# HKS V-Cam, slightly mental price?



## CabbageMS (Feb 8, 2011)

Hey all, I've been looking at the HKS V-Cam kit as the idea intrigues me. 

However the kit seems to be about 2 and a half grand. That seems like a fairly mental amount of money! Do people genuinely pay that or am I missing out on some cheaper vendor? I've looked at Nengun and RHD japan?


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## Nocturnal (Nov 5, 2004)

Yes, it is crazy money... and yes, people pay that. 
I think most owners just go for bigger bottom end if they want more low end response now...
But if you have money to burn...


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## tonigmr2 (Sep 12, 2002)

Must admit I am considering this system, mainly as I don't want to change my engine or build a forged one. Is it mainly sold on response?


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## Nocturnal (Nov 5, 2004)

It is suppose to give better response.
But if you ask me, this is one of those time when they say "there is no replacement for displacement".

By the time you get the cam in, get it working, map it, etc...
You can probably use that same amount of money and get newer turbo that will give more power and response, or a bottom end that will push more air for more response.

And of course, less moving parts mean less to go wrong.


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## Brains (Jul 6, 2010)

I've got a vcam but it was bought by previous owner and I must agree that if you have the money then get a rb28 or rb30 instead! 

Or both if you're nuts


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## RonniNielsen (Jan 14, 2011)

Brains said:


> I've got a vcam but it was bought by previous owner and I must agree that if you have the money then get a rb28 or rb30 instead!
> 
> Or both if you're nuts


I feel offended 

2.8L vcam works quite well. 

I only bought it because I went all the way on my build, and because im nuts.. if yuor not dooing a "propper" engine, i woulden bother...

Ron


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## Nocturnal (Nov 5, 2004)

Don't get me wrong, I do think V-Cam is a good system.
But it is one of those thing that you do when you have "ran out" of things to do.

If you have a fully build 2.8L and you want more response, then V-Cam is a good answer.
But if it is just a standard 2.6L I wouldn't bother... there are much more efficient ways to get better result for the same money.


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## [email protected] M/S (Feb 16, 2002)

I have a dyno plot of a car fitted with Type A v=cam kit we carried out some dyno pulls at different cam angles, it is good reading , will sort it out and post in up next week when I am back in the office.


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## CabbageMS (Feb 8, 2011)

I'd be interested in reading that Mark. I presume the only thing it could give you that more displacement doesn't is a bit better fuel economy?


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## Brains (Jul 6, 2010)

RonniNielsen said:


> I feel offended
> 
> 2.8L vcam works quite well.
> 
> ...


Sometimes being nuts is a good thing  
Your build is pure awesomeness! 

The system is great and it is a unique upgrade on our engines but I feel that it's really the last upgrade you do when you already have everything else due to the very high price.


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## BushyBoy (Nov 1, 2012)

CabbageMS said:


> I'd be interested in reading that Mark. I presume the only thing it could give you that more displacement doesn't is a bit better fuel economy?



Anything to improve fuel economy with current fuel prices is good, but over 2 grand to do so....


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## camlob (Nov 8, 2008)

Yeah, I feel the price for the V cam is crazy. Coupled with the amount of Dyno time to do it right. Not too many tuners here know how to map a variable cam. I recall, on a DC 5, the tuner just left it in one position! Lol.....


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## matty32 (Dec 18, 2005)

depending on the type you get and modifications, id say you will never go back to a standard rb


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## [email protected] M/S (Feb 16, 2002)

Dyno plots as promised re V cam kit on a RB28 fitted with a T04Z.

Type B V cam kit

Dyno plots are at 0.8 bar with no mapping work to trim the fuel/ignition maps due to VE change with the cams timing being moved.











This dyno plots also shows the car doesn't need the inlet cam running below 90 ATDC or above 115 ATDC but the exhaust cam wasn't played with while playing with the inlet cam timing.


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## .::TopSky::. (Nov 4, 2010)

My dream build uses a V-cam.

Why? Because from what I´ve seen it works well and I feel that something like the V-cam is missing in the RB. If the RB was built today it would most likely use something like the V-cam.

I think its worth the money. After all, tuning a Skyline GTR has never been cheap.


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## camlob (Nov 8, 2008)

Wow no wonder you guys like it, the graphs look really good. The 85 degree light blue line is perfect for me. I'll ask my tuner if he can do this


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## Cris (Sep 17, 2007)

As I understand it the VCam system (at least the entry level model) works very much like the VCT system on the RB25 NEO. If you don't want to spend HKS money I beleive that the Nissan system can be adapted to operate on the RB26.

I saw some threads on SAU and if I've understood it you need cams, a solenoid and appropriate headwork, obviously some sort of controller too though I understand that this can be done with the Link and I'm sure others. I'm sort of tempted by this avenue. I'm thinking of upgrading my cams and if by doing a little extra I can see a bit more power throughout the rev range then what's not too like?

PS I'd agree though for £3k or whatever the VCAM would probably be better spent on a 2.8+ kit.


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## Brains (Jul 6, 2010)

Are those graphs done with the cam locked at the specific angle? 
If so then it should be possible to get the best parts of all of those graphs.

Starting at 75 atdc and moving along to 125 higher up in the revs.


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## [email protected] M/S (Feb 16, 2002)

> As I understand it the VCam system (at least the entry level model) works very much like the VCT system on the RB25 NEO. If you don't want to spend HKS money I beleive that the Nissan system can be adapted to operate on the RB26.


RB25 system on moves the cam from max to minimum and it is only around 10 degree of cams movement; 

There is no cam position measurement on the RB25 either so this would need to be engineered into the cam to make the kit work like the HKS kit even if you was going to use a Link G4 to control the cam.

The HKS kit(s)can be bolted into a engine without any internal engine work.

TYPE A and B cam kit work the same way with just different cam angle movement.




> Are those graphs done with the cam locked at the specific angle?
> If so then it should be possible to get the best parts of all of those graphs.
> 
> Starting at 75 atdc and moving along to 125 higher up in the revs.


Yes this is what we do when we tune the V cam kit's , you also need to carry this out at different boost levels and throttle positions to build a full cam map.


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## camlob (Nov 8, 2008)

[email protected] M/S said:


> RB25 system on moves the cam from max to minimum and it is only around 10 degree of cams movement;
> 
> There is no cam position measurement on the RB25 either so this would need to be engineered into the cam to make the kit work like the HKS kit even if you was going to use a Link G4 to control the cam.
> 
> ...


Is it possible to source a V cam kit from you together with the cam map, and ecu? Maybe supply me a baseline map then my tuner can further tweak the fuel, ignition settings etc? Is the ecu a HKS? My tuner is familiar with R35's and I think f con pros. He doesnt touch cam maps...lol


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## [email protected] M/S (Feb 16, 2002)

Where are you based?

Whats the spec of your car?

Your tuner doesn't touch cam maps? think he is missing a huge part of making a car perform better than stock.


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## camlob (Nov 8, 2008)

[email protected] M/S said:


> Where are you based?
> 
> Whats the spec of your car?
> 
> Your tuner doesn't touch cam maps? think he is missing a huge part of making a car perform better than stock.


Based in Manila! 32 c year round. I am getting the car tomorrow and it currently has 750cc injectors, 255walbroh fuel pump, SS intake pipes, z32 and power fc, 3" mid pipe to a HKS exhaust. I plan to put gt2860-5 in the next month or so. After realizing the work on putting a aftermarket oil pump, I decided to do it at a later date. Maybe think it out thoroughly on whether a crank collar and other stuff should go along with it.

The tuner is what the HKS importer uses. And you are right that he is missing out. 

Pls email me at [email protected]. Maybe I can source some other stuff from you.


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## tonigmr2 (Sep 12, 2002)

So is it a waste of time to put this on a non-forged 2.6?


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## [email protected] M/S (Feb 16, 2002)

tonigmr2 said:


> So is it a waste of time to put this on a non-forged 2.6?


no not at all Tony , I will have dig out of another dyno plot of a R34GTR fitted with Type B V cam kit ( we modified the Type B kit to fit on a stock motor so if and then the customer upgraded he has the best kit for his car)

Will sort this out today and post up.


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## Brains (Jul 6, 2010)

[email protected] M/S said:


> no not at all Tony , I will have dig out of another dyno plot of a R34GTR fitted with Type B V cam kit ( we modified the Type B kit to fit on a stock motor so if and then the customer upgraded he has the best kit for his car)
> 
> Will sort this out today and post up.


If you would combine the dark blue line and the purple line from your first graph wouldn't that represent a type A vcam? 
Then it's movable between 85-110 degrees which if I recall correctly is what type A allows.


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## [email protected] M/S (Feb 16, 2002)

that is correct. But not all engines like to use the full cam movement , you can see that on the dyno plot I put up yesterday.


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## Brains (Jul 6, 2010)

[email protected] M/S said:


> that is correct. But not all engines like to use the full cam movement , you can see that on the dyno plot I put up yesterday.


Yeah there wasn't really any gains outside of those timings. 
What type of engine would you suggest to run a type b on?


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## [email protected] M/S (Feb 16, 2002)

but these dyno plots where to just to show what the V cam does I didn't re-tune for each cam positions, so the car may end of running more cam angle.

up to around 600ish BHP 2.6/2.8 litre 2530,s/GT-RS or T04Z turbo,s


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## Brains (Jul 6, 2010)

Thanks for your answers anyway! 
It's not that many tuners that have used a vcam system so it's very interesting to see real results from someone with experience. 

It also shows how important cam timing actually is on an engine.


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## Cris (Sep 17, 2007)

[email protected] M/S said:


> RB25 system on moves the cam from max to minimum and it is only around 10 degree of cams movement;
> 
> There is no cam position measurement on the RB25 either so this would need to be engineered into the cam to make the kit work like the HKS kit even if you was going to use a Link G4 to control the cam.
> 
> ...


Thanks for the info Mark. It's always hard to sort the fact from the fiction. I had imagined that the HKS system would be superior.


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## r34skyline (Oct 20, 2004)

[email protected] M/S said:


> no not at all Tony , I will have dig out of another dyno plot of a R34GTR fitted with Type B V cam kit ( we modified the Type B kit to fit on a stock motor so if and then the customer upgraded he has the best kit for his car)
> 
> Will sort this out today and post up.


yes please  very interested.

are you able to post up some boost graphs before and after as well?

would love to see some other 2.6 2530's/-5's comparions


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## [email protected] M/S (Feb 16, 2002)

RB28 fitted with 2530,s Type B V cam kit. F-con etc etc




















Will have a sort out for some RB26 graphs as well.


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## RonniNielsen (Jan 14, 2011)

Mark, would you by any chance have a dyno graph of a RB28 with -10/gtrs turbos and vcam?

i desided by the way, that I will come over to the uk, drop my car off with you, and visit a mate for a cuple of days, depending on how long you need it. 

after the winter ofc :/

Ron


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## [email protected] M/S (Feb 16, 2002)

nope never built a RB28 with -10's and Vcam I am afraid sorry , sounds like it would work well thou.

Will be good to see you next year then.

thanks


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## [email protected] M/S (Feb 16, 2002)

RB26 GT-SS Type A V cam kit.





















pretty responsive motor.


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## tonigmr2 (Sep 12, 2002)

Yeah that's what I hoped it would be. Fancy one with the R34N1 turbos I have. Food for thought.


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## matty32 (Dec 18, 2005)

if i can get access to a decent scanner, i have about 15 dyno runs of the Hipo Gio gave me with various mods through the years including several with the 2.8 and limited v cam

if i can scan them i shall post up.


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## Sub Boy (Jan 28, 2008)

There was talk of some pre-production Dual V-Cam HKS kits?!? 

Has anyone got any info on these or Pics?


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## camlob (Nov 8, 2008)

Sub Boy said:


> There was talk of some pre-production Dual V-Cam HKS kits?!?
> 
> Has anyone got any info on these or Pics?


Sorry for the noob question, so the current v cam kit is for one cam?


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## Sub Boy (Jan 28, 2008)

camlob said:


> Sorry for the noob question, so the current v cam kit is for one cam?


Yup, Have a look at some of the pics of them, You will notice a lump on the intake side cam cover, there is the actuator under it.


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## [email protected] M/S (Feb 16, 2002)

Not heard anything regarding a exhaust V cam kit but if it was released it would mean a change of ECU crank triggering as the stock CAS would need to be moved.

But from my time of tuning late model 350Z/370Z with both inlet and exhaust variable cams the exhaust cam will not give you the huge gains you get from playing with the inlet cam.

In my opinon it wont be worth the costs for the gains you would get.

You cans see from the dyno plots posted up the V cam does give a huge gain in mid range torque and turbo spooling. You do need to spend time gettting the cam position correct on cruise to give some fuel economy back thou.


Mark


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## AH_HUH (Nov 14, 2012)

I had the HKS V-cam step1 type A fitted to my 34 gtr a few years back and the gains were 30kw through the midrange higher.


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## r34skyline (Oct 20, 2004)

thanks Mark!

do you have any with before and after? these are my results with 2.6, 2530's, Type A - very keen to see what you think?
So this is back to back runs, no V-cam installed to V-cam installed and tuned. Prev intake camshaft was 256, 9.something lift/duration










i believe that was at full advance until high 5000rpm - 6000rpm?


what i didn't notice was much better response in terms of full boost. Whilst there are much better rpm response gains in terms of torque, at best boost came on say 150rpm earlier. 

I'm sure i'm missing a technical explanation for why the torque curve might move 500rpm+ to the left, but i would have thought boost would similarly do the same. This does not seem to be the case.


Fuel is E85 and boost is 21-22psi


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## [email protected] M/S (Feb 16, 2002)

what was the cam advance @ 6500+rpm.

Being type A you might not be able to retard the cam off enough at high rpm/high boost but the original cam spec may of been set up perfect so you may not get any gain top end. But the gain in the mid range you have will make the car seem much more alive.


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## r34skyline (Oct 20, 2004)

i'll have to check, but i think it's effectively 'off' at that point? (as in little advance...) - ex-cam gear is set at -3 degrees i believe

what i don't quite understand is at say 4000rpm, if you look at the torque graph, i reach 300nm 700-800rpm earlier, but the boost curve graphs look quite similar, about 100rpm difference most the way....


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## [email protected] M/S (Feb 16, 2002)

What was the exhaust cam timed at? not just the cam vernier position.

To get the car to rev on you will need to retard the cam right off to say 116+ ATDC. To make the car spool earlier you advance the cam i.e 102 ATDC to flow more air @ lower RPM.


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## narface (Apr 9, 2010)

Sub Boy said:


> There was talk of some pre-production Dual V-Cam HKS kits?!?
> 
> Has anyone got any info on these or Pics?


Sorry to bring up an old thread. It took me a while to go through my stack of GT-R books and magazines to find the attached picture. Taken from volume 92 (May 2010) of GT-R Magazine, this is HKS's BNR34 with a dual V-cam set up.

Back then, HKS was testing out a dual V-cam set up for the 2.8 litre RB26DETT. They described the exhaust V-cam comes in around 1000rpm, and they saw improved fuel economy. The article also mentioned they were developing a high pressure fuel injection system for better fuel atomisation.

It's been over 2 years since this article was printed, so we can safely assume HKS decided not to mass produce the exhaust side V-cam. Probably due to cost? As this thread's title stated, the V-cam has a mental price. Now imagine doubling this price for the exhaust side V-cam! Not everyone can afford a fully variable dual cam setup.


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## northstar34 (Jul 24, 2009)

Very interesting, it's a shame nothing has come of it.

Also contemplating a vcam on a 2.8 but understand peeps views on going displacement instead.

What are the type b's going for now? using a to4z.


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## Brains (Jul 6, 2010)

Today i got to see the difference on how the cam timing affects the power band.
The difference between activated vcam and deactivated was up to twice the amount of torque between 2500rpm and 5000rpm.


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## [email protected] M/S (Feb 16, 2002)

It enhances the VE so much advancing the cam at low RPM.


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## jasaircraft (Feb 15, 2009)

Mark, so in the case we where to do our own vct solenoid in a 26 head mod...
1: We would need an rb25 intake cam (or rb25 aftermarket) ? Does it have some special oil line or something on the front for it to rotate?
2: Could we just activate/deactivate the system in an on/off manner like Toyota's 20v vvt system? (I ask this because I kinda understood it should be pulse width modulated?)
I hope to install this some day, and also get a hold of an rb30 block.


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## jasaircraft (Feb 15, 2009)

Doing some extra research, I believe we would have to get rb25 neo camshafts right? So they can couple with the VCT cam gear that has the lump that does the actual rotation?
OR do we just need the gear lump with the gears?Camgear?


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## [email protected] M/S (Feb 16, 2002)

It isnt as simple as that , the RB26 head wont take the RB25 NVCS solenoid easily.

The V cam isn't just on and off like the RB25 system i.e it retards the cam 10 degree's at a certain load/rpm point it variable i.e you can move the cam in degrees' with duty cycle.

Someone will be able to engineer it I am sure but your also need an ECU to control the cam movement.


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## R32 Combat (Jan 29, 2004)

I did look at making a V-CAM from scratch. I do not think it is difficult, but it would take a while. Ideally you'd need a slightly different camshaft casting, like the HKS one, but you could mod a standard one for the oil feed.

GM have an electric version that is solenoid operated so there is no oil and could be bolted to any car. 
That is the way forward, a bit like the R35 having an electrically operated transfer clutch pack rather than hydraulic.

Times have moved on and the skyline stuff is starting to look dated


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## Corsa1 (Sep 8, 2003)

Andy your right but to do a kit is there a market for it?


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## [email protected] M/S (Feb 16, 2002)

If the kit was around £1500-00 I would expect it to sell but not in great volumes.


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## Corsa1 (Sep 8, 2003)

Mark getting the cam blank made would be the hard bit has it took quite long to track some RB26 blanks down


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## [email protected] M/S (Feb 16, 2002)

The HKS V cam blank is much larger dia around the 2 front journals to allow the drilling for the oil feed to supply the variable front pulley. The front pulley is derived from a 2JZ variable cam pulley.


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## Cris (Sep 17, 2007)

[email protected] M/S said:


> If the kit was around £1500-00 I would expect it to sell but not in great volumes.


The NZ company I spoke to was looking for something of that order for their 'kit'. Fitting was of course an extra cost. I decided not to bother, with VAT and duties/shipping you're nearer to £2,000.


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## R32 Combat (Jan 29, 2004)

To get pressurized oil into the end of the cam requires only a turned diameter, which could be done on a 'stock' camshaft. Machine a groove in it, build a dummy camshaft bearing and bolt it to a standard cap. Bingo, oil control to the camshaft. Retrofit an 'vanos' type pulley, can't see it being difficult. I looked at the 300ZX pulley, but as Mark said, kind of pointless because of the tiny movement.


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## jasaircraft (Feb 15, 2009)

R32 Combat! I think your idea of the GM electric is great! Do you have links to see one? The deal would be how to attach it to the cam and to the gear that touches the belt...
PWM shouldnt be a problem with an aftermarket ecu, also you could base your pwm table against rpm.


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## tarmac terror (Jul 16, 2003)

Surely someone like Kent, Piper, Newman etc could be persuaded to get involved and assist in development?.

If costs were sensible then I might even be persuaded to part with some £££ myself for a kit..

TT


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## jasaircraft (Feb 15, 2009)

Do you mean this one ?
GM's Variable Valve Timing System Performance Test - Hot Rod Magazine

It would stand too high and touch the bonnet...

Can anyone confirm that rb25 neo camshafts are rb26 compatible?


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## R32 Combat (Jan 29, 2004)

jasaircraft said:


> Do you mean this one ?
> GM's Variable Valve Timing System Performance Test - Hot Rod Magazine
> 
> It would stand too high and touch the bonnet...
> ...


No, that one is oil fed.


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## jasaircraft (Feb 15, 2009)

What engine does it come in?


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## infamous_t (Jul 9, 2007)

Has anyone looked at using later VCT tech like CVTCS?
Seems to be used on a very wide variety of late model Nissans including the R35.


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## Cris (Sep 17, 2007)

tarmac terror said:


> Surely someone like Kent, Piper, Newman etc could be persuaded to get involved and assist in development?.
> 
> If costs were sensible then I might even be persuaded to part with some £££ myself for a kit..
> 
> TT


Such a kit already exists. There is a company in NZ who will sell it to you.

I had a conversation with them (nice chaps) and the end result was that it didn't seem worthwhile for the cost involved.

From memory the kit was a little less than £800 (plus shipping and duties), this included appropriate cams and solenoid. You'd need a couple of RB25 bits and then to machine the 26 head to accept. My mental calculator said that the cost was likely to be knocking on £1500-2000 all in which put it on the back burner for me. I also wondered if I could source an HKS kit for similar money...

Of course those with different set-ups/deeper pockets might find that it works out for them.

For those interested the company was Elite Racing Development in NZ.


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## infamous_t (Jul 9, 2007)

In NZ or Aus?
I know ERD in Aus but I think they shut up shop mid 2013


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## Cris (Sep 17, 2007)

infamous_t said:


> In NZ or Aus?
> I know ERD in Aus but I think they shut up shop mid 2013


My memory says NZ though it could have been AUS I suppose. It was a year or two ago when I spoke to them.


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## Audiophile (Sep 23, 2009)

This is old topic but could not find Elite Racing Development in NZ, but there should be one in Queensland Elite Racing Developments - Queensland - SAU Community, looks like forum user THE DAN is the guy to talk to.

So when budgeting this build 

RB25DET Intake cam pulley - 45-200 EUR
Nissan Skyline RB25det R33 GTST Inlet Cam Pulley | eBay 

Since HKS used modified Toyota cam gear in their application, this could be adapted too?? 
I do think the reason why they went with Toyota unit is that you can eighter adjust it 2 times or it allows them to give camshaft more advance then Nissan unit does

In VVTI toyota has 2 stage advance mechanism 
https://www.youtube.com/watch?v=bAwN8JOmNrs \

These pulleys are found in IS300 GS300 Supra engines, you name it..
Genuine Toyota Lexus GS300 IS300 SC300 Supra 13050 46010 Camshaft Pulley LH | eBay 
=
RB25DET neo6 Intake cam by Tomei 
Tomei - Procam Rb25Det R34 Neo6 In 260-9.15Mm - Enjuku Racing Parts, LLC

What comes to Nissan VCT solenoid then I would forget the Nissan OEM solenoid and build similar to this by relocating the VCT solenoid


























When you are able to relocate the solenoid it really does not matter what brand you use, ford solenoids are priced cheaper 
NEW 2004-2008 Ford 5.4L 3V Variable Camshaft Timing Control Solenoid - VCT | eBay 

Of course this kit needs some custom manufacturing but there is nothing that can be done. Adapting Toyota cam gear must be the hardsest.

Does anyone know how many degrees on Nissan VCT and how many degrees adavance on Toyota VVTI


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## [email protected] M/S (Feb 16, 2002)

Nissan VCT (RB25/SR20) only has 2 postions open and closed normally around 10 deg (advance/retard)

The Toyota VVTI inlet pulley which is the same as the Nissan 350Z inlet cam control is variable between 0 and approx 40deg advance from fully retarded.

both of these systems require oil feed via the camshaft , the Toyota system using duty cycle together with cam position sensor to control the cam position in closed loop control.


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## Audiophile (Sep 23, 2009)

Most adjustable cam gears can be moved +/- 10 degrees which is 20 degrees of cam timing on most aftermarket cam gears. 

Thanks Mark for explanation. Does that mean that you are able to control cam position from 0 to 40 degrees with 1 digit step? 


On HKS V-cam step 1 Variable amount 30° , step 2 Variable amount 50°

As you can see from HKS V-cam manual they are using cam angle sensor to monitor whats going on means that their system dynamically contols. 
http://1jzmerc.com/files/hks-faq/hks-vcam-system-rb26-instruction-manual.pdf 

As we can see from this pic, HKS oil feed and valve are side by side.













[email protected] M/S said:


> Nissan VCT (RB25/SR20) only has 2 postions open and closed normally around 10 deg (advance/retard)
> 
> The Toyota VVTI inlet pulley which is the same as the Nissan 350Z inlet cam control is variable between 0 and approx 40deg advance from fully retarded.
> 
> both of these systems require oil feed via the camshaft , the Toyota system using duty cycle together with cam position sensor to control the cam position in closed loop control.


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## Chris_Gojira (Oct 1, 2012)

For the people thinking about buying, but don't want to spend this amount of money.
We currently have a combo of V-Cam + Stroker kit on sale until the end of 2015.

HKS Special GTR Offers - PartBox Performance and Tuning Parts

Regards,
Chris


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## [email protected] M/S (Feb 16, 2002)

Audiophile said:


> Most adjustable cam gears can be moved +/- 10 degrees which is 20 degrees of cam timing on most aftermarket cam gears.
> 
> Thanks Mark for explanation. Does that mean that you are able to control cam position from 0 to 40 degrees with 1 digit step?
> 
> ...



The RB25/SR20 can only move the cam in 1 position either max advance or max retard. nothing in between and this I think is crank degree's (would need to have a read up) when you control this from a Link the duty is either 0% or 100%. fully open fully closed.

Where as the V-cam kit (Toyota/Nissan) it is totally variable. and as oyu say up to 50 degree crank. say 90 deg to 140deg ATDC. Running the cam fully advanced will make the car spool far earlier and retarding the cam will make the motor rev out.


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## jasaircraft (Feb 15, 2009)

Ok, so buying a rb25neo intake cam (a tomei typeB for example) should be the same as buying one for a rb26 with the added gain that you can put the rb25neo (or non neo?) vct pulley there? of course you have to have the vct pulley right? I dont think the rb26 intake pulley can attach to the rb25neo cam?

Can the 350z or toyotas vvt pulley be adapted easily?


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## Audiophile (Sep 23, 2009)

AS far as I know and have found out RB26 in and ex cam gears are exactly the same, same goes for aftermarket cam-gears, they are interchangable.

RB25DET exhaust cam gear is same as RB26 in/exhaust cam gear.

RB25 DET intake cam and camgear/pulley is different because its VCT and no you cannot put RB25DET intake cam or NEO6 intake cam on RB26 intake cam pulley but I suppose what you can do is to Put NEO Intake cam on Regular RB25DET cam pulley with VCT...so you need NEO cam because its similar profile to RB26DET cams and made for mechanical lifters and you need RB25DET intake cam pulley because it bolts to NEO cam mechanism.

If im not wrong then both 2jz and RB26 have 48 teeth in cam pulleys..if they share same teeth design it means that they are exacly the same in diameter.


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## jasaircraft (Feb 15, 2009)

Fortunately i have a clients supra with a 2jz vvti in for the moment... so what should i measure...


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## jasaircraft (Feb 15, 2009)

Cannot rrmove the pulley cuz he wont like it of course


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## Audiophile (Sep 23, 2009)

https://www.youtube.com/watch?v=1KQGRulDJSk 

Found this video..

https://www.youtube.com/watch?v=bAwN8JOmNrs


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## jasaircraft (Feb 15, 2009)

60 degree is quite a lot, could there be any risk of piston/valve contact on the max advance position? I suppose the nissan vct mechanism inside the pulley is similar? If it is I guess a solenoid similar to the vvti solenoid could be pwm to use the nissan pulley in a "vvti" manner?


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## FRRACER (Jun 23, 2013)

You would expect HKS would have checked no contact with in the 50 odd degree range they timing advances by to ensure no piston to valve contact. Another reason why they advise on recessed Pistons.


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## [email protected] M/S (Feb 16, 2002)

They say to run either Type B or Pro kit you need Step 2 pistons which have a larger valve cuts out.


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## FRRACER (Jun 23, 2013)

So has anyone in the UK got a V Cam that actually works and are getting good response and torque? Any dyno graphs before and after?


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## Audiophile (Sep 23, 2009)

So if one uses new intake cam on rb26 thats originally for RB25DET NEO6 engine (mechanical lifers and same base cycle for cam as RB26) made by tomei

http://www.enjukuracing.com/products/tomei-procam-rb25det-r34-neo6-in-260-9-15mm.html

It should work just to make sure to have ex cam with suitable profile as well...
My current engine*have*Trust cams

IN 256 /9.1mm

EX 264/9.1mm 

So after replacing Intake cam with RB25 NEO6 camshaft I would have

IN 260/9.15mm**(with variable 10degrees of variable tuning)

EX 264/9.1mm

As far as I know stock cams are 240deg/8.25mm*

In HKS V-cam

Step 1 has duration of 248 valve lift 8.6mm

Step 2 has duration of 264°, valve lift 8.7mm.

Step pro has specially designed cam that has duration of 264°, valve lift 10mm...


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## [email protected] M/S (Feb 16, 2002)

We fitted and tuned a few cars and lately we have controlled the V cam with a LINK G4+ ECU so no need for all the extra boxes that HKS use.

This car was a while ago; Just some dyno work to work out where we want to tune the cam to so we carry out controlled dyno pulls at a set cam postion; 2.8 T04Z Type B V cam

You see that the extremes of the control the gains aren't as good as milder numbers we have found ever car is different regards tuning , always gives a good gain.




This wasn't fully tuned at 0.8 bar just to get an idea where the cam needs to be for the biggest gain in power band width.

Dyno plot below is a 2.7ltr built motor again running a T04Z with before and after fitting a Pro V cam kit , we did swop from F-con to Link G4+ when fitting the V cam kit but it gives a good idea how the V cam adds spool and the dyno plot doesnt show the gain in response while driving.


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## FRRACER (Jun 23, 2013)

Is it normal for variable inlet cam setup to have more duration on the exhaust cam? The Supra guys tested staggered equal and reverse staggered cams and found that while a longer exhaust duration helps spool up it lost power everywhere on the curve when compared to equal or staggered cams. We usually reverse stagger on drag engines with singles.


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## Audiophile (Sep 23, 2009)

[email protected] M/S said:


> We fitted and tuned a few cars and lately we have controlled the V cam with a LINK G4+ ECU so no need for all the extra boxes that HKS use.
> 
> This car was a while ago; Just some dyno work to work out where we want to tune the cam to so we carry out controlled dyno pulls at a set cam postion; 2.8 T04Z Type B V cam
> 
> ...


Mark, do you tune v-cam dynamically vs rpm giving it certain degree of advance at certain rpm or is it with set position on-off. For example you give cam 10 degree advance when VOT from 0rpm untill it gets to full boost and the you set it back to 0 untill redline...?


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## Audiophile (Sep 23, 2009)

Copy from HKS manual

PRODUCT CHARACTERISTICS
This product is to add the variable valve timing system to the RB26 engine. This system continuously sets the valve timing to the value which was calculated from the preset map utilizing the engine oil's pressure.

By changing the intake camshaft's valve timing corresponding to the engine conditions, the slip-back of the air-fuel mixture made at low-mid RPM can be reduced; it improves the charging rate in the cylinder and increases the torque. Also, tuning the valve timing and the engine RPM can improve the torque in all RPM level. The increased combustion gas can raise the boost faster even with a large size turbo. At idle, the overlap becomes smaller. It stabilizes the combustion, reduces the engine vibration, and produces a cleaner exhaust gas mixture.

Type A was designed to work with Nissan stock pistons. The kit works only by replacing the stock camshaft to HKS V-cam. However, the maximum variable angle was set up to 30°; therefore, Type B shows better torque improvement at low RPM. The maximum variable angle for Type B was set up to 50°; therefore the pistons must be replaced to HKS Forged Piston Kit. Modification to Modification to the cylinder head and/or replacing valve train parts is not necessary.

Type A was designed to be installed onto the stock engine. Therefore, if the bottom side of the cylinder head was modified, the cylinder head gasket is thinner, and/or the valve recess is shallower than the stock, Type A cannot be used. 

The following parts are required to use Type B: 
HKS Forged Piston Kit for RB26DETT (P.N. 2103-RN017, etc)
The allowable engine RPM to use the stock valve spring is 8,000 rpm.

The following operations must be done to install this product:
Measuring the valve timing
Measuring and adjusting the valve clearance
Measuring V-P (the clearance between a valve and a piston)

The following operations must be done to preserve the product's performance and safe use:

Setting the fuel injection volume and ignition timing.

Correcting the valve timing map

This product adjusts the valve timing by the engine oil's pressure. In any of the following case, the oil pressure is decreased the best fuel injection volume and ignition timing cannot be set:

The oil pump cannot provide sufficient amount of flow due to too low engine RPM.The low viscosity oil is used. The oil becomes high temperature. The high temperature oil lowers the viscosity and decreases the oil pressure. The engine oil is degraded. The abrasion of the oil pump widens the clearance. The oil pump inhales air at rapid acceleration or circuit driving. When the valve timing variable setting is not sufficient, it's recommended to replace the oil pump to the large capacity pump such as HKS Oil Pump Upgrade (P.N.2503-RN001). This product was developed to improve engine output. Improving engine output may affect the oil and/or water temperature, the oil pressure, and the fuel volume. To preserve engine performance, maintain engine conditions when driving.


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## Audiophile (Sep 23, 2009)

Took some photos of the RB25 head, VCT pulley, solenoid, cam 

As you can see the oil goes inside the cam from those 2 holes:









This is the bolt that holds the cam and cam gear together..as you can see there is hole inside the bolt as well








'

This is Nissans VCT solenoid. Can someone confirm how this operates..does it lets the oil flow through it when its on or does it lets oil though when its off meaning that does the cam pulley is -10 degrees at its off position and when you let oil pressure to it it turnes back to 0..? 









VCT cam pulley 









This is were you normally would put VCT solenoid.









This is the most interesting part. One channel looks to be a cam oiling and the other for the VCT but wich one is wich and how it operates I dont know yet. 









Could be that the solnoid closes the circualtion hole and thats how the presure is built inside the cam?


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## BenTaylor200 (Dec 5, 2001)

It'll be the same as the SR20:


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## Audiophile (Sep 23, 2009)

Not about the RB25DET but copy from this site 

https://z32.wikispaces.com/Variable+Timing+Control

Variable Timing Control

Variable Timing Control (VTC, sometimes called Variable Cam Timing (VCT), or NVCS (Nissan Variable [timing] Control System or Nissan Variable Cam System) was the name given to the variable cam phasing system featured on the VG30DE(TT) and other similar engines from the era. While similar in application, it is functionally very different and should not be confused with Honda's VTEC system, which was introduced around the same time.

Twin Turbo 
For the VTC to turn on, the following conditions must be true:
Temperature between -49°F and 230°F. Vehicle speed 6 MPH or higher (0 MPH on some earlier ECUs) Then, the ECU will enable the VTC when the TP (calculated engine load) is above 23ms. The VTC is cut (disabled) at 5900 RPM. The TT ECU still has a parameter to enable VTC by RPM alone, but it is set at 6100 RPM, above the 5900 RPM VTC cut. Because of this, it is essentially ignored. The TT's VTC is enabled by TP and disabled by RPM.


The VTC solenoid is a solenoid valve mounted to the back of the head, directly behind the intake camshaft. In it's "resting state" (off), it allows oil which had entered the front of the camshaft to drain back out through the rear. Once activated, the VTC solenoid "plunger" presses on a check-valve at the rear of the cam, effectively blocking the flow of oil from leaving the cam through the rear. This forces oil to pressurize the front chamber in the VTC gear at the front of the cam.

Comments: Isnt the logic same in RB25 det with the difference that one solenoid does the whole job?


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## Audiophile (Sep 23, 2009)

Does anyone have picture of the HKS V-Cam system without the cam cover?

BR
markus


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## Audiophile (Sep 23, 2009)

Plase note the pins for cam angle










Intestringly HKS cam has oil feed through 2 different holes while Nissan Stock cams and NEO cams have just one hole drilled through the camshaft. 










Those 2 holes will meet the part in cam cover where solenoid is inserted feeding the oil to the cam




































Looks like the PRO version has more advance solution for cam angle


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## nismo1118 (Dec 7, 2005)

Does anyone have a source for the RB25 VCT pulley? I'm looking to do the conversion as well but still looking for a good source for this part and RHDJapans price just seems a little to high.


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## Audiophile (Sep 23, 2009)

Nissan VCT and Toyota VVTI unit side by side:









Toyota VVTI unit has exactly the same diameter and number of tooth as Nissan UNIT









tooth profile is just a little different from the tooth bottom toyota is more square shape and nissan seems to be moor round..but id say 97% identical.


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