Block the EGR

[Slavic]

I did this mod (quite) a few weeks ago. It resulted in a 3.5 MPG increase (from 26 to 29.5 MPG) on a car with a bad EGR (flashing code 12).

I'm writing this from memory and will update when I confirm the correct sizes or any discrepancies. The instructions are for an EFI car. You may or may not need the same tools for a carb.

Much thanks to keruhas184 for hosting the pictures.

Tools:
- Ratchet (a pipe or breaker bar may be helpful)
- A 1/4 socket (12mm I belive) and two extenders at least one of them 1/4 or one longer 1/4 extender needed to loosen the two nuts holding the EGR. 1/2 or 3/8 are too thick and the edge of the EGR doesn't allow them to be placed on the nuts. One of the bolts is too deep to be able to turn the ratchet if using only one short extension.
- 10mm (I think) socket for the bracket
- Screw driver
- Telescopic magnet
- Scissors and/or a cutting knife
- Paper
- Marker
- Asbestos free high temperature gasket material (#1966 is the cheapest one I found for $3.50 a roll (12" X 20"X 1/32") at Pep Boys)

00 On EFI the EGR is located close to the engine oil cap towards the firewall


01 Remove two bolts to loosen the bracket.
02 Remove the cap/clip off of the EGR with a screw driver. Remove the hose attached to the EGR.
03 While prying the bracket away (you can remove 3-4 more screws holding it on the right side to make it easier) loosen the two nuts holding the EGR in place using Telescopic magnet to prevent loosing them.
04 Remove the EGR then press the bottom of it against a piece of paper rubbing the edges to get the outline (or against the gasket material if it works for you or pick up a new gasket at an auto parts store for a $1 and mark around it on the gasket material. Then just cut the new gasket out with a cutting knife).
05 Fold the paper at the middle of the screw and diaphragm holes, then cut a half circle. You need to block the square hole with gasket material and cut out the round ones for the screws and the diaphragm so as to allow the EGR to function or rather fool the ECU into thinking it functions. Place the template on the gasket material and mark it's outline. Cut the gasket out with a cutting knife. Replace the EGR with the new gasket in place. I found the telescopic magnet useful when getting the nuts back on. #1966 gasket material is thin (1/32") so I double layered it just in case, but I'm not sure that was necessary. OP mentioned using aluminum flashing.
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[keruhas184]

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[Accordtheory]

You did it the hard way. All you have to do is loosen the 2 nuts that hold the tube onto the side of the intake manifold, and slide a piece of sheetmetal into the gap, with a little bit of form a gasket material on it, and the tighten the nuts back up. It doesn't have to be a tracing of the gasket, it just has to cover the hole. It takes like 2 minutes, seriously. I did this on my car before I built my turbosystem and noticed no difference at all... Now there is no way for me to run an egr system even if I wanted to, as my aftermarket B16/B18C5 manifold doesn't have any provision for it. Neither does my header, for that matter.

[AccordAddict]

so removing the egr valve just gives you better gas mileage? i guess thats cheaper than buying a new egr valve right? i hear theyre expensive.

[AccordAddict]

or i mean blocking it is cheaper and better gas mileage? so i loosen the nuts that keep the tube to the manifold, and slide some metal in there, and tighten it back up? but doesnt that tube have to be used? What happens when its blocked? where does the gas (or liquid or w/e) go?

[A20A1]

Recirculating the exhaust gases helps lower combustion temperatures which allows you to run more timing advance without pinging... this will give you a slight increase in performance... however it's not always good to have the egr active, at certain temps and rpms the egr is not needed, and can hinder performance... Hopefully the ecu is set to operate the EGR at the best possible time...

The part about emissions is that NOx is produced if the combustion temp is too high.

[Slavic]

Recirculating the exhaust gases helps lower combustion temperatures

I'm not very familiar with the workings of an IC engine so take it easy on me here and help me understand how the same oxygen deficient exhaust gas that's hot enough to burn 1500 degree rated paint off of a header can help lower combustion temperatures?
It is my understanding that what we want in our air intake is air as close to the ambient temperature and as rich in oxygen as we can get and the EGR was only there to decrease pollution.

[A20A1]

The recirculated exhaust gases have already combusted, so they don't reburn when entering the combustion chamber, which displaces part of the normal intake charge slowing the rate of combustion which cools the temperature.

You can only suck so much air into a cylinder N/A, and if you add fuel to the mix you displace some air, thats why newer engines introduce the fuel after the air has entered the cylinders and after the valves are closed, so they can get the maximum amount of air into the cylinder. Much more efficient.

[Slavic]

The recirculated exhaust gases have already combusted, so they don't reburn when entering the combustion chamber, which displaces part of the normal intake charge slowing the rate of combustion which cools the temperature.

OK I see. Less oxygen entering. That would also decrease the power produced in the combustion as there is less charge to burn, right? But you're saying that loss would be made up for and then some because it "allows you to run more timing advance without pinging... this will give you a slight increase in performance"

I think I'm now at least following what you're trying to convey. However, I can't help but think that not recirculating the blistering hot oxygenless exhaust gas and instead using coolant additives to lower the engine temp would produce better results overall.

[A20A1]

This isn't me this is some site that talks about advances in EGR technology... the gasses aren't dumped into the intake manifold... it's computer controlled making it much more percise, the reason why some people say they loose power when the EGR throws a code, the ECU is probably retarding the timing a little and adjusting the fuel mix... to some safe mode.

On turbo engines the EGR has a cooler it goes thru first before being injected into the intake stream. I suppose thats why some people opt to go for the CO2 injection, but you need a constant CO2 source...

If you want to add a cooler to your EGR, it might run better...

I dunno about the coolant idea, it helps in it's own way but... I'm not sure if the rate of heat transfer is enough to safeguard against detonatioin on it's own.

[AccordAddict]

So if i block the egr will i increase or decrease performance? I have a fuel injected engine if that helps.

[AccordAddict]

mmmmmkay ill try and understand what you said. how much does all the materials cost? i have the tools already.

[AccordAddict]

anyyyyyyyone????

[keruhas184]

Man, read the thread first. Then ask questions.

[AccordAddict]

i did. its really technical though. could someone give me the Dummies: Block the egr version?

[Slavic]

i did. its really technical though. could someone give me the Dummies: Block the egr version?

Actually, someone already did:

You did it the hard way. All you have to do is loosen the 2 nuts that hold the tube onto the side of the intake manifold, and slide a piece of sheetmetal into the gap, with a little bit of form a gasket material on it, and the tighten the nuts back up. It doesn't have to be a tracing of the gasket, it just has to cover the hole. It takes like 2 minutes, seriously...

I belive he was talking about the EGR TUBE shown in the attached pic. Thanks Accordtheory.

[Accordtheory]

yeah, but I don't even recommend doing it, it's not really noticeable

[AccordAddict]

does it increase or decrease performance??? i have a FI engine.

[k-roy]

If you think that hot air lacking oxygen is good for performance then leave it in place.

[AccordAddict]

lol, so i guess its better to block it off eh? what is the type of metal or paper i need (paycheck tommorow) might do this mod tommorow, and get my cat back exhaust piping done.

[k-roy]

read the thread again man

[AccordAddict]

You did it the hard way. All you have to do is loosen the 2 nuts that hold the tube onto the side of the intake manifold, and slide a piece of sheetmetal into the gap, with a little bit of form a gasket material on it, and the tighten the nuts back up. It doesn't have to be a tracing of the gasket, it just has to cover the hole. It takes like 2 minutes, seriously. I did this on my car before I built my turbosystem and noticed no difference at all... Now there is no way for me to run an egr system even if I wanted to, as my aftermarket B16/B18C5 manifold doesn't have any provision for it. Neither does my header, for that matter.

ok the part where it says "and slide a piece of sheetmetal into the gap, with a little bit of form a gasket material on it, " i dont get what he is saying. does he mean go buy a piece of sheet metal, then get some kind of "GASKET MATERIAL??? WTF???" is that some kind of paste in a tube or something? i dont get that at all. i read in the otehr post get an asbestos free high temperature gasket material. is that the same thing? is it some kind of metal tat you cut? if so, the procedure would be loosen the nut and take the egr tube off, put some gasket metal sheet on the end and tighten it back up? plz clarify, thanks