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Old 11-12-2009, 06:00 PM   #1
cre

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Sorry, I was just waiting for more info or something... just hit me as more of a "look what I have" thread when it's already been shown. I just think people need to step it up a bit in this group...empty threads like this make for poor reference as there is no text (hence no key words) for a future user to have much luck finding it and also the fact that most newbies have no idea what the EGR system is or what it does or why you'd remove it.





E.G.R. = Exhaust Gas Reticulation system. The EGR is an emissions control device with a nice bonus; It's used to cool the engine and thus reduce NOx emissions. The EGR system is only active at part throttle driving (not at idle and not at WOT) and as such does not affect power output at loads of around 70% or higher. While it doesn't affect things at WOT it does help coold the engine back down more quickly when you come back off of it. It's a popular device for people to remove either for cosmetic reasons (as is the case in two-step-n's build, which isn't mentioned here) or just due to the false belief that it will net them more power. In newer vehicles the system is also temperature controlled to ensure that the exhaust gasses are just the right temp to do the job.

Honda has been using an aggressive EGR type of system for decades now as a means of boosting their fuel economy. As the EGR system dumps inert gasses back into the engine it effectively reduces the engine's overall displacement. Take a 3 liter engine, add one liter of inert gas and BAM! you're now running a more fuel efficient two liter.... but only until you floor it. Sadly, the system doesn't move enough gas in our vehicles to help out in a big way with the mileage thing.

The most common issue that people have with the EGR system is that the actuator or the vacuum diaphragm will stick, leaving the system open. This can cause problems with the vehicle at idle and will most certainly result in power loss at higher loads when it should otherwise be shut off. **It can also be a big annoyance to work around if you're constantly servicing the engine as in the case of a race car.

And here's a Toyota technical article about it if you want more in depth reading:
http://www.autoshop101.com/forms/h61.pdf
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Old 11-12-2009, 06:23 PM   #2
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S'pose your right, although with EGR being such a common system on cars nowadays almost anyone with previous mechanical experience is likely to have already run across a sticky EGR valve at some point or at least read about someone else's troubles with it.

Even my old Pajero has the damn thing (it lasted about ten minutes before I disconnected it, as it wasn't already stuck open I decided not to give it the chance to!).

I never even considered anyone would remove one for cosmetic reasons, simply because most people I know just remove the vac. pipe (or blank it if already stuck) to avoid/cure running issues, provided the vehicle in question can pass emissions without.

I think over here they have a worse reputation than they deserve because most stuff a few years old will easily pass our emissions test without EGR operating so people fail to see the point, and when one eventually does stick open the system in general gets tarred with the same brush.
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Old 11-12-2009, 07:06 PM   #3
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That's a waste of effort really. These fail so infrequently that the benefits (reduced engine temps, higher spark advance, reduced knock) outweigh the potential headache, IMO... especially on an engine which likes to go through head gaskets . Disconnecting the vacuum lines doesn't mean the system won't vent, a broken actuator will leak regardless, a block off is the only way to fully ensure closure. Otherwise, you still need to diagnose the system if you have related problems.

You're also assuming that people who come here for help have experience with this kind of thing. Most don't have that much and as such shouldn't be encouraged to make changes they don't understand both the pros and cons to.


Pros: Reduced engine temps, better fuel economy (minimal on MKIII's), higher spark advance, reduced knock. These are all HUGE at mid-high loads when the combustion cylinder temps are the highest and the engine is more prone to knock.

Cons: If it leaks, your car will have issues at idle, possibly while it's warming up and it will cost you some power at WOT; it's not pretty; and it can be a pain in the ass to work around if the engine is still in the car... I HATE that part.



EDIT: Oh, it's not just the way things are over there... Over here it's much the same. A long time ago the old muscle car guys decided that anything they didn't understand and absolutely ANYTHING called an emissions device was bad... let's just forget the whole thing about science and 40 years of continued research and developments... Ignorance is not something to be proud of, yet it seems so many people like to wear it as a badge.

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Old 11-13-2009, 02:49 AM   #4
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thats the 2nd egr to stick on me so i didnt wanted it anymore and it looks better without one i think! I also don't need to worry about emissions anymore because the car is registered up North where emission testing isn't required.
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Old 11-13-2009, 03:17 AM   #5
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You said it was a weekend toy, so I honestly am not concerned about its longevity... it's the daily drivers which see the most wear. I'm not ragging on you in your posts... just making sure others know that your build is not necessarily what's best for their purposes and why.
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Old 11-13-2009, 03:59 AM   #6
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Quote:
Originally Posted by cre View Post
That's a waste of effort really. These fail so infrequently that the benefits (reduced engine temps, higher spark advance, reduced knock) outweigh the potential headache, IMO... especially on an engine which likes to go through head gaskets . Disconnecting the vacuum lines doesn't mean the system won't vent, a broken actuator will leak regardless, a block off is the only way to fully ensure closure. Otherwise, you still need to diagnose the system if you have related problems.

You're also assuming that people who come here for help have experience with this kind of thing. Most don't have that much and as such shouldn't be encouraged to make changes they don't understand both the pros and cons to.


Pros: Reduced engine temps, better fuel economy (minimal on MKIII's), higher spark advance, reduced knock. These are all HUGE at mid-high loads when the combustion cylinder temps are the highest and the engine is more prone to knock.

Cons: If it leaks, your car will have issues at idle, possibly while it's warming up and it will cost you some power at WOT; it's not pretty; and it can be a pain in the ass to work around if the engine is still in the car... I HATE that part.



EDIT: Oh, it's not just the way things are over there... Over here it's much the same. A long time ago the old muscle car guys decided that anything they didn't understand and absolutely ANYTHING called an emissions device was bad... let's just forget the whole thing about science and 40 years of continued research and developments... Ignorance is not something to be proud of, yet it seems so many people like to wear it as a badge.

No offense to your post there.... but I strongly disagree ! If the block off plates are installed correctly with a coated cometic gasket. they will never leak. And there are 2 plates to install not just one. As far as the warm up or power at Wot, no problem when running stand alone fuel management. and if your exhaust is big enough, heating up is not an issue. If you convert your pulley fan to electric fan it will stay alot cooler. FMIC will help too.
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Old 11-13-2009, 04:46 AM   #7
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Quote:
Originally Posted by evosupra View Post
No offense to your post there.... but I strongly disagree ! If the block off plates are installed correctly with a coated cometic gasket. they will never leak. And there are 2 plates to install not just one. As far as the warm up or power at Wot, no problem when running stand alone fuel management. and if your exhaust is big enough, heating up is not an issue. If you convert your pulley fan to electric fan it will stay alot cooler. FMIC will help too.
You need to reread this whole thread... We were talking about the EGR actuator leaking... dunno how you got that actuator = block off. Again, no idea what the hell you're talking about with warm up and WOT... you're lost sir.

Oh, and electric fans don't cool the gasses IN the intake... sheesh. Sleeping at the wheel?
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Old 11-13-2009, 05:30 AM   #8
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my buddy has a 7mgte swapped into a 88 toyota pick up with the same block off plate now for about 6mons and never got one leak so far! its also driven everyday! but yeah it would suck if it started to leak because its not ez to get back there!
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Old 11-13-2009, 01:21 PM   #9
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Whoo, cre after reading how this thread's developed I have to agree that EGR is not as widely understood as I thought & anyone who's in doubt would do well to read your posts.

What I was saying about disconnecting the actuator pipe before a failure occurs I stand by though (not that I'm recommending it for the Supra, in fact bearing in mind the 7M's headgasket appetite, I'd say it's a rather bad idea for a regular driver) just as a general "prevention is better than cure" solution on vehicles that can be run without failing emissions, especially diesels on which the EGR more readily fails due to particulate content in the exhaust), in my experience the majority of EGR leaks are caused by a dirty & sticking valve or actuator & not by any mechanical failure.

I suppose I'm just a bit lazy where a daily plodder of a diesel like the pajero's concerned & really the advice should be "if it's broke DO fix it" for any vehicle, but like many I'm guilty of just running something like that as it is, so long as it passes emissions. Incidentally, when I showed the guy that's having the Pajero from me I hooked the EGR back up & it still works! Anyway that's enough rambling from me, back onto supra EGRs...
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