EGR; replace, block, plug or leave alone?

[thealleyboy]

The "soup-can solution" would certainly do the trick. On mine, I eliminated the pipe - with a plate on one end, and a threaded plug on the other.

Again, I'll reiterate my point that these motors were not specifically designed for anti-smog apparatus, so these devices are not integralto the engine performing properly. Maybe some of the international Sube Board members will back me up on this. You won't find nearly as much emissions controls on vehicles intended for 3rd world markets. All this smarty-pants talk applies only if you intend to utilize this extra equipment. If you have made a conscious decision to elimate the system (and by this I mean completely eliminate), those items become irrelavent.

As complex as these cars have become, it still comes down to the basics when you strip away all the extras...

 

good luck, John

[torxxx]

you've got a great point there man. I remember when board members were freaking out because I was going to remove all the emissions stuff on it.

 

The thing to realize is that diesel powered cars and trucks dont have to pass emissions tests. They puke out some nasty ************. But then it comes to our little 4 cylinder engines. We have to pass a under the hood inspection and a computer tested inspection up here in alaska. Its rediculous that I have to IM my gas engine and diesels get away free.

[mikeshoup]

you've got a great point there man. I remember when board members were freaking out because I was going to remove all the emissions stuff on it.

 

The thing to realize is that diesel powered cars and trucks dont have to pass emissions tests. They puke out some nasty ************. But then it comes to our little 4 cylinder engines. We have to pass a under the hood inspection and a computer tested inspection up here in alaska. Its rediculous that I have to IM my gas engine and diesels get away free.

Actually, part of the reason why diesel engines get away without emissions testing is because diesel engines really burn cleaner. There's isn't nearly as much CO or HC output, only slightly more NOx and SOx. What makes disel engines seem so nasty, is they have a high particulate output. Cleaner diesel fuels, ultra low sulfer diesels, and biodiesels are making them run more cleaner than they ever have before.

[naru]

Fuel efficiency mode

 

EGR has been used to increase fuel efficiency on many cars since the

mid-1980s. During steady throttle cruise conditions, EGR is used to reduce

throttling losses. Throttling losses are energy that is used to create intake

manifold vacuum and overcome the intake restriction of the throttle. It takes significant horsepower to create the intake manifold vacuum that occurs under cruise conditions.

During light-load cruise conditions, the EGR valve is gradually opened much more than is necessary for NOX emission control.The open EGR valve

reduces intake vacuum and replaces some intake airflow with EGR flow.The reduced intake airflow reduces engine power, but the throttle is gradually

opened to replace the lost airflow. Either the cruise control or the driver does the throttle opening.

Because the EGR valve is opened very gradually, the driver doesn't even

notice that he is opening the throttle to maintain speed. The end result is that intake airflow and therefore, the fuel flow are both slightly reduced, but intake manifold vacuum and throttle losses are significantly reduced. The benefit is reduced fuel consumption under freeway conditions. This EGR based fuel efficiency mode is common on EGR equipped vehicles built during and after the mid-1980s.

 

Ignition advance

EGR flow can be used to allow increased ignition timing advance. That means

the computer strategies used to control ignition timing are heavily influenced by

EGR.

As EGR flow increases, ignition timing is automatically advanced. Anytime

EGR is reduced, ignition timing is automatically retarded. This response seems

to be especially strong and quick on OBD II vehicles. It is so effective that

disabling EGR will rarely result in a NOX emission failure in loaded mode

emission tests. But, disabled EGR valves will usually result in increased fuel

consumption and reduced power because of the impact on ignition advance.

 

Combustion chamber temperatures

EGR reduces NOX formation by reducing combustion temperatures. The

exhaust gases that are recirculated slow the combustion process and reduce

peak temperatures. Modern engines that use EGR systems are designed to

perform very well with the slower combustion that EGR causes.

When the EGR system on one of these engines is disabled, combustion

chamber temperatures can rise dramatically and actually melt components. The

advanced computer-controlled systems on newer cars prevent this from

happening, but it still occurs on many older cars.

[WoodsWagon]

Thanks for using paragraph's 2 and 3 to support my claims.

 

But we're just a bunch of smartypants and should shut up.

 

While you're ripping off all the emmisions junk, remember that you must replace your exhaust headers with the largest possible to help the massive power that you have tapped in the engine flow out. Rip off the Egr, and when you rip off the carbon cannister and all it's vacuum lines, which must be sucking power away, make sure to notice the whopping milage and power gains.

[Buddy]

My '92 Loyale is missing on power, has rough idle and idle goes up/down when hot. I red a little on the forum and the both TPS and EGR came out as potential problems. I looked at my EGR and the inner is kinda hard to move. Then I realized it been unplugged. So I have what seem to be an unplugged faulty EGR.

 

The car is a winter beater but as I like to work on cars I change small things here and there. I'm wondering what I should do with the EGR valve. Replug it? Change it? Remove it and put a block off plate? Or leave it as it is?

well if you have to do emissions testing in your area then it probally will affect it on passing the tests. those are my .02

[thealleyboy]

 

Ignition advance

EGR flow can be used to allow increased ignition timing advance. That means

the computer strategies used to control ignition timing are heavily influenced by

EGR.

As EGR flow increases, ignition timing is automatically advanced. Anytime

EGR is reduced, ignition timing is automatically retarded. This response seems

to be especially strong and quick on OBD II vehicles.

 

OBDII is the standard ECU protocol on 1996-06 vehicles.

The older motors (ie EA82's) were not designed to coincide with this modern system. The older ECU's had limited "override" features, were not very effective, and are easily disabled.

 

John

John

[Subarian]

I can't believe this thread is still alive. Bottom line is this: you can try it without making a permanent mod (see my previous posts on this topic) and if you like the results, keep it. If not, it takes about 60 seconds to undo.

 

Oh, and if you melt your pistons, it's not my fault!

[GeneralDisorder]

Fuel efficiency mode

 

Naru - I agree with what you are saying completely, however. EA81 and EA82 carbed engines have no computer control at all. You are right that the EGR if properly and accurately controlled, can yeild improvements in both performance and econemy. The hard truth however for these engines is that no EGR control is performed at all. They receive ported vacuum from the carb routed first through a therm vacuum valve to keep it from being used while the engine is still cold.

 

Basically what I'm saying is that your are correct, but that it simply does not apply to many early subaru's due to their lack of software control over the system in question. The early SPFI systems didn't do anything with it either. Their sensors do not include anything to sense or control the EGR valve - only an EGR solenoid to once again turn it on once operating temp is reached.

 

The whole ODBI, ODBII thing is just silly since none of this gen of Subaru's are complient.

 

GD

[86subaru]

so my question is can you block off the egr on a SPFI motor ?? and try it

[naru]

Naru - I agree with what you are saying completely, however. EA81 and EA82 carbed engines have no computer control at all. You are right that the EGR if properly and accurately controlled, can yeild improvements in both performance and econemy. The hard truth however for these engines is that no EGR control is performed at all. They receive ported vacuum from the carb routed first through a therm vacuum valve to keep it from being used while the engine is still cold.

 

Basically what I'm saying is that your are correct, but that it simply does not apply to many early subaru's due to their lack of software control over the system in question. The early SPFI systems didn't do anything with it either. Their sensors do not include anything to sense or control the EGR valve - only an EGR solenoid to once again turn it on once operating temp is reached.

 

The whole ODBI, ODBII thing is just silly since none of this gen of Subaru's are complient.

 

GD

 

I don`t know why you would think computer control of the EGR and ignition advance is a prerequisite.

No ECU black majic is necessary to open the EGR enough to reduce throttling losses at cruise.

 

Even though it doesn`t directly sense EGR position or flow,the SPFI computer is optimizing ignition timing based on expected EGR flow.

Remove the EGR and you have less than optimum timing.

 

Same argument applies to EA-81s.

Even the clunky old mechanical advance distributors in our EA-81s have curves optimized for a certain EGR flow.

Remove the EGR and now you have too much advance at cruise and subsequent detonation unless you have modified the vacuum advance.

 

No problem you say,I`ll just retard the timing a couple degrees.

Now the timing is too retarded all the time except part throttle cruise.

I can hear the chorus now of "but I don`t hear any pinging."

Either you are not hearing it or you weren`t running enough ignition advance to begin with.

 

 

I can`t take credit for the info in my last post hence the OBD reference.

[GeneralDisorder]

I don`t know why you would think computer control of the EGR and ignition advance is a prerequisite.

No ECU black majic is necessary to open the EGR enough to reduce throttling losses at cruise.

 

Even though it doesn`t directly sense EGR position or flow,the SPFI computer is optimizing ignition timing based on expected EGR flow.

Remove the EGR and you have less than optimum timing.

 

Same argument applies to EA-81s.

Even the clunky old mechanical advance distributors in our EA-81s have curves optimized for a certain EGR flow.

Remove the EGR and now you have too much advance at cruise and subsequent detonation unless you have modified the vacuum advance.

 

No problem you say,I`ll just retard the timing a couple degrees.

Now the timing is too retarded all the time except part throttle cruise.

I can hear the chorus now of "but I don`t hear any pinging."

Either you are not hearing it or you weren`t running enough ignition advance to begin with.

 

 

I can`t take credit for the info in my last post hence the OBD reference.

 

If that were true, then haveing the EGR turned off during warm up would cause pinging - which it does not.

 

Plus the vacuum advance curve for these engines is the same as it was before they started adding EGR. A happy upgrade to the EA71 in the Gen 1's is to use the EA81 breakerless distributor.

 

The EGR on an EA81/EA82 is there for emissions only - just as it was in 1973 when first introduced by GM. Most people disabled those as well since they made the engine run like crud.

 

I have run both with, and without it - Weber and Hitachi. No difference that I could notice, and I have a vacuum pump and guage to verify that the EGR is working properly. Not to mention I can see it open when I rev the engine. And I know what pinging sounds like.

 

GD

[naru]

If that were true, then haveing the EGR turned off during warm up would cause pinging - which it does not.

 

HUH? What are you talking about?

 

All cars w/EGR have different advance curves than thier non-EGR predecessors.

A different curve is necessary because of the slower burn w/EGR.

To not have a different curve would mean leaving power and MPG on the table.

 

The fact that YOU are not perceptive enough to notice any difference doesn`t mean anything.

[thealleyboy]

Nare, it's obvious that you are a big EGR fan, and if you choose to run this system on an EA81/82, that's cool.

But to imply that these emissions systems are essential to cars of this era is just plain wrong. These motors were designed to operate without this equipment. Emissions controls evolved after these motors were engineered, and Fuji updated the cars to meet the particular regulations in effect in the markets where the cars were sold. These motors were never redesigned to be emmission compliant. Instead, this was accomplished by bolting on whatever anti-smog equipment the EPA said was necessary, and tuning the motor to these specs.

This design was old in the 80's, and is downright ancient if you want to talk ODBII.

 

Your lecture on emissions systems would be perfect for the New Gen forum...

John

[torxxx]

I agree

[Subarian]

EA82, Weber 32/36, 4 degrees additional initial advance (to compensate for altitude), blocked EGR, run this way for 100,000 miles, and NO knock, detonation, pinging, etc.

[Ross]

Nare, it's obvious that you are a big EGR fan, and if you choose to run this system on an EA81/82, that's cool.

But to imply that these emissions systems are essential to cars of this era is just plain wrong. These motors were designed to operate without this equipment. Emissions controls evolved after these motors were engineered, and Fuji updated the cars to meet the particular regulations in effect in the markets where the cars were sold. These motors were never redesigned to be emmission compliant. Instead, this was accomplished by bolting on whatever anti-smog equipment the EPA said was necessary, and tuning the motor to these specs.

This design was old in the 80's, and is downright ancient if you want to talk ODBII.

 

Your lecture on emissions systems would be perfect for the New Gen forum...

John

 

The NZ didn't even get egr 'till some time in the mid to late '80s.......

[WoodsWagon]

We're talking about a 1992 Loyale here folks. This isn't an EA81.

The EA82's were deffiniatly designed with emissions equipment in mind.

The EA82 was probably designed in the early 80's, and emmision controll legislation for the US came in like '74 I think. So the idea of reducing NOx was not outlandish. And the method's for doing it were proven by then, so it wasn't a crappy V8 smothered in an equal weight of black magic emmision controll vacuum lines, pumps, thermo swiches, and vacuum motors.

[GeneralDisorder]

We're talking about a 1992 Loyale here folks. This isn't an EA81.

The EA82's were deffiniatly designed with emissions equipment in mind.

The EA82 was probably designed in the early 80's, and emmision controll legislation for the US came in like '74 I think. So the idea of reducing NOx was not outlandish. And the method's for doing it were proven by then, so it wasn't a crappy V8 smothered in an equal weight of black magic emmision controll vacuum lines, pumps, thermo swiches, and vacuum motors.

 

Actually, the EA82 is just an EA81 with different heads. The rest of the differences are there to accomidate the OHC design - the oil pump and water pump were changed to run off the timing belts, and some idlers and tensioners were added. But basically the engine is the same at it's core. Remove the heads from both, and it's easy to mix up which is which when the shortblocks are laying in the garage. Have to look for the cam on the EA81. There is almost no increase in HP from the EA81 hydro lifter to the EA82 hydro lifter (carb). The EA81 solid lifter with smaller intake valves makes 72 HP, but the hydro lifter engine with larger valves makes considerably more when coupled with a bigger carb and better flowing exhaust as the EA82 got standard. In reality, they both are the same engine just with different valve systems. The HP ratings are so close as to be dependant on things other than the core engine.

 

GD

[habib99]

the oil pump and water pump were changed to run off the timing beltsGD

 

 

 

isn't the water pump run off the alternator belt? If not I've been mixing my water pump up with something else all this time!! :-\

[[HTi]Johnson]

Actually, the EA82 is just an EA81 with different heads. The rest of the differences are there to accomidate the OHC design - the oil pump and water pump were changed to run off the timing belts,...

 

GD

Then what is that thing that is inline with my alternator's belt? Is it the radial defibrillator?

[GeneralDisorder]

isn't the water pump run off the alternator belt? If not I've been mixing my water pump up with something else all this time!! :-\

 

I can't remember anymore - I could be thinking of the Audi timing belt I did last week. :-\ I remember that the belt covers have to come off to replace it tho.

 

That just makes it MORE like the EA81 tho, not less... and really if you think about it, you can change the accesories and their placement/design all you want - the core engine is the same. The EA81T used the EA82 style power steering pump for example, but NA EA81's used a larger, more clunky setup.

 

GD

[subaru_styles]

water pump were changed to run off the timing belts

 

??

[GeneralDisorder]

??

 

Your attempted humor at my expense is not appreciated

 

I've done more timing belts than you have ever seen in your lifetime pal - so sue me if I get em mixed up sometimes. The point I was making had nothing to do with being 100% accurate - we are having a theoretical discussion in this thread about the EGR system, and why it may or may not be important to a specific engine model. Someone sugested the EA82 was designed with the EGR in mind, and my accersion was the EA82 is simply a logical expansion on the already sucessful EA81 design. What belt drives which accesory is not important to the underlying discussion in *this* thread. Things might be different if we were discussing changing a water pump or timing belt.

 

GD

[TheSubaruJunkie]

Ok kids, calm down.

 

-Brian