B6 S4 bhw compound turbo build

mrmoto35

Veteran Member
Joined
Aug 14, 2013
Location
Cypress, CA
TDI
'13 Passat TDI SE w/SR
Can anyone comment whether I should powdercoat the intercooler piping black or leave it stainless ? Im on the fence
This is just me, but I like the idea of powdercoat. My personal choice would be black so as to retain an "OEM" look. But black may have slight heat implications...Either way it looks great!

As others have said your fab work is brilliant!! It all looks top shelf. Everything in the engine compartment is nice and clean, nothing looks cluttered. Great stuff, thanks for sharing this with us!
 

Machineman

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Joined
Aug 25, 2014
Location
ontario canada
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2007 RS4 Titanium 3.0TDI & 2013 Touareg TDI & B6 S4 BHW Swap Biturbo
This is just me, but I like the idea of powdercoat. My personal choice would be black so as to retain an "OEM" look. But black may have slight heat implications...Either way it looks great!

As others have said your fab work is brilliant!! It all looks top shelf. Everything in the engine compartment is nice and clean, nothing looks cluttered. Great stuff, thanks for sharing this with us!

Thanks and yes I agree the black will look more oem this project is far from OEM lol but it's nice to keep things looking like they're supposed to be there
 

Machineman

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2007 RS4 Titanium 3.0TDI & 2013 Touareg TDI & B6 S4 BHW Swap Biturbo
I have some bad news as well the low pressure turbo blew up on the weekend the cause is likely related to the fact that the oil line was too small feeding the distribution block and will be replacing it with a 6an braided line the good news is I will be upgrading the turbos to a td06h 25g billet and a td04hl 15t or 19t maybe TDImeister can comment on that as i am unsure of whats more suited 15t flows 420cfm 19t is 500cfm 25g is 850cfm the good news is I can keep my original housings
 

Machineman

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2007 RS4 Titanium 3.0TDI & 2013 Touareg TDI & B6 S4 BHW Swap Biturbo
I'm also working on building up a fresh long block with a ported oversized valve head and hopefully a 11mm lift cam I'm going to try and turn it into a street monster 4cyl
 

[486]

Top Post Dawg
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Mar 1, 2014
Location
MN
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02 golf ALH
for HP turbo sizing, the flow volume remains constant despite increases in air density, so you need to use gas compression formulas to figure out where you're at on the HP side

I find that mass flow based maps are easier to work with, as you simply multiply the airmass values by whatever the inlet air is above the atmospheric air density and temperature the map was made with.
Running an LP PR of 2 and an HP inlet temperature of 80F, you might multiply the mass flow values for the HP compressor map by 2.
LP PR 2, HP inlet 150F, you'd multiply by 1.6 or whatever. Calculate the difference in inlet density.

MHI maps are volume flow based, however.
This avoids needing to specify inlet temperature and pressure on the compressor map, but it makes things a little different in the calculation side. I just converted my maps to mass flow rather than figuring out the volume flow.

I'd imagine playing around with a few gas law calculators you could figure it out.
 

TDIMeister

Phd of TDIClub Enthusiast, Moderator at Large
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May 1, 1999
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Canada
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TDI
Sorry to hear about the ruined LP

Need interstage as well as intake manifold pressures and temperatures to make any sort of educated determination.
 

Machineman

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ontario canada
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2007 RS4 Titanium 3.0TDI & 2013 Touareg TDI & B6 S4 BHW Swap Biturbo
Sorry to hear about the ruined LP

Need interstage as well as intake manifold pressures and temperatures to make any sort of educated determination.

I agree do you think 800cfm 25 G lp is too big in conjunction with the 13 G? As these are the same price and if I'm buying a new one I want to buy the most Suited I read somewhere that your low pressure should be roughly twice the flow your high pressure the 20 G I was running is a little under half 25 G is a little over half
 

[486]

Top Post Dawg
Joined
Mar 1, 2014
Location
MN
TDI
02 golf ALH
25g is 60/78, so pretty close to the HX40 I'll be trying out with a 19t HP
IIRC I looked into a 15t HP and it was lining up reasonably well with the hx40, the 13g isn't all that much smaller

yours'll probably be together first, though, so any numbers I come up with real world won't do you much good, haha
 

Machineman

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ontario canada
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2007 RS4 Titanium 3.0TDI & 2013 Touareg TDI & B6 S4 BHW Swap Biturbo
Finally got my flow bench somewhat working now I'm starting to understand a bit of the limitations of these cylinder heads at factory lift versus 12 mm lift there's very little increasing flow maby 3% I don't think these require more lift I think duration is more important and larger valves and porting I think the ports and valves are simply just too small for much more gains and the exhaust definitely has more room for improvement
 

Horia

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Jan 29, 2017
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Romania Prahova
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Audi A5 3.0 TDI
Hi! Do you have knwoldge of a device similary to VFIZ able to fit on a B8 3.0 tdi, besides P3 gauge ? Something like Awron, who does it only for bmw...
And how about your audi 3.0 tdi, are you still continuing the project? Good luck ! :) you have pm ....
 
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Machineman

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ontario canada
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2007 RS4 Titanium 3.0TDI & 2013 Touareg TDI & B6 S4 BHW Swap Biturbo
Can anyone comment weather at - 6 feeding 2 - 4 lines is enough oil in theory it should be but I'm worried about blowing my new Turbo does the factory TDI oil filter housing output enough oil from one fitting to supply to turbos??
 

Windex

Top Post Dawg
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Apr 1, 2006
Location
Cambridge
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05 B5V 01E FRF
It's not the housing that flows the oil - it's the oil pump.

No mention in the thread - I assume your BHW block is BSM deleted?

If so, the best option for oil flow would be an ALH pump with BRM oil pump gears (fastest oil pump RPM). You may open pressure relief valve cold, but you will have the largest oil volume hot.

You have 4 feeds off that line? 2 turbo oil feeds and...?
 

[486]

Top Post Dawg
Joined
Mar 1, 2014
Location
MN
TDI
02 golf ALH
two dash 4 lines
meaning two eighth inch feeds

it's got plenty of flow available, it's a full-port 12mm hole straight into the output from the cooler.
Mine's just an 1/8" npt tapped into the end of the stock turbo feed banjo bolt, so two from one hole as well.

but you can't be certain that the lines are flowing oil without actually checking, sometimes the liner gets folded over when the ends are crimped on
ETA: are you bringing a -6 over to a distribution block with the -4 coming from that to the turbos? Might take a second or two to get oil out to the turbos, I think I slowly killed my HP by backing out before oil pressure came up, repeated over months. You take apart the blown one yet? May just find a piece of scuzz in the thrust bearing oil hole, it's only about 1/16"
 
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Machineman

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2007 RS4 Titanium 3.0TDI & 2013 Touareg TDI & B6 S4 BHW Swap Biturbo
Yes 2 dash 4 from block with one dash 6 feeding before i had 3/8 od tube with .312 id I switched it to dash 6 for piece of mind and yes I took the turbo apart the thrust bearing look like it was smoked like overheated and the compressor side Journal bearing was a little bit looser than turbine side I just don't want this to happen again my only other option is run two separate lines then run the one off of the oil pressure sender port
 

All Stock

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Oct 6, 2014
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Michigan
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AHU
It's not the housing that flows the oil - it's the oil pump.

QUOTE]

Correct, but the housings can restrict the flow. Not sure on the ALH but I've done major work to the older AHU version to support the housings ability to output. Consider everything in the flow as an orifice size. as it gets smaller pressure goes up but not the flow.
Also a simple rule of thumb to consider is that for every 90 deg bend with a radius is the rough equivalent of pushing the same diameter tube 10 lineal ft. Distribution blocks can be messy for flow and worse the fittings in and out of them and on the turbos. Add that all back to the pumps ability to flow against restrictions.

I am thinking a "Y" block as close to the first turbo as possible and then the longer line down to the furthest turbo. Input from pump and longest run -6 or -8 and outputs to turbo -4. assuming that from the pump to the output of the housing is smooth and open enough for hi flow.
 

Machineman

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2007 RS4 Titanium 3.0TDI & 2013 Touareg TDI & B6 S4 BHW Swap Biturbo
Not really looking forward to redoing this if you look at a powerstroke 6.4 the factory twin turbos are fed with 3/8 OD hardlines with a tee both Turbos are fed the same size as what's fed into the tee and those turbos are much larger in frame
 

[486]

Top Post Dawg
Joined
Mar 1, 2014
Location
MN
TDI
02 golf ALH
If you're worried about it just run larger line. Can't over-oil a journal bearing turbo unless you're running crazy oil pressure like a dead cold mitsubishi will do.

Maybe crack the lines while it's running to make sure oil's getting out there.
 

Fix_Until_Broke

Top Post Dawg
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Aug 8, 2004
Location
Menomonee Falls, Wisconsin, USA
TDI
03 Jetta, 03 TT TDI
I ran an adapter from the oil filter housing port to a -6 male, then ran -6 hose to a -6 branch tee at the LP turbo, then ran a -4 down to the high pressure turbo.

So far so good after 1 year/15k miles. A -6 is 56% larger than a -4
 

Machineman

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2007 RS4 Titanium 3.0TDI & 2013 Touareg TDI & B6 S4 BHW Swap Biturbo
I would do such but my low pressure turbo is very tight for space
 

[486]

Top Post Dawg
Joined
Mar 1, 2014
Location
MN
TDI
02 golf ALH
remember your lp is td04 based, his is td06

that'd probably tuck right in within the envelope of it, I really like the simplicity of it.
 

Machineman

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2007 RS4 Titanium 3.0TDI & 2013 Touareg TDI & B6 S4 BHW Swap Biturbo
I'm going to install my Hardline back on and then I will make one more Hardline so that each turbo has a separate line
 

Machineman

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2007 RS4 Titanium 3.0TDI & 2013 Touareg TDI & B6 S4 BHW Swap Biturbo
With having extra power it's nice to have larger brakes too Switched at the original brakes for 6 pot Front and 4 pot Rears with separate parking brake calipers I also made Billet engine mounts to keep the engine from moving too much and replace the two piece Center Drive Shaft with a aluminum one piece because the Driveline shudder Under full Boost was incredible
 
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