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Y2KGUII ZD Wgn
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Discussion Starter #1
I’m on a roll. Today I finished off my dual Dawes setup and quite pleased with it to, not automated like Chaz’s yet (many thanks for your input Chaz since I started looking at this a year ago), that’s another project for the future. Currently have a switch on the dash beside the driving lights and it all works well. I’m as happy as a dog with two d***s.


Low boost side is set at 8-10psi and not sure whether it is imagination (power of suggestion) but it seems a little smoother around town when taking off from lights etc, as though everything comes on a little softer than when on high boost, ??????? We’ll see.


Interesting when you drive on low boost then get onto a freeway and switch over, instant 100C EGT drop, much more noticeable then when I was using the needle valve.


Damn it’s getting harder to fit things under the bonnet in accessible places though.

But I love being a ZD30 Patrol owner.
 

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ZD30 Out - L77 In!
nissan patrol
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Aha! Well done mate. That should be ok provided you don’t nail it at the lights and overboost below 2000rpm. My automated system just makes that impossible to do as a safeguard, but I have been known to hit the high button at the lights for that extra bit of go. I agree the engine feels less stressed and quieter at lower rpm around town. Good work!
 

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Currently in PAD rehab
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... must look into that torque converter mod too ...
 

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Grenade Master
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Thread dig,
I finally managed to do mine, now I found myself looking at EGT gauge more than the road in front of me. ;)
I'm in a sort of tuning mode (currently set at 8 psi for low boost) to see how the fuel consumption pans out and than will try to setup some sort of automated setup. (if I could only find the link to that electronic gizmo Chaz is using ......)
Cheers
 

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Quote# Low boost side is set at 8-10psi and not sure whether it is imagination (power of suggestion) but it seems a little smoother around town when taking off from lights etc, as though everything comes on a little softer than when on high boost, ??????? We’ll see.

Hey Geeyoutoo, the whole dawes, needle valve, vnt screw adjustment set up seems to have some unexpected dynamics in my ongoing experience of searching for the perfect setting.
Your comments on lower boost setting via low boost side set at 8-10 is very much like my experience too. While I am only a single dawes set up, I noticed the other day that when I opened my dawes up to reduce max boost to 8-10psi, my spool up rate also greatly decreased through the 2-3k rpm range. Why is it so watson?? Interestingly I had to open my dawes up 5 full turns from my 15psi setting to get it around 8psi.
The dawes must start to leak a bit before actually dumping enough positive pressure into the vnt actuator to limit max boost, and in doing so it reduces the spool up rate (so I think anyway), actually helping the engine feel less laboured and more free to rev off the line and with a light right foot. I played around with mine considerably, nearly wearing out the bonnet latch, dropping boost right down, raising boost right up, and even disconnecting the dawes all together for a max boost of 27psi(out of interest). With the auto box particularly, it seems the adjustments have to be just right to get the desired result of not having too quick a spool up rate, and not being too sluggish for too long when cold, with the exact max boost pressure not to go into limp mode under moderate acceleration with pressure over 15 psi. If I change one setting, such as the dawes max boost setting, I also have to check and re adjust the spool up via needle valve etc. Not sure if the manual boxed patrols have quite as much trouble getting it right as the auto lives in the 2 to 2.7k rpm range when driven normally.
This is an interesting post to read, although I am not aiming on a dual set up:) cheers.
 

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Thread dig,
I finally managed to do mine, now I found myself looking at EGT gauge more than the road in front of me. ;)
I'm in a sort of tuning mode (currently set at 8 psi for low boost) to see how the fuel consumption pans out and than will try to setup some sort of automated setup. (if I could only find the link to that electronic gizmo Chaz is using ......)
Cheers

Try here

http://www.patrol4x4.com/forum/nissan-patrol-gu-gr-10/automated-dual-dawes-set-up-29107/

and

here

Frequency Switch - Jaycar Electronics

Grogey
 

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Q..................... With the auto box particularly, it seems the adjustments have to be just right to get the desired result of not having too quick a spool up rate, and not being too sluggish for too long when cold, with the exact max boost pressure not to go into limp mode under moderate acceleration with pressure over 15 psi. If I change one setting, such as the dawes max boost setting, I also have to check and re adjust the spool up via needle valve etc. Not sure if the manual boxed patrols have quite as much trouble getting it right as the auto lives in the 2 to 2.7k rpm range when driven normally.
This is an interesting post to read, although I am not aiming on a dual set up:) cheers.

Hi,

I've run a single dawes and needle valve for ages now. I can't say it was hard to find settings that suited. Once i nailed 15-16psi on the dawes which i did easily on first setting it up i then spent a few weeks trying different needle valve set ups. I found it easy enought o keep spool up as per Chaz's curve. It spools very stably and predictably. The only issue i had was, when once reducing spool to help economy. This was generally fine until i found, when going up fast hills, boost would die off when i'd back off a little to maintian the speed limit. The fall in boost led to higher egts. A half to full turn closed resolved that.

Might be worth cleaning out your dawes valve as i don't believe it should play any part until close to or at its bleed limit. If its not sealing well it will mess with your needle settings.

I still debate that the increase in egt i found when backing off slightly could have been more to do with the turbo doing less work as i backed on the accelerator. As in the the drop in temp across the turbo fell from say 200 under full load to maybe 100 under light load, therefore cylinder temps may actually have been failing as i saw post turbo temps rise. This is just a theory.

Grogey
 

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Y2KGUII ZD Wgn
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Discussion Starter #8 (Edited)
Quote# Low boost side is set at 8-10psi and not sure whether it is imagination (power of suggestion) but it seems a little smoother around town when taking off from lights etc, as though everything comes on a little softer than when on high boost, ??????? We’ll see.

Hey Geeyoutoo, the whole dawes, needle valve, vnt screw adjustment set up seems to have some unexpected dynamics in my ongoing experience of searching for the perfect setting.
Your comments on lower boost setting via low boost side set at 8-10 is very much like my experience too. While I am only a single dawes set up, I noticed the other day that when I opened my dawes up to reduce max boost to 8-10psi, my spool up rate also greatly decreased through the 2-3k rpm range. Why is it so watson?? Interestingly I had to open my dawes up 5 full turns from my 15psi setting to get it around 8psi.
The dawes must start to leak a bit before actually dumping enough positive pressure into the vnt actuator to limit max boost, and in doing so it reduces the spool up rate (so I think anyway), actually helping the engine feel less laboured and more free to rev off the line and with a light right foot. I played around with mine considerably, nearly wearing out the bonnet latch, dropping boost right down, raising boost right up, and even disconnecting the dawes all together for a max boost of 27psi(out of interest). With the auto box particularly, it seems the adjustments have to be just right to get the desired result of not having too quick a spool up rate, and not being too sluggish for too long when cold, with the exact max boost pressure not to go into limp mode under moderate acceleration with pressure over 15 psi. If I change one setting, such as the dawes max boost setting, I also have to check and re adjust the spool up via needle valve etc. Not sure if the manual boxed patrols have quite as much trouble getting it right as the auto lives in the 2 to 2.7k rpm range when driven normally.
This is an interesting post to read, although I am not aiming on a dual set up:) cheers.
After this thread was started (didn't think I'd see it again) I settled on 10psi as the low side setting. I don't use it as much now as my spoolup rate is quite slow since another mod and when I'm cruising I'm only around 6-9psi and getting good economy.

Sometime back we put it on the dyno and run both settings, funnily I had a big bounce off the Dawes opening on both high and low but it was huge on the low side, fitted a little surge tank at the VNT to defeat it. Max torque was basically the same but there was a 15hp difference in outright grunt between High and Low.

Not sure what you mean by opening the Dawes up, initially I thought you had readjusted it but then you say you had to open the needle 5 turns, so I'm a bit confused. If you do dismantle the Dawes have a look for oil in behind the spring, this can slow down the Dawes reaction. My pick up point was in the bottom of the pipe into the IC which would collect very tiny amounts of oil over a period of time (you can never fully stop it).
 

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After this thread was started (didn't think I'd see it again) I settled on 10psi as the low side setting. I don't use it as much now as my spoolup rate is quite slow since another mod and when I'm cruising I'm only around 6-9psi and getting good economy.

Sometime back we put it on the dyno and run both settings, funnily I had a big bounce off the Dawes opening on both high and low but it was huge on the low side, fitted a little surge tank at the VNT to defeat it. Max torque was basically the same but there was a 15hp difference in outright grunt between High and Low.

Not sure what you mean by opening the Dawes up, initially I thought you had readjusted it but then you say you had to open the needle 5 turns, so I'm a bit confused. If you do dismantle the Dawes have a look for oil in behind the spring, this can slow down the Dawes reaction. My pick up point was in the bottom of the pipe into the IC which would collect very tiny amounts of oil over a period of time (you can never fully stop it).
Hey Gu2. Sorry i didnt mention needle at all as far as I can read? By opening up, i did mean releasing the tension on the spring. Initially I had to stretch the spring to even get 15psi. I am wondering if a stronger spring might allow a crisper operation, but this may increase the bounce we get with hard throttle and quick boost pressure rises to the limit? Mine doesnt seem to have any oil in it. I do have it cable tied to the suction pipe of the air con however which is cold most of the time. I have just been well out of town again this arvo and am quite happy with the way its all functioning. Recent addition of a 3" system necessitated adjustment again:(
Would you do the dual dawes set up again? I am thinking its not really worth the mucking around....cheers old mate.
 

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Y2KGUII ZD Wgn
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Discussion Starter #10
Yes your right I miss read it....... 5 turns on the Dawes not needle, bloody senior moment. I drove for some time on my single setup for which I too had to stretch my spring (5mm) when I originally went for more boost. I would leave the spring as is, if you can hit 15psi when you want too, that's fine.

Would I do it again, Yes, but with qualifications, after a lot of refinement I rarely use my needle anymore but I would still do that again as it gives me increased flexibility especially when towing various weights in various conditions, as does the low side Dawes.

As said originally the low side was considerably smoother around the city, but with my very low spoolup rate there is not much difference between the two now, fuel eco is good as well but the low side does still have a slight edge, not as much as before though, but as indicated, those 15 extra horses have to be fed sometime............
 

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GU2, with the dual dawes set up, it seems your saying that your spool up rate slightly lower on the low dawes setting? If so, can you understand why? I can only think that with mine, by lowering the max boost setting to under 10, the ball leaves its seat under less spring tension earlier, affecting the vnt effectively just the same as opening the needle valve bleed a bit more?? Am I dreaming? Mine definetely spooled up slower and felt less laboured at the lower rpm's with the lower max boost setting on the dawes.
By the way, having adjusted my vnt just right before fitting the 3" system, I now have my needle opened about where it was before adjusting the vnt grub screw. I think I will tweak that again too so I can shut the needle again. Cheers.
 

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Discussion Starter #12
No, my spoolup rate is the same on both, as a matter of fact I reckon I could open the Dawes further on the high side and nothing much would happen as my VNT adjustment is probably more the governing factor now, I get absolutely no spike in high boost at all, not even 1 psi but I do get 1psi spike in low boost. For yours, also remember your getting to 8 psi fairly quickly no matter what and once that happens the boost bleed into the vacuum side holding the boost at 8psi is going to smooth out the operation.

Interestingly, I have found my engine to be much more tractable at lower revs with the lower spoolup, it took a long time to find the "Sweet Spot" but it was worth the hours of trialing. I have read similar comments by others who have done this, high boost/high spoolup doesn't necessarily mean all go.
 

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No, my spoolup rate is the same on both, as a matter of fact I reckon I could open the Dawes further on the high side and nothing much would happen as my VNT adjustment is probably more the governing factor now, I get absolutely no spike in high boost at all, not even 1 psi but I do get 1psi spike in low boost. For yours, also remember your getting to 8 psi fairly quickly no matter what and once that happens the boost bleed into the vacuum side holding the boost at 8psi is going to smooth out the operation.

Interestingly, I have found my engine to be much more tractable at lower revs with the lower spoolup, it took a long time to find the "Sweet Spot" but it was worth the hours of trialing. I have read similar comments by others who have done this, high boost/high spoolup doesn't necessarily mean all go.
This may be a helpful post for others also looking for that sweet spot. I have mostly had petrol engines and mostly older ford 6 and then v8s. Turbo diesel dynamics are very different, and looking for better performance is very educational.
As you say, high boost and particularly high spool up rate at lower rpms can reduce performance rather than enhance. Too much turbo work at not enough rpm's certainly makes the whole thing labour. Too little turbo and combustion and egt issues mean less performance. Getting it right accross the rpm range and still having enough boost to keep egt's in check under load is not easy to perfect. I guess that is what a proper ECU system ought to do:confused:

My situation when dropping my max boost via the dawes adjustment yielded and unexpected and significant change in spool up rate. It was not particularly noticable in performance at lower rpm as I already have a good spool up rate with about 8-9psi at 2k rpm under moderate throttle. But, when I unwound the dawes to give a max boost of 8-10psi rather than 15-16 psi, I noticed that at 2k rpm I had about 4-5psi not 8-9psi. I still hit max boost under moderate throttle at about 2.5k rpm and had about the same amount of boost bounce as the system settled in. My spool up rate was definetely slower with the lower max boost even before getting to the maximum.
Perhaps an additional vacuum tank in the vnt line may help control this. I get up to 2psi bounce and it usually bounces several times before setttling under full throttle. I am also using 4mm poly irrigation tube for my needle valve line with in cab instillation and have wondered if this size tubing causes some issues?
I have also noticed that having the needle closed fully and removing the needle valve and its tubing from the system at the vnt line tee all together also results in different spool up characteristics.
This thread is about dual dawes systems, and I had thought that might be the answer. Lower spool up to a a point, and lower max boost to a point certainly seem to improve fuel economy which I am chasing. But, having the max boost right is also vital particularly when pulling a heavy CT at highway speeds on long trips when the home is a long way off! With the Auto box, its really not possible in my experience to run a max boost over 15psi as I get limp mode when accelerating in second and third at moderate to hard throttle.

Still not convinced its worth the effort to go to duel dawes. Finding that sweet spot takes a little time and experimentation it seems. Cheers...
 

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I fitted the dawes and needle valve about 5-6 years ago and thanks to Chaz for taking a couple of my phone calls for help!

Ive always been confused by how it works, even after having it explained to me here a couple of times :doh: .

I just leave my needle on full and it seems to work great, it hammers off the mark and seems to go great on the highway. If i wind it down around town the egts just get high and it feels gutless, so i leave it flat out.

My main concern is damaging my engine but at 190k and nads fitted at 80k all seems fine, for now, i must admit the grenading is usually floating around the back of my mind.:neutral:
 

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I've got just the standard single dawes and needle set up. I've tried many different tunes but the last year or so i've be using a slow spool speed. I too have found the slow spool rate to yeild the best city driving and city fuel economy. When i backed my spool off i had to bump my dawes up abit to keep high load EGT's under control. After 3 years of experimenting with these setups i have found my current one to be the best.

Another note for those playing around with this that might be of interest. I've found if you use a really slow spool rate it can affect your fuel economy in a negative way too. It's about finding the sweet spot.
 

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I fitted the dawes and needle valve about 5-6 years ago and thanks to Chaz for taking a couple of my phone calls for help!

Ive always been confused by how it works, even after having it explained to me here a couple of times :doh: .

I just leave my needle on full and it seems to work great, it hammers off the mark and seems to go great on the highway. If i wind it down around town the egts just get high and it feels gutless, so i leave it flat out.

My main concern is damaging my engine but at 190k and nads fitted at 80k all seems fine, for now, i must admit the grenading is usually floating around the back of my mind.:neutral:
Apart from genading, fuel economy and drivability, I am also concerned for turbo life, given that in stock form, boost is often very low, and at cruising speeds too, hence the higher egt's with ECU controlled boost. I am loath to go back to the stock boost control, knowing that my egt's will be all over the place and considerably higher than under manual boost control. But, and it is an unknown but for me, will it negatively affect my turbo life running at a constant higher boost load???
Would a twin dawes controled system be beneficial in this regard? Perhaps, not much more so that running a slower spool up rate, and closing the needle a turn when needing a bit more boost? In my opinion, the manual control is good, certainly irons out some of the dead response at times with the standard system, but its not perfect, and the side affects on turbo life, extra blow by and fuel economy if not set just right make it a bit of a fiddling exercise. I speak from experience with Auto box only..:)
 

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Ok, bit of a thread dig.... but looking at going from single to dual dawes. I have the second dawes here ready to go, just need to get hold of the valve solenoid and I can get underway.

Can someone tell me where and what part no they've used for this. I just went to pirtek and described what I needed and he seemed to understand... but going by the picture in the book he was looking at, it looked nothing like the ones everyone else has used. Never mind it was going to be $59.00 + gst + air bag freight.... so almost $100 by the time I got it.

I know Pirtek are very $$$, but are they really this expensive??
 
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