EGR Block = Turbo Damage ?

Glend · **Posted:** Fri Dec 21, 2012 3:00 am

Folks, I'd like to here from others that have blocked off EGR. I run the GDE ECO FT tune, and Keith is telling me that by blocking EGR I will reduce the life span of the turbo due to loss of the surge protection feature that is inherent in both the stock software and the GDE tunes (ie, they blip open the EGR valve to bleed off overboost and protect the turbo). If blocked this can't happen.

I should add that in Export models, like mine, blocking EGR does not raise a CEL or throw a code, so its an easy thing to do. I have had mine blocked off for over a year with no problems.

I have researched on other diesel vehicle forums and the practice seems widespread (blocking) and very little gets mentioned about turbo failures as a result.

So what's the consensus from those that have done it? Is there an alternative way of providing surge protection?

Hoosier CRD · **Posted:** Fri Dec 21, 2012 6:32 am

In all due respect, I think that it is very wise to listen to--and heed--Keith's insight. He certainly has an experience and knowledge base on this engine and vehicle that deserves proper deference.

With that said, I would also make sure that the EGR is fully closing. If you think that you are losing some amount of performance due to a partially open EGR, then making sure that it is opening/closing properly is key. Hope this helps.

kjjet · **Posted:** Fri Dec 21, 2012 10:04 am

Glend wrote:

Folks, I'd like to here from others that have blocked off EGR. I run the GDE ECO FT tune, and Keith is telling me that by blocking EGR I will reduce the life span of the turbo due to loss of the surge protection feature that is inherent in both the stock software and the GDE tunes (ie, they blip open the EGR valve to bleed off overboost and protect the turbo). If blocked this can't happen.

I should add that in Export models, like mine, blocking EGR does not raise a CEL or throw a code, so its an easy thing to do. I have had mine blocked off for over a year with no problems.

I have researched on other diesel vehicle forums and the practice seems widespread (blocking) and very little gets mentioned about turbo failures as a result.

So what's the consensus from those that have done it? Is there an alternative way of providing surge protection?

First: Overboost is uncommon, unless you are pushing the engine to its limits. Leting even the smallest amount of EGR exhaust into the intake sysyem is bad for your engine.

So...you have to ask yourself:

Do i push the engine to the point i may overboost and hurt the turbo? Or

Do i let EGR exhaust continue to damage the engine by slowly eating at the internal parts?

My choice was to removed all the EGR equipment. The turbo is a cheaper replacement than the engine. Plus...i dont push the engine to its limits.

MrMopar64 · **Posted:** Fri Dec 21, 2012 9:04 pm

The EGR valve isn't opened for overboost protection.

We open the EGR valve for surge protection. When you're operating at high boost then immediately take your foot off of the pedal, we open the EGR valve in order to equalize the pressure between exhaust and intake manifold which allows a controlled deceleration of the turbocharger rotating assembly at a lower rate of boost decrease. we also open the turbo charger vanes in such maneuver for the same reason.

By mechanically eliminating this feature, you could potentially find increased failures due to low cycle fatigue of the compressor wheel.

I would leave it as-is and let it keep working......

geordi · **Posted:** Fri Dec 21, 2012 11:36 pm

I lost an engine while having the turbo controlled by an SEGR and the GDE tune (so effectively blocked for 30k miles) when the turbo failed.

I lost a second engine (and NOT the turbo) after another 60k miles with the EGR fully blocked by welding it shut. I do not agree that our turbo needs such a 'feature' when the very-mechanically-similar VW TDI VNT turbo (also by garrett) does not have a similar function.

I have reasons to believe that this turbo may be too close to its own operational limits for this engine, but that is only supposition at this time. What I have evidence to prove, is that I did not suffer a turbo failure for ANY reason that can be related to boost surging or the inability to slow down at any 'balanced' rate. The turbo failed (conclusively) for reasons of insufficient lubrication at very cold temperatures, with insufficient warm-up time and resulted in the shaft seizing and snapping the turbine wheel off at high RPM. The engine failed in short order after this, as a result of the loss of oil pressure.

I do not believe that this egr-related nanny system is a useful function. YMMV.

Glend · **Posted:** Sat Dec 22, 2012 1:15 am

Hmm, thought provoking comments for sure and pretty much backs up what I see in searches on the Net. Surge Protection (sorry for using overboost) is an issue for all turbo diesels (it would seem) and there are certainly turbo models equipped with Anti-surge features or capablities but i am unsure as to how these work.

I tend to support the view of kjjet, in that I do not over use my right foot and boost is almost always well below peak. Occassions when I might bury the throttle and then back off quickly just don't happen in my driving style.

The benefits of keeping every last bit of soot out of the engine are significant in my view, and prospects for benefits through surge protection are less tangible.

cevans · **Joined:** Wed Aug 24, 2005 12:48 pm **Posts:** 278

Glend wrote:

I run the GDE ECO FT tune, and Keith is telling me that by blocking EGR I will reduce the life span of the turbo due to loss of the surge protection feature that is inherent in both the stock software and the GDE tunes (ie, they blip open the EGR valve to bleed off overboost and protect the turbo). If blocked this can't happen.

I've talked with Keith about this before, and he told me the same thing...I guess I don't get it.

Traditionally diesel motors, including our trucks, don't have a throttle body that closes when you come off the accelerator. Therefore there will always be airflow through the motor, and at 2.8L a good deal of it to. Surge typically happens on gasoline motors when the person comes off the throttle, the throttle plate closes and blocks airflow. Surge is a condition of exhaust manifold pressure being lower than the intake manifold pressure, causing the turbo to reverse direction.

Glend · **Posted:** Sat Dec 22, 2012 6:56 pm

"Surge is a condition of exhaust manifold pressure being lower than the intake manifold pressure, causing the turbo to reverse direction."

I have a boost gauge on the dash which shows both positive and negative pressure from zero, the sensor is tapped into the top of the intake body. I rarely, and I mean rarely, see a vaccum like condition on the boost gauge (indicating a reverse of flow). The only time is seems to show up is on startup. If the vanes are feathering then doesn't the surge have a way out anyway?

geordi · **Posted:** Sun Dec 23, 2012 1:19 am

That would be my thought. I also don't believe that the turbine can reverse quite that easily, when it is spinning at 25,000 rpm plus... And that the airflow through the exhaust manifold is always flowing and always in the same direction. Simply 'reducing the pressure' should not cause any operational reversals either - The pressure could (in theory) push backwards on the compressor vanes... But that would be an exceptional case, since the engine is also still drinking in that same pressure from the intake! The only way I can see that as an operational possibility, is if the FCV throttle plate suddenly snapped closed while at high boost. This is not possible under normal operations, so I don't think the surge is either. Final nail in this coffin for me: If the pressure in the intake DID cause the turbo to reverse suddenly... Why wouldn't we be hearing about turbo compressor wheels that have UN-SPUN themselves from the shaft while installed? There certainly would be enough force available, if the shaft is reversing under high boost and 40k RPM...

It doesn't happen. Period.

Upon kicking off the gas pedal suddenly while at high boost, the only reaction is the instantaneous cutting of the fuel supply to the cylinders. The pistons ramp down in RPM, continuing to inhale the boost pressure from the intake as they slow (over the span of maybe a second) and at the same time, the exhaust pressure is vacated from the now-fully-open VNT, slowing the turbine while the excess boost is simply sucked through the engine.

This thing breathes a LOT of air normally... That hairdryer isn't ever going to try and push pressure through a solid wall of a throttle plate, I don't think that it can ever 'reverse and bark' either.

Glend · **Posted:** Sun Dec 23, 2012 3:02 am

Maybe I have over reacted on this. I emailed Keith to discuss just what the Tune does in relation to EGR flow and how the FCV butterfly is used. I was told that the butterfly is always held open except for its closing on shutdown, and the EGR valve is NEVER opened except for bleeding off surge and so it is as effective as a mechanical block already. With the Tune in place and prior to blocking off EGR I was noticing that the oil did get contaminated and blackened but at a much slower rate than a stock tune. With the Blocking plate in place there was no contamination and the oil has stayed clean. I admit to being confused, I am told one thing by GDE but the oil seems to be telling me something else.

If the Tune does totally shutdown EGR (except for surge protection) then I am tempted to remove the block.

I guess I also saw the block as a way to allow the bypassing of the EGR cooler (route the line right back) and reduce the heat soak of cooling the EGR valve - which GDE has previously said could reduce temps by 40-50F.

Mixed messages.

Joe Romas · **Posted:** Sun Dec 23, 2012 1:33 pm

When my son got a phase 2&3 Rocket Tune for his TDI Jeff, Mr Rocket tune, advised him to go easy to avoid trouble from his turbo spiking.

So yes the EGR at certain times only must be a good thing.

DOC4444 · **Posted:** Sun Dec 23, 2012 7:16 pm

Keith has gone on record here as to the fact that with ANY of the GDE tunes, exhaust gas NEVER enters the intake, even when boost is being "bled". You may have misinterpreted your oil observations. You found the oil to have less "color" over successive changes, right? We saw the same pattern, as well. We now go about 3000 miles before the oil has any color at all. I think you would have seen the same pattern regardless as to whether you blocked off the EGR or not.

DOC

geordi · **Posted:** Sun Dec 23, 2012 7:26 pm

I find the oil color comments interesting, and hope you can clarify that for me:

You pour in a dark honey colored oil, and you can still see through it for 3000 miles? It stays the same color on the dipstick?
I bought my CRD with 30k miles on the original engine, and installed the SEGR within the first week. I had actually bought the SEGR from here before I even got the CRD.

So for 30k miles of the original engine, it had stock EGR (two of them according to the service reports) and then never again. For the next 30k miles of that engine (before the turbo failed) and another 70k miles on the replacement engine (which also started at about 60k)... Every time I changed the oil, it was pitch black shortly after the initial 10 second idle-to-fill-the-filter. I **NEVER** had the oil stay see-through for more than the first day or so. It might have some minor translucency... But stay 'clean' like I had just put it in? Not once, even when I was running short 3000 mile changes to wash out the engine.

How can you account for this difference? I wasn't towing or beating on it most of the time, and since I live in a rural area, every drive I take is at least 15 miles one-way from home.

DOC4444 · **Posted:** Sun Dec 23, 2012 8:14 pm

At 110K miles, we go about 3K miles before the oil has significant color. I change it soon after. Obviously, there is no exhaust gas or much blow-by getting in the oil.

DOC

jeepdan · **Posted:** Sun Dec 23, 2012 9:14 pm

I have seen the same results for a long time with the GDE tune.
At 3,000-4000 miles on the Mobil 1 0w-40 it still looks very clean, you can easily look through the oil and see the dipstick. Nothing like pretune days where the oil turned black after the first drive.
I change my oil at 6,000 mile intervals and my engine is still inhaling it's oily crankcase vapors :wink:

Not that it makes a difference, but I have never seen Mobil 1 0w-40 with a dark honey color, it has always been a light honey color.

geordi · **Posted:** Sun Dec 23, 2012 9:25 pm

I had always had significant CCV airflow, and the oil was completely black by the end of the first DAY. I wonder what was different, because both engines behaved in this way.

DOC4444 · **Posted:** Sun Dec 23, 2012 11:03 pm

Not sure what you mean by "significant CCV airflow". Have you NOT been venting your crankase to the atmosphere? I certainly have been for the last 80K miles.

DOC

Glend · **Posted:** Thu Dec 27, 2012 1:35 am

After GDE's advice that they 'only use the EGR valve for surge protection', I decided to pull my EGR block out. WHen I dropped the EGR short pipe to the intake elbow the block was completely black with soot on the EGR valve side and completely clean on the intake side - I can only assume that when the Tune opens that valve for surge protection that soot is getting through as well. Because of that I cleaned it all up and reinstalled my EGR block, as I don't want any soot getting back into the engine.

Perhaps blocking EGR back at the exhaust manifold and leaving the EGR input pipe open to the atmo might allow surge protection functions without the mess.

geordi · **Posted:** Thu Dec 27, 2012 2:34 am

DOC4444 wrote:

Not sure what you mean by "significant CCV airflow". Have you NOT been venting your crankase to the atmosphere? I certainly have been for the last 80K miles.

DOC

Yes, of course. What I meant was that my EHM seems to have a decent amount of wind coming from it at idle, and I can only imagine more under load. It isn't like my older 454 Chevy RV which has individual CCV filter-caps, that don't seem to pass 1/4 the amount of air that the EHM does from the same number of much smaller VM diesel pistons.

Make more sense?

DOC4444 · **Posted:** Thu Dec 27, 2012 7:58 am

Vehicle acquired at 17K miles. I started running SEGR at about 35K miles along with an IM SII ECU. (GDE was not on the tuner map then.) At about 55K and four oil changes later, the oil stopped being instantly black. Switched to GDE tunes at around 65K miles and disabled SEGR. in another 15K miles and three more oil changes, it got to where it is now, taking 3K before it gets dark, but still not opaque.

Many other people have noted similar experience. In your case, maybe your SEGR was not working or EGR was stuck open a little/could not close completely? Then, when you finally blocked off the EGR totally, there was so much buildup in the motor that it has never had a chance to gradually clean out, yet/ever?

BTW, I have been using mostly M1 00-40, changing to 5-40 in the summer.

DOC

EGR Block = Turbo Damage ?

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