Blocking Egr

[snotboy]

I know this question has came up alot and i looked and never found a straight answer. What is the real benifit of blocking the egr valve off if there is any? Any down sides to blocking it off? I read somewhere it could cause pinging? True or not?

the reason im asking is because my egr bracket was broke i tryed welding it back together and well did seal so good around the head. I want to know if its worth blocking it off or just finding another egr valve.

 

[GrimJack]

The only benefits that I am aware of:
- cleans up the engine bay
- might reduce the heat around the #6 cylinder, where the EGR cooler is.

Drawbacks...
- No EGR means you won't run as green friendly as you can.
- from what I understand, the EGR essentially gives you free octane while cruising. I don't think it does anything at other loads, though.

 

[snotboy]

thanks any more info i should know

 

[Yellow 13]

I think it was suprasport.com that claims blocking the EGR gives you better combustion. I asked them about the benefits and they said its really only to clean up the engine bay.

Edit: The EGR system is a common inspection point for smog areas, but there are many folks who choose to remove the EGR system for a little extra combustion efficiency - Suprasport.com

 

[GrimJack]

Combustion efficiency... ya, riiiiight. If that were the case, why is it so hard to pass the cruise dyno test on smog without it?

 

[Nick M]

The only benefits that I am aware of:
- cleans up the engine bay
- might reduce the heat around the #6 cylinder, where the EGR cooler is.

Drawbacks...
- No EGR means you won't run as green friendly as you can.
- from what I understand, the EGR essentially gives you free octane while cruising. I don't think it does anything at other loads, though.

That is exactly right. Putting spent exhaust gas in the intake displaces some oxygen resulting in slightly less cylinder pressure and a resultant reduction in NOx. That is what the design is. With less cylinder pressure, you can cheat on octane rating to a point.

 

[jetjock]

It's interesting to note EGR was initially researched as a detonation reduction technique. It's ability to reduce NOx was a serendipitous discovery. My opinion is there is little to nothing to be gained by removing it and much to lose.

 

[johnathan1]

wow, this is very interesting!

 

[snotboy]

thanks for the info

 

[daledoe]

Mint. I only new half that, now I know the full resons.

 

[jdub]

It's interesting to note EGR was initially researched as a detonation reduction technique. It's ability to reduce NOx was a serendipitous discovery. My opinion is there is little to nothing to be gained by removing it and much to lose.

Damn...learn something new every day. Considering what happens to the 7M when it detonates, sounds like to me the EGR is a little added insurance.

 

[Red Dragon]

except EGR doens't function at WOT, so if you are detonating at cruise, you have much bigger problems that lack of an EGR... :icon_bigg

It lowers combustion temps (less oxygen to burn the fuel), which lowers the NOx, but again doesn't do this at WOT, IIRC.

 

[jetjock]

That's true. Nor does it operate at idle. But all that's by design because it's been relgated to NOx duty. I don't know why but it was never implemented for detonation even though that was it's original research goal and it does work. You have to learn all this crap when you get a smog license

 

[bobiseverywhere]

It's interesting to note EGR was initially researched as a detonation reduction technique. It's ability to reduce NOx was a serendipitous discovery. My opinion is there is little to nothing to be gained by removing it and much to lose.

Why do you think this and then why is it that the original design the JDM version of the Engine does not have this. If it was that advantageous wouldn't Toyota want to equip the item on all Supras

Just my curiousity as well. Since i was thinking of taking it out and why its not on the JDM cars.

 

[IHI-RHC7]

Hmm, interesting, I think I'll stick to my ADI, though.
It should work better

 

[jetjock]

Why do you think this and then why is it that the original design the JDM version of the Engine does not have this. If it was that advantageous wouldn't Toyota want to equip the item on all Supra. Just my curiousity as well. Since i was thinking of taking it out and why its not on the JDM cars.

Why do I think what? That EGR was originally researched as a way to reduce detonation? A) When I trained for smog certification I had to learn the history of emissions equipment. B) It makes perfect sense it would reduce detonation for the reasons Nick pointed out. I'm sure a little Net research would confirm both points.

Why isn't it on JDM cars? Japan doesn't have the same emissions requirements as US cars, although Japan does have some powerful queer car laws (why do you think all those JDM engines are imported here?).

Cali cars are even more different than Federal cars. For example the software in a Cali Supra's ecu is different. The bottom line is EGR is an emissions device. Removing it serves no purpose and does more harm than good in ways I've never seen mentioned here. For example it's assumed the ecu could care less that you removed an EGR system it "expects" to be there. Guess again.

That emissions equipment hurts performance is a myth left over from the old days when it actually did. Why don't you yank your O2 sensor out too? The car will run better and make more power if you do. The O2 sensor is there solely for emissions yet I don't see guys pulling them out in droves.

In addition to trashing the environment (which many don't seem to give a rodent's rectum about and are very quick to forget everyone else shares it with them) it's a violation of law to tamper with emissions equipment in every state in the US, even those that don't conduct emissions testing. It's also a violation of federal law.

 

[bobiseverywhere]

But that was not really my question

If it is good for redusing detonation it would make sense that Toyota would have equiped this to all there 7M Engines yet they did not. So Detonation makes sense but seems not to be the reason why it is there. US supra or JDM detonation is still bad why protect one and noth the other that makes no sense so i think the detonation reason is good andswer but i don't belive that to be its inteded purpose or it would be on all the Cars

I know different places have different emmisions laws but if it was good for protecting the engine you figure it would be in all of them.

 

[jetjock]

As I said, I don't know why EGR use for detonation surpression was abandoned or never implemented. I only know that was what the original research was based on. This was many, many years before the Supra was introduced so perhaps it has something to do with the control methods available back then. EGR research happened long before emissions came into play and it's ability to reduce NOx wasn't employed for a long time.

Or it could simply be because of electronic spark control. ESA wasn't possible at the time initial EGR research was done you know. There could be all kinds of reasons. Tell you what, I'll save you the trouble of finding the answer by doing it for you. Standby.

 

[Nick M]

EGR is going the way of the do-do on new cars, if not completely gone. Variable cam timing has the same effect. Overlap reduces NOx. In old ass high performance cams with a lumpy cam, the lumpyness is from having both intake and exhaust valves overlap for a longer time. This greatly improves scavenging at higher RPM. But it pumped out a lot of hydrocarbons.

So away went overlap to reduce HC's. And in came EGR to lower NOx, which came in when the overlap went away.

Variable cam timing allows us to have overlap only when we want it. The side benfit is a very flat torque curve over an extended rpm range.

Does it matter why it was first devolped?

 

[jetjock]

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