Compounds for the Passat

Rub87 said:

If you look carefully u'll notice that the pressure regulator for the case pressure builds a certain pressure differential over the pressure at inlet of the pump. So if u increase pump inlet pressure case pressure will rise just as much and timing piston will see no difference at equal n108 duty cycle.

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Aha! If the case pressure regulator is differential rather than absolute then that makes things a lot easier.

FUB - those are motor mounts. I have a feeling Jon's vision is going to get a little blurry if they're anything like as stiff as 034's equivalent

The least painful upgraded motor mounts I could find.

Rub87 said:

I cannot really understand why the effort to regulate pressure before pump down to 15 psi? Back in time I just had a ABF fuel tank with pump without any regulation and it worked just fine. I think the pump did put around 5 bar at idle.

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learnt something again, a diesel specialist told me it should never be higher than 0,5 bar.

if that worked for you it will be one of my next mod's.

I ran a 60psi pump once and blew the main seal right out of the Injection pump. Did the same on a 2.0 16v PD Tandem pump and that caused worse problems than a bit of spilled diesel

I'm have around 0.7 bar idle and 0.5 bar at wot. To pd liftpumps connected with Y piece
One with stock pressure valve and one without it. Other wise I reached 1.5 bar at idle.

Drove around for years with 5 bar, no issue, i first had a fpr but the unit was chinese and started to leak, then i thought what the heck, lets try without, worked just as well, so since then i drove just with a stock ABF tank directly to 1.4 tdi filter (without the hole for thermo element) to the pump.

Of course if you run a stock filter with thermo element you should block this and route it directly to the tank

i had a non thermo filter at the time and it still blew the seal. i'm sure 2-3bar is not an issue but you might have been lucky with 5 bar! haha

I think for those who are worried they could just pinch the pump body next to the seal a few times so the seal it held in place..

A guy i did the tuning for with a 12mm pump used a decent pump meant for continental cr system (hp pump without mechanical tandem pump, much like cp4.2) which made over 7 bar when dead headed. He then also used the stock filter, which was a bad idea, so he blew all the time the return lines of the injectors and even split a feed line to the pump. Still the seal at the pump shaft didnt leak or move. Now he installed a pressure regulator to regulate the pressure to 2-3 bar and used an inline filter of a CR engine so the return line is again pressure free and the feedpump is relieved. It was clear that this pump did not have a built in relief and was not meant to be dead headed when the pump was powered during ignition on but engine not running...

So for those who use a pump without relief like bosch 044 or some walbro external its bad idea to use no pressure regulator. If you use a pump with built in relief for safety valve at a reasonable pressure below 5-6 bar then you are just fine.

Wow. Amazing.

A couple of questions:

First, the ultra-newb question, Is this an ALH engine?

Second, is your "small" (second?) turbo (the one that's fed from both the turbo that's bolted straight to the exhaust manifold, and the tube from the EGR port on the exhaust manifold; Is that the "LP" turbo?) a divided scroll housing turbo, or... I guess I don't really understand how your setup works. Could I get you to explain it to me? I did read the whole thread first, but... Well, newb. :-/

Thanks in advance. 260 HP and 460 lb-ft to the ground out of 1.9l is amazing.

The low pressure turbo is the larger of the two. It generates high flow rates. Not sure how they are plumbed.

Its an AHH engine, similar to AHU - pre ALH.

On the exhaust side:
Exhaust manifold -> small turbo and bypass wastegate ->big turbo -> downpipe

Cold side:
Air filter -> big turbo -> small turbo -> intercooler -> intake manifold

OK, sorry, lemme try it this way.

The "small turbo" is the one with the rusty exhaust turbine housing? And the "large turbo" is the one with the shiny exhaust turbine housing?

When I was asking before, the shiny one looked smaller to me, which I guess is my bad for using terms that I only think I understand, instead of being really specific like this.

Correct, look at the compressor housings, you can see 'big' and 'small' much easier.

Little teaser

https://youtu.be/JeXeygSAorA

at least there ifsfuel

Could you explain how you are incorporating the n75 with the wastegate? Also, the external wastegate (well both I guess) use emp for input correct? Last question, do you do your own ecu tuning and does it use the standard AHH ecu?

Awesome build!

The N75 is only tee'd into the external wastegate, it modifies the force by adding vacuum to the bottom when the turbos are spooling up to prevent it from bypassing when exhaust pressures are higher than intake pressures.

Dang was talking to a buddy about this and looked it up, looks like the last post was almost literally a year ago...whats new??

I haven't driven the car for almost a year

Mice ate most of my engine harness last winter and I haven't had time to work on it, so it sits for now.

well make some time for it !!.
this tread was the inspiration for my one twin turbo build.
love to see you improve your set up.

Its spring time... feed the hawks with them harness eating mice and start playing with it again...

Another year of copper mouse feasting?

Another year of too busy to work on it

I ve been reading through the post and i have to say that it"s a very nice build love to see it working again.