Blocking the EGR Valve

[the ferret]

Hi Harry and welcome, the guys n girls on here are pretty friendly and always ready to help, have a read below, might help you decide what to do.
Please note, this is not my work, only borrowed it for ya, cheers Rod.


Quote: "Ok, regarding the new CRD, I would recommend the purchase of a scan gauge as it can read the ECU and provide lots of valuable information such as boost, temperatures, current fuel usage etc.

I would also recommend the installation of an EGT gauge, once these are installed on the truck, you can get a feel for how the motor is performing and decide if it is working to spec based on that information.

To answer your direct question, the CRD does not require a dawes valve as the ECU limits the boost to around 15psi very effectively. The members that have installed them have probably bypassed the ECUs control of the turbo and blocked the EGR system like ............ has shown in this thread.

The CRDs ECU is far more advanced than our Di models which is good and bad, the good is that you can usually block the EGR and there is no need to alter the VNT grub screw because the ECU still controls the boost to around 15psi.

The bad is that it has enough smarts to know that the EGR is not flowing and it will throw up an error code (which the scan gauge can easily clear). If you did want to block the EGR and were not going to purchase a scan gauge, I would recommend that the EGR blocking plate have a 10mm hole in the middle to allow some flow so that the ECU does not throw up the fault code

[hekarewe]

What is EGR (Exhaust Gas Recirculation) and why should I block it?

Wiki link for in-depth explanation.

TLDR;
*EGR works by recirculating a portion of an engine's exhaust gas back to the engine cylinders.
*EGR deletion results in an increase in fuel economy as high as 25%.

Some people have also noticed an increase in power and a quicker turbo spool. IF there are any power increases at all, they would have to be pretty minute. However, I can attest to a quicker turbo spool up by at least a few hundred revs.

How do I block the EGR Valve?

It's a pretty easy do-it-yourself job. Allow an hour or so to do the job, and make sure the motor is cool enough to work on comfortably.





This is what the EGR blanking plate should look like..



The easiest way to do this job is to loosen the 2 nuts as pictured in the 2nd picture. You don't need to take them all the way off, just loosen them enough to be able to pull the EGR Valve (big brass ufo looking thing) away from the manifold. All we are doing is sliding the plate in.

For the plate, you'll want some thin sheet metal.. I used stainless steel. I have read that tin is fine. Not too sure about alluminium.. I've read is may corrode but I'm not sure. You want to basically end up with a shape similar to what I quickly draw in the last picture. As you try to fit it, you will see where it needs to be refined to the correct shape. For this, I used Tin Snips and a round file.

Once you get a plate that fits, you slide it in between the Manifold and the EGR Valve, then tighten the 2 nuts back up. Simple as that.

Good luck!

being as handy as a set of t!ts on the bull wherre could i get the templets made up???? and do they need gaskets on eithere side

[the ferret]

Give me a PM, I have heaps, cheers Rod.

[DrHarry]

Brilliant Mr Ferret, thanks for the CRD info! PM sent about shim.

Harry

[timn]

My 3ltr had been blowing a huge amount of black smoke and getting really bad over the last 3 months. I was thinking it may have been an injector or a pump issue however i know with the Mit's Tritons they close up the EGR to clean the engine's of the soot build up so I gave this a go and its worked a treat, i have noticed a slight increase in power and the smoke has almost gone. Easy fix for an hours work!!!!

[DrHarry]

Thanks to the shim from Ferret I have now blocked the EGR in my 2008 CRD GU. The boost has certainly changed on the turbo. Previously it would rarely hit 15, now it rarely hits 18...in other words it is generally sitting a bit higher under all conditions than previously but I think is still acceptable. Would anyone see a problem in this slight overall rise in boost?

I sense that the motor is more responsive off the mark with no flat spots as I go up through the gears. I guess that means the turbo lag is gone that was there before. Fuel economy as per the Scangauge is unchanged.

I have had the coded come up twice in 10 days since I did the block but readily removed with the Scangauge.

I haven't done anything about the butterfly valve mainly 'cos I am not sure how to get to it! Does it matter? Should I bother?

Harry

[the evil twin]

What butterfly valve?

How are you measuring boost pressure ?... off the Scangauge MAP?

If you back off the Trubo boost pressure back to max 16 PSI you will gain about 1.5 to maybe 2 litres per hundred better fuel economy (higher boost = more fuel)

The reason the vehicle feels more responsive is that the spool up of the Turbo is now much quicker and the pressure is higher which may (I stress only may) give you problems with boost spikes. Up to you if you wish to crank back on teh VNT screw or fit a Dawes and Needle valve. I would do one or the other.

[Warthog]

In areas like Africa with poor fuel, blanking the EGR also has the effect of stopping loads of cr*p building up around the valves and manifolds, not sure how much of a difference it makes in areas with better fuel quality, but from the first head rebuild I did on my 2.8 the buildup of gunge in there was phenomenal, after a thousand miles (and the second rebuild due to a cooking incident) there was no build up of anything... now it's just cooked again after another 1000 miles want to put a 4.2 in it, will hopefully do away with the EGR question!

[diffhead]

what is egr and why is it used?.. simply its exhaust gasses re- entered to the combustion chamber. most people think its to use up the last of the oxygen left after combustion......... WRONG. there is next to no oxygen left. its all about emmisions. basically you are putting hot air mixed with clean air back into your engine which makes it run less efficiantly but lowers emmisions.. if you run an intercooler you should be pissed off and rightly so.. trucks run both egr and scr .. what is scr? its an injection of urea directly into the exhaust to do the same thing so instead of compromising hp all you have to do is inject urea. no matter what you do with the engine.. why do car owners put up with egr? dont have the option!

[DrHarry]

My updated after some more fiddling. I have the 2008 CRD with diesel gas fitted. I fitted a boost guage which noted normal levels up to 15max. I did the EGR block which saw occasional boost up to 17 but by and large the boost seems well controlled by the ECU as I was told to expect in a CRD.

I have just added a 2.5" mandrel exhaust and a pyro gauge and now I am seeing frequent over boost up to 19-20 under light load in 2nd or 3rd gear, on a slight incline. EGT 350-450.

Should I now just adjust the actuator a little? Will this level of boost be likely to do any harm to my engine?

cheers
Harry