[OldMav]

Just a point to consider @Phdv61 with the minimum leaver set screw. I have a turbo dyno machine which is used to set VNT actuators against absolute flow values, so it is very VERY accurate. Setting the minimum lever set screw you can go past stall point of the vain's which will not drive the turbine wheel actually it is very sensitive less then a 1/32 turn to go from stall to flow with turbine wheel speed picking up considerably if you fluke the right setting. The dyno test machine has the ability to set turbine flow volume at absolutes using temps and barometric values with pressure. Using Nissans set spec for vacuum and rod travel even with 4psi pressure flowing into the turbine the VNT will stall with less than 1/8 of a turn out on the limit screw on a new std ZD30 turbo.

I cannot comment on your setup or the altitude change and difference to this limit screw position as i have no need too, we just dont have a need here in AUS for this attribute. But with your second needle valve and setting minimum vacuum at start would go a long way to get the vain's out of stall quickly and effectively.

I like and commend you for thinking outside the square on this subject, the second needle valve has huge potential and merit. Closed VNT vain's until max boost will not drive compressor volume i have proved this on the turbo dyno bench test machine. The vain's must open through acceleration and can be set as to not hinder spool or boost pressure rise. Boost pressure rise and boost spool is not a measure of a turbos ability to flow volume fast, but density is. As you have found out with your playing with MAF values you can get a lot more flow in spool with less boost pressure. SOOOOOO many pundits just cannot get this concept with turbo charging. As you may be aware its contributed to EMP exhaust manifold pressure and density efficiency of the compressor wheel and its drive power requirement and its start efficiency RPM. Your STD ZD30 comp wheel is not very good at building density or volume until 85,000 rpm and then some, boost value has absolutely nothing to do with this ability, its about turbine drive and EMP. Your STD cast comp wheel was never designed or could be cast in a fashion to build density with volume early like modern CNC machined billet comp wheels.

The STD turbine wheel and VNT design is quite good but doesn't have the drive capacity or phi values to meet the requirements of the heavy cast comp wheel for altitude changes you are talking about, a light billet CNC comp wheel in a similar configuration will be a lot more forgiving at altitude changes with flow volumes.

My interest here and for your idea is to have a mechanical system using current equipment to control the VNT on the auto fitted ZD30 patrol. These auto partols have a few issues due to the auto always imposing load on the engine even when changing gears so the turbine VNT never gets a chance to unload the EMP when using the mechanical control system. Consequently driver input of lifting your foot and depressing in traffic will send the EMP through the roof which leads to deceleration surge which will kill any turbo in the very short term. This little turbo has a small thrust washer and very close together bush bearings which is not very forgiving of deceleration surge.

The CRD auto version using the vacuum solenoid has programming to pop the vain's open for a split second when you lift your foot to release EMP using the TPS as its input. Fitting a mechanical VNT control systems will not compensate for this so the auto patrol will always be susceptible to deceleration surge and turbo complete destruction. Some remap tuners do use the vac solenoid and will get your results if they can understand how a VNT turbo works and its short falls. The Di ECU doesn't have anything close to the adjust ability the CRD versions have auto or manual.

A final note of advice on your playing with the minimum set screw i would suggest you set it back to Nissans spec of -0.68psi at 0.2mm and adjust no more than 1/32 turn from there. It really does make a huge difference on spool volume and mainly transitions on all on road driving conditions. With your trial and error you may already be at this setting. Nissan did do a lot of R&D on this turbo to suit the ZD30 engine especially the Di version. I believe this R&D was done in Poland on a turbo test machine exactly like and brand as the one i have at my disposal.

And again i commend you for thinking outside the box, that is very rare even for engineers.
But there is always a down side here when playing with stuff you done have full and complete appreciation on. I highly suggest to others here to not play with the set screw its very VERY much a tiny weeny turn of the screw to not doing as you expect. But if you must, buy your self a good hand operated vacuum pump with gauge and set the bloody screw as per factory spec to start with as from experience they are never correct. Then have a play with different positions using the pump and gauge as a guide. If you have already played with rod length then you need to set the rod length using the other two Nissan vacuum spec and clearances.. Even then you are still in no mans land as you cannot set the initial minimum flow setting Nissan has set for turbine flow against vain position for this ZD30 engine and its exhaust gas flow and temp volume. This can only be set on a VNT flow bench as Nissan do or more precisely Garret Do. Also different tunes and timing and fuel values will change exhaust gas volume and pulse so adjusting the stop position for a higher tune engine will require a more open vain position not a more closed vain position. Timing is a huge changer on exhaust gas volume hence spool / drive and volume flow through the turbine. So setting the screw and rpm open positions can be set using MAF / MAP values within reason, so thats a very good guide given by @Phdv61.

Off note i understand you are French so your written word can and is a little difficult and can be read with different than intended meanings i had trouble understanding your instructions hence i asked Ross to Email you on instructions with explanations and drawing, you did very well and cleared up much of my interpretations. Maybe our prominent learned ZD30 member miss read a lot of your writings, i see he has retracted much of his comments now. Hope he sticks around to add his perspective and maybe a trial experience using your concept.

 

[Phdv61]

Hi @OldMav,
thank you so much for taking the time to provide such detailed info. Greatly appreciated.

yes, I am french, and my apologies if sometimes It is hard to understand what I am trying to explain. I am editing my posts all the time when I read them a second or third time, and think I am not specific enough ( or just to correct spelling mistakes ).

I have discovered all what you are mentioning over 18 months of studies, work, and tests, doing some retro-engineering as I had absolutely no data about my ZD30 Garett turbo ( and no knowledge about how it was working...).

I have experienced too when changing my exhaust to a 3", that the difference in back-pressure was implying to modify the minimum vanes aperture, and that less than 1/8th of a turn had a huge impact. My starting point at sea-level, 1013 mbar, is therefore at 53.5% pwm. At 55.9%, the lever is pressing a lot on the original setting of the limiting screw...

The beauty with electronics, is that I can now set the pwm value very accurately at all times, according to any law, and any sensor valur, and therefore maximize the airflow which is the objective. Not boost. I am glad I found someone to confirm ( even if normally, more boost gives more airflow, if backpressure is not going "to the roof").

My limiting screw is now useless to me, apart from preventing the vanes to close too much and damage my turbo. in case of actuator or other bits and pieces... failure.
But, the same way I had to open slightly the vanes at 0 mbar "boost", I can still close them a bit more if the ambiant air pressure is much less. and even more if the ambiant pressure is VERY low. Don't you think ?

The nice thing with the Nissan MAP is that it is absolute, and can be used as a barometer

To do that 'altitude test' with your dyno, you would need to have a huge reserve of vacuum at -300mbar, and place your turbo inside, and then start absorbing flow at that pressure whilst making the exhaust wheel turn... Or go high in the mountains. I have no dyno, so I went high in altitude to do testing, and improve the spool-up at low (and very low) ambiant pressure.

I can ensure you all of us who have been driving in altitude feel the lack of power, due to air density being very low, and the turbo not spinning until you reach 0 mbar boost. I doubt Nissan engineers did that test, going in altitude ( and where too by the way ?).

So I think, their setting and test is just done at sea level, more or less. And I fully agree, at sea level, DON'T TOUCH the limiting screw if you do not have a suitable and adapted electronic vanes management.

If they were to go at 3000m, they would see that they could close the vanes a bit more, and that they would see no negative impact, all the opposite. You can get the turbo to spin quicker and earlier, but you have to open the vanes continuously until you reach the standard setting at 0mbar.

So be ensured that, as soon as the boost starts building up -300, -280, -260... I open the vanes gently until I have 0mbar boost, and I am at the sea-level setting. It works beautifully and my lady is now drivable.

For the auto, I have to think again, but during my test I was able to get the surge you are mentioning on my Manual T, which you get easily with a one-dawes-one needle if the setting is not done properly. And the same if the vanes close too quickly if your max vanes closure is not properly adapted to your Patrol configuration. May be I am wrong, but you can hear that noise very clearly.

If the vanes are opened correctly at all times (ie electronically), I think you can get rid of this even on an auto.

One of the members of another French 4WD site invented a dual actuator mechanical system, connected to both inlet manifold and exhaust manifold, to make sure that EMP was not high at all times, opening the vanes as soon as EMP builds up too high.

Last but not least, if you have an EMP sensor (apparently you all have one), it would then be matter of acquiring (digitizing) it and taking it into account into an electronic vanes management system.

Sorry again if I am not clear or 'arrogant'.
I do my best.

 

[Phdv61]

I forgot :
on the AUTO, the three valves should work, and you should not get the surge you are mentioning, as the second Needle will make the vanes more open, for a longer time when you depressed the throttle. So EMP will not build up suddenly,

Edit,

like what they do with a dawes set at a high pressure. In fact, as soon as the boost is below that maximum, the vanes will close almost fully and suddenly, hence the surge. And as a result, your unique option was to 'sacrifice' spool-up by opening your Needle.
I know, I experienced that, and was not happy at all with it.

And yes, I said TWO needles. The spool-up needle needs to be there to adjust the vaccum level like for the one-dawes-one-needle. Therefore, any slight positive pressure flow coming in will start making the vanes to open.

End of EDIT

The difference being that you might be able to have an even more "agressive" spool-up since the vanes will start opening much sooner.

And try the two needles, with an even more agressive spool-up, as vanes would start to open as soon as boost builds up. I am convinced you'll be able to get something better than what you have today, for sure.

It won't be as good as a properly tuned electronic vanes management, but far better than the one-dawes-one needle arrangement.

 

[Phdv61]

@OldMav , each time I read your email, I found another interesting question to answer.
You say ' on the auto, you have no time to unload EMP'.

One idea : use the 'pedal up' TPS/ECU signal to control a solenoid letting fresh air in the vacuum hose.
This will drive the vanes wide open, letting all EMP away.

Originally, I had implemented such a feature in my electronics, by detecting, much eariler than 'pedal-up', a maximum reached in boost/RPM, and opening the vanes for 300ms roughly to achieve that very purpose.

But I do not need it anymore, as my electronic management does not need to have high boost to get high airflow.
Even with the stock turbo, with its old design and 'imperfections'.

I'd love to play with a modern turbo

 

[Phdv61]

@Bidja ,
I edited my post in answer to your 'how to get MAF' data ?' on page ...7.
In fact, ECUTalk gives you RPM and MAF on older ZD30. And you can write those to a .csv file.

On true OBD2 Y61 Patrols (from 2005 or 2006 onwards), ELM327 compatible, you have plenty of available software to acquire and display lots of data and sensors.

All what you would need to do, is acquire such a data file, making sure you only 'tick' RPM and MAF (and MAP if you have access too), so that you can then draw the result using an Excel spreadsheet and importing the file.

If you have difficulties, you can PM me anyfile, and I'll do it for you.
Do not acquire more sensors, or otherwise the sampling rate will be too low ( number of measures per second), as the limit is the 9600bits/second of the OBD2 or OBD2-Consult port.

Reason why I developped a separate real time acquisition software running at 115 200 bits/s to better see what I was doing... with real time graphs.

 

[Bidja]

@Phdv61 installed 2nd needle and have need to do further adjustment to achieve satisfactory result.

Note: VNT actuator set at 13.5”Hg (just below 500mbar) for lever to touch vane limit stop screw. Use hand operated vac pump with gauge.

Observations: (compared against run using only Dawes + 1 needle_initial run)

Left Dawes and 1st needle set as per initial run (Dawes 300mbar and needle adjusted to provide max boost @ 24psi.

Installed 2nd needle (spool), set @ idle, open needle so actuator rod just starts to drop (lever off stop) and then closed needle ¼ turn(normal practice that I use to set full manual boost control spool rate).

Interesting, with introduction of the spool needle and no change to the boost controller and 1st needle, the max boost dropped from 24 to 16psi. Adjusted max boost Dawes needle back up to 24psi and then was only ¼ turn off valve seat. With only a ¼ turn of adjustment left and with a small increment of closure (1/8th of a turn) the boost would rapidly go >30psi (off scale). Was so touchy as compared to when no spool needle was used.

Ran well lugs at 13-1500 rpm @ nom 10psi(much same as initial run and VNT vac sol/Tillix_info), Cruise (100kph) 10-11psi down from 12 (EGT up from 300 to 350C and haul / test hill EGT rose from 420 to 500C(not good), VNT vac sol / Tillix do this at 420-450C).

What do you think?

Thinking of giving it increased spool rate and checking boost behavior.

Maybe reduce Dawes from 300mbar down to 200mbar out of interest, and

compare operation against Tillix and needle valve(normal manual boost control _ @ max boost 24psi).

Edit: For Interest_timed run 60-120kph/4th gear/33" tyres):
Tillix/VNT vac sol _ 14sec
Tillix / max spool _ 14 sec
Phdv61 Dawes/1 needle (max spool) 12 sec
Phdv61 Dawes + 2 needle (current 1st run) 15 sec

My onboard UltraGauge can measure RPM, MAP and MAF via OBD11 but cannot save or transfer data. Will speak further re data collection after a few more trial runs.

 

[OldMav]

Just remember you dont make power with low EGT, its not about lowering EGT its about stable EGT at peak load. That being 550 post turbine or 750C pre turbine. If you could have 550C for every Rpm valve that would be ideal. If your EGT stabilizes at 500C post turbine at peak power then that is a very nice safe compromise. Any lower is wasting exhaust temp expansion to drive the turbine. More temp equals more gas volume that can be used for turbine drive to get more compressor volume, that isn't boost value either.

 

[Phdv61]

Bidja,
encouraging start, although I find it strange your 12s phdv61 vs 15s phdv61 difference in your runs.

You should, again forget about 'MAX boost' for a moment, and look at MAX AIRFLOW with "phdv61" settings.
Watch the MAF value as a priority, and maximize it, even if boost is lower. You don't mention your MAF values by the way, and how they compare to what you had before.

I see no reason, if properly set, for you to have a 12s run with Dawes +Needle, starting with a vacuum at 950mbar (no spool-up needle), and having to wait, once the dawes is open to get -500mbar in the vacuum hose to start opening the vanes, unless, the sudden opening at +300mbar boost is enough to make the vacuum jump in one go at -500mbar, regardless of the Needle limiting the flow behind it. What do you think @OldMav ?

YES Needle behind dawes is VERY touchy, as vanes fully closed is around -500mbar vacuum, and vanes fully open -200mbar. So setting has to be very accurate, so that the opening is not too fast, not too slow. 1/8th of a turn seems more than normal to me.
Setting vacuum using a solenoid, you cannot imagine how 0.5% pwm make a hell of a difference at say, 2200RPM, and can give you a BIG variation in boost and/or airflow.
I had to adjust my electronics and sw at almost 0.2% pwm accuracy, to eliminate any peak or drop and get precisely the boost I wanted at given Revs/speed ( 80km/h, 110km/h cruising) or under load ( hills)

Yours being a CRD, I understand the fueling on that one might depend, unlike 2000 ZD30, upon both MAP and MAF value ? Possible ? I don't know, sorry.

Otherwise,I recommend not to exceed 18psi at something like 1800rpm under load to start with or you will most probably build-up back pressure. Only watching the MAF vs RPM will tell you if your setting is correct or not and if you managed to get the maximum airflow.

I believe you need to work further on your Dawes + Needle behind dawes setting, as well as your spool-up Needle to get it working as it should. I think you should be able to get the same good 12s run ( if CRD ECU is not that much different from 2000 ZD30 ).

Also, you should be able on your 08 CRD to find proper software to be able to store sensor data on file.
cheers

 

[Bidja]

YES Needle behind dawes is VERY touchy, as vanes fully closed is around -500mbar vacuum, and vanes fully open -200mbar. So setting has to be very accurate, so that the opening is not too fast, not too slow. 1/8th of a turn seems more than normal to me.
Setting vacuum using a solenoid, you cannot imagine how 0.5% pwm make a hell of a difference at say, 2200RPM, and can give you a BIG variation in boost and/or airflow.
I had to adjust my electronics and sw at almost 0.2% pwm accuracy, to eliminate any peak or drop and get precisely the boost I wanted at given Revs/speed ( 80km/h, 110km/h cruising) or under load ( hills)

OK the sudden change of boost (as a reference attribute) is caused,

at the point of vanes fully closed is around -500mbar vacuum, and vanes fully open -200mbar

?

The 1/8 turn was an estimate to convey a concern of where a change was dramatic ", it was actually when dawes needle was moved only the slightest amount at that point that caused a sudden rise of boost.
I then now should observe how MAF value is influenced at that point?

The info you provide here does assist me to further understand.

Will now demand a new screen on UltraGauge to:

Watch the MAF value as a priority, and maximize it, even if boost is lower. You don't mention your MAF values by the way, and how they compare to what you had before.

Will do.
To be honest I have not concentrated on MAF values for last 12 months as most of my efforts have been concentrating on actuator adjustment to suit progressive changes to my induction setups(using pwr/Torque/EGT and timed run attributes) for assessment of performance change/improvement throughout.

Thanks.

 

[Phdv61]

if the slightest change make a dramatic change, you may have something wrong somewhere.

So let's go to basics, and forget about performance at his point.
You need to understand precisely what you get, and why, when you change any setting.

Reminder : the spool-up needle defines the max closure of the vanes point.
If you have a limiting screw which is properly set, and ONLY when you have your Dawes + Needle connected, Dawes set-up to open at 200-300 mbar + Needle open enough so that some flow goes through, you set up your spool-up Needle to have the rod gets more or less where it was before at idle. This will ensure a starting point of vanes closure IDENTICAL to what you had before. Then, and only then, will you be able to increase spool-up a bit more by closing it a bit more.

Once spool-up Needle is set, level of vacuum in the actuator hose is somewhere between -420 and -500mbar.
You can then drive, and check how the MAF value goes up, and the boost builds-up.

If it is too quick and/or too high, open the Needle behind the dawes a bit more. And vice-versa if the MAF increase and/or boost increase is too slow. Don't try and reach the boost you had before for the same RPM at the moment. Be patient. Watch MAF voltage at all times.

Once you are comfortable with the driving you get, try and explore the effect of closing a bit more your spool-up Needle, to increase spool-up. Keep the max boost at the same level by opening a bit the Needle behind the Dawes.
Feel comfortable all the time. Take your time.

Once you will 'master' both effects ( spool-up & max boost ), at say 20psi max at 2000RPM under load ( for the sake of setting a known point on the curve ), watch the Maximum MAF value you get on gear 3 for instance (manu),and the value you get at 2000, 2500 and 3000RPM.
Then you can 'play' with your valves to check the effect of any partiular mod you apply, on the MAF voltage. Find the maximum you can get.

Depending upon your inlet tubing, your exhaust, your IC, your remap and fueling tables, you may find YOUR 'best point', and you'll see the boost you are at. It could be less than before. No worries. It is not an issue. only MAF matters. Clearly with real-time graphs, it would be much quicker and easier. But you will have to do with what you have access to.

I am sure you have understood the principles behind all this. And @OldMav does better than I do, so he might be able to guide you better than me, as he speaks and write a better Australian than me

The unknown to me is what a CRD ECU does, and what sensors it uses to manage vanes and fueling.
On my old lady, MAP is unused.

 

[geeyoutoo]

@Phdv61 on our old girls you can disconnect the MAP and nothing changes, did this way back in testing, you cannot do that on a CRD.

 

[Bidja]

@Phdv61 Do understand the method for setting up full manual boost control (Dawes/Tillix + needle valve for spool rate control). Very similar as required for your setup with only minor variation.

Must say though, including the procedure/process info for setting your VNT boost control is as important as providing the schematic diagram for the install. Cool

For Info_I am not hung up on operating at the max boost that the turbo can provide and do not wish for that. The turbo that is used can produce in excess of 30psi but for engine longevity and reliability, boost has been limited to nom 25psi. Happy to operate at lower levels.
This potential for 30psi boost is reason why I opened the Dawes (300mbar) bleed needle so to get an appreciation of where 24psi was and then knew the acceptable control max limit.

Once spool-up Needle is set, level of vacuum in the actuator hose is somewhere between -420 and -500mbar.

Another good reason for vac gauge in line to actuator but near as same for vac applied to set for lever to hit vane angle limit stop which complies.

When I first installed your setup with max spool (no 2nd needle)

Went ahead an hooked up a Dawes+needle (without use of the 2nd needle valve), prefer to run my CRD at max spool with manual boost control set up. Used a compressor to set Dawes at nom 300mbar prior to install, adjusted to the ear and listened for initial release of air thru Dawes. Installed with the use of spare needle valve that was in cab. Found it very easy to set max boost @ 27 psi. Can confidently obtain max boost >30psi with good control.

Will check vane limit screw stop with feeler gauges and vac hand pump next service as FMIC piping in the way.

Will do some testing over next few days or so and will let you know result.

Couple of pics of set up mate and do run 76mm tubing from airbox to turbo.

 

[Phdv61]

Ok @Bidja

I believe I understand what is happening with your Dawes+Needle behind, no spool-up needle setting (what you call max spool-up):

When you do not have the 'spool-up' Needle in your arrangement, the vanes in reality do not open from 300mbar as the level of vacuum needs first to reduce from -950 mbar (full vacuum) to -450mbar (more or less start of vanes opening, if this is the level of vacuum at which your rod starts to move).

It means that your vanes start to open at quite a higher boost (may be 700mbar ?). And it looks beneficial because your current 'max spool-up' is, in fact, far too low and can be increased quite a bit, even if your vanes opened sooner than what you have with you dawes-unique needle setting, and well below your max boost setting. clear enough ?

The very fact you have gained 2s compared to your other runs is very encouraging to me. It means there is plenty of 'left over' air to recover.

I don't know the characteristics of your turbo, nor how your screw limiter was set, but this is the direction you have to investigate.

As I mentioned earlier, with one-dawes one needle, it is the same effect of too high a spool-up which leads you to open a bit the spool-up Needle at the expense of spool-up... of course.

NO need here, as the vanes will start opening much sooner. the factory setting maximizing the spinning down low is to be used at sea-level.

So if I were you, I would increase the spool-up to start with, playing then with the second needle to adapt the rate of vanes opening.

cheers.

 

[Bidja]

Yes, we refer to max spool when you operate with the spool needle fully closed against seat or have solenoid to block off positive air flow into vac line to actuator or no needle valve fitted.

It means that your vanes start to open at quite a higher boost (may be 700mbar ?). And it looks beneficial because your current 'max spool-up' is, in fact, far too low and can be increased quite a bit, even if your vanes opened sooner than what you have with you dawes-unique needle setting, and well below your max boost setting. clear enough ?

Agree.

At present with spool needle set for lever to hit stop at nom 500mbar, I have 1.8 turns of turns of spool needle remaining to close against valve seat. I will explore increasing spool to maximise MAF against RPM and attempt to maintain boost at 20psi @ 2000rpm with Dawes needle.

 

[Phdv61]

THIS IS IT ! You definitely need to increse your spool-up down low. with the 3 valves arrangement, and get your turbo to start spinning earlier down low.
Keep us informed, but I am now very confident. and you should be able to gain even more time in your run when properly set.

 

[Bidja]

THIS IS IT ! You definitely need to increse your spool-up down low. with the 3 valves arrangement, and get your turbo to start spinning earlier down low.
Keep us informed, but I am now very confident. and you should be able to gain even more time in your run when properly set.

With the introduction of my h/f turbo the main reason for adjustment of my actuator rod length was to get the turbine to spin up faster of which after many hours of trialing, have achieved a good spool result IMO the need was driven by the fact that the turbo was not set up on a flow bench at the start.
Use to run a 600x300x76mm T&F top mount cooler that required a 12.5 "Hg for lever to hit stop and now same core size (bar & plate) front mount cooler that provide a different drive which suits me and is set at 13.5"Hg. This 13.5"Hg setting for FM was also driven by the introduction of the 4" thru air box with K&N 9" pod filter and 4" snorkel (breaths well).

Look forward to more testing with you boost control.

 

[Phdv61]

I understand all that.
But you may need to think outside your current 'box'.

The real issue is that your ECU software, unless modifed ( and I am not talking 'maps' here ), was not written for your configuration. And the difficulty is to know what it is doing. We can only guess.

When you say you have optimized your spool-up, you have done it with your ECU opening the vanes the way it was programmed to do. So unfortunately, you will have to start all over again, since you are now the one deciding when you want to start opening the vanes, and at which rate (second needle). You can even start opening the vanes from boost 0 if you wish by getting rid of the dawes !

That has an impact on where to set the 'initial' spool-up.
You may understand easily that if you start opening the vanes at boost zero, and not boost 10spi, you may increase the closure of the vanes at idle, as, as soon as you press the throttle, boost will start buiding up and opening the vanes !

So the good run you have experienced was due to the pneumatic opening of the vanes at higher boost than what the dawes was set at. I am sure you have now understood the reason why, and why you have to play with your limiting screw too.

You have one more degree of freedom to use now.

By the way, I got the EGT-Exhaust manifold feedback from my friend Vincent running a two Needles only setting.
over one hour of recording and different runs, maximum reached was 617°C on a long run at 3500RPM climbing a hill with max boost set at 18psi. But at 110km/h flat motorway no wind, that guy was gettting 400mbar boost , little throttle used and a very stable 300°C.

 

[Phdv61]

Last but not least, if you have shorten you rod, your ECU may not be able to open fully the vanes by now.
Shortening a bit the rod is useful when you experience a little drop with Revs going up when ECU is still in control.
That happens when the ECU is opening the vanes too widely, at a given MAF/MAP value.

My rod is set at its maximum length, pushing the lever to vanes fully opened when motor is off. So I have all the possible range available to me.

 

[Bidja]

Phil, actuator rod starts to rise when 5"Hg is applied and when I remove actuator and rod assy I am sure the vane lever arm does not drop at all so assume vanes can open fully. My actuator function is very closely to within Nissan spec but will check stop screw position as @OldMav referred.

Will continue to trial 3 valve set up to obtain a satisfactory result before embarking on an other configuration(eg: 2 needles without Dawes).
Thanks John

 

[Phdv61]

Excellent. I am confident you'll get the most out of your patrol configuration now.