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1 Dawes/Tillix + 2 needles, or just 2 needles, or ... 3 ! : better VNT Control for 3.0L

58K views 621 replies 28 participants last post by  nipagu72 
#1 ·
Thank you for bringing another interesting mod I would not have conceived of off my own bat!
At present I'm relatively happy with my dawes/needle setup compared to what it was like standard.
However, the thing that niggles me is the compromise between having a descent spoolup for driving and having to live with cruising at high boost.
What I've noticed is sustained high boost on cruise is both not needed and sky rockets the intake air temp. Its amazing how quick intake temps come down with a slow spool but then you loose driving response...
This mod I think will keep driving response with fast spool and enable intake temps to drop between duty cycles.

Sent from my Patrol using Tapatalk
If you want to test a far better arrangement leaving behind the limitations you just mentioned try this :
1/ PUT A NEEDLE BEHIND THE DAWES ( ie in serie with). MAKE THE DAWES TO OPEN MUCH MUCH EARLIER ( ie unscrew it almost to max, so that it opens as soon as some positive pressure is seen by the dawes ).

2/ SET THIS SECOND NEEDLE in such a way that you reduce the quantity of positive flow being injected into the vaccum hose of the actuator.

3/ DON'T FORGET to set again your first needle as you wish your spool-up to be.

This will make sure the vanes open continuously whilst RPM goes up, and wil get your VNT to work as it should, and not transformed into a stupid two-stage turbo.

Try and find the best arrangement to suit your driving and until you get a continuous rise of boost with RPMs.
Check the MAF value, as only FLOW matters, not boost !!! High pressure & little flow (MAF tension) means higgh back pressure and little efficiency. Smaller pressure and high MAF tension means high flow of air and fuel injected, and therefore POWER.

Your Patrol will run like never before. Believe me.

I have now thrown away my digibooster, and using my Patrol (2000) MAP to regulate the VNT with my own electronics, which allows me to get what I want when I want it.

But the three valves arrangement is the best and cheapest arrangement you can get. It mimics what an ECU would do quite accurately. And works beautifully once you have understood what you do with the valves.

Watch the limp modes though. If the flow of air you get is too high, MAF will be too high, and unless you control/reduce the MAF tension, you'll get limp modes if you push the flow too high. (note : the FLOW, not the boost).
 
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#372 ·
If you use the ball valve at 'max boost', it means the vanes will not open fully until that max boost, as set, is reached.
If you read carefully and watch the diagram above, you will notice that the point at which the turbo is more efficient, is with its vanes half opened ( which means a vacuum of around (-500 + -200) /2 = -350 mbar in the actuator hose.

Then, the vanes should be ( or can be) kept at that level until max boost is at reach.
Then the vanes have to be opened quite rapidly to keep the max boost under control.

What you can do first is to connect a vaccuum gauge on your actuator hose to see how your valves arrangement behaves, expecially when you reach max boost. and if you watch MAF value too, even better.

Most probably you will see that a different arrangement of your valves, with the boost needle a bit more closed, the tillix made to open a bit earlier, and regulating the flow with a needle behind it will ensure a better breathing (and MAF value) than what you have today.

Most of the time, your actuator should dance around -350mbar vacuum (+-50mbar), with reasonable boost, and only go higher (meaning -300 .. - 250mbar) under 'heavier' load.

Keep in mind boost is not necesarily your friend. You should find a place where you can do always the same "runs" and measure the precise time it takes, for instance, to go from 40km/h to 90km/h. Only those run will tell you if your arrangement is better or worst than the previous ones. Not just a glance at a boost gauge if you see what I mean.

Driveability (and MAF value) is definitely what matters.
 
#373 ·
another diagram with some more info.
What we want to achieve with valves will never be "perfect", but closer to what a proper and performing vanes management would do (in blue).

522752


Hope it helps your understanding.
If the Tillix "leaks", it is not an issue. The needle behind it will allow to regulate, and your boost needle and spool-up needle too. The more degrees of freedom, the better., providing you understand well which one does what.
 
#374 ·
Are you saying to set my tillex to open at less pressure than I currently have it (I do already have a needle after the tillix)?

Incidentally with my vac guage in the cab, I can see it sits predominantly at around 10 inches of mercury (350mbar)🙂.
 
#379 ·
sorry 10" Hg means 350mbar absolute, and therefore... -650mbar relative. so vanes are fully fully close if I am not wrong. if the case, not good.
Do you have a spool-up needle ?
No. My vanes are fully closed at 14" Hg relative



between 7 and 14 psi boost, my vanes are half-closed (= half-opened).
pwm is around 40%, and vacuum around -350mbar relative = 650mbar absolute = 19" of Hg
At 19"Hg my vanes will be firmly closed. I'm not sure why yours is different here but I know 2 others that are fully closed at 13-14"Hg so I think that is normal.
I am talking only in relative pressure/vac.
Is it possible your figure has been mixed up in translation?
 
#381 ·
Massive thanks to everyone, especially @Phdv61 and @OldMav

Took the truck for a decent run this morning..
Central Coast out to Penrith and back and I am ecstatic with the performance..
Pulls 5th gear up long, steep hills at 120 egts didnt go above 460⁰ and I had more too.
Cruising at 115 10-15psi on flat egts steady around 320.
It's amazing and I haven't had the ecutalk on yet.... Can't even imagine how good it's going to be once I get peak MAF voltage
 
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#382 ·
Really is good innit!
Just finished my second tank of fuel through it since doing it, and it looks like I'm getting slightly better fuel economy out of it too. My fuel light normally comes on consistantly around the 500 miles mark. First tank came on at 520, and yesterday 526. Thing is, I've been flooring it quite a bit more than usual whilst I experiment and get this thing set-up. Also, I haven't fully adapted my driving to take advantage of the extra torque, so think I can get further fuel gains once I stop messing with it and use a higher gear where it wasnt previously possible with one needle set-up. It's the mod that just keeps giving :)

Sent from my SM-A705FN using Tapatalk
 
#384 ·
@Phdv61 Just had to do it _ Decided to test out the Tillix + 3 needle arrangement. Did not have 3rd needle (for downstream of Tillix), so as I have done on other setups, utilized the Tillix thread leak design feature for bleed control.

Arrangement worked very well (was impressed actually), provided for a gradual rise of MAF along with the increase of RPM. The early MAP trace could be improved with introduction of the #3 needle (more +ve flow downstream into vac side) to provide greater control for gradual opening of vanes early.
Experienced no spike/dip of MAF/MAP_that is good. Will be doing more adjustment of all valves as is setup.

Max MAF 27 lb/min (200g/s) @ 3900rpm.
MAF 60g/s at 1500RPM under load, lugs well _ different units (onboard gauge).
Good drivability.
Max boost 20psi (spools well).

Is this Right
Set (adjusted) the #2 needle (one before Tillix to vac) _ at idle, applied a bit of saliva on end of needle outlet hose and set +ve pressure flow to provide a bubble that stayed formed for approx 1/2 sec before burst _ does this sound about the right flow setting. Room to play.

Run was 3rd gear (1500-4000rpm)

Any comments Phil...


522867
 
#400 · (Edited)
Phil, located the CRD MAF "signal wire" was the Yellow w/Green stripe.
After identifying relevant wire, came in from behind MAF socket and gentle slid a small safety pin in under the shrink band of the insulated wire and made contact with the core conducter (no physical damage and taped down pin in place).

Used multimeter placed adjacent to onboard UltraGauge (EM Plus).
Readings with veh stationary G/Box in neutral _ eng at running temp.

Actuals observed:
MAF (volts) / MAF RATE (g/s) / RPM
1.8/17/750(idle)
2.5/35/1450
3.0/60/2250
3.5/96/2950
3.75/120/3330
4.0/148/4000
4.1/160/4330
4.2/172/4000

Had to accelerate up at a faster rate to obtain the 4.2v / MAF rate. Assume that when engine is under loaded condition the MAF vote output would be greater_is that correct?
Max MAF 27 lb/min (200g/s) @ 3900rpm.
MAF 60g/s at 1500RPM under load, lugs well _ different units (onboard gauge).
As recorded under load condition MAF/MAP output run 3rd gear.
 
#385 ·
Hi John,

Hard to say.
Your Patrol is so different than mine, with a different turbo. But since you understand it all, you are the only one who can trial and test to achieve the best result for your Patrol.

I have modified my electronic firmware and software so I can modify my maps 'on the fly', and check the results on graphs and gauges. If only I had developped this earlier, I would have saved hundreds of hours of my 'learning curves'. That said, I had already found 'my' 'optimum' setting.

Needle 2 defines the slow opening of the vanes whilst revs go up.
If you open too much, boost will not build-up quickly enough, if you don't open them quick enough, boost will build-up quickly but you will have back-pressure, bad eco, high temp, and loose much more on MAF than what you gained on MAP. You now know that better than anyone else I suppose.
I can only suggest to find an arrangement which gives you a nice drive, and then explore around it how to improve it.
and go for your runs to compare with what you had before. Only judge of piece at the end of the day.

Sorry not to be able to help you more.
 
#388 · (Edited)
@Bidja
I found with the Tillix I didn't require the needle in its line either so removed it...
Yes with using the thread leak for positive air flow into vac seems quite well balanced. Found that just above 20 psi that the MAF/MAP did a sudden dip (sudden opening of vanes/excessive back pressure), so may benefit from opening Tillix a few psi earlier and adjust needle #3 downstream of Tillix to ease rate the opening of vanes a bit more. Then again 19/20 psi maybe most suited for MAF output_will need to test.

522901
 
#387 ·
@Bidja
You essentially have what I've been testing now except my tillix is set to open at around 11 psi. I'm going to change that to 20 and test .seems everyone is happy with that.

I've got the torque app working now and trying to get a handle on all the sensors available (not as many as I would have thought though). The max air flow I have measured is 180g per second. I guess that is the difference between your turbo and a std one. Also prob changes depending what size inlet piping the maf sits in. Mines 3".
 
#389 ·
@Bidja
You essentially have what I've been testing now except my tillix is set to open at around 11 psi. I'm going to change that to 20 and test .seems everyone is happy with that.

I've got the torque app working now and trying to get a handle on all the sensors available (not as many as I would have thought though). The max air flow I have measured is 180g per second. I guess that is the difference between your turbo and a std one. Also prob changes depending what size inlet piping the maf sits in. Mines 3".
With your Tillix plunger / seat leaking and using valve downstream you could have the flow adjustment with or without taping the thread (think you have taped thread).
If you are using the needle downstream, try setting the Tillix at 17psi and bring boost up with downstream needle adjustment(control vane opening early).

Torque App sensors _ Likewise for me, the BlueDriver Pro App that I use, is a bit limit on accessing sensors. More parameters are read by the ECU, but I think that Nissan does not allows user access to all.

Phil assessed some results of mine 6 months back and suggested 20% higher MAF
Discussion on Turbo's, MAFs, Limp.

The MAF valve displayed now is used as a "Ref /baseline" actual flow may even be more with induction changes (inlet ducting from airbox to turbo also 3").
Also prob changes depending what size inlet piping the maf sits in. Mines 3"
 
#391 ·
@trev zd30 Current setup_ i.a.w Phil's schematic dwg is:

#2 needle is fitted before Tillix_boost ref pick up from FMIC piping close to Turbo (cold side)_to vac
Tillix fitted but no downstream needle(#3)_Boost ref pickup in FMIC piping near inlet manifold adjacent to MAP ref take off(hot side).

Spool needle fitted(needle is Dawes 2 way flow) used a non return valve so functions as a Tillix needle.
 
#392 ·
@Bidja
I am running the same set up and I find it awesome. Now I have ecutalk im just getting it better and better. Only thing is I wish I could see AFRs but I guess you can't have it all lol
 
#393 ·
Guys, do not forget that
  • if you modified the diameter of your inlet tubing,
  • and if your MAF is plugger in a portion of the tubing with a wider diameter
the air flow seen by the MAF will be reduced, and the same with its voltage
any software converting the volts in lbs/min will be wrong, and will uder-estimate the real airflow.
Reducing the airflow seen by the MAF will get the ECU to ask less fuel to the IP, and will result in a loss of power.
If you had a remap, hopefully the tuner measured the exact airflow using a specific system and MAF, to set the fueling Maps of the ECU ( and may be not...).

Augmenting the diameter of the inlet where the MAF sits, on a stock patrol ( no remap), like adding diodes or a resistor to reduce its voltage, result at the end of the days into a loss of power, even if it allows to kill Limp modes.
Only a MAF electronic/software control or a REMAP can fix the limp "properly".
 
#394 ·
Guys, do not forget that
  • if you modified the diameter of your inlet tubing,
  • and if your MAF is plugger in a portion of the tubing with a wider diameter

Reducing the airflow seen by the MAF will get the ECU to ask less fuel to the IP, and will result in a loss of power.
If you had a remap, hopefully the tuner measured the exact airflow using a specific system and MAF, to set the fueling Maps of the ECU ( and may be not....)
I believe the tuners here factor in for the increased diameter in inlet piping when remapping.

The factor is not that big given most upgrade to 3" intake piping, but if you measure the standard MAF housing, it's nearly 3" anyway.

Tuners also have the option to recalibrate the TPS and give it more sensitivity
 
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#395 ·
If the turbo vanes are properly managed, I am not sure modifying the piping brings a lot more air in the stock turbo. The 2052 map shows a maximum of 22-23 lbs/min at 18psi, I suppose with no restriction in the inlet diameter...
I wish I new how 4.45V of MAF voltage convert into lbs/min, but I would bet very close to this maximum.

As a matter of interest, tell me the direct measure of voltage you get at the back of your MAF, and the corresponding lbs/min reading that you get on your software. That will give me a point of reference to be able to convert my MAP(bar) vs MAF(Volts) into MAP (bar) into MAF (lbs/min) and superimpose it on the 2052 map to see how my current setting "prints" on the 2052 MAP, and if I can improve the VNT management even further. for fun.
 
#397 ·
which year is yours ? 2008 ?

never mind the turbo. What I need to establish, is the conversion table between volts and lbs/min.
If you can provide several points, even better ( 3V, 3.5 V, 3,75, 4V, 4.V1, 4,2V, 4,3 V ). I will interpolate between them with a polynomial curve, and it will do. may be the lower points will match the ones of the curves I found on the net.
We'll see.

Edit : from 2005 onwards : red wire, ECU pin 35. MAF back : pin 4, red too.

522920
 
#399 · (Edited)
I did not find the info in this thread. It looks like the wires have a different color...

The one showing between 1.6V and 2.1 V at idle is the one.

found this attachment :
 

Attachments

#408 ·
I have reported your points, and extended, the internet curve I found :

View attachment 522959
Hi Phil, understand now that you were only wanting to use my MAF signal voltage / MAF rate so to obtain a correlation between the two so you could calculate a MAF rate against your MAF signal volts recorded.

And yes, I only use the MAF rates observed as a means of identifying the magnitude of change against a set baseline ref measurement (my build). ECU remap was live with current induction setup.

To capture the MAF signal volts was a good excise and have left pickup terminal in place_may hook up gauge.
 
#403 ·
here is a first printout of gears 1,2,3, for MAF converted into lbs/min with your conversion data.
Standard inlet, stock turbo, stadard MAF housing, DYI VNT electronic management
I can get MAF to reach 4.35V at 3049 RPM without pushing hard. PLENTY of air. Real MAF at idle 2.16V, corrected at 1.8V. from 2,45V, MAF_out to ECU =MAF_in except when limp value reached (capped to MAF limp value until RPM exceeds limp threshold). Never drove so well.

522960
 
#404 ·
Phil, the MAF data that I supplied, with only eng load applied (vehicle stationary), values would be much lower that what you have obtain when:
I can get MAF to reach 4.35V at 3049 RPM without pushing hard.
Would the accuracy of the data conversion factor used be in question (very approximate as engine would be operating at a different load/torque rating as compared to your readings?.

eg: the data I supplied with MAF volt reading say MAF @ 3.8 v provides_ 16.5 lb/min (125g/s) @ 3500rpm (veh stationary_minimal load)
as compared to my actuals when doing 3rd gear run MAF/MAP runs provided_ 25 lb/min (190g/s) @ 3500rpm (say 50-60% eng load)

Can you help me understand the data comparative accuracy and relevance when the actuals are captured under different operating conditions.

Also can you go back to basics and explain what you have done here so we all better understand(good learning to be gained)_be much appreciated.
 
#405 ·
Hi John,

1/ As said previously, since your inlet tubing is modified, your MAF cannot measure the airflow in absolute.
2/ I am not sure the 'response'" of your MAF is identical to my own NISSAN MAF which has a different reference.
Therefore it is even harder to compare.
3/ what is comparable is definitely what some one, like geeyoutoo, with a similar Patrol, of the same year, and the same MAF reference would get as MAF voltage at different RPM. But Geeyoutoo also modified his inlet tubing.
So unless the portion which carries the MAF is the original one ( same surface), data can't be compared either.

I have compared my data to someone else's with the same MAF and Patrol but fully stock, and my MAF voltage is around 0.3V higher. meaning more air. I can exceed 3.55V at 2000RPM, .... and see 4.4V at higher Revs.
NO REMAP, NO MORE FUELING at this stage. It is what I was looking for.

When you have the ECU managing the VNT ( even when helped by valves ), the "regulation laws" and parameters which drive the opening/ closure of the vanes are NOT under your control. So you get, at the end of the day, what your ECU decides to do, + what you add with your valves, which may also have an impact on what the ECU does.

Ì hope you follow me...

What is important to me is NOT to see that you can get little air ( little MAF value) under no load, and more MAF value under a bigger load - that is a given - but what MAXIMUM MAF voltage can be reached by modifying your setting, for a given load. Simpler to do with MAX load ( hence the graph I draw which provides MAP vs MAF coded in RPM over a few minutes of driving. So I can see the max MAF value for various RPMs.

More load means more fuel, more exhaust gaz, more air, more MAF voltage.
Maximizing MAF voltage whatever the load and RPM, means that the flow of air is always maximized. It is the reason why you have a turbo, and here a VNT in particular. Max power is obtained when the maximum air can be gained, and the right fuel mixture can be applied to keep a good combustion and efficiency. more air + more fuel = more power.
As soon as you have "power on demand", you just press the pedal, air inflow is maximum, which means you can add more fuel, and your Patrol is more "responsive" = nicer to drive.

Not sure if I am clear enough, as I am quite simplistic here. But you surely catch the principle.
Cheers
 
#406 ·
3/ what is comparable is definitely what some one, like geeyoutoo, with a similar Patrol, of the same year, and the same MAF reference would get as MAF voltage at different RPM. But Geeyoutoo also modified his inlet tubing.
So unless the portion which carries the MAF is the original one ( same surface), data can't be compared either.
Hi Phil, just to clarify. Yes my intake is modified pre MAF housing and post MAF housing, I stayed well away from bigger aftermarket MAF housings for reasons of stability. I drew up and dimensioned the std pre and post 2004 MAF housing and the aftermarket verson to get a complete picture of how the system worked, from this I did trial machining out a std housing and also creating a 25mm bypass of the MAF housing to reduce MAF voltage and hence limp, yes they had an impact, but at an all round cost so threw those trials out and went for electronic solutions that clipped voltage where I wanted, not across the board, the remap Harley did being the crowning glory.

My ECUTalk allowed me to document many aspects and therefore improve performance. I'm not a Hp whore, those days are well behind me, driveability for touring was my goal and I have achieved that.

As has been witnessed many times, it is amazing what Hp/torque can be pulled through a std MAF housing, but, 3L engines of our vintage are not renowned for producing both massive Hp at reasonable rpm and massive torque down low, compromise is the key.
 
#407 ·
Hi Ross,
all this is well understood.
I just wanted to explain that only calibrating MAF voltage vs quantity of air can ensure a correct knowledge of how many grams of air are sucked into the cylinders.
On a stock car, that is done during the design and dev phases. any mod modifies these maps.

Like yourself, I am not after HP, but happy to get “free” additional ones if available, and a nicer driveability.

I was pointing out that we cannot, unfortunately, compare our MAF voltages since our Patrols are from the same year, but differents in configuration.
 
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