disabled and all that extra emmissions goes right out the tailpipe; all bone stock right from the factory. So how is that OK but having it disabled @ idle is not?

Finally, the EGR only works when it is NOT CLOGGED. If your EGR system is clogged, which it will be on 90% of the cars with 100k+ miles unless it has been cleaned, then you have effectively just BLOCKED YOUR EGR and are "polluting" right now as we speak. What about those hundreds of thousands of Volvo owners? I don't see hundreds of people getting on here asking why all the sudden they are failing emmissions and being labeled as gross polluters by their states.

[thelostartof]

eh i made a big post but this works better

yea sure it rasies the intake temps .. but what about combustion temps .. two VERY different things

so untill you can prove that combustion temps are dropped it really isn't doing all that much .. as its already been proven that it drops combustion temps(i mean hell that's what its there for as that's what reduces the NOx)

nevermind the improved fuel economy from it

and part of the big post i had .. CARB legal parts are only for certian parts of an engine like the manifolds and other stuff .hence y headers and cats need carb certs yet the rest of the exhaust after it doesn't need it .. as as the downpipe is AFTER the manifold no certs needed

if you can remove the EGR retune the ECU for it and still pass smog that is up to cali's standards then more power to ya but most of those other states standards mean crap as as you said you can pass w/o a cat which pretty much kills all of those HC's left there... you wouldn't happen to have that sheet w/ the #'s your car scored w/o a cat do ya?

and how many cars spend that much time @ w0t .. where as 90% of the cars on the road spend all of that Time @ part throttle where the EGR is working

wow this is turning out to be almost 1/2 of the size what i was gonna post anyways

that's volvo bad design if it is heating up the intake temps as on my volvo there is a nice foot line metal pipe running from the valve to the intake so 'heat' soak as it be from it isn't an issue nor is it on most cars that are setup like that ...maybe something like what the ford guys do i using a spacer made of a better maternial can drop those temps back to norm as if its disabled @ w0t how can it be bad when you floor it if the valve is closed and that pipe from the valve to intake is cool from nothing flowing in it

[Slater]

eh i made a big post but this works better

yea sure it rasies the intake temps .. but what about combustion temps .. two VERY different things

so untill you can prove that combustion temps are dropped it really isn't doing all that much .. as its already been proven that it drops combustion temps(i mean hell that's what its there for as that's what reduces the NOx)

nevermind the improved fuel economy from it

and part of the big post i had .. CARB legal parts are only for certian parts of an engine like the manifolds and other stuff .hence y headers and cats need carb certs yet the rest of the exhaust after it doesn't need it .. as as the downpipe is AFTER the manifold no certs needed

if you can remove the EGR retune the ECU for it and still pass smog that is up to cali's standards then more power to ya but most of those other states standards mean crap as as you said you can pass w/o a cat which pretty much kills all of those HC's left there... you wouldn't happen to have that sheet w/ the #'s your car scored w/o a cat do ya?

and how many cars spend that much time @ w0t .. where as 90% of the cars on the road spend all of that Time @ part throttle where the EGR is working

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I have a wideband with EGT on the way. So I'll let you know when I have FACTS to post; not opinions, theories, and speculation.

I'll try and find my old test certs with the tests. Since this was 6 years and 3 cars ago, I doubt I kept them but I'll look.

My fuel econ has not changed with my EGR disabled. The BSR ECU that runs pig rich has done more for killing my fuel econ than disabling the EGR.

Anyways, it's clear you have your opinion and I have mine. No one is twisting anyone's arm to disable their EGR. I can tell you that I am certainly not the first to look at doing this. People have been bypassing emmissions controls since emmissions controls were invented. That is nothing new. If someone is scared to, doesn't want to, doesn't believe in it, doesn't feel it's worth it, doesn't know how to, can't sleep at night because they did it, or doesn't care in the first place, then goodie two shoes for them. I don't dump used oil down the drain, so don't treat me like I do. If you really want to be the emmissions nazi do something about every diesel truck on the road, 2-stroke lawn equipment with no emmissions controls whatsoever, and don't forget cows which have always been the #1 creator of greenhouse gas far surpassing cars. Also 3rd world countries which have no EPA, emmissions testing, or other forms of environmental protection. Why do you think almost all of the metal foundry business is gone from the US? It's all the EPA crap that is impossibly expensive to comply with - if a company is to stay afloat they have to move overseas where there are no or very little restrictions - just pollute away. When you look at it like that, my little EGR being disabled at idle on a car I drive 3xs a week is pretty insignificant -> equal to about 3 cow farts in the grand scheme of things.

[thelostartof]

If you really want to be the emmissions nazi do something about every diesel truck on the road, 2-stroke lawn equipment with no emmissions controls whatsoever, and don't forget cows which have always been the #1 creator of greenhouse gas.

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its funny because volvo is the leader in the new diesels and thier EGR and what not for smog .... nevermind the biggest problem w/ diesels are the NOx emissions which EGR is made to remove(Hence y cali almost outlawed the sales of all new diesel cars because they didn't meet the NOx spec

and yea i do my part i eat way to much meat than one should .. must kill those cows

and yea i'm all for going after the big companys that make all of the smog and letting all of the cars go back to being just a big displacement engine w/ one or two things on it and that's it .. none of this smog crap but its how it is as we all know those big companys will never stop polluting so someone has to do something ..

and yea i know we each have our own opinion on it .. and like i said if you can do it all and still pass smog more power to ya. but in the real world i've seen cars w/ bad egr's or clogged ones running like jerk, having all kinds of running issues. so saying that 90% of the cars here have clogged systems is kind of hard to say if the cars are showing no signs of problems.

i've just never seen an engine built/designed for an EGR run right w/o it as it was built w/ that in mind, so if the ECU is the only fixed needed it would be really nice