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At the risk of being a bore , I am chasing results from someone using a HKS Step 1, 2 or Pro Vcam. I am running out of time so have asked the same question on 2 threads, sorry

NO TALK, how about a back to back comparison from before and after the Vcam ?

I have read threads from this and other sites talking about Vcams, the Pros and Cons but must have missed all of the proof from both sides.I am looking at Vcams and trying to get my head around them but so far I have only found talk, nothing to compare the before and after.

Looking at using a Vcam for my 3.2 stroker build and if possible see some results.

I have asked a few blokes on PMs but it seems they are too busy to reply with an answer showing the results ???

Surely some Dynos would give a little indication of the difference.

I do know that Dynos do not give you a true driving feeling of work that has been done .

Car is now 437awkw on pump and 475 on E85 and 874Nm @ 5250rpm

What would one expect from adding a Vcam
 

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I have no experience with variable cam timing on rb engines. But the engines we have played with increased width of power band at top end when we advanced exhaust cam timing after about 6000 rpm. All non turbo engines but it would rev out freely without it feeling tight anylonger.
 
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RB25 NVCS is a very very simple set up 2 positions of inlet cam postion. approx 10 degrees of difference.

Crude as only 2 postions unable to tune the base timing in so changing distance between crank and cam will and can change cam base postion.

RB motorsport can supply a RB25 based system for a RB26 circ around £2640-00 inc vat for a 260 deg cam and £2995 inc vat for a 270 deg cam. all with new parts.

The HKS variable cam pulley is from a Supra not a Subaru motor (late 2JZ)

The HKS system use a billet cam to allow the extra drillings to supply/drain of controlled oil pressure and to allow live cam postion to be read so allow closed loop cam position (just like a VQ35 or VR38 Nissan engine

It is worth it I feel allowing the engine to come up on boost approx 1000rpm earlier and still rev out if an idea scenario Spend sometime on a dyno playing with cam timing advance the inlet cam 10/15 degrees and see how much earlier the car will spool on full throttle and also on part throttle. then retard the cam right off and see how much better the motor will rev on making power.


Yes expensive it gives a good result thou.
 

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RB25 NVCS is a very very simple set up 2 positions of inlet cam postion. approx 10 degrees of difference.

Crude as only 2 postions unable to tune the base timing in so changing distance between crank and cam will and can change cam base postion.

RB motorsport can supply a RB25 based system for a RB26 circ around £2640-00 inc vat for a 260 deg cam and £2995 inc vat for a 270 deg cam. all with new parts.

The HKS variable cam pulley is from a Supra not a Subaru motor (late 2JZ)

The HKS system use a billet cam to allow the extra drillings to supply/drain of controlled oil pressure and to allow live cam postion to be read so allow closed loop cam position (just like a VQ35 or VR38 Nissan engine

It is worth it I feel allowing the engine to come up on boost approx 1000rpm earlier and still rev out if an idea scenario Spend sometime on a dyno playing with cam timing advance the inlet cam 10/15 degrees and see how much earlier the car will spool on full throttle and also on part throttle. then retard the cam right off and see how much better the motor will rev on making power.


Yes expensive it gives a good result thou.
Have you seen the RB Motorsport kit in action compared to a hks? Was going to go for the RB Motorsport one after I've sorted out my bottom end build, and popped a single on ;)
 

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RB25 NVCS is a very very simple set up 2 positions of inlet cam postion. approx 10 degrees of difference.

Crude as only 2 postions unable to tune the base timing in so changing distance between crank and cam will and can change cam base postion.

RB motorsport can supply a RB25 based system for a RB26 circ around £2640-00 inc vat for a 260 deg cam and £2995 inc vat for a 270 deg cam. all with new parts.

The HKS variable cam pulley is from a Supra not a Subaru motor (late 2JZ)

The HKS system use a billet cam to allow the extra drillings to supply/drain of controlled oil pressure and to allow live cam postion to be read so allow closed loop cam position (just like a VQ35 or VR38 Nissan engine

It is worth it I feel allowing the engine to come up on boost approx 1000rpm earlier and still rev out if an idea scenario Spend sometime on a dyno playing with cam timing advance the inlet cam 10/15 degrees and see how much earlier the car will spool on full throttle and also on part throttle. then retard the cam right off and see how much better the motor will rev on making power.


Yes expensive it gives a good result thou.

So basically mark it's acting as a really long duration cam giving overlap low down to spool turbo then retarding cam higher the rpm?

I have hks 280 10mm cams and the more overlap I have the earlier the turbo spools and earlier the torqur comes in. So in theory if I went for 300degree 11.5 mm cams il get the best of both worlds and how would a vcam pro compare?
 
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Have you seen the RB Motorsport kit in action compared to a hks? Was going to go for the RB Motorsport one after I've sorted out my bottom end build, and popped a single on ;)
Not tuned a GTR with this kit but tuned a few RB25 and SR20 with the same idea , it works but will never be as good as a variable closed loop system with the ability to retard the cam as the revs raise so holding the power to the
redline.
 
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So basically mark it's acting as a really long duration cam giving overlap low down to spool turbo then retarding cam higher the rpm?

I have hks 280 10mm cams and the more overlap I have the earlier the turbo spools and earlier the torqur comes in. So in theory if I went for 300degree 11.5 mm cams il get the best of both worlds and how would a vcam pro compare?
No not like that. you need to advance the cam to make the car spool early then retard the cam at the top end;

Running a cam that aggressive will make the cam pretty cammy at lower revs.
 

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No not like that. you need to advance the cam to make the car spool early then retard the cam at the top end;

Running a cam that aggressive will make the cam pretty cammy at lower revs.

Yes advancing inlet and retarding exhaust gave my engine most response but it got to a point we had to stop due to idle roughness and drivebility low down. Of course that's then sacrafisin top end so my theory was then going bigger duration eliminates that?

Also how do you think a vcam pro only being 10mm lift would compare to say a tomei 290 11.5?
 
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Yes advancing inlet and retarding exhaust gave my engine most response but it got to a point we had to stop due to idle roughness and drivebility low down. Of course that's then sacrafisin top end so my theory was then going bigger duration eliminates that?

Also how do you think a vcam pro only being 10mm lift would compare to say a tomei 290 11.5?

Longer duration isnt the way to go , it will just move everything to the right on a dyno plot;

What are you trying to do? bhp figures or a drivable car?

The Pro V-Cam kit is the way forward as you advance and retard the cam 50 degree's. best of both worlds , car will idle nicely spool pretty hard and rev out nicely.
 
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Discussion Starter #72
I had an interesting talk with Rod Bell earlier, and they are now offering there own VCam system, manufactured between themselves and a Japanese partner. It seems to be working really well, making the cars a lot more drivable. He also said one customer (who was running large turbos):

Before the setup was getting 0.3bar at 3k rpm, was now getting 0.5bar.

Interesting and just over the £2k mark makes it far more affordable. :)
 

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I had an interesting talk with Rod Bell earlier, and they are now offering there own VCam system, manufactured between themselves and a Japanese partner. It seems to be working really well, making the cars a lot more drivable. He also said one customer (who was running large turbos):

Before the setup was getting 0.3bar at 3k rpm, was now getting 0.5bar.

Interesting and just over the £2k mark makes it far more affordable. :)
Thanks for sharing that. :)
 

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I had an interesting talk with Rod Bell earlier, and they are now offering there own VCam system, manufactured between themselves and a Japanese partner. It seems to be working really well, making the cars a lot more drivable. He also said one customer (who was running large turbos):

Before the setup was getting 0.3bar at 3k rpm, was now getting 0.5bar.

Interesting and just over the £2k mark makes it far more affordable. :)
Does this system need the same type of Pistons (I think the top is different) as the v-can type 2 and pro, or can you have normal type Pistons?
 
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RB25 NVCS is a very very simple set up 2 positions of inlet cam postion. approx 10 degrees of difference.

Crude as only 2 postions unable to tune the base timing in so changing distance between crank and cam will and can change cam base postion.

RB motorsport can supply a RB25 based system for a RB26 circ around £2640-00 inc vat for a 260 deg cam and £2995 inc vat for a 270 deg cam. all with new parts.

The HKS variable cam pulley is from a Supra not a Subaru motor (late 2JZ)

The HKS system use a billet cam to allow the extra drillings to supply/drain of controlled oil pressure and to allow live cam postion to be read so allow closed loop cam position (just like a VQ35 or VR38 Nissan engine

It is worth it I feel allowing the engine to come up on boost approx 1000rpm earlier and still rev out if an idea scenario Spend sometime on a dyno playing with cam timing advance the inlet cam 10/15 degrees and see how much earlier the car will spool on full throttle and also on part throttle. then retard the cam right off and see how much better the motor will rev on making power.


Yes expensive it gives a good result thou.

RB cam specs listed on here a while ago;

See above

can run with a stock piston so approx 9.1mm lift
 
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