NVCS on HI CAM...Help..

[sidewaymambo]

Someone might able to give me some idea, thanks..

I found a set of Tomei cams, 264 IN/EX..and the IN cam stated support NVCS..however from my understanding is the NVCS won't work if you change to after market cam gears...so does it mean to let the IN cam works well, I need to use the stock cam gear for IN cam and after market cam gear for EX cam?

thanks..

Phillip

[GTS-t VSPEC]

Phil,

Yes, that's my understanding. But with aftermarket cams I see no point in keeping the NVCS anyway.

See'ya:burnout:

[sidewaymambo]

could you tell me a bit more why I don't need to keep the stock cam gears? thanks

[GTS-t VSPEC]

With aftermarket cam gears and cams you can dial in the desired response you want. There doesn't appear to be any advantage to the NVCS once you have gone for a different set of cams.

See'ya:burnout:

[Sydneykid]

Hi guys, we have Tomei cams (256's on both inlet and exhaust) in the R34 GTT, it has an adjustable camshaft pulley on the exhaust and runs VVT on the inlet. It makes 260 rwkw using a GCG Hi flowed R34 GTT turbo. The camshafts were designed to work with the VVT, so it has a very nice power powerband. They only added about 8 rwkw to the max horsepower but around 20 to 25 rwkw through the range. They also removed that flat feeling you get on high powered RB25DET's just after they come on boost. Off boost performance is also noticeably improved.

Having driven this car a number of times on the street, drag and circuit, I reckon it is simply the best all round standard internal RB25DET I have seen.

Bottom line, if you are going to put some new camshafts in your RB25DET, then buy ones designed to work with the VVT, I reckon it is definitely worth it.

Hope that helps.

[sidewaymambo]

Hi, GTS-T and SydneyKid..thanks once again..

So Sydneykid..does the R34 GT-T you refered, pickup the cam shaft and cam gears bolt on together and the VVT works straight away without modification?

the reason I ask is that the cam shaft I have specfied / stamped as support NVCS, but I could not find the Tomei cam gear support NVCS..

I rang some workshop, and been told need to machine the tomei cam shaft / tomei cam gaer to support factory VVT / NVCS, and this really confuse me..

did I overlook some where...thanks in advance..I will try to take some pics of the cam shaft and post tonight..

[JNR24]

look forward to that post sidewaymambo

[GTS-t VSPEC]

I think Sydneykid is using the stock inlet cam gear, as this is the one that uses NVCS, and any adjustbale cam gear on the exhaust side, as it doesn't affect NVCS.

It will depend on whether your after maximum power or streetable power. If your after streetable then follow Sydneykids directions.

See'ya:burnout:

[sidewaymambo]

Thanks GTST, I was thinking keep the stock cam gear for the inlet side with the tomei inlet shaft...but hope there is one cam gear can support NVCS and that's will maximise all benifit from this mods..

[GTS-t VSPEC]

I believe you can have the factory cam gear slotted, so it makes it adjustable, not sure if this effects the NVCS though.

See'ya:burnout:

[sidewaymambo]

So, what's on the R34 GTT? SydneyKid? thanks

[Sydneykid]

This is son of Sydneykid

hey sidewaymambo

Between the two of us i can definately say that we have never seen an adjustable cam on the inlet of an RB25DET. So that answers that question.. it is simply never done.

I believe that VVTi is a similar to adjustable cam sprokets, on VVTi makes them infinitely adjustable... but i ain't overly sure

Son of Sydneykid

[Steve]

Sorry this is a little off topic,

What cam manufacturers make cams that support he VVT - I was told that if I go aftermarket cam on the inlet (in this case HKS) I would have to loose the VVT?

[sidewaymambo]

to SydneyKid and GTST:

I have been thinking this as well...and I believe the best way is install the IN cam gear and compare to the stock cam gear..IF my turbo (T67/TD06-25g) is going lag as hell, I want to see what NVCS can help at low~mid range, and what after market cam gear can do. Does it sound like a good plan? What you recon?

My mods at moment are stock engine with stock boost, Trust cooler, Pod filter, 3" Fujitsubo system , PowerFC

Parts ready to bolt on: TD06-25g, trust ex-manifold, Front pipe, Nismo 550cc injectors, large fuel pump, fuel regulator, Q45 AFM, ProfecB..

But sure, I will have those mods on get a figure and graph and compare after the cams / gears on..looks like a long way..we will see..

Thanks to all.

to steve: if VVT = NVCS, then as first post, that Tomei make them..

at bottom of page..cheers..

http://www.tomei-p.co.jp/_2003web-catalogu...2_cam_RB25.html

[Steve]

Sidewaymambo, yes it is - thanks very much. Something that may be worth considering with the NVCS - an adj inlet cam gear is usually only about 1deg adjusted, so it wouldnt make much difference - as far as I can tell?

[GTS-t VSPEC]

Usually 2deg advance on the inlet cam gear. I have a set of cam gears coming for mine next week (TRUST). I was just planning on putting the Exhaust gear on, but I might do both, to see the effect of removing the NVCS.

See'ya:burnout:

[Steve]

If you want to see the effect of removing the NVCS, just unplug it for a while:)

[GTS-t VSPEC]

Yeah, but then your not advancing the inlet cam gear, so it's not a reasonable comparison.

See'ya:burnout:

[Steve]

True, do you know how much the NVCS adjusts timing by.

On the power fc, peak hold gets states the timing advances something like 40 odd degrees, cant remeber exactly, but its not a small figure.

[GTS-t VSPEC]

I have an aftermarket computer, so can't I advance the timing via that instead of with the NVCS?

See'ya:burnout: