2.5TDI + bi-vnt-turbo

[shadowmaker]

wow, this is definately the most serious van build i've ever seen, apart from old air coolers

can you give me any maths on how you worked out the shape and area of the slot between the plenums on your intake manifold, and also the reducing cross section of the primary plenum? i have been attempting to make a 2 plenum manifold for my mk3 TD but i havnt found any real engineering data, just pictures.

You'd be suprised if you knew more about my old air coolers... There are things that can't be seen on these pictures... On purpose...

You just decide what size your charge pipes are going to be (= Xmm) and make a conical primary plenum from Xmm -> almost 0mm. Mine is 76mm -> ~20mm. Calculate slot area to be less than charge pipe area. Keep in mind that slot is crusial for the flow... Also you need to think where you want the air after it has entered in your second plenum...

With high speed even air seems to have mass. This is the whole point of dual plenum intake. It won't make you more horsepower (at least that not its primary function), but it can keep your AFR identical in every cylinder so it is more of a safety feature when you really want to push the limits.

It's time for sauna and refresments... Outside temperature is -25 degrees of Celsius (-13F)...

[shadowmaker]

Got suspension parts from sandblasting/painting.



Polyurethane bushings are on their way.



Some colour matching for Brembos to suit D2 calipers. Used semi-matt clear coat to match hard anodised finish on those D2s. Silver/white texts and these are ready to go.



Year 2009 has come to its end. Happy New Year 2010 to everyone!!!

[Greg Roles]

Love what you're up to. That plenum custom fabrication is just amazing. I like the science behind the work, and applaud your mad efforts to make a crazy VW bus.

I'd love to pick your brains about just how big a true low restriction post turbo exhaust needs to be on a diesel. Seems that the old rule of as big as possible to minimise restriction, but given a diesels volumetric efficiency and overall gas flows, I'm getting a feeling even my 2.0 TDI is going to need a 3" plus system. If you look at the last post on my tinkering thread in the diesel section, theoretically I'm calculating some huge exhaust flows, and I'm starting to think I need to go huge to get those last few hp ( which is what it's all about baby! )

Interested in what you and your mad mates think about what is really necessary.

[gldgti]

You'd be suprised if you knew more about my old air coolers... There are things that can't be seen on these pictures... On purpose...

You just decide what size your charge pipes are going to be (= Xmm) and make a conical primary plenum from Xmm -> almost 0mm. Mine is 76mm -> ~20mm. Calculate slot area to be less than charge pipe area. Keep in mind that slot is crusial for the flow... Also you need to think where you want the air after it has entered in your second plenum...

With high speed even air seems to have mass. This is the whole point of dual plenum intake. It won't make you more horsepower (at least that not its primary function), but it can keep your AFR identical in every cylinder so it is more of a safety feature when you really want to push the limits.

It's time for sauna and refresments... Outside temperature is -25 degrees of Celsius (-13F)...

thanks for that - in fact this is basically what i had done with the primary plenum - however i belive the area of the slot that i used was far too large - i calculated it to be equivalent to a 4" circle, where my charge piping and conical inlet was 2" diameter.... theres the problem i see now many, many thanks, now i can get back to fabricating after work! i suspect a new intake with longer runners and decent plenum will go nicely with the new turbo on my AAZ.

[shadowmaker]

Love what you're up to. That plenum custom fabrication is just amazing. I like the science behind the work, and applaud your mad efforts to make a crazy VW bus.

I'd love to pick your brains about just how big a true low restriction post turbo exhaust needs to be on a diesel. Seems that the old rule of as big as possible to minimise restriction, but given a diesels volumetric efficiency and overall gas flows, I'm getting a feeling even my 2.0 TDI is going to need a 3" plus system. If you look at the last post on my tinkering thread in the diesel section, theoretically I'm calculating some huge exhaust flows, and I'm starting to think I need to go huge to get those last few hp ( which is what it's all about baby! )

Interested in what you and your mad mates think about what is really necessary.

2,5" is good for 200-250bhp
3" 250-300bhp
3,5" 300-400bhp
4" 400-500bhp
5" 500+bhp

This is a rough estimate what is used here with diesel engines, but I see no harm going bigger except weight. DP is crucial as there gasses are at their hottest and it should be bigger than exhaust (first 1-1,5m). Just keep transitions smooth use large radius bends if possible. Muffler(s) should be kept at the very end of the pipe as restriction is at its lowest there (cooler gasses). One free flow muffler with "muffler style" end tip is all you need with turbo engine to make it almost soundless. Actually you can get away with no muffler at all, just don't use side pipe etc, or have too big tip size. Muffler style end tip takes the most annoying sound away, so I have always used it in my builds.

And please, don't use 100% methanol in your W/M spray. That's a bad idea...
If you want more fuel, just use bigger nozzles to be safe. 15-20% methanol mix with water is safe. Anything more than 30% and you are really pushing it with a high CR engine...

[shadowmaker]

thanks for that - in fact this is basically what i had done with the primary plenum - however i belive the area of the slot that i used was far too large - i calculated it to be equivalent to a 4" circle, where my charge piping and conical inlet was 2" diameter.... theres the problem i see now many, many thanks, now i can get back to fabricating after work! i suspect a new intake with longer runners and decent plenum will go nicely with the new turbo on my AAZ.

You should also make the slot a bit wider at the beginning as you need to force air to those two-three first cylinders. You can also use coanda-effect to feed the first cylinders.

[6thgear]

very very very very envious of your truck! subscribed and looking forward to learning of further progress! keep it up!

[shadowmaker]

very very very very envious of your truck! subscribed and looking forward to learning of further progress! keep it up!

No need to be jealous as this van is killing me both mentally and economically...


Polyurethane bushings.





Hmm... There seems to be a big hole in the back of the van...

[gldgti]

You should also make the slot a bit wider at the beginning as you need to force air to those two-three first cylinders. You can also use coanda-effect to feed the first cylinders.

and now i see the reason for the nice flat plate curving away from the charge inlet on your primary at the union of the charge pipe inlet and the secondary plenum. wonderful!

[shadowmaker]

My fake 4 pot D2. Located at the opposite ends of the van will fool eye even more + my camera is distorting colours somewhat. I bet their are going to be just fine.



More poly bushings.



It is beautiful outside as there's frost everywhere and only -4C. Sadly I'm too educated and need to work inside...