Power Valve Actuator (PVA) Mod

Engines and Engine Systems
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Blitzpatrollie
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Re: Power Valve Actuator (PVA) Mod

Post by Blitzpatrollie » 28 Oct 2013 19:50

As far as I know this valve is there to limit the amount of initial torque put on the gearbox and diffs, and I can see why that is, you really have to nurse it out of the blocks otherwise you spin the wheels. Really loads of torque. Would make sense to me that Nissan put this there to protect the gearbox/diffs, which they would have to guarantee for a length of time/distance from new.

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Re: Power Valve Actuator (PVA) Mod

Post by Gerrit Loubser » 28 Oct 2013 21:53

No' there are much cheaper ways of limiting engine torque on an electronically controlled engine than fitting an expensive valve and actuator to the inlet system.

As far as I know, the valve simply adjusts the effective length of the inlet manifold to provide lengths that are closer to the optimum, both at low and at higher engine speeds. As such it would not make sense to fiddle with the system unless it is malfunctioning. Think about it: why would Nissan spend money to add a feature to the motor that makes it worse when they were not forced to do so?

To the guys who have fiddled with the operation of the variable induction system: Are you sure that you have actually made things better? Have you measured this improvement properly? Are you sure it is not the placebo effect at work?
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Re: Power Valve Actuator (PVA) Mod

Post by JohnBoyZA » 29 Oct 2013 05:03

"Are you sure it is not the placebo effect at work?"

Man I need to find a dictionary... :think:

Loving this thread, but not sure where it's going :wink:
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Re: Power Valve Actuator (PVA) Mod

Post by Coltenator » 29 Oct 2013 07:10

Did this mod +- 3000km back and found no real improvement on fuel consumption.
There is a slight improvement on bottom end torque , but nothing to go bonkers about.
I found the cruise control bypass mod was more helpful and really works well , especially while towing in manual mode in 4th gear
and really easy to do :mytwocents:
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Re: Power Valve Actuator (PVA) Mod

Post by Wheels » 29 Oct 2013 08:48

Did this mod and had it on for about +- 6000km and found no real improvement on fuel consumption. Changed back to the original setup.
There is a slight improvement on bottom end torque but no real reason to do the mod.
I think on the manual box you might see more change in behavior. The auto box seems to soak up the differance and no fuel saving there.

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Re: Power Valve Actuator (PVA) Mod

Post by Tinus lotz » 29 Oct 2013 21:53

It changes the lenght of your inlet manifold that only happens after about 3.500 rpm but we dont normally drive there

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Re: Power Valve Actuator (PVA) Mod

Post by Blitzpatrollie » 07 Nov 2013 20:55

Hi guys,

Okay, my fuel consumption was right down to 3.9km/l, so reversed the mod. @Gerrit, no placebo effect there, definite loss of low end torque on going back to pre-mod. I still figured that the vehicle is heavier on juice than it should be, so I cleaned the MAF sensor with Electrokleen (Spanjaard), and on Monday did a trip from Nelspruit to Kwamhlanga and back, and over 550km, recorded fuel consumption of 6.46km/l, which I think is great considering where I was.

Another thing, after my major service at Nissan Nelspruit, I was told that my Oxygen sensors are sharp (I specifically asked them to test them for me). So today I was looking for a fuel leak (which there was, on the subtank hose), so thought i'd check on youtube how to test an oxygen sensor. So I plucked them out and tested myself, both of em stone dead. The one sensor's wires had NO insulation left so was not sending the ECU any voltage. And the %&$#ers at Nissan reckon its all good.

So I went over to Bosch Diesel, and bought 2 universal senssors for R590 ea incl VAT, and installed them. Noticably smoother on idle, haven't test driven yet, but I think surely the engine was overfuelling to compensate for the lack of voltage sent to it from the sensor. Time will tell and I'll let you know. I'll post a new thread explaining how the universal sensor differs from the one that was in.

Anyway, not to get off topic, my point here being that I did the PVA mod in the hope of saving fuel, but there are other things to check, MAF, O2 sensors etc. DONT TRUST YOUR STEALER IF THEY TELL YOU THE SENSORS ARE OKAY!! CHECK THEM YOURSELF!!

The link to the vid that demonstrates how to test the O2 sensor is here:

http://www.youtube.com/watch?v=QM2jO0_Cah0

Cheers!

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Re: Power Valve Actuator (PVA) Mod

Post by Clem » 08 Nov 2013 04:44

Interesting - thank you. Let us know what happens with your fuel consumption.

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Re: Power Valve Actuator (PVA) Mod

Post by JoshJ » 21 Aug 2017 17:51

Hi Gaven,

What was the outcome of the sensor change?

I was just chating to Tinus and them about the huge surge in power once you go over 3500rpm and we eventualy ended up on this topic. So I just read the thread. And was wondering on your sensor outcome.
My Patrol idles a bit rough. Might be those sensors?
Being alive is a Blessing!!

Regards,
Joshua

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