Compounds for the Passat

andy2

Veteran Member
Joined
Sep 24, 2004
Location
Bowmanville,Ontario,Canada
TDI
13 Jetta,94 Golf drag car 585bhp,Samurai buggy BHW 300bhp,97 Ram cummins
Nice touch with the flange to ensure flatness Jon ;).Are you sure you don't need a compressor bypass to go with that massive turbine bypass :p
 

A5INKY

Vendor , w/Business number
Joined
Sep 4, 2007
Location
Louisville, KY
TDI
2006 Jetta TDI, 2002 Eurovan Westphalia VR6
That last pic really shows how nicely packaged of a set-up you achieved. Nice.
 

duwem

Veteran Member
Joined
Apr 11, 2012
Location
Wi
TDI
2002 Golf GLS TDI 5 Speed
So for us simpler folk, the pipe coming out of the top of the stock exhaust manifold, that was the EGR, and now your using it to wastegage to control boost? But the bigger turbo looks like it already has a wastegate built in?
 

JFettig

Vendor
Joined
Aug 18, 2010
Location
Blaine, MN
TDI
B5 Passat, 2010 Jetta
duwem,

That is the high pressure turbo exhaust bypass. The little turbo cannot handle all the exhaust energy and would boost out of control without it. Ideally I'd use a small non-vnt turbo without a wastegate and use the big wastegate to control the boost pressures but I have the VNT and can be more flexible controlling it.

Control of the low pressure(big) turbo is completely separate from the control of the high pressure turbo, the LP turbo takes care of itself with the stock wastegate, I'll set it between 16 and 18psi. The bypass wastegate is also a safety device of sorts, EMP:IMP is usually around 1 and its pretty consistent except for some situations(spool and high RPM), so that it will be set up to open when exhaust differential pressures are too high and it will keep the turbo from overboosting individually.

Andy,

I'm 100% sure I don't need a compressor bypass :), they're very well matched and the LP can't handle the pressure ratios needed to use a bypass.
The turbine bypass was the smallest one I could find! Its 38mm.
 

andy2

Veteran Member
Joined
Sep 24, 2004
Location
Bowmanville,Ontario,Canada
TDI
13 Jetta,94 Golf drag car 585bhp,Samurai buggy BHW 300bhp,97 Ram cummins
It would be nice to have a smaller external wastegate for the smaller displacement diesel's.There just doesn't seem to be anything smaller than 38mm as you mentioned.It just might be tricky to control as you may not need to bypass much to regulate the 2056.

I'm really surprised that none of us compound guys have bought the turbo shaft speed gauge yet ? It would be neat to monitor the high pressure turbo to determine what is going on.

I have been fortunate and not blown a High pressure turbo yet without knowing shaft speed,Knock on wood ! I pay attention to pressure ratio's and exhaust manifold pressure.
 

Fix_Until_Broke

Top Post Dawg
Joined
Aug 8, 2004
Location
Menomonee Falls, Wisconsin, USA
TDI
03 Jetta, 03 TT TDI
Last edited:

JFettig

Vendor
Joined
Aug 18, 2010
Location
Blaine, MN
TDI
B5 Passat, 2010 Jetta
Andy, that isn't a 2056! 2056 is way too big for a high pressure turbo on a daily driven TDI.

Thanks Matt!

Found someone with a plasma cutter, chopped the hole in my downpipe for my LP wastegate port, will get the downpipe finished soon, waiting on flex and V-band
 

shadowmaker

Veteran Member
Joined
Jan 30, 2007
Location
Finland
TDI
2.5TDI
Like this?

http://www.micro-epsilon.com/custom-designed-sensors/OEM-Automotive/Turbolader_rpm/index.html

http://www.micro-epsilon.com/download/products/dat--eddyNCDT-turboSPEED-135--en.pdf

I'm more concerned with the torque on the HP shaft than the overspeed (though the speed does become a concern in straight compound (not sequential) at higher RPM's).

Jon - nice looking work!
Anyone have price tag for that? What about display?

What torque are you talking about?
 

Fix_Until_Broke

Top Post Dawg
Joined
Aug 8, 2004
Location
Menomonee Falls, Wisconsin, USA
TDI
03 Jetta, 03 TT TDI
Waiting on a price - will let you know, but I'm guessing $1000-1500. No display, you run this into your data acq. It can be scaled to 0-10v output or it will give 1 pulse per blade or 1 pulse/rev if you have a counter/rate meter - these can be had for relatively cheap (<$200) from RedLion, Omega, etc

Some quick back of the bar napkin math here...If the LP turbo is running at a PR of 2 the density of the air coming into the HP turbo is roughly double. The torque on the shaft of the HP turbo is roughly double since it's moving air at twice the density. Obviously there's some safety factor built in as there are hundreds if not thousands of compound setups running around every day, just something to be aware of as LP PR's start creeping up so does the torque on the HP shaft.
 

Fix_Until_Broke

Top Post Dawg
Joined
Aug 8, 2004
Location
Menomonee Falls, Wisconsin, USA
TDI
03 Jetta, 03 TT TDI
Sensor itself is ~$650 (there are a variety of diameters/lengths available)
Signal conditioner is ~$1300 - this provides the sensor with power and interprets it's signal to convert it to an analog voltage or pulses.

Right around $2k total
 

[486]

Top Post Dawg
Joined
Mar 1, 2014
Location
MN
TDI
02 golf ALH
Looks like a hall effect sensor and an analog/digital converter to me.
Or even further broken down, a coil of wire wrapped around a magnet, an op-amp, and a transistor.

I don't know much about electronics, but you should be able to give a buddy electrical engineer $500 to make you something similar.

Only issue with making one I could see would be resolution, so let's go with a worst case with 150krpm, with a 6 blade impeller that would be a 15 kHz output signal.
 

Digital Corpus

Top Post Dawg
Joined
Mar 14, 2008
Location
Ontario, California
TDI
'97 B4 w/ 236K mi body, 46K mi soul
Looks like a hall effect sensor and an analog/digital converter to me.
Or even further broken down, a coil of wire wrapped around a magnet, an op-amp, and a transistor.

I don't know much about electronics, but you should be able to give a buddy electrical engineer $500 to make you something similar.

Only issue with making one I could see would be resolution, so let's go with a worst case with 150krpm, with a 6 blade impeller that would be a 15 kHz output signal.
They state that it's an eddy current sensor. This is the same as the lift needle sensor in VE TDI's 3rd injector. An eddy current sensor requires an AC power source along with low frequency and high frequency filtering in order to read it's output. Converting the pulse(s) to an analog DC voltage from 0-10 V requires a bit of work after that.

A 6 blade wheel at 150K RPM will give 900K pulses per min. However since this is not a sinusoidal waveform, the bandwidth to reliably pick up the pulses would be north of 10 MHz.
 

Alcaid

Veteran Member
Joined
Sep 5, 2006
Location
Norway
TDI
See signature
Then the Garrett Turbo Speed Sensor Kit w/ Gauge at 415$ looks like a steal in comparison

 

Scott02

Veteran Member
Joined
Jan 17, 2006
Location
near Youngstown, OH
TDI
Too Many
Some quick back of the bar napkin math here...If the LP turbo is running at a PR of 2 the density of the air coming into the HP turbo is roughly double. The torque on the shaft of the HP turbo is roughly double since it's moving air at twice the density. Obviously there's some safety factor built in as there are hundreds if not thousands of compound setups running around every day, just something to be aware of as LP PR's start creeping up so does the torque on the HP shaft.
I was a tad surprised at the horsepower required on the shaft on the HP turbo after running through some of my own calcs.

With that said, it's still no where near the horsepower required to run the 2056 (2256 / whatever) as a single at power levels that some are pushing from a single.
 

Fix_Until_Broke

Top Post Dawg
Joined
Aug 8, 2004
Location
Menomonee Falls, Wisconsin, USA
TDI
03 Jetta, 03 TT TDI
Good find Alcaid - The micro epsilon one goes to 400k RPM vs 180k on the garret one, but that should be enough for most turbos we're running here. I think the micro epsilon one also works with ti wheels with it's eddy current design - it's definitely a lab grade unit.

Jon - sorry for derailing your thread
 

duwem

Veteran Member
Joined
Apr 11, 2012
Location
Wi
TDI
2002 Golf GLS TDI 5 Speed
Date has been set for the Door Country Cruise...now you have a deadline on this project ;)
 

JFettig

Vendor
Joined
Aug 18, 2010
Location
Blaine, MN
TDI
B5 Passat, 2010 Jetta
haha, my last order of parts comes in on Monday but this weekend and next weekend are not looking good for working on the car!
 

dieseleux

Théoricien -TDIClub Contributor
Joined
Nov 14, 2006
Location
Pas assez loin pour vider ma tank!
TDI
Jetta TDI 02
Turbo rpm sensor: small steel rod machined to install flush in compressor casting, few hendred turn of small wire cooper, a magnet, some electronic...
Easy to do!



Dieseleux
 

[486]

Top Post Dawg
Joined
Mar 1, 2014
Location
MN
TDI
02 golf ALH
I'm more concerned with the torque on the HP shaft than the overspeed (though the speed does become a concern in straight compound (not sequential) at higher RPM's).
I don't think the torque on the shaft would be much of a concern.

Sure, there'd be a lot higher density air going through the high pressure compressor, but (correct me if I'm wrong) the HP turbo should be more or less just "idling along" once the larger low pressure turbo is spooled.

More in detail on my thinking, the smaller "high pressure" turbo makes for quick spool, and lets you ramp the fueling up quicker. Wastegate (referenced to intake manifold pressure) should open before the smaller turbo starts choking off the engine (you see this happen even with the stock tune, the MAP reading begins rising unchecked above the commanded boost level as the vanes are eventually all the way open) . The increased exhaust volume from all that is spinning up the larger "low pressure" turbo, which really starts to get going when the nice hot exhaust from the wastegate starts hitting it. The wastegate is unloading the high pressure turbo by bypassing most of the exhaust past its turbine, the larger "low pressure" turbo takes over and just blows through the idling "high pressure" turbo.

Or I guess you could have the wastegate open at a fixed exhaust manifold pressure and then it would keep the "high pressure" turbo loaded and working. I have no idea the amount of intake manifold pressure these engines can take though.
 

Fix_Until_Broke

Top Post Dawg
Joined
Aug 8, 2004
Location
Menomonee Falls, Wisconsin, USA
TDI
03 Jetta, 03 TT TDI
What you're describing is more of a sequential setup, and in that case you typically need a bypass valve around the HP compressor otherwise it becomes a restriction between the LP turbo and the engine. The torque on the HP shaft would be low in this case as you describe

What Jon's got going on is a compound setup where all the air from the LP compressor goes through the HP compressor and gets it's pressure raised again.

[I'm making these numbers up for a very simplified example, but you'll get the idea] If you want to get 35lb/min of air through a 1.9l motor at 5000 RPM you're going to need 60 psi of boost for an overall pressure ratio of ~5. There are not many (any?) turbos that can achieve that pressure ratio at that mass air flow rate and still be any sort of driveable every day (ie spool below 3500 RPM). However there are many turbos that in a compound arrangement will move 35lb/min of air at a pressure ratio of 2.0 to 2.5 and be able to spool by 2000 RPM and still deliver the air at 5000 RPM. Put two turbos in series at a PR of ~2.25 each and you get an overall PR=5, decent street/highway manners and the ability to move 35lb/min of air.

See how easy it is ;)
 

[486]

Top Post Dawg
Joined
Mar 1, 2014
Location
MN
TDI
02 golf ALH
See how easy it is ;)
Yeah, I did all the calcs on paper for 3 PRs, 3 ambient temperatures, and intercooled/non on my 7.3 IDI, then put them to all the maps I could find.
You know what it told me? The same that everyone on the forums does, HX35 or GT3582 :p

Anyways, cool. I didn't know how much pressure these engines can withstand being that there's only 4 relatively small head bolts per cylinder, and the c/r is still pretty high (unless the pd150 pistons decrease that).
 

Fix_Until_Broke

Top Post Dawg
Joined
Aug 8, 2004
Location
Menomonee Falls, Wisconsin, USA
TDI
03 Jetta, 03 TT TDI
Ok, so you know just how easy it is then :)

There's a few TDI's running over 50 psi...peak cylinder pressures (ie: injection timing) are probably more of an issue than the the actual boost pressure.
 
Top