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louie b

By louie b,
in Engines & Forced Induction

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louie b Community Regular

louie b

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http://m1117.photobucket.com/linkcodes/?mediaUrl=http%3A%2F%2Femob1117.photobucket.com%2Falbums%2Fk591%2FLouieb2%2Fimage.jpg%3Ft%3D1314743154&pbauth=1_uLEBonVPfaLdh1h3YMYz2e1EILJvGJo33A2pzSgrTZql7p%2FscAJPVCC62bFBgzkEH8ZnGZu7Dbhm355v9K9N70qolpGwlNdudLdbf%2F0sM9oKKO01Sa0D2jv%2FQZ%2B7yqIrYydsQF%2FOMr%2FlW6rekUTYyBm85Xb%2FEzulgxf5l0E%2F3yw%3D

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Lithium Grand Master

Lithium

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Hey guys yes VCT is turned off it was

Dropping off at hi rpm now it has another kick

He also said that the front pipe an pod are holding it back...

Peak power is more likely to be held back by your fuel system than your front pipe and pod. VCT can be turned off mid way through, so have it on until 5000rpm to boost your torque up to that point (you're definitely missing torque out down there), then turn it off to ensure that it maintains the same high rpm power you are currently seeing.

The reason it feels like a stout kick up high is before its lacking the torque the motor could be making up until 5000rpm, the engine is designed to rely on VCT to have a good spread of torque - you're potentially missing out on ~10% of the torque you COULD be making at 4000rpm, which you'd definitely know about.

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Lithium Grand Master

Lithium

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Was it fully tuned with it both engaged and disengaged? Dynoing with VCT off in areas where the engine is tuned with it on - or vice-versa, means that the tune will be off for the current state which could give a misleading indication of where the curve intersection point should be in an ideal situation.

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Room42 Proficient

Room42

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Was it fully tuned with it both engaged and disengaged? Dynoing with VCT off in areas where the engine is tuned with it on - or vice-versa, means that the tune will be off for the current state which could give a misleading indication of where the curve intersection point should be in an ideal situation.

When you say fully tuned, do you mean an individual tune either way? The comparison was done on mine with only one tune, the current one. I lost 20rwhp in the middle from having it off. It made no difference above 3900 so that's where we left it.

Also, DVS JEZ mr nissan would have worked out the vct switching point based on a car running 5 to 7 psi through a stock turbo with an entirely stock car. Its possible that when a car gets everything on it swapped over from the computer to the tailpipe that it would have a different vct switching point.

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Lithium Grand Master

Lithium

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Mr nissan would have spent alot of time working out the best VTC switching point

Probably, but when we are tuning non-factory setups with non-factory ECUs we don't have the luxury of using whatever rules Nissan implemented - nor can we be assured that they are calibrated to perfectly match whatever deviation we have from what they designed in the first place. We can't even be sure that they had our best interests (ie, powah!!) at heart, I know of other manufacturers definitely making decisions on this kind of thing based partly on how "exciting" it feels (often at odds to the outright best performing), emmissions, fuel consumption as well.

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