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Old 01-10-2012, 05:13 PM   #31 (permalink)
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Quote:
Originally Posted by UFO View Post
Right, the N18 alone controls the EGR flow. What I am saying is there is no intake throttle to help regulate the flow, like on PD VWs, or my Jeep Liberty CRD.

What I have learned since I wrote that is the EGR level is only checked at idle, so it is irrelevant what the MAF response to EGR is at any other engine condition. At the time I did not have enough output range in my circuit to make the ECU happy. My freeware VAG-COM has been invaluable.


So the N-18 duty cycle is not changed at all other than idle? I've never hooked up a LED to see if it pulses on an off. If it does change duty cycle than the vacuum applied to the EGR valve would change and EGR flow would also change.



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Old 01-11-2012, 12:32 PM   #32 (permalink)
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Quote:
Originally Posted by Josh8loop View Post
So the N-18 duty cycle is not changed at all other than idle? I've never hooked up a LED to see if it pulses on an off. If it does change duty cycle than the vacuum applied to the EGR valve would change and EGR flow would also change.



..
No, EGR is active all the times the ECM deems it necessary. It is only tested at idle.

The EGR is modulated with the duty cycle of the N18, I've seen it on an oscilloscope.
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Old 01-11-2012, 11:51 PM   #33 (permalink)
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i do not think so

reduced MAF signal will result in
less fuel to the system , greater FE , leaner mixture or same mixture when EGR is active , just less of it .

EGR operation reduces MAF flow

EGR functions by DISPLACING area in the combustion chamber with an inert gas
exhaust ,
thereby
reducing the available engine displacement volume and combustion pressure during the time EGR is in operation

how do you suppose eliminating EGR will increase FE in your system ? theory says no .

the ALH engine does have intake restriction via a throttle valve to enhance EGR flow and
to shut the engine off when key is switched to
off
a 2001 beetle would have an ALH engine ?

i also have VCDS
and use it daily - today it is version 11.1- i also use the actual VW scan tools ,
imho you should register your VC software as there are many additional things that will be made available ....
i would not use any software to tamper with the Mother VW settings in engine management .

do not use bio diesel , ever , in any VW diesel engine , another subject .

Last edited by mwebb; 01-11-2012 at 11:54 PM.. Reason: do not use bio diesel in any VW engine
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Old 01-12-2012, 01:33 AM   #34 (permalink)
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Quote:
Originally Posted by mwebb View Post
reduced MAF signal will result in
less fuel to the system , greater FE , leaner mixture or same mixture when EGR is active , just less of it .

EGR operation reduces MAF flow

EGR functions by DISPLACING area in the combustion chamber with an inert gas
exhaust ,
thereby
reducing the available engine displacement volume and combustion pressure during the time EGR is in operation

how do you suppose eliminating EGR will increase FE in your system ? theory says no .
EGR reduces NOx by decreasing combustion temperature, which has the side effect of decreasing thermal efficiency. By disabling that system, I am increasing the engine's ability to extract work from the fuel. THAT'S the theory, and I hope to have some measure of data to support it soon. To which "theory" are you referring?

Quote:
Originally Posted by mwebb View Post

the ALH engine does have intake restriction via a throttle valve to enhance EGR flow and
to shut the engine off when key is switched to
off
a 2001 beetle would have an ALH engine ?
It's only used to shut off the engine, it is not used as part of the EGR system
Quote:
Originally Posted by mwebb View Post
i also have VCDS
and use it daily - today it is version 11.1- i also use the actual VW scan tools ,
imho you should register your VC software as there are many additional things that will be made available ....
The freeware version IS the actual VW tool. Not sure what you mean.
Quote:
Originally Posted by mwebb View Post
i would not use any software to tamper with the Mother VW settings in engine management .
Why not? And who is doing that? I use the VAG-COM to validate the performance of my mod.
Quote:
Originally Posted by mwebb View Post
do not use bio diesel , ever , in any VW diesel engine , another subject .
Indeed, it might reduce your fuel costs, your carbon footprint, your emissions, increase your fuel mileage, your engine reliability. Don't do it.

Honestly, if you are going to criticize what I am doing, at least bring some facts or data.
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Old 01-13-2012, 12:06 AM   #35 (permalink)
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no

Quote:
Originally Posted by UFO View Post
EGR reduces NOx by decreasing combustion temperature, which has the side effect of decreasing thermal efficiency. By disabling that system, I am increasing the engine's ability to extract work from the fuel. THAT'S the theory, and I hope to have some measure of data to support it soon. To which "theory" are you referring?
EGR adds inert gas to the combustion chamber to reduce combustion pressure thereby reducing combustion temperature which MAY reduce NOX formation if the temperature is brought below the value needed to form NOX said to be around 2500f
AND
EGR reduces combustion chamber volume making the engine displacement smaller - small engines operated at higher loads are more efficient than large engines operated at low loads
that is one
theory that is a fact
EGR when operating reduces MAF flow which reduces fuel added by MR ECM
which reduces fuel consumption
another fact


It's only used to shut off the engine, it is not used as part of the EGR system
The freeware version IS the actual VW tool. Not sure what you mean.
Why not? And who is doing that? I use the VAG-COM to validate the performance of my mod.
Indeed, it might reduce your fuel costs, your carbon footprint, your emissions, increase your fuel mileage, your engine reliability. Don't do it.

VW uses the throttle plate to increase pressure differential between intake and exhaust allowing increased EGR flow

Vag-Com is obsolete
currently known as VCDS and it is NOT the actual VW scan tool although it is used by some VW tech s for some things , the actual VW scan tools have many functions that are not present in VCDS .
VCDS graphs and logs , VW scan tools do not
VW scan tools have GFF and GF , and communicate to Mother VW for software and adaptation abilities that VCDS does not have .
VCDS does not communicate with address 25
Immobilizer

more facts


Honestly, if you are going to criticize what I am doing, at least bring some facts or data.
EGR is good , EGR reduces NOX and improves Fuel economy
EGR does not operate at WOT and therefore does not reduce max availible power
there is no good reason to delete it

Bio diesel is bad
it cloggs up particle traps with ash , ash is not purged during regen
particle traps damaged by Bio diesel are not warrenteed by Mother VW and Partical traps are not inexpensive
Bio diesel is bad
bio diesel leaves behind deposits that completely close intake passages so that the engine can not run
and Bio diesel leaves behind deposits that freeze up variable vane turbo chargers , effectively killing them although sometimes the vanes can be UNclogged , most techs can not UNclogg them
have you ever encountered glow plugs taht have been broken off in the cyl head because the tips were carboned in place and would not release as the glow plug was removed ?
i have
bio diesel is bad , what ever you may think , what ever blarney you may have been told , there is no money to be saved by using it in a modern diesel engine .

more facts

your turn
---------------------


VCDS graphed data showing boost actual can not equal boost specified at WOT , there are no leaks -
bad turbo , 2011 jetta

Last edited by mwebb; 01-13-2012 at 12:34 AM.. Reason: Freeware un registered Vag Com is NOT an actual VW tool
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Old 01-13-2012, 03:58 AM   #36 (permalink)
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The ALH engines do not have particle traps, and so there is no purging.

Regular diesel fuel also leaves behind deposits in the intake; based on the discussions on the TDI forum, I am not the only one that has removed the ALH intake and found there is only a dime-sized hole remaining due to all the soot deposits from non-biodiesel use. Whether bio-diesel also causes this or not, I would still want to check the intake every time I have to change the timing belt.

Carbon clogging of turbo vanes can also happen with regular diesel; this is not a unique problem for bio-diesel. The cause is driving like a grandma, not the fuel. And the stock VNT-15 on the ALH is less prone to clogging than earlier turbos. Solution to this problem is to drive the car like I stole it on occasion.

Can't speak for the glow plugs; haven't read about these kinds of issues on the TDI forum and haven't had the problem. Of course that doesn't mean there isn't such a problem, just that I haven't seen anything about it.

Despite that possible problem, I am still very much in favor of bio-diesel and will put the highest bio-blend in that I can find (currently B20).

You are right however that bio-diesel is not good for later models of VW diesels (such as the 2011 you are talking about). I still hold out hope that future iterations of the VW diesels will 'play nice' with bio-diesel!

Last edited by NachtRitter; 01-13-2012 at 04:09 AM.. Reason: Correcting some information after verification
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Old 01-13-2012, 05:47 AM   #37 (permalink)
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I have had swelled glow plugs before.
I think the best way to remove them is snap them off and fish them out through the injector hole.
If you have tiny injectors where this wont work you will have to pull the head off or live with 1 less functioning glowplug. On a 4 cylinder this might make cold starts pretty rough, on a V8 its not so bad.

EGR might be good for gas engines, but most of the diesel users who delete EGR report better fuel mileage.
If EGR was so great why aren't some of the latest gasoline engine generations using it?

EGR in a gas or diesel is full of soot. Soot is abrasive like dirt. Why would I want dirt going into my engine?

Layers of diesel exhaust soot and motor oil from the crank case vent does a pretty good job a clogging intakes with sludge. When I tore my diesel down the sluge in the intake ports was between 1/8 and 1/4 of an inch thick. It was caked on so thick I could have stuck birthday cake candles in it. It took over an hour in the parts washer for each head to get the ports cleaned out and that was after I pressure washed them with a 0 degree nozzle.

Now that its gotten colder lately my cold starts with B10 bio diesel involve a lot more white smoke. Next fill up will be with regular diesel. I have not been using bio diesel for very long so the mix sloshing around in the tank is some where around B5 to B8 mix.
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Old 01-13-2012, 08:37 AM   #38 (permalink)
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Quote:
Originally Posted by mwebb View Post
reduced MAF signal will result in
less fuel to the system , greater FE , leaner mixture or same mixture when EGR is active , just less of it .

EGR operation reduces MAF flow

EGR functions by DISPLACING area in the combustion chamber with an inert gas
exhaust ,
thereby
reducing the available engine displacement volume and combustion pressure during the time EGR is in operation

how do you suppose eliminating EGR will increase FE in your system ? theory says no .

the ALH engine does have intake restriction via a throttle valve to enhance EGR flow and
to shut the engine off when key is switched to
off
a 2001 beetle would have an ALH engine ?

i also have VCDS
and use it daily - today it is version 11.1- i also use the actual VW scan tools ,
imho you should register your VC software as there are many additional things that will be made available ....
i would not use any software to tamper with the Mother VW settings in engine management .

do not use bio diesel , ever , in any VW diesel engine , another subject .


The ALH engine(1999.5-2003) does have an anti shudder valve(ASV) which by the Liberty CRD guys and others is called throttle valve. The only time to my knowlege that it is active on the ALH is when you stop the engine. There is no demand for it to actuate during normal driving conditions. The EGR is forced in by the exhaust backpressure, and would need to over come whatever boost pressure the intake is seeing at the time. In the CRD realm, the throttle plate is most likely used to enhance EGR flow as you mention in a more active implementation-the ALH EGR is rather rudimentary.

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Old 01-13-2012, 11:33 AM   #39 (permalink)
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Quote:
Originally Posted by mwebb View Post
EGR is good , EGR reduces NOX and improves Fuel economy
EGR does not operate at WOT and therefore does not reduce max availible power
there is no good reason to delete it
EGR does reduce NOx. On a gas engine, there are some circumstances where EGR can improve FE due to reducted throttling losses. EGR on a diesel is a different story. I've worked with and tuned diesels for years (both EGR & non-EGR) and have never, ever, ever seen a scenario where adding EGR improved FE. EGR can often produce better fuel economy at the same NOx level, but just adding EGR will always reduce FE.

Not sure where you got the information that EGR doesn't operate at max power. I've seen lots of diesels where there's EGR all along the torque curve.

Quote:
Originally Posted by mwebb View Post
Bio diesel is bad
it cloggs up particle traps with ash , ash is not purged during regen
particle traps damaged by Bio diesel are not warrenteed by Mother VW and Partical traps are not inexpensive
When made properly, biodiesel doesn't contain any more ash than traditional diesel fuel. The ASTM standard for traditional diesel fuel (ASTM D975) calls for ash <=0.01% mass. The ASTM standard for B5 & B20 (ASTM D7467)
also calls for ash <=0.01% mass. The spec is exactly the same for ash.

Of course, sometimes people use some crappy biodiesel that they made in their garage. Of course there can be problems there. But you'll have the same problems if you burn crappy conventional diesel fuel--but it's not a biodiesel thing.

If anything, biodiesel should extend the life of the particulate filter, because biodiesel typically produces about 10 times less particulate than conventional diesel fuel. Even B20 typically produces about 1/2 the soot than conventional diesel. Less soot produced means fewer regens, therefore more DPF life.

Quote:
Originally Posted by mwebb View Post
Bio diesel is bad
bio diesel leaves behind deposits that completely close intake passages so that the engine can not run
and Bio diesel leaves behind deposits that freeze up variable vane turbo chargers , effectively killing them although sometimes the vanes can be UNclogged , most techs can not UNclogg them
have you ever encountered glow plugs taht have been broken off in the cyl head because the tips were carboned in place and would not release as the glow plug was removed ?
i have
How is biodiesel going to leave deposits in your intake?! In a diesel the fuel is injected directly into the cylinder, not the intake. The only way anything from any fuel could get in your intake would be if you have EGR. Even then, it's after the fuel has been burned. What exactly are these supposed deposits? Most all the deposits that cause problems with VG's, glow plugs, etc. are primarily soot and, as I've already stated, biodiesel produces far less soot than conventional diesel.
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Old 01-15-2012, 04:58 AM   #40 (permalink)
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Quote:
Originally Posted by Diesel_Dave View Post
When made properly, biodiesel doesn't contain any more ash than traditional diesel fuel. The ASTM standard for traditional diesel fuel (ASTM D975) calls for ash <=0.01% mass. The ASTM standard for B5 & B20 (ASTM D7467)
also calls for ash <=0.01% mass. The spec is exactly the same for ash.

If anything, biodiesel should extend the life of the particulate filter, because biodiesel typically produces about 10 times less particulate than conventional diesel fuel. Even B20 typically produces about 1/2 the soot than conventional diesel. Less soot produced means fewer regens, therefore more DPF life.

Most all the deposits that cause problems with VG's, glow plugs, etc. are primarily soot and, as I've already stated, biodiesel produces far less soot than conventional diesel.
Biodiesel is good, unless you are cold starting an IDI at 15'F.

Quote:
Originally Posted by Diesel_Dave View Post
I've never, ever, ever seen a scenario where adding EGR improved FE.... but just adding EGR will always reduce FE.

I've seen lots of diesels where there's EGR all along the torque curve.
Remove all doubt, for me I just delete the EGR.

I say just don't listen to non-diesel people on the subject of anything diesel related.

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