Deleting Vct/vvt For Cam Upgrade?

[Reflector]

Hey all,

First up YES I have searched the forums and google thoroughly and have not found a conclusive answer to my question, secondly please don't come on here asking - 'Why are you deleting VCT? It's better for low-mid range blah blah' because I'm upgrading to cams that are not compatible for VCT for a higher powered build.

Currently building up my R33 RB25DET to support (aiming towards) 300-350rwkw on Pump 98. I know that is a huge variation in a power figure but I am not banking on a specific number, the engine/mods are being build to support that power but as to how safe the end result is is ultimately up to the tune/tuners.

The head is away getting ported/polished/dedagged etc... and I am buying a set of Camtech cams - specs as follow:

IN/EX 272deg

IN/EX 9mm Lift

No vvt/vct on inlet

My question is. With the head off, is there any additional welding/filling up of oil galleries in the head in order to delete the VVT/VCT? Or is it just as simple as removing/blocking up the existing sensor? I don't particularly want to have the sensor hanging out the side of the head when it's not in use as I was hoping to just screw in a threaded bung.

I have the two adjustable cam gears ready to go and the aftermarket ECU is a Link G4.

Edited December 3, 2012 by Reflector

[GTSBoy]

Are cams even needed?

[Simon-S14]

Head work in general isn't need for that power level

[Reflector]

Are cams even needed?

Not when the motors in pieces, thank for the input

Head was coming off anyway. The port/polish job was something we decided to get done while it was all apart anyway. It's only going to be beneficial

in the long run.

[GTSBoy]

I ask my question again, for those that apparently don't understand English that well. Are cams even needed? As in....at your proposed power level, is the benefit of a WILD CAM worth the downside?

I propose to you that it is not and that you would be better off with less WILD CAM and more VCT.

[Simon-S14]

to answer your question its as simple as removing the VCt gear and cam and putting new cam in along with the new cam gear. no welding required.

as for the solenoid, you coild just fit a bung i guess

[Reflector]

I ask my question again, for those that apparently don't understand English that well. Are cams even needed? As in....at your proposed power level, is the benefit of a WILD CAM ™ worth the downside?

I propose to you that it is not and that you would be better off with less WILD CAM ™ and more VCT.

Perhaps I took your answer as sarcasm because I'm use to people having a stab at others assuming they know nothing. I retract my comment and YES I understand english and had I of known you were referring to the size of the cams I wouldn't have assumed what I did. The cams in question will be beneficial to my situation. Put simply, the more air flow + more fuel = more power output. Having the head ported + the increased flow due to the cam, the more power I will achieve.

to answer your question its as simple as removing the VCt gear and cam and putting new cam in along with the new cam gear. no welding required.

as for the solenoid, you coild just fit a bung i guess

Thanks Simon, this is what I was hoping for.

[R31Nismoid]

What turbo is being used?

What porting being done?

What RPM is being used?

Those 3 generally come well into play at the time of cam selection.

[GTScotT]

We all like to go the whole hog when building a motor but honestly your cam choice and suggested power output are poorly matched.

The cams you have mentioned indicate something along the lines of: power starts at 5000rpm and revs to 9000rpm.

For myself, if trying to build the fastest 300-350kw RB25 I could it would sport both VCT and 256/9mm Poncams.

If you built an identical car, and ran 272/9mm cams at the same suggested power level I can almost guarantee you it will be the slower car.

I appreciate this is not what you asked, and that this is exactly what you said you dont want in response, but I believe in giving the right information and not trying to help someone after they have made the wrong purchase.

GL

[GTSBoy]

I'm with him ^ but I wasn't as polite.

[raZ1911]

From research and looking what tuners/ engine builders say either stock or 256/ Poncams would be fine and keep VCT.

[abr33]

I make 340 ish on stock cams. I will admit we're at the upper limit of them. But drivability is like stock.

[Reflector]

What turbo is being used?

What porting being done?

What RPM is being used?

Those 3 generally come well into play at the time of cam selection.

GTX3076R 0.82

3 angle valve grind, bowl is being opened up and the head is being de-dagged and tidied up.

Redline increase to 8000rpm, Ideal shifting point will be low 7000's to max 7500rpms

We all like to go the whole hog when building a motor but honestly your cam choice and suggested power output are poorly matched.

The cams you have mentioned indicate something along the lines of: power starts at 5000rpm and revs to 9000rpm.

For myself, if trying to build the fastest 300-350kw RB25 I could it would sport both VCT and 256/9mm Poncams.

If you built an identical car, and ran 272/9mm cams at the same suggested power level I can almost guarantee you it will be the slower car.

I appreciate this is not what you asked, and that this is exactly what you said you dont want in response, but I believe in giving the right information and not trying to help someone after they have made the wrong purchase.

GL

I appreciate and respect the nature of this post Scott. I understand what you're saying. The poncams are a good quick drop in choice, I know because I've used them. I'm up for creating something unique. Perhaps the poncams may be suited for a faster street car - then again, are there many rb25det dyno results showing the difference in cam choice alone? I also believe in trial and error. If I end up with poor performance, this will be another result to add to those asking the same question, if it does work effectively, again, the results pave way for those wanting to know whether a larger cam will be beneficial to their current (or future) set ups. My suggested power figure was ONLY a target. If the engines potential has more in it, I'll be ecstatic, but I will be relying on the tune to be suited to a safe set up without pushing the engine beyond it's limits.

Edited December 3, 2012 by Reflector

[R31Nismoid]

Shifting by 7500rpm, with that turbo, the cams are way too big - one would almost say the turbo is as well unless you spin to at least 8000, it qont stop making power there either on stock cams. You'll easily get 8200-8500 out of it (I did with my GT3040, span to 8500 stock cams).

You won't really make more than 300rwkw on 98. The GTX series needs more boost than 98 will safely support, which means E85 or you'll only just hover the 300rwkw mark on a good day (legitimately).

People have tried big cams with mid sized turbos, and pulled them out... So we know it doesn't work effectively

[Reflector]

Shifting by 7500rpm, with that turbo, the cams are way too big - one would almost say the turbo is as well unless you spin to at least 8000, it qont stop making power there either on stock cams. You'll easily get 8200-8500 out of it (I did with my GT3040, span to 8500 stock cams).

You won't really make more than 300rwkw on 98. The GTX series needs more boost than 98 will safely support, which means E85 or you'll only just hover the 300rwkw mark on a good day (legitimately).

People have tried big cams with mid sized turbos, and pulled them out... So we know it doesn't work effectively

Everything I've put into this system will be 'E85 ready'. Unfortunately, there are no Local E85 pumps around that I know of. I am not at all arguing the point (at which this topic has drifted towards now) that lower duration cams are not more effective, I am simply going to try it. Worst case scenario I buy another set of cams really. Is this not part of motorsports in general? We test, we trial and we get results . Believe you me though, I'm not being ignorant to the information you're all telling me.

[GTSBoy]

Yuh, but it's been "tested, trialled and lack of resulted" already, by others, who learnt. Might as well profit from that unless you actually intend to go straight to 350 - 400.

[FineLine]

for the power level you are seeking just listen to what people are saying here.

VCT is a huge plus not a negative. Your car will be so much more responsive and driveable with it.

[Tai1or Made]

Not 100% relevant but 550kw on a stock RB26 head, cams and all.

http://www.skylinesaustralia.com/forums/topic/320243-rb2630-par-gear-box-r33-build/page__st__80

[Dose Pipe Sutututu]

I would honestly keep the VCT and find cams to suit...

there are GT-R boys out there that spend top $$$$ on HKS V-CAM kits to get the low down we GTS-t owners have.

You stated you're "upgrading" to non VCT cams, so I am assuming you haven't bought the cams yet. Honestly do some thinking first.

[Deathwish]

Apologies for interupting this thread, Im building a RB30/25 and aiming for 800bhp. I know that at higher revs i need solid lifters Which i have in an old head from my old RB25 engine which revved to 10,000rpm. im doing a new head as the old one's got a crack in it. I've had it welded but am not too sure about using it on a forged set up in case it destroys itself. So what im asking is..... Can the oil feed for the vcy just be blocked off? and if it does and i use the solid lifters, do the lifters still get oil from the standard oil feed, especially as im going to be blanking off the rear of the two head oil feeds and restricting the other.

Many thanks for all info given.