You really need to have the engine out of the car to take the EGR completely off. There is an Exhaust Gas Recirculation Cooler on the back of the engine. It allows some exhaust gas (3%) to go back into the throttle body to mix with the new air coming in. It causes the combustion to be cooler, and helps decrease NOx. You can take the EGR cooler off and block the hole in the back of the head, then rip all the plumbing off. Alternatively, you can simply block the EGR feed into the Throttle Body (or intake manifold in MKIVs) with a plate at the EGR control valve.
There are several concerns. First, if you don't remove the EGR cooler and block the outlet in the head, you will get a very high temperature buildup around the #6 cylinder. Why is it #6 is usually the first to go in older engines anyway? Second, you will raise the internal combustion temperature in each cylinder, and believe it or not, potentially loose HP at low to mid range RPM. Third, (and this is up to you, I really could care less, but you should know, especially if you ever sell your car and the buyer gets stung) you will violate Federal Law and perhaps not pass visual smog, depending on where you live.
Everyone says, "Japanese cars don't have EGR", and they are right. But Japan has very strict emissions controls, and you pass or you don't drive the car. That's why there are so many 40K mile Japanese engines for sale. They rip the old one out and put in a brand new engine, and sell the polluters overseas. Worn valve seals, worn rings, you name it. If you are burning “any” oil, you don’t pass. Since a new engine is cheaper than a complete rebuild, well...you can figure it out.
I also have never seen, or even heard of, a dyno test that proves removing the EGR helps. However, an illegal Catch Can that bypasses the PCV will keep the TB and intake manifolds much cleaner.
christian, i have not received one e-mail from you since we last talked. i am still holding the parts for you. my e-mail is [email protected]. you can even call me at work 661-267-2648
8-5pm mon-friday pacific time.
yonaga is right about some of that but he is mixed up also.
first, japanese engines are not pulled because of high emissions. they are pulled out because after 3-4 years of owning a car in japan, registration triples. imagine paying $1400 to register your supra. so most people over there trade cars in put the registration money into a down payment.
the EGR does not cool the combustion chamber it actually heats it up slightly to burn more emissions(nox). the cooler plate on the back just runs the exhaust gas back through the head to cool the exhaust gas slightly before it goes back into the combustion chamber
why would you need a dyno test to figure out if rmoving the EGR makes more power? it is common sense. hot exhaust gas doesnt really burn all that well compared to air/fuel.
if you lose power when you take it off, then why do mkiv guys take theirs off all of the time. if it helps power, then why doesnt everyone put one on? top fuel cars, honda,muscle cars?
and you dont need to take the engine out to remove the EGR. just the head. and the whole system should be removed, not just the valve itself. cooling plate and all.
I also stand by my comments regarding emissions testing in Japan. Count the number of used engines available, then count the transmissions and LSDs.
No flame titesupra, but common sense....tells me the sun goes around the earth, and that night is a direct consequence of day. However, we have other means of determining if I am correct. That's also why we have dynos and races.
Thanks for the cment I have no idea who to believe. But I've taken out the EGR system from my older Z car and been off for ~10 years and had no problems with the motor, it passed emissions everytime, and no I don't monitor my combustion temps on this car. Purpose? because it was leaking and I didn't want to buy a new one. Emissionswise, it depends on where you are. I still don't get it, no matter how it is explained how EGR lowers combustion temps, is it the re-introduction of exhaust/burnt gases(contents) to the intake? is it the hot (temps) exhaust gases re-introduced to the intake? If so, why is there a cooler? I never had a problem with the other car, that's why I did it on the Supra, main purpose on this one? cleaner looks, less stuff to fail later. I have no idea aout the Japanese engines deal
JT2ma71, the EGR cooler cools the exhaust gas before it runs through the control valves and into the TB or intake manifold on MKIV turbos. It is around 1300 F when it comes out of the engine, so it is passed through the cooler as the first step. It will heat up the intake air, but as there is only 3% or so exhaust mixed in, the increase is not much. What it does is lower the combustion temperature that would otherwise occur, and keeps it below the point there most of the NOx occurs.
Since the EGR system is designed not to operate when the engine is cold, at idle or WOT, removing it won't gain you much, since WOT is where the power daemons live. I doubt you would see much difference on a dyno or the track, because you run at WOT.
If you do take the cooler off, you need a 20mm machine screw, with a 20 mm long thread to use as a bung to plug the hole. These can be hard to find at Home Depot, but you might go to a machine shop where they may have one, or could cut you one for a few dollars. Tell them it’s for an exhaust manifold, so the material they use will be heat tolerant.
I don't have a spare bolt, sorry. If I remember right, the bolt is a 16mm and long enough so the end will be flushed with the port. I tapped the hole to the same thread pitch of the bolt about 3/4" deep, not all the way. Then machined the bolt down to 14mm, 3/4" from its head. Or, you could just tap it for an NPT plug
What orders the amount of the exhaust gas recircyled into the intake manifold. In Mazda RX7 the EGR valve is opened at specific RPM range! This will of course lead to degrease of acceleration big time.
So, is the EGR valve open at specific RPM range or is it opened at specific mass air flow range (at specific range of strain)?
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