Blocking EGR valve... Good idea or bad idea?

[Phill G]

The great EGR block question. I've a 2005 GU IV and I've just replaced the entire upper half of the ZD30 engine. New everything from cams to head to valve train. I've spoken to engineers, mechanics and other folk who've been faced with the same decision. Block or not? Some folk speak of better fuel economy and faster compressor spool ups, others say that the EGR should be left open due to the ECU requiring the readings to compute the fuel injection map and that the mixing of the exhaust gasses with the air lowers the combustion temp, thus keeping the exhaust temp down. Even with the use of a Dawes valve to control the boost. I've just spent $4K rebuilding this Renault throwoff and don't want to do it again. I haven't restarted the engine yet and want to find out all the pros and cons before I do. I don't have the $$ to get it dyno'd and tweaked by a professional workshop at $210 for the dyno and $110/hr for the tweaking. Ideas, people???

[rusty_nail]

Aitis007 can answer this question best for you mate.... GEORGE where you at!!!

if he doesnt see this thread shoot him a PM with a link to this thread and ask if hell answer your question

Edit: Also, you should head over to the introduction thread and introduce yourself mate, its just a little something we ask of all our new members here.

[the evil twin]

EGR isn't there for any engine "performance reason, indeed it is an anti performance measure which is why it is blocked by the EGR valve at medium to high throttle settings by the ECU in the factory setup.

EGR is an anti-pollution strategy to reduce Nitrogen Oxide emmissions (a significant component in smog) at idle and/or low engine loads so predominant in urban areas therefore the decision is basically simple, screw the engine or screw the planet.

EGR is ported pre-turbo which is why it affects the Turbo characteristics when it is blocked , a tweak of the factory actuator or a Dawes/needle valve soon sorts it out

AFAIK in the ZD30 the EGR position has no affect on fuel mapping, more the other way around, could be wrong tho

So, it's up to the individual...and, Yes, I blocked the EGR on my CRD so I was a bad boy and I adjusted the actuator rather than fit a Dawes.

[Cuppa]

the decision is basically simple, screw the engine or screw the planet.



Yep, that’s what it comes down to.

[threedogs]

for the CRD they say drill a 10mm hole so the ECU thinks the EGR is normal.
or buy a Scan-gauge to fix check engine light.
I found on my Di it made a improvement,
so yeah block it and then go kick a Koala lol nah dont do that

[kevin07]

for the CRD they say drill a 10mm hole so the ECU thinks the EGR is normal.
or buy a Scan-gauge to fix check engine light.
I found on my Di it made a improvement,
so yeah block it and then go kick a Koala lol nah dont do that

no drilling holes it defeats the purpose when I blocked my egr I got better spool as in I took off faster. and on its own dropped my egts somewhat, coupled with a buedesert 2.75 exhaust made my car quicker and lowered the egts more, by small amounts no need to adjust actuator or add a dawes and needle valve. again im not saying adding a boost controller would not have been better but for me it was fantastic. now back to the question go look at some pictures of the filth that having a operating egr causes at the intake and that should answer your question. kev

[outback]

The great EGR block question. I've a 2005 GU IV and I've just replaced the entire upper half of the ZD30 engine. New everything from cams to head to valve train. I've spoken to engineers, mechanics and other folk who've been faced with the same decision. Block or not? Some folk speak of better fuel economy and faster compressor spool ups, others say that the EGR should be left open due to the ECU requiring the readings to compute the fuel injection map and that the mixing of the exhaust gasses with the air lowers the combustion temp, thus keeping the exhaust temp down. Even with the use of a Dawes valve to control the boost. I've just spent $4K rebuilding this Renault throwoff and don't want to do it again. I haven't restarted the engine yet and want to find out all the pros and cons before I do. I don't have the $$ to get it dyno'd and tweaked by a professional workshop at $210 for the dyno and $110/hr for the tweaking. Ideas, people???

I assume you have a ZD30 Di ..

EGR blank. NO holes in it end of issue.
Add Dawes valve set about 15 psi.
Also add catch can in the system.

ONE BIG thing. Trash current glow plugs if they have been in for over 80,000 km.
Glow plugs past 80,000 km just change, no discussion, be they ceramic or metal.
Add glow plug timer set to max of 30 seconds.
If the vehicle has done over 100,000Kms have the injectors physically checked. If any are out of specs, nozzle size etc change them.
Change the intercooler to a bigger one. Junk the Nissan one as its crap. Also with new IC make sure you have a fan with it.

Cheers

[outback]

simple, screw the engine or screw the planet.

Yep, that’s what it comes down to.

When I see people with "Save the planet", type stickers and are not blowing black or white smoke I will consider the issues.
Till then i will service my little diesel and make sure it has based engine performance and minimal environmental impact.

[apalsson]

When I see people with "Save the planet", type stickers and are not blowing black or white smoke I will consider the issues.
Till then i will service my little diesel and make sure it has based engine performance and minimal environmental impact.

And when I see "save the planet" greenies who don't heat their houses with a logfire, I will also participate in something constructive
Until then, let them cover their neighbours in obnoxious wood fire smoke and drive their Commodores to the nearest protest meeting