Intake manifolds

I'm finally able to start moding after 4 years so I'm dropping in a Vnt17 with malone stage 1 tune, wuzetem .230 (or .260 [please advise]) injectors and 3 bar maf. I've been doing some research into turbos and manifolds and have found that the exhaust tu e really shouldn't be connected until the last possible moment due to exhaust valves being open at the same time. And all of the Borg Warners' and Garretts' come with manifolds that are set up in a way that they will get this back draft of exhaust. Does anyone know about a manifold for this issue (I can find several for the 1.8L turbo but none for the 1.9L ALH).THANKS

Welcome to the TDI club!
I wouldn't suggest .260's because they can be pretty smokey. Being as you're in the PDX area (I am as well) it may fail a visual inspection at DEQ due to excessive smoke.


As for your question about manifolds, I don't quite understand what you mean by "back draft of exhaust," are you talking about the EGR line that connects the EGR cooler to the turbo?

Sweet thanks for the nozzle tip. So when the exhaust is going through the manifold in the one that come with a vnt17 there is no separation between the exhaust pipes the exhaust valves on cylinders one and two(firing sequence 1,3,4,2)are open at the same time but since there is more pressure coming from cylinder one and draw pressure from cylinder two a small amount of exhaust goes into cylinder 2 before the valve closes leaving less volume for fresh air fuel mixture creating inefficiency, the same goes for cylinders three and four but to a lesser degree because cylinder four is be numer three. It's better explained by the YouTube channel engineering explained in his "mazda's secret to efficient turbo" linked below (hopefully).
https://youtu.be/nxVOyL4r7Qc

Ossan,
You don't need, or want, .230 nozzles, go down a step to .216.
My Wuzetem .230s are too much really for my RC4 tune at 26psi
with a LOT of air.

Kind of comparing apples to oranges there. Honestly the amount of exhaust that bakcflows into each cylinder at the exhaust manifold is so minute its not worth losing any sleep over it. Millions of these engines are out and about, some with Vnt15, 17, 17/22, with no issues.

Search and study the term “reversion dam”

Nero Morg said:

Kind of comparing apples to oranges there. Honestly the amount of exhaust that bakcflows into each cylinder at the exhaust manifold is so minute its not worth losing any sleep over it. Millions of these engines are out and about, some with Vnt15, 17, 17/22, with no issues.

Click to expand...

Like Nero Morg says, the tuning 'secrets' for high-reving gasoline engines do not
apply to these low-reving diesel engines. There are plenty of special techniques
that do apply that will keep you on your toes, though.