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25 Vct Refitt To A 26 Head?

XRATED

By XRATED,
in Engines & Forced Induction

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bubba Grand Master

bubba

Posted
Posted

The VCT on OEM engines is there to give you the best of both worlds.. top end and low end. It has its' benefits in performance applications but most people don't care.. they just give it more revs before they drop the clutch :D

PM-R33 Grand Master

PM-R33

Posted
Posted (edited)

You guys ever driven a car that had VCT and then got rid of it? SR's and RB's with VCT removed are shit down low. Hell, RB26's are shit down low. Not that many people care about such things on big power cars, but for a daily driver it does makes a difference.

Edited by PM-R33
PM-R33 Grand Master

PM-R33

Posted
Posted (edited)

Maybe your VCT wasn't working because there is a difference. Considering i can control my VCT with the microtech and turn it on or off, yep, there is a difference. Good mate of mine took the VCT off of his S15 because they tend to fail on the SR20 and he regrets it, very noticable power loss down low.

I'd be curious to see how a stock turbo RB26 would go with VCT on it considering i find them quite crap down low for what they are, however that's probably just lag from the twin setup (maybe this aint as bad on a R34, only been in R32 and R33 GTR's).

Edited by PM-R33
XRATED Veteran

XRATED

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I'm in the states right now and a buddy of mine just bought a HKS V-Cam set up for his 33GTR. It has a fairly large single and pumps out 780 odd whp. He made alot more bottom end and especially midrange power with the V-Cam system set up correctly.

I would like simmilar results for my own 26, however I don't want to spend 5-7k on a brand name item.

I have an aftermarket ecu that I will be able to use to controll a pressure controll valve, I will have to get a cam custom cut, line up some oil pasages and use a 25 VCT gam gear? Then spend some (free) time in r and d...

I'm just trying to find out if anyone has had any results (good or bad) trying VCT on a 26 head.

Cheers

J

GT-RZ Community Regular

GT-RZ

Posted
Posted
Maybe your VCT wasn't working because there is a difference. Considering i can control my VCT with the microtech and turn it on or off, yep, there is a difference. Good mate of mine took the VCT off of his S15 because they tend to fail on the SR20 and he regrets it, very noticable power loss down low.

I'd be curious to see how a stock turbo RB26 would go with VCT on it considering i find them quite crap down low for what they are, however that's probably just lag from the twin setup (maybe this aint as bad on a R34, only been in R32 and R33 GTR's).

Baring in mind turning a VCT off is not the same as running a camshaft that is designed to run without any form of VCT.

I can see VCT having benefit on the road with stop start driving in traffic etc which is most likely the major benefit of having it.

IMO correct cam choice and adjustable cam gears is more than enough. In saying this i have never had a direct comparison.

Never saw anything too impressive in comparison with that HKS car either with the 26 VCT.

sebastion Proficient

sebastion

Posted
Posted

VCT is not all about low end power guys, its also about the efficiency of the engine, this is due to the overlap of the timing between the intake and exhaust camshafts (small duration favourable at low rpm and larger duration at high rpm, because of the time it takes the air to get into the combustion chamber) so essentially due to the increase in efficiency this also in turn leads to increase power and more importantly torque. personally I do not see to many issues involved with fitting the vct to a 26 head, just a little bit of machining required, but no reason why it would not be feasible, We would like to see this carried out, as it may well turn out to be a good option compared to the hks system and could be every bit as effective.

good luck with it mate, and if we find that anyone has done this will let you know.

R31Nismoid Grand Master

R31Nismoid

Posted
Posted
you will probably find its cheaper to just use the neo head. why reinvent the wheel?

Exactly, MUCH cheaper infact, probably to the tune of 4k give/take.

For other than the sake of "saying" you have a RB26 head, i see little point in not using the RB26 head if you want the VCT and so on. the HKS V-CAM is too expensive for what it is when you can just put a NEO head on, and get an adapter for the RB26 intake side.

Who cares what head is on there? Does it do a better job, yes. So therefore you use it.

bigmikespec Veteran

bigmikespec

Posted
Posted
Who cares what head is on there? Does it do a better job, yes. So therefore you use it.

It is the same reason why some people (including me) dont want to use an RB30 block.

If you are sure it does a better job you must know more than most...? >_<

R31Nismoid Grand Master

R31Nismoid

Posted
Posted
It is the same reason why some people (including me) dont want to use an RB30 block.

If you are sure it does a better job you must know more than most...? :D

I was comparing the 26 head to the 25 head.

VCT vs no VCT... pretty easy especially when the thread is about - VCT on heads

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