DIY-disabling EGR and Air recirculation! - Page 3 - PeachParts Mercedes-Benz Forum

300SD81 · #31 08-26-2006, 06:38 PM

Removed all the vac lines to the EGR, plugged both connections, my transmission shifts MUCH smoother than before, I can slam down the gas and not feel like the trans is going to fall out when it shifts from first to second.

Flyin4now · #32 07-10-2007, 12:30 AM

Ok EGR and ARV disabling experts out there, please tell me how to disable both of these on my 1985 (Federal) 300D. I have been having this whistling for quite some time right after upshifts and have determined that it must be the ARV. I'm tired of hearing this. Do I have to install a blocking plate on the EGR, or is there another way? I guess I need a step-by-step procedure, since I'm a newbie to these modifications. I thank you, in advance, for your advice/tips.

Thanks,

Ken

#33 07-10-2007, 12:36 AM

Put a BB or other blockage in the vacuum tubes to each.

JimmyL · #34 07-10-2007, 12:38 AM

Quote:

Originally Posted by ForcedInduction

Put a BB or other blockage in the vacuum tubes to each.

Now where exactly do these BB's go? I am going to lose some later this week on the wagon.

#35 07-10-2007, 12:49 AM

After 4,004 posts, you honestly think I believe you haven't seen a thread or two (thousand) about the EGR and ARV?

Flyin4now · #36 07-10-2007, 12:55 AM

ForcedInduction, I only have 43 posts, so does that mean I get another question?

Ok, so a BB in both vacuum lines to each. Why do I read posts of a blocking plate for the EGR? Is that a better way, or another way?

Thanks,

Ken

#37 07-10-2007, 01:03 AM

Quote:

Originally Posted by Flyin4now

Ok, so a BB in both vacuum lines to each. Why do I read posts of a blocking plate for the EGR? Is that a better way, or another way?

BB's in the vacuum lines will disable their function. A blocking plate will completely block any exhaust flow if it leaks or it will allow you to completely remove it from the engine. They both work but the block off plate will really clean up the appearance of the engine and simplify the vacuum system.

Either will improve the performance and economy of the engine at the expense of an absurdly small increase in NOx emissions.

See THIS attachment for what the EGR and ARV look like.

JimmyL · #38 07-10-2007, 01:18 AM

Quote:

Originally Posted by ForcedInduction

After 4,004 posts, you honestly think I believe you haven't seen a thread or two (thousand) about the EGR and ARV?

You know me, I need pics. Preferably crayon.......

{stickmen are OK too}

whunter · #39 02-17-2012, 02:56 PM

for new members

atypicalguy · #40 07-09-2015, 12:41 AM

I always thought an air recirculation valve was designed primarily to prevent surge. Of course it may be that there is never enough boost on a stock engine to cause surge, but no one seems to have mentioned that function of the ARV in this thread.

Proctor750 · #41 09-18-2022, 11:17 PM

Throwback time!

Questions:

1. OP stated he opened up the ARV to place a nut under the internal spring to ensure it never opens even with the vacuum line removed/plugged. Is this necessary?

2. Eliminating ARV could cause overboost conditions -True or false?

3. If eliminating all of the vacuum lines you may as well remove everything on the passenger side including the cabin ventilation line. What does this do and how does removing it have an impact?

4. Will disconnecting the electrical connections at these modules have any side effect on a 91 om603 (w126 350SDL)?

gsxr · #42 09-19-2022, 09:25 AM

1) Shouldn't be necessary unless the ARV is leaking, which is unlikely.

2) False. Can't cause overboost. Only a stuck-closed wastegate can do this.

3) Eliminating all the vac tubes cleans up the engine compartment and reduces possibilities for leaks, depending how/where the vac system is blocked off. The ventilation line is needed if the vac consumers are operational, if removed/disabled the vent line can also be removed.

4) IIRC the 1990-up models have a vacuum-operated wastegate? If so, disabling some items may cause the ECU to kill boost. I've never owned a 350SDL and can't remember the exact setup. You'll need to do some more research. Might need to convert to a pressure-operated wastegate if this is the case. I had to do this on my 1993 300D 2.5T.

5) I assume all the questions are for a 1991 350SDL?

Proctor750 · #43 09-19-2022, 05:34 PM

Gracias.

Yes all for a 91 350 rod bender.

So where did you source the wastegate which worked with the stock turbo?

gsxr · #44 09-19-2022, 05:46 PM

Quote:

Originally Posted by Proctor750

Gracias.

Yes all for a 91 350 rod bender.

So where did you source the wastegate which worked with the stock turbo?

The 2.5L has a smaller turbo with different wastegate. There's a long thread on the forum with details.

Unfortunately, that wastegate will not fit your 3.5L turbo. I'm not sure what part number to get, but I think the wastegate from a 300SDL (86-87) may fit, assuming you have a Garrett turbo. Maybe someone else has already done this?

Proctor750 · #45 09-20-2022, 09:42 AM

How does ecu kill boost? Any way to confirm it does this? Engine seems super similar to the 3.0.
I need to look at the wastegate when i get home.