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Probably a question for Sydneykid...

My 33 came across to the Aussie side with an aftermarket Chipped ECU. The car was labled a freak cause it constantly made 10-15kw more than any other car with the same mods.

A strange thing occured to me, the VCT with the "chipped ECU" wasn't being activated untill 5000-5500rpm. Also was running massive timing advance. I am wondering if there is any advantage from doing this???.....I can't see how there could be unless it has a different inlet cam. Anyway felt really cool, sort of had three power bands.

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https://www.sau.com.au/forums/topic/24647-controlling-vct-on-rb25det/
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I thought the vct on thr RB25 was activated on startup and acted to improve low to midrange torque cutting out at some point in the higher rev range. My EMS computer is supposed to optimise performance by setting the optimum point to cut out the VCT to give the best output for both low and high revs

VCT on teh RB25 is activated in the lower/mid range

~2000rpm

Im running a Wolf v4, and while we were initially tunning it we had some time to fool around with the VCT on the dyno

We did a comparo by changing its activation point and basically the conclusion we came with is its best left where its designed for

We had it active "ala honda vtec style" higher up in the rev range and it wasnt as efficient in making power as it was lower down inthe lower to mid range

hope this helped

as whistla said it works best where its designed for.

i dont think the nissan engineer's put in that operating range because they can , they have spend a hellofa lot more R&D then any of us ever could..

if you want to help the VCT work more effectively try a adjustable exhaust cam wheel .

I was waiting to find this: http://www.tomei-p.co.jp/_2003web-catalogu...haft-specs.html or something similar until I posted:)

NVCS comes in just over 1000 rpm and cuts out at 4500rpm on RB25DET.

the best way I have heard of optimising NVCS is by doing two runs on a dyno, one with the NVCS switched on, one with the NVCS unplugged. Where the lines cross it the best point to switch off.

easy:D

Originally posted by Steve

the best way I have heard of optimising NVCS is by doing two runs on a dyno, one with the NVCS switched on, one with the NVCS unplugged.  Where the lines cross it the best point to switch off.

easy:D

This is exactly what i told my mechanic to do when programming/tunning the Wolf 3D. I believe that unless you change internals the optimum point is at the factory setting. This proved true, when tunning my car.

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