EGR Block Off Plate

[Poodles]

It would more than likely just pop the HG, which nobody would look into why it happened, just assume the 7M sucks...

 

[jdub]

Not that I ever heard of....
Mine runs fine.

Yeah...you're doing it, so it must be fine. The usual logical fallacy.
The fact is you don't know George.

I know what I've seen on EGTs and I know what the TCCS fuel/timing maps are tuned for. The effect EGR has on combustion temps is a fact. I agree with Poodles.

 

[ForcedTorque]

The more I read from Mr. Poodles, the more I agree with him!

 

[Kristian_Wraae]

^ While I agree with leaving EGR intact the information in that post concerning the O2 sensor is mostly nonsense.

Unlike Jdub I gave up long ago but I'll say this one final time: EGR was originally developed and used for detonation suppression. It's ablity to reduce NOx was a side benefit that wasn't used until many years later.

Quotes from various Toyota service training publications:

EGR Impact on the Engine Control System:

"The ECU considers the EGR system an integral part of the entire Engine Control System. Therefore the ECU is capable of neutralizing negative performance aspects of EGR by programming additional spark advance and decreased fuel injection during periods of EGR flow. By integrating fuel and spark control with the EGR metering system engine performance and fuel economy can actually be enhanced when the EGR system is functioning as designed."

Note the wording about increased timing and lowered injection. What will happen if the ECU does that expecting EGR flow to be there but it isn't? The manual provides an answer: "If EGR is commanded but doesn't flow severe detonation will occur".

From the section on how EGR effects emissions and driveability:

"Too little EGR will cause detonation and emissions failure. Because EGR tends to reduce volatility of the air/fuel charge loss of EGR typically causes detonation to occur."

Run sans EGR and you'd better, at minimum, up the octane. I won't go into the emissions part of this equation because the morally bankrupt self centered "it's all about me and what I want, screw everyone else" attitude among many owners, especially younger ones, is well known. I'm not going to change them. About all I can do is hope their engines keep blowing up...

While I fully agree with you in what you say regarding the theoretical impact of blocking the EGR system I have one question:

I talked to a friend of mine today who deals in used mkIII parts. He told me that the ECU from older Supras (88) with EGR and those without EGR (they came both ways here) have the same ECU. He says the part number on those ECUs are exactly the same. I don't know if Toyota made changes to the ECU later on regarding the EGR system. But it seems to me that the impact of deleting EGR must be rather small if the same ECU has been used for those two models. Wouldn't you agree?

One other point: After putting back my EGR system I noticed that my car gets much better mileage (24 miles pr gallon at normal varied driving).

 

[figgie]

What was your Air/fuel ratios with & without a functioning EGR ?

It is irrelvant.

Just like if you were to run Ar through your car. It is inert. No amount of heat will do anything with it. That means the Lambda is UNAFFECTED DUE TO EGR or not!

on that note.

the new cars are using EGR to increase gas mileage even more!

It is quite simple really. The EGR displaces N2O2. That means that the motor is not injesting as much air and as such does not need more fuel.

So one of the cars that uses this trick, Honda Insight. They have a 1.0L engine on them. They are filling the engine with 30%ish EG. That reduces the "logical" displacement to .7L while the EGR is active and at that same exact time, reducing pumping loses (engine braking). Of course to much and the car starts to sputter.

Guess what happens in other cars that are tuned for this. Same thing. If the Supra was to do the same exact method.

The physcial displacement is 2998 cc but at 30% EG reduces it 2098.6cc. That is a liter worth of not filling the engine up along with decreasing pumping losses.

So EGR is coming to the forefront, anti-detonation, NOx reduction, and displacement reduction.

 

[SWD Fredester 3]

It is irrelvant.

Just like if you were to run Ar through your car. It is inert. No amount of heat will do anything with it. That means the Lambda is UNAFFECTED DUE TO EGR or not!

on that note.

the new cars are using EGR to increase gas mileage even more!

It is quite simple really. The EGR displaces N2O2. That means that the motor is not injesting as much air and as such does not need more fuel.

So one of the cars that uses this trick, Honda Insight. They have a 1.0L engine on them. They are filling the engine with 30%ish EG. That reduces the "logical" displacement to .7L while the EGR is active and at that same exact time, reducing pumping loses (engine braking). Of course to much and the car starts to sputter.

Guess what happens in other cars that are tuned for this. Same thing. If the Supra was to do the same exact method.

The physcial displacement is 2998 cc but at 30% EG reduces it 2098.6cc. That is a liter worth of not filling the engine up along with decreasing pumping losses.

So EGR is coming to the forefront, anti-detonation, NOx reduction, and displacement reduction.

OK, not to jump this thread but I have a question. My car came back from
the shop after being rebuilt without the EGR system. I am running an AEM
EMS on it but after reading this thread it sounds like I should put the system
back on the car. Will I need to retune the AEM to accommodate the addition
of the EGR? The car definitely does not pass emissions now. What are your
thoughts on this?

 

[figgie]

OK, not to jump this thread but I have a question. My car came back from
the shop after being rebuilt without the EGR system. I am running an AEM
EMS on it but after reading this thread it sounds like I should put the system
back on the car. Will I need to retune the AEM to accommodate the addition
of the EGR? The car definitely does not pass emissions now. What are your
thoughts on this?

I would yes.

This would definetly need a re-tune along with configuring when the VSV opens and closes the EGR valve. This should help in the NOx reductions which sometimes go sky high because of a lean mixture (trying to lean out a portion of the map). Very critical in the lower rpm, mid-load cells.

 

[Kristian_Wraae]

OK, not to jump this thread but I have a question. My car came back from
the shop after being rebuilt without the EGR system. I am running an AEM
EMS on it but after reading this thread it sounds like I should put the system
back on the car. Will I need to retune the AEM to accommodate the addition
of the EGR? The car definitely does not pass emissions now. What are your
thoughts on this?

Someone told me that the AEM doesn't know how to control the EGR system.

I don't know if it is correct.

 

[figgie]

Someone told me that the AEM doesn't know how to control the EGR system.

I don't know if it is correct.

It does not need to. Toyota made it a logic function.

on or off.
under 4000 rpm @ TPS > 40% = On.

else Off.

done.

what that means, if the AEM has an output that can be table assigned.

RPM v TPS%.

4000 RPM below AND 40% tps and below. On.
Above 4000 RPM or above 41% TPS. Off. Connect to EGR VSV. Done.

 

[SWD Fredester 3]

It does not need to. Toyota made it a logic function.

on or off.
under 4000 rpm @ TPS > 40% = On.

else Off.

done.

what that means, if the AEM has an output that can be table assigned.

RPM v TPS%.

4000 RPM below AND 40% tps and below. On.
Above 4000 RPM or above 41% TPS. Off. Connect to EGR VSV. Done.

Thank you for the info, I will start digging the system out of the parts box
I got back and see if I can get it back on by the weekend. I need to have
the car retuned anyway because it's running rich.

 

[Nghty89]

Hmm, makes me think of an article I was reading today in an old modified mag - issue sept. 2005. The article was about how the JDM market was starting to go greener while keeping the power output up, and the noise level down. Title "The Real JDM - Legal Speed", the author talks about how even the 621whp, Autech Tsukada BNR34 GTR is completely street legal. :evil2: In fact, most of the T1GP cars and others, capable of lapping Tsukuba circuit in 58.65 seconds, would also be drivable in CALIFORNIA of all places... Pretty expensive for those parts though... I.E. - A'PEX Super Catalyzer (130cpsi=extremely high flow cat!), or the active tail silencers that work at low rpm's to keep noise down, and stay open for higher flow during wot runs (due to spring pressure)

Anyways, yes, this does make me want to reconnect the egr system (bought that way, supposed jdm engine, possibly usdm ecu... no clue...), especially since it seems a myth that it increases hp by taking it off :biglaugh: