EGR mod on d40

daza · Apr 2, 2011

series 4 - 2.5 litre EGR Blank

Hey all,

First post!! thought id share some photos of an EGR mod on my series 4 D40. I decided to block off both sides of the pipe with blanking plates to stop any turbulent flow into the pipe from either side, and also to stop carbon building up in there from the exh side. I just finished it today took about and 40 mins all up.

As far as fuel economy goes, im sitting on 11.1 LPH at the moment with 265/70/17's. The car has 23k on the clock. Would like to try this ECU reset also, can anyone tell me whether the ECU reset has the possibility of reducing fuel comsumption? Is it worth doing anyway now that ive blanked the EGR?

Hope the pics are of some benefit. I just used a shim i found at work. looks like about .8mm

Hunty · Apr 2, 2011

daza said:
Hey all,

First post!! thought id share some photos of an EGR mod on my series 4 D40. I decided to block off both sides of the pipe with blanking plates to stop any turbulent flow into the pipe from either side, and also to stop carbon building up in there from the exh side. I just finished it today took about and 40 mins all up.

As far as fuel economy goes, im sitting on 11.1 LPH at the moment with 265/70/17's. The car has 23k on the clock. Would like to try this ECU reset also, can anyone tell me whether the ECU reset has the possibility of reducing fuel comsumption? Is it worth doing anyway now that ive blanked the EGR?

Hope the pics are of some benefit. I just used a shim i found at work. looks like about .8mm

Thanks for the pics Daza. Im only a newby to the site as well. You arent worried about the mod affecting your warranty

daza · Apr 2, 2011

Hunty said:
Thanks for the pics Daza. Im only a newby to the site as well. You arent worried about the mod affecting your warranty

No problems.. No I'm not too worried.. If it isn't throwing any codes and there's cleaner air going in then it should be all good..

Hunty · Apr 2, 2011

Ok your probably right about the warranty. Keep us posted with how you go with the lag and the economy.

daza · Apr 2, 2011

im sure the warranty would be void for altering the engine, but i think the engine would be less prone to failure in the long run because its getting clean air. In saying that though, id still take the plates out if the check engine light came on before i took it to nissan to get checked out.

I have definately noticed a small difference with the lag, it seems easier to take off from a set of lights and response in general while driving seems a little better too. We'll see how the economy goes in a tank or so.

Old.Tony · Apr 2, 2011

The change in removing the EGR from this device isn't huge, but it is there.

There are two other EGRs.

1) At the beginning of the intake stroke (piston has finished rising after expelling exhaust gases and is now JUST starting to fall to draw in cool air) the exhaust valve is open. If the turbo is NOT boosting, some air is drawn in from the exhaust valve as well. To adjust this, we'd need to change the camshaft.

2) The PCV system. Blow-by enters the crankcase, picks up oil, most of the oil is separated from the blow-by (which, remember, is just exhaust gas) and is piped into the air intake in FRONT of the turbocharger compressor, so that blow-by is actively sucked from the engine. My solution to this will be to fit a catch can and vent the PCV to atmosphere.

daza · Apr 3, 2011

G'day old Tony.

The first one you mentioned is basically scavenging..you can see this when doing a valve set. You'll notice intake and exhaust are slightly open simultaneously or as people like to call it "on the rock".

I think most engines do this to an extent and even when the engine is not under load (not boosting) there would only be a fairly small amount of exhaust gas left in the pot if any.. The force from intake air will usually be higher than any type of exhaust back pressure

Does this sound right old.Tony.. Or have car companies started trying to reuse a lot of exhaust gas by closing the exhaust valve quicker..I can only go by what I've learnt and would be interested to know.. I do a lot of work on underground mining gear where emissions a quite a lot higher and EGR is not present. Instead the valvetrain is designed to scavenge exhaust gas really well.

Is the crankcase breather plumbed back to the intake on the 2.5s? If so has anyone made a catch can.. Would be interested to get some ideas for another little project

bluessv · Apr 3, 2011

I've just purchased the "Provent 200" catch can from Western filters via ebay. They are clearly one of the most expensive however are CLEARLY one of, if not, the best on the market. Manufactured by Mann Hummel.

The only thing that I'm thinking is about what Tony mentioned. I thought the catch can was still fed back into the front of the turbo charger (after being filtered) and NOT vented into the atmosphere??

Old.Tony · Apr 3, 2011

daza said:
G'day old Tony.

The first one you mentioned is basically scavenging..you can see this when doing a valve set. You'll notice intake and exhaust are slightly open simultaneously or as people like to call it "on the rock".

I think most engines do this to an extent and even when the engine is not under load (not boosting) there would only be a fairly small amount of exhaust gas left in the pot if any.. The force from intake air will usually be higher than any type of exhaust back pressure

Does this sound right old.Tony.. Or have car companies started trying to reuse a lot of exhaust gas by closing the exhaust valve quicker..I can only go by what I've learnt and would be interested to know.. I do a lot of work on underground mining gear where emissions a quite a lot higher and EGR is not present. Instead the valvetrain is designed to scavenge exhaust gas really well.

Is the crankcase breather plumbed back to the intake on the 2.5s? If so has anyone made a catch can.. Would be interested to get some ideas for another little project

It's entirely likely that the scavenging process is precisely as you describe it, and it's not been enhanced to add more exhaust gases to the combustion chamber.

After all, they've got both the PCV and the EGR systems doing that job for them already!

Old.Tony · Apr 3, 2011

bluessv said:
I've just purchased the "Provent 200" catch can from Western filters via ebay. They are clearly one of the most expensive however are CLEARLY one of, if not, the best on the market. Manufactured by Mann Hummel.

The only thing that I'm thinking is about what Tony mentioned. I thought the catch can was still fed back into the front of the turbo charger (after being filtered) and NOT vented into the atmosphere??

That's where it's supposed to go. But I put 2 and 2 together and figured that it's just a bunch of extra exhaust gas going straight back into the intake.

It's like coming up for air after a deep dive, and copping a whale fart. I'm sure our cars aren't happy about that either, and when I get my hands on a Provent, I'll vent the bloody thing alright!

Leprechaun · Apr 3, 2011

Not that much exhaust gas going through the PCV, just a small amount of blowby very small % to the total intake air + it would be illegal to vent to atmo.

I've fitted a Provent but still sceptical about its effectiveness as I'm working on a project at the moment trying to condense pyrolysis oils. Not that easy without large amounts of water cooled surfaces.

bluessv · Apr 3, 2011

Was just reading some interesting info on a Pathfinder forum about the EGR mod not being safe. They were referring to the R51 model with the same motor as our D40's.

They were talking about something to do with needing to install some type of valve to protect from turbo spikes, etc. It was all way over my head but sounded like some of them knew what they were talking about??

Anyone heard of such things?? Are those that have the brains completely satisfied that a simple EGR blanking plate is not doing any long term damage to any other components??

daza · Apr 3, 2011

Leprechaun said:
Not that much exhaust gas going through the PCV, just a small amount of blowby very small % to the total intake air + it would be illegal to vent to atmo.

I've fitted a Provent but still sceptical about its effectiveness as I'm working on a project at the moment trying to condense pyrolysis oils. Not that easy without large amounts of water cooled surfaces.

When you fitted the system was there a fair bit of oil in the PCV line??

I'm going to check mine next weekend and decide whether if really needs it.

Old.Tony · Apr 3, 2011

On the PCV: The more blow-by, the more exhaust gas is pushed into the intake. May not be a huge amount, but it's some and it reduces efficiency. Is it legal to vent it? Nope. It's about as legal as blocking the EGR off.

As for the EGR, it's entire function is to pump exhaust gas INTO the intake. I would have thought that a spike in the boost pressure would only occur when the turbo is fully spooled up with the vanes wide open - that's with the throttle all the way down - and at that point in time, the EGR valve is closed anyway. As you release your foot from the pedal, the ECU would be closing the vanes off, backing off the boost pressure ... the worst the thing can do is increase boost pressure above what is normally used at that throttle level. Our turbos aren't running so close to the limit that it would present too much risk, I would think.

I'm happy to be educated on that though.

daza · Apr 3, 2011

The way I see it is if the ECU hasn't thrown a code for blocking the EGR on anyone's d40 then one would imagine it can't be affecting things too greatly.

SimonD40 · Apr 13, 2011

I have Blanked afew EGR's on R51 and D40 and i have not a a light come on, all the the owners have reported great results.
i have only had a Ford Ranger throw a light so i drilled a 10mm hole in the plate all fixed (thanks Chip it for that advise)

MickDooit · Apr 27, 2011

Mod done with my D40, works well. Runs cleaner, more efficiently and with a little more down-low power. Thanks for all the info and input from everyone.

One question though; what is the heat exchange thing with the two pipes running in and out of it and the exhaust recycler runs through it?

Cheers, Mick.

Old.Tony · Apr 27, 2011

Mick, that's designed to cool the EGR down a little. I dare say it doesn't manage to cool it a great deal - but that's what it's for.

EGT = 500C or better. Radiator = 95C. It's going to have some effect!

shortjake · May 18, 2011

SimonD40 said:
I have Blanked afew EGR's on R51 and D40 and i have not a a light come on, all the the owners have reported great results.
i have only had a Ford Ranger throw a light so i drilled a 10mm hole in the plate all fixed (thanks Chip it for that advise)

Just a thought.... Does that mean that our engines arnt as smart as the fords, and is not picking up on the blocked egr? Or could it be an actual deeper problem that just a blocked egr that ford will pick up but Nissan ecu won't?

Old.Tony · May 18, 2011

shortjake said:
Just a thought.... Does that mean that our engines arnt as smart as the fords, and is not picking up on the blocked egr? Or could it be an actual deeper problem that just a blocked egr that ford will pick up but Nissan ecu won't?

In order to pick up on it, you'd have to either have an O2 sensor in the EGR valve, or a flow-rate metering device in there.

I would be surprised if it were done. The thing that makes me think it isn't likely is that the EGR is only there to allow the car to meet emission control standards (in particular, the output of nitrogen oxides). Because it's purpose is to let the car meet a standard and it's not there for actual performance, I doubt they'd put in some elaborate detection mechanism looking for its removal.

The heated oxygen sensors in the exhaust are different, because reliance is placed upon the presence of oxygen in the exhaust in order for a DPF/CAT burn to take place. The sensor is therefore required and a mechanism for checking its operation is also not unreasonable, especially since the check is so simple: vary the amount of fuel by a small amount, and look to see if the HO2S reflects these small variations.

EGR mod on d40

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