PD100 has variable intake manifold...

[n1das]

Awesome, this post really cleared things up for me. So the actuator to unplug is the one immediately below the EGR correct? I'll do this tomorrow and see my results. I wasn't able to see those pictures before.. very beneficial. When I was messing with the switch manually the spring did feel quite strong. So if this is correct then those who have held there linkages 'open' with zip ties have in effect been closing off the smaller ports?

Could be....if the zip ties were used to pull the actuator to simulate vacuum applied to it, then YES, they are closing off the smaller ports instead of keeping them open.

MrCHill and I played with an intake manifold assembly to be sure we were doing the right thing. We weren't sure what the default position was with no vacuum applied to the actuator so we studied a BEW PD 2-piece IM assembly laying around in the shop. It isn't obvious with the IM installed on the engine. You have to look at the IM assembly all by itself to see how it works with the actuator attached.

Bottom line is the mod is VERY simple: Unplug the vacuum hose from the IM actuator and plug the end of the hose with a golf tee or something similar. The smaller openings in the IM assembly will remain OPEN all the time.

Good luck.

 

[PDJetta]

Thanks Dave. I do believe I will cut this vacuum line. I will do it near to the vacuum switching valve on the firewall and install a screw in the stub attached to the switching valve.

I think with my RC 2 programming, the intake flap may stay in the open position. I read a post by Jeff Roberts stating this I believe.

--Nate

 

[n1das]

Thanks Dave. I do believe I will cut this vacuum line. I will do it near to the vacuum switching valve on the firewall and install a screw in the stub attached to the switching valve.

I think with my RC 2 programming, the intake flap may stay in the open position. I read a post by Jeff Roberts stating this I believe.

--Nate

Mine was switching open/closed with RC2+ tuning. Leaving it open all the time made a huge difference. It feels like I have a PD150 IM installed. Also with my BEW intake manifold on the ATD PD engine, it doesn't do any good to have the variable setup because the ATD's ports aren't split like with the BEW. The ATD's intake ports are like an ALH engine.

Time will tell what the effects on MPGs are. I suspect they might improve slightly because engine can breathe better. However my heavy right foot might negate any improvements because of how much better it drives!

 

[PDJetta]

I just did this mod. Took five minutes. The vacuum line to the diaphragm that closes the intake flaps has an inline connector right in the middle. I simply unplugged the connector, leaving the connector on the actuator side with its vacuum line. I then put a screw in the line leading from the vacuum solinoid and neatly wire tied the lines. Be careful if you do this, because the VNT actuator vacuum lines runs in the same bundle as the variable intake runner flap vacuum line. It was easy to identify the correct line in my case, since I have a boost valve teed into the VNT line.

The EGR cooler bypass flap valve vacuum line is in this bundle too, but mine is already plugged too, since there is not anything for that line to connect to!

I will report if I notice any drivability or fuel economy difference.

--Nate

 

[TDI'ed]

Charlie has updated my tune.. now the EGR is disabled alongside the throttle valve. I must say the turbo spool is super smooth now from 2000 onwards.. the acceleration out of first is much much better without the stagger from 2500 rpm! I highly suggest either getting your tune updated or doing this mod.. makes a massive difference.

edit: am I correct in thinking the throttle valve = the variable flaps? or should I also unplug the vacuum line to the actuator? I am not sure if the throttle valve charlie speaks of is the anti shudder valve or these individual valves in the intake?

 

[n1das]

I just did this mod. Took five minutes. The vacuum line to the diaphragm that closes the intake flaps has an inline connector right in the middle. I simply unplugged the connector, leaving the connector on the actuator side with its vacuum line. I then put a screw in the line leading from the vacuum solinoid and neatly wire tied the lines. Be careful if you do this, because the VNT actuator vacuum lines runs in the same bundle as the variable intake runner flap vacuum line. It was easy to identify the correct line in my case, since I have a boost valve teed into the VNT line.

The EGR cooler bypass flap valve vacuum line is in this bundle too, but mine is already plugged too, since there is not anything for that line to connect to!

I will report if I notice any drivability or fuel economy difference.

--Nate

You should notice a driveability improvement immediately if your tuning was operating the 2-piece IM actuator. I have RC2+ and my tune was doing that. Doing the mod made a HUGE difference. No more staggering effect at 2500 RPM during gentle acceleration.

If your tune already commands the actuator to be open all the time then you should notice no difference in driveability or MPGs.

I think the easiest way to do the mod with no risk of messing up any other vacuum lines is to simply unplug the vacuum line at the IM actuator and plug the end of the vac line with a golf tee or something similar. Done!

 

[n1das]

Charlie has updated my tune.. now the EGR is disabled alongside the throttle valve. I must say the turbo spool is super smooth now from 2000 onwards.. the acceleration out of first is much much better without the stagger from 2500 rpm! I highly suggest either getting your tune updated or doing this mod.. makes a massive difference.

edit: am I correct in thinking the throttle valve = the variable flaps? or should I also unplug the vacuum line to the actuator? I am not sure if the throttle valve charlie speaks of is the anti shudder valve or these individual valves in the intake?

The "throttle valve" is the anti-shudder valve in the EGR/ASV assembly and is electrically operated. The actuator you need to disable is vacuum operated and is on the variable IM assembly where the individual valves are which close off the smaller intake ports. Since you noticed an improvement this suggests you did the right thing.

This is why I suggest doing the mod right at the actuator for the variable IM assembly and not further back on the vacuum line. It's the least confusing and you know you've got the correct vacuum line. Just unplug the vacuum hose at the actuator and plug the end of the hose with a golf tee or similar and you're done.

Good luck.

 

[n1das]

BUMP. Anybody tried this mod yet with a BEW PD and stock tuning?

The mod: Unplug the vacuum hose going to the actuator that controls the variable intake manifold assembly. This will cause the variable intake manifold flaps to remain fully open all the time. Plug the end of the vacuum hose with a golf tee or something similar to prevent a vacuum leak. Done!

 

[TDI'ed]

I have to say I'm amazed at how much smoother this car revs in first now. I haven't unplugged the vac yet as I am unsure if my tune is keeping thm open but I'll probably just unplug them anyways. The asv sure was messing with the spool under partial throttle though, drives like a different car now!

 

[PDJetta]

You should notice a driveability improvement immediately if your tuning was operating the 2-piece IM actuator. I have RC2+ and my tune was doing that. Doing the mod made a HUGE difference. No more staggering effect at 2500 RPM during gentle acceleration.

If your tune already commands the actuator to be open all the time then you should notice no difference in driveability or MPGs.

I think the easiest way to do the mod with no risk of messing up any other vacuum lines is to simply unplug the vacuum line at the IM actuator and plug the end of the vac line with a golf tee or something similar. Done!

I just went for a nice long drive and I notice absolutely no difference in operation with this vacuum line disconnected and plugged (car runs great, as usual). I suspect Jeff (Rocketchip) had this function disabled. I did notice when I got my RC #2, my fuel economy immediately improved by 2-3 MPGs.

I unplugged the hose in the middle because the actuator was completely inaccessable from the topside (I suppose I could have gotten to it if I removed the plastic upper boost pipe, but that is a real pain). I am positive I got the correct hose too, because I traced it right to the intake flap actuator diaphragm, right above the turbocharger.

--Nate

 

[milehighassassin]

Does anyone know which way the flap is closed and open? I don't have the actuator attached anymore. I want to make sure it is locked fully open.

 

[darkhorse]

Does anyone know which way the flap is closed and open? I don't have the actuator attached anymore. I want to make sure it is locked fully open.

Counter clockwise is closed.

 

[milehighassassin]

Thanks!

 

[JB05]

n1das, thanks for the clarification. Post #20 had me thinking that the IM flaps were closed until vacuum was applied. I did not know about the affect of the actuator keeping them open without vacuum. I just went out and undid my previous mod, but with the solenoid unattached and plugged up with a screw. In other words the actuator does not have any vacuum applied.

 

[PDJetta]

Counter clockwise is closed.

Yes, if you look at the picture posted earlier of the BEW intake with intake flaps and actuator, this appears to be the way it is set up. Vacuum applied to the diaphragm pulls the rod against actuator spring tension, rotating crank counter clockwise, closing the flaps. No vacuum allows the spring tension to hold the flaps open.

--Nate

 

[VWBeamer]

Disconnecting the actuator has eliminated the bucking surging I sometime had at part throttle at 1800-2400 rpms.

 

[PDJetta]

I just remembered that I disconnected the VIM actuator a few months ago too, and I noticed no difference (runs just as good), but I read somewhere on this list that RC programming disables this anyway, so I may have not changed anything. The only things my vacuum pump operates now is the brake booster and the VNT actuator on the turbocharger! EGR cooler bypass flap? Who needs it without the EGR cooler!

--Nate

 

[n1das]

I suspect I haven't changed anything either in my 05 ATD PD JWagen. My RC2+ tune likely takes care of the VIM. Anyway the VIM vacuum line is disconnected and plugged with a golf tee so the VIM is guaranteed fully open all the time.

I'm curious if anybody with a BEW PD with stock tuning has tried running with the VIM wide open all the time and wondering if they've noticed any improvement.

 

[VWBeamer]

I suspect I haven't changed anything either in my 05 ATD PD JWagen. My RC2+ tune likely takes care of the VIM. Anyway the VIM vacuum line is disconnected and plugged with a golf tee so the VIM is guaranteed fully open all the time.

I'm curious if anybody with a BEW PD with stock tuning has tried running with the VIM wide open all the time and wondering if they've noticed any improvement.

http://forums.tdiclub.com/showpost.php?p=3003960&postcount=168

 

[ig109]

Dug this thread out of the grave.. FWIW.. I cleaned the intake on my PD100 04 Jetta Wagon last week.. Broke the little vacuum actuator for the Lower intake Flapper.. So I Zip tied it wide open..

First day out it fell on its face (limp mode?) scanner says low EGR flow..

I found what I believe to be the correct actuator on fixmyvw.com and it should be here this week.. The bracket was busted as well but I tig welded that back together..

I ended up putting the EGR back on the car (originally planned to block it off) due to the availability of the Malone Dynamic EGR tune for warmup..

So in short.. I guess the Variable intake flapper must be operational for the engine to flow the proper amt of EGR..