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You might say is kind of old school, but my navara has the same features. problably not on the same location but it has 2 solenoids and 1 or 2 butterfly valves.
If you block the egr and don't remove the butterfly, might cause trouble since the engine is not getting any gas or air at low and medium load.
So I think in order to block the egr, the whole system has to be modified as well.
 
Discussion starter · #22 ·
virgilio7 said:
You might say is kind of old school, but my navara has the same features. problably not on the same location but it has 2 solenoids and 1 or 2 butterfly valves.
If you block the egr and don't remove the butterfly, might cause trouble since the engine is not getting any gas or air at low and medium load.
So I think in order to block the egr, the whole system has to be modified as well.
quite correct. commanly the main butterfly is disabled. the butterfly is normally used to help pull in more EGR. but the down side is it causes a pressure spike which slows down the turbo. some of the guys fit blow off valves and it helps. however its much better to just remove the butterfly.
having the butterfly working shouldn't hurt. no problem fuel wise as the motor is runing very lean anyway. the worse thing is the lack of air can lower the effective compression a bit. most of the motors have the MAP sensor after the butterfly so the ECU controls the butterfly so it doesn't choke the motor to much. however the navarra has the butterfly by the turbo, before the butterfly so it can't measure the actual air pressure the motor gets. that may be a problem.

someone told me the ZD30 butterfly dosn't do anything. however i've just disconnected it and the motor seems to run a whole lot smoother in the low throttle range. i'll have to do some testing and see what conditions the valve closes.
 
Discussion starter · #24 ·
wrong valve.

there are 2 valves (not 100% sure on the 2.5 motor but they should be the same). the shutoff valve has a dual acuator on it and you will notice it closes when you shut the motor off (its what gives that nice smooth shutdown) and opens back up once the motor stops. its on the cross over tube.

the other butterfly is on the inlet manifold and shuts off one halve of the manifold. afaik its normally closed at idle and opens as soon as you touch the throttle. if you want to see what it goes like with it permantly open then simply connect permant vaccum to it by bypassing the solinoid.
imho its problerly left as is.
 
Discussion starter · #26 ·
tweak'e said:
however i've just disconnected it and the motor seems to run a whole lot smoother in the low throttle range. i'll have to do some testing and see what conditions the valve closes.
shows why you have to do testing. the difference must have come from the new tank of fuel as the solenoid i disabled doesn't alter the butterfly operation ! :shock:

please see http://www.nissan-navara.net/viewtopic. ... 5814#15814 for info on the butterfly.
 
Discussion starter · #30 ·
with the D40's (or anthing with variable turbo's) you have to watch you don't end up overboosting as a result of blocking EGR.
 
tweak'e said:
with the D40's (or anthing with variable turbo's) you have to watch you don't end up overboosting as a result of blocking EGR.
I don't know if mine do overboosting since I don't have boost gauge :? All I can say is I don't feel any difference. The D40 Manual shows that:
The EGR volume control valve remains close under the following conditions.
 Engine stopped
 Engine starting
 Low engine coolant temperature
 Excessively high engine coolant temperature
 High engine speed
 Accelerator pedal fully depressed

So, seems like permanently closing the EGR dont really makes much difference in performance.
I did this mod just to keep the intake manifold clean of soot.
(A cusco's catch can is on the way too for similar reasons)
 
Discussion starter · #32 ·
blocking egr does not change maxium power. it only changes power at part throttle ie at cruise.

before doing mods fit a boost guage and if you can fit an EGT guage. they are a must for modding turbo diesels.
 
tweak'e said:
before doing mods fit a boost guage and if you can fit an EGT guage. they are a must for modding turbo diesels.
Couldn't be more agree with this.
It will be my next step (ASA I manage to gather some budget.. :| )

The EGR mod is just I couldn't wait to do it as I though it wouldn't harm the Engine..
I'll set back the EGR and keep testing.

Thanks for the info.
 
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