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nissan
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Discussion Starter #1
Reading some of the other threads has got me thinking...

Since I setup my dawes/needle valve I've found that all my adjustment on the needle valve is within the first 1/4 turn. It's fairly difficult to explain, but basically as soon as I open the valve the actuator arm drops away from the stop screw very quickly, up to about 5mm at 1/4 turn.

From there, you can open the valve all the way and the arm will slowly drop down through its range until the valve is fully open.

All my adjustment seems to be in that first 1/4 turn... Haven't done extensive testing (as it seems to have been working as it should).. If I open it further I get very little boost until quite late in the rev range. From reading all the NADS literature most talk about adjustment in 1/2 turns.

I've replaced the vacuum lines in the control system, as well as the vacuum lines under the intercooler which didn't do anything. Am contemplating trying a different needle valve out of curiosity.

Any of the NADS gurus had anything similar? Is this normal behaviour? As I said I haven't worried about it as it seems to be setup nicely at the moment, just something interesting :)
 

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What valve is it? Mine is a pirtek job 1/8 th.it has pretty fine adjustment. Off the top of my head it almost 10 turns from seated to fully out. Ill confirm this later.
Its the same as geeyous.he may be able to add info too.
So the finer the adjustment the more turning required.
How many turns from seated to all the way out on yours?
 

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Y2KGUII ZD Wgn
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What needle valve do you have, I have the 6 turn Italian valve and it was quite sensitive when I was using it. There are various valves available, I came across one last year that had 3 turns and you only had to crack it to get a reaction, on the other hand Darren's new valve has 10 turns available so it is much less sensitive to small adjustments.

You also have to take into account the minor variations you will find between each vehicle/turbo setup. I would not be too worried about that at all, 1/4 turn is doing its job.

I/3 turn down (.3mm or 0.010") on my grub screw took away the need for me to use the needle at all, so small adjustments are not uncommon.
 

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Discussion Starter #4
Cool, thanks... that more or less confirms my thoughts that it is normal.

I'm pretty sure mine is an Italian job, from memory it takes about 6 full turns until its fully wound out. The question of if it's normal or not has been nagging at me for about the past year, but as you say it is doing its job.

I might relocate the valve into the cabin so I can play with it a bit more on the fly.

Given how much of an effect very fine adjustments to the VNT arm have, I can certainly see how people get into trouble when they dive straight into fiddling with the grub screw.
 

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Update yes shy of 6 turns. 3/4 of a turn got me to a bees whisker off the grub screw. Then a further 3/4 turn out where mines been for a long time
 

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Y2KGUII ZD Wgn
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Cool, thanks... that more or less confirms my thoughts that it is normal.

I'm pretty sure mine is an Italian job, from memory it takes about 6 full turns until its fully wound out. The question of if it's normal or not has been nagging at me for about the past year, but as you say it is doing its job.

I might relocate the valve into the cabin so I can play with it a bit more on the fly.

Given how much of an effect very fine adjustments to the VNT arm have, I can certainly see how people get into trouble when they dive straight into fiddling with the grub screw.
You won't regret moving it in the cab, not that I think it should be adjusted constantly, that is not realistic or recommended, just the fact that it gives so much flexibility under a range of circumstances you may see in doing further mods, or just trying to improve fuel eco under low load circumstances.
 

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Mines in cab. Ive said it before i live at sea level 1007hpa. I work at 600 odd mts above sea level 934hpa. I wind my needle IN quater of a turn as i get to moss vale to achieve same spool and response.
Good...bad tuning on the fly?I dunno but air gets thinner up there :)
 
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