ZD30 DI boost with nads

[june]

have been in archives [zd30 di turbo egt] and was wondering wether I have set nads up correct. dawes/needle valve have been in for several months now and seems to work how it should. [it was set up by chaz link] I notice in some of the posts that hwy driving[100klms] a lot of you are running boost around 10 psi. my boost doing 100klms is 12psi . this boost will stay at this reading cruising down the hwy. is this what it should do. I thought it might vent off down to 5psi and start climbing again. maximum boost is 14psi. egt are between 250/280 degrees c. I am happy with the set up but just want to check.

[threedogs]

That's sounds fine ,my is 10psi @ 100kph, My max is 15psi and temps re the same.
I'm happy as with the way mine performs atm.
Very crisp and perky might be the term

[Sir Roofy]

Hi june what you have there is pretty good each moter has its own charcteristrics so woudnt worry to much
if you want to fiddle with it just turn the dawes down a hair width to get what you want

[threedogs]

If you feel 12psi is a tad high for 100 kph back off
the Dawes one full turn only and see how that goes.

[mudski]

No need to back the Dawes off, just back off the needle valve. Backing the dawes off will alter the maximum boost level. Opening the Needle valve will correct the cruise boost level.

[june]

thanks guys this is very interesting. you guys have been around for some time now and your advice is valuable. so I got roofy and 3D saying back off the dawes and mudski saying open needle valve to correct cruise boost. please note I am mech minded but average so explain in simple terms. so mudski what does setting the cruise boost do? as I said in first post boost stays at 12 psi does this change it. and 3d and roofy how do I know if boost is too high when cruising. all I know is doing the nads has stopped the high boost spikes and dropped egt down.

[mudski]

O.k The all the dawes valve is for is to take away the ECU's control of the boost limit. So say for instance, you set it to 15PSI, which is what most people set it too. The needle valve controls how fast the turbo spools up. Wind it up too much and you will see your boost quickly go up and past your 15PSI, usually around 2psi higher it will go, and then settle at your maximum 15psi level. Don't wind it up enough and you will see how long it takes for your turbo to create the desired amount of boost. And you will feel it too, the car will go like a slug.
Whilst cruising at 100k's it is best to have the boost sitting around 10psi, too low and your EGT's will go up, too high and your just wasting the turbo's effort for no gain at that speed.
So think about it. If you back off the Dawes valve all you are going to do is change your maximum boost level and still probably get 12psi at 100k's.
I, only last week, had my boost at 12psi at 100k's. Its been that way for ages and I just got lazy and didn't do anything about it. Even though it takes a whole 2 minutes to do. I backed off the needle valve, took it for a spin and now it sits spot on 10spi, my "boost bounce" has gone too. I can floor it and it stops dead on at 15psi.
Before I did this actually, I will say that I was hitting "limp mode". ONLY, whilst dragging out 3rd gear up to hills in my area. I could drive it any other way, floor it hard or drive like like Roofy :) and it would hit limp mode. After opening up the needle valve this has gone too.
So take note. If you ARE getting limp mode and your boost is set at 14-15psi, try opening up the needle valve a little too.

[june]

now that's what I like! someone that can put it into plain English. when driving normal on road that is! going through gears on my troll boost goes to maximum set boost of 14 psi and settle back to 12psi on hwy. so if I tweak with needle valve to 10 psi will it help with egt.[reminder that I am only average] and no I don't get any limp mode since fitting nads

[threedogs]

I've been playing with my boost for a while now, not to go against Mudski
but I set my boost of 10psi at 100k via the Dawes and Chazs' rule of thumb
Then with needle valve closed and idling open the needle valve till arm on turbo moved,
I then locked it off, and to be honest my patrol has never run this crisp or hard since I've had it
3yrs. Won't be fiddling any more, seems Like a dyno may be a waste at this stage as happy as.

[mudski]

@ June, your EGT's a good now. Don't worry too much. But remember, Higher boost = lower EGT's but there is a point where the higher boost becomes useless. Like cruising at 100k's. Your over working the turbo for nothing.



I've been playing with my boost for a while now, not to go against Mudski
but I set my boost of 10psi at 100k via the Dawes and Chazs' rule of thumb
Then with needle valve closed and idling open the needle valve till arm on turbo moved,
I then locked it off, and to be honest my patrol has never run this crisp or hard since I've had it
3yrs. Won't be fiddling any more, seems Like a dyno may be a waste at this stage as happy as.
Not to go against TD the almighty. But if you set the boost at 10psi, it will be 10psi period. With the dawes there is only one point you can set it at. Thats why the needle valve comes into play. Kinda.

[june]

i did the same 3d I set it up as chaz. so what I will do is take mudski advice and adjust needle as pretty happy where max boost is. so to lower boost with needle do I turn it anti clockwise and how much. eg. 1/4 turns or full turns.

[threedogs]

With the needle valve closed ,idle engine and slowly open needle valve watching turbo, as soon as the actuator arm begins to move[fall away]
nip up lock screw on needle valve. as per Chazs' directions. I seriously cannot fault mine ATM, in a nut shell its flying. I get 12.8 around town BTW.
Not bad for a 4x4 with 200k on it, it drives like a new one imo. I'm very happy

Not everyone has the needle valve fitted.
Which ever way you turn it do it in 1/2 turn sectors remembering which way you went.
From what youre saying I would screw needle valve in 1/2 turn like closing it off and see what happens.
You should restrict turbo spool up rate, IMO I cant see how it changes boost

[Choicebro]

Hi Guys,

Just on the topis of needle valve and dawes does anyone have someone they recomend for doing this on the south side of brissy.I will need to put the gaiges in all so probably the pillar pod set up. Whats the cost approx for this. This is our first fourby so pretty new to this sort of thin. I have a chip and exhaust fiited already and know i need the gauges. Any info is much appreciated. Cheers.

If someone down my way is open to offers of beer and cash to help me install this is also an option.

[threedogs]

Give nissanewby a pm he may be able to help if not point you in the right direction

[june]

i can't fault mine either 3d but reading a lot of post most are running 10psi down the hwy. I did set it up to chaz's instructions. I will try what you said and close needle valve to see if it will drop boost.

[mudski]

With the needle valve closed ,idle engine and slowly open needle valve watching turbo, as soon as the actuator arm begins to move[fall away]
nip up lock screw on needle valve. as per Chazs' directions. I seriously cannot fault mine ATM, in a nut shell its flying. I get 12.8 around town BTW.
Not bad for a 4x4 with 200k on it, it drives like a new one imo. I'm very happy

Not everyone has the needle valve fitted.
Which ever way you turn it do it in 1/2 turn sectors remembering which way you went.
From what youre saying I would screw needle valve in 1/2 turn like closing it off and see what happens.
You should restrict turbo spool up rate, IMO I cant see how it changes boost
It technically doesn't change the boost, as the dawes does this but whilst cruising at a constant rpm adjusting the needle valve will, in a way, change the current boost level at that range by opening or closing the VNT slightly.
I will never doubt the knowledge of others and Chaz, but to my own findings on what I did last week, I have proven to myself for this to be right, as I had 12psi at 100k's, max boost set at 15spi. All I did was open the needle valve more and my boost at 100k's went down to 10psi. Like I said I will never doubt others, TD and Chaz have a lot more knowledge than me but my findings don't lie. I am happy to be told I am incorrect.

[june]

all i can do is a play with it. I try with the needle valve first. if I get it wrong I will set it back up like I did in the first place. [chaz link] at least with these posts I have more understanding of how dawes/needle valve operate. i'll keep you all posted on the outcome thanks

[threedogs]

You may now need to fine tune it a bit more. As you said if your happy with the way it performs,
you can return to those settings. I just kept putting boost in till it limped, then realised my leaking IC
couldn't be helping, more boost more leaking. After fitting new welded IC I needed to remove boost to
the point where I had no limp. At the stage now where I feel it can't get any better.

[june]

i tried mudski idea by opening needle half a turn and it did do what he said. ended up with 10psi boost down hwy .egt went down approx 5 to 10 degrees [hard to say as gauge is digital] . still not sure if I should leave it like this or go back to the chaz method. maybe when I did it chazs way I locked needle valve off too early when watching arm on turbo move.

[june]

i ended up starting all over using chaz instructions and I did lock off needle too early. I took note where valve was locked off originally and was out half a turn to its new position. this has got it 10 psi @ 100k's and max boost is 15psi. mudski idea was right. it is a fine line in setting needle valve especially when i'm half blind. thanks guys

[threedogs]

Great to see you have it sorted, when you say half blind
is it blind like 2.5 prescription lens or bottom of bottle blind LOL.

Edit;;; you say you have digital gauges, do they flicker or pretty well stay still

[june]

Pyro is the only digital gauge, it is quite sensitive, eg, cruising down the highway with the slightest amount of throttle it could go between 250-270 degrees C and if I had my melon in a schooner glass, I would have got the needle valve right the first time around. LOL

[threedogs]

You'll have to do a fuel run now to see what you achieve.
ATM I'm running 305 MTZs and returning 12.8 per 100 around town,
so pretty happy that's for sure. My other set of wheels are OE mags with 285s
Cooper ATRs. But not sure if they will better my fuel figures

[june]

once it stops flogging down with rain i'm heading up to sunny QLD. so I'll have plenty of testing time and fuel figures cheers

[threedogs]

Keep safe, look forward to your next post,