Best place to source mild cams for the RB25det quickly and cheaply

[RBVS]

yea i might look at the exhaust cam and keep the standard inlet cam. (what the jms car had at one stage)

[Cubes]

U didn't do springs did u Steve?

[Steve]

I'm confused, I have seen 256, 260 and 264 described as "Step 1".  Plus I have 264 described as "Step 2".  So I just call them 256, 260 or 264, "Step" is a useless term.

AFAIK, step 1, 2 etc are terms coined by the Japanese for levels of tuning, as in:

Step one HKS inlet cam is 256/8.8, step one exh is 264/9.0. Step one inlet is the only HKS cam you can keep NVCS with.

Step two are higher lift, and larger duration on inlet (264), there fore you can have a 264 step 2 cam.

[Steve]

Joel, yep, standard springs and lifters. not planning on running huge rpms, and the cams arent that agressive.

[Sydneykid]

Thanks Steve, but I'm still confused, help me out here;

If Step 1 means "the biggest cam you can run with VVT", what is Step 1 on an RB20 or an RB26 that don't have VVT?

A 264 on the exhaust is Step 1, but a 264 on the inlet is Step 2. That sounds illogical, am I right? Or is that only RB25's and 264/264 is Step 1 on RB20/26's?

What is a 256 inlet and 260 exhaust, is that Step 1 or 2?

What is a 260 inlet and 264 exhaust, is that Step 1 or 2?

If I have a 264 at 9 mm, that's Step 1 right? But only if it's an exhaust cam, yeh? What if I have a 264 at 9.5 mm, is that still Step 1?

Hang on, if I have 264/264 at 9.15 mm for a GTR that would be Step 1, but the same cams are Step 2 for an RB20. So if I have a GTR with 264/264 I can say they are "Step 2 cams". That can't be right, can it?

It would make more sense if;

Step 1 meant no other mods, just stick the cams in and they will work

Step 2 meant you have to change the valve springs if you fit these cams

Step 3 meant you have to machine the head for nose clearance and change to offset buckets as well as the valve springs if you fit these cams

Step 4 means as well as all of the above, you have to increase the size of the flycuts in the pistons or recess the valves into the head or use a thicker head gasket to use these cams.

Now that would make sense to me.

[Steve]

Thanks Steve, but I'm still confused, help me out here;

If Step 1 means "the biggest cam you can run with VVT", what is Step 1 on an RB20 or an RB26 that don't have VVT?

A 264 on the exhaust is Step 1, but a 264 on the inlet is Step 2.  That sounds illogical, am I right?  Or is that only RB25's and 264/264 is Step 1 on RB20/26's?

What is a 256 inlet and 260 exhaust, is that Step 1 or 2?

What is a 260 inlet and 264 exhaust, is that Step 1 or 2?

If I have a 264 at 9 mm, that's Step 1 right?  But only if it's an exhaust cam, yeh?  What if I have a 264 at 9.5 mm, is that still Step 1?

Hang on, if I have 264/264 at 9.15 mm for a GTR that would be Step 1, but the same cams are Step 2 for an RB20.  So if I have a GTR with 264/264 I can say they are "Step 2 cams".   That can't be right, can it?

It would make more sense if;

Step 1 meant no other mods, just stick the cams in and they will work

Step 2 meant you have to change the valve springs if you fit these cams

Step 3 meant you have to machine the head for nose clearance and change to offset buckets as well as the valve springs if you fit these cams

Step 4 means as well as all of the above, you have to increase the size of the flycuts in the pistons or recess the valves into the head or use a thicker head gasket to use these cams.

Now that would make sense to me.

Hold on a second, I never said step one means "the biggest cam you can run with VVT", please re-read.

The following applies to RB25:

HKS 256 step on inlet cam is the only cam (HKS make) that still allows the use of VVT. Tomei, from memory, make a 260?

HKS refer to different levels of tuning as steps

Step one HKS cams are 256in/8.8, 264ex/9.0

Step two are larger, step three are larger again.

I am pretty sure HKS do a step 2 inlet which is 264, it has a larger lift than the 256, and obviously a longer duration, which would explain your confusion at 264 step on and 264 step 2. I am not as sure, but I believe they also do a 264 exhaust that is similar lift, in that it isnt a direct bolt on.

Different engines have different durations and lift for their steps, obviously.

If you look at a catalogue (which I know you refuse to own;)) they have different levels of tuning. Each sucessive 'step' requires more work, for different levels (or steps) of tuning, and the step 1's are a straight bolt on. The steps were described to me much as you pointed out in the latter part of your post - but I didnt pay alot of attention at the time, as I was after cams that allowed me to use VVT and were a direct fit and kept reasonable idle without the need for vacuum tanks for brakes etc - I didnt look past a direct bolt on, as IMHO, it would be overengineering a car being used for street and light track work.

Does that help?

[lukits01]

correct me if Im wrong but doesnt HKS make 256 exhaust Cams for RB25DET? and they state its for NVCS engine. and they dont say anything about 264 exhaust cams working with NVCS.

I know the VVT is only in the inlet cam, so how does that make sense?

would both 256 and 264 exhaust cams bolt on into the head without modification?

[Steve]

where did you see that?

[lukits01]

this is from nengun and taka kaira had the same chart I think

HKS Cam Shafts

[rev210]

the HKS 264 exhaust cam works with the NVCS and they do have an NVCS 256 & 264 RB25det intake cam as well.

[Steve]

I cant understand why they would put up a 256 NVCS cam for exhaust. I was told that they also do a 256 inlet that is for use without NVCS, perhaps they have their wires crossed, and should have 256 in, with and without NVCS instead of a 256 exh with nvcs?

I was told the only HKS cam I can get to run with NVCS is the 256. This was by a friend who rang Japan for me to find out what options I had.

[Amaru]

I was under the impression the "step" levels reffered to the amount of lift on the camshaft

For example

HKS Step 1 camshafts are all 8.7mm lift

HKS Step 2 264 in/ex camshafts are 10.0mm lift

HKS Step 2 272/280 in/ex camshafts are 10.2mm lift

This applies to the RB26DETT, HKS dont seem to list "Step" options for the RB25DET.

[Sydneykid]

Hi Steve, I am still confused, help me out here...

You posted;

"Step one inlet is the only HKS cam you can keep NVCS with."

I posted:

"the biggest cam you can run with VVT"

The only difference I see here is I assumed "HKS" where you said "HKS". But otherwise don't they mean the same thing?

If HKS only have ONE inlet cam for VVT, then it must be the "biggest", surely? It can't be the "smallest" because the standard cam is "smaller".

Does anyone, other than HKS, use this Step 1, Step 2 categorisation? I have never seen it on any Jun or Tomei camshafts we have used.

[Steve]

I dont know about anyone else, sorry, Yes I was referring to HKS only, as other places make larger cams that can be run with NVCS.

Not so confusing now is it, you answered your own question. I know it is being pedantic, but context can be hard to convey over a forum, so I beleive some times it is warranted, such as now.

But really, if you are having such a hard time grasping the concept, why hold on so tight, doesnt really make a huge difference if you call something step one, or mild upgrade or bottom of the range?

[lukits01]

so for mild upgrades

if I wanted to change only the exhaust cam shaft

how does the 256 compare with the 264?

does idle quality suffer?

[Clint32]

Steve, i have a HKS 272, 8.53mm lift cam for the inlet side of rb25, and i will be getting a 272 8.7 HKS RB26 cam for the exhaust cam ai its the only one i can find to match. The cams not listed anywhere but its new with HKS stamped into it.

[Steve]

special order? or a regrind?

[Clint32]

not a regrind and i would doubt hks would make a special order for one cam, who knows

[BOOSTD]

I have just installed some Tomei 264 8.5mm cams. Doesn't enable the use of VCT. Not sure what to set the cam wheels to... Have the inlet on +2 degrees and exhaust on 0. I have lost power low down and gained quite a silly(feelings wise) amount after 6000rpm. Has anyone used these cams before. I am thinking maybe the exhaust side is not spot on like the 256 poncams. Hopefully I can gain some low end with some exhaust retard.

Any info would be greatly appreciated

Matt

[Sydneykid]

Hi Matt, somewhere between 2 and 4 degrees retarded on the exhaust is the most common.