s15 upgraded cams with VCT

[s15dave]

Afternoon folks,

got a quick question for you tech heads out there.

looking for some experiences and/or recomendations for the cam shafts in my s15 (its a japanese import type R, just for information)

current mods: decent exhaust (split dump, 3", few mufflers), the "free boost upgrade"

near future mods: front mount intercooler, gready emanage ultimate.

so short story, the dreaded VCT rattle has started to get worse. started off as a rattle at start up, but fairly sure it is rattling when it engages at ~4000 rpm, then quietens down from 6000+.

quotes from nissan reveal the parts to be quite expensive.

so i get thinking should i get some upgraded cams instead and delete the VCT.

now my understanding is that stock intake cam (and exhaust?) is 248 degrees. does anyone know what effect the VCT has on this? ie how much does it change it?

as if i get say some 264 cams, does the VCT + 248 = more than 264?

now this brings me to my next point, am i better off keeping the VCT with the 264 cams and getting even more benefit from the VCT (264 + VCT = ~280+?), and this leads onto the question, does anyone have any experience with using the stock VCT system with upgraded cams?

i dont completely udnerstand what the VCT does, i know it doesnt change the duration, more changes the timing of the whole intake itself.

If i can utilise the VCT benefits with the uprated camshafts, that would be awesome.

i guess the main drama is do aftermarket cam shafts tend to fit with the VCT? or would i need to have something custom made.
any insight would be much appreciated.

 

[DeanS15]

most aftermarket cams can be run with vct no problems, there is the threaded drilling on the end of the inlet can to install the sprocket to. i run tomei 256 poncams and there is a lovely spread of power, it works perfectly with the vvt. don't do away with it, only on big power cars have i seen people talk positively about doing that, in all other cases people said they lost lots of driveability....

 

[s15dave]

ahh very interesting. thankyou for the reply.

well that is good news!

so im better off just buying the new VCT parts, and getting some cams while im at it? (with i guess springs and whatever supporting valve train mods would be required)

 

[DeanS15]

for the spec, i wouldn't bother with cams mate. there are more useful modifications to spend your money on at that level such as injectors, air flow meter, electronic boost controller etc. i wouldn't say it's worth a cam change until you upgrade turbo. if/when you do change them, then yes it is worthwhile doing the springs and retainers too

change the solenoid first (or borrow a friends to check), see if that fixes it, if not its the sprocket ($$$) or earmuffs

 

[sjt47y]

yups agree, do other mods first. if u intend to do engine i suggest u do it at 1 go. I did the engine twice and could be doing it 3 times... total waste of money, need to run in and retune. dont go through the same process as me.

 

[AllanOrr]

You can run any cams with VTC
I have HKS Step 3 Cams Intake 264 exhaust 272 that are for the VTC that are due to arrive in the next week or so but if your not going full out the step 2 cams might be better for your set-up

 

[_Wing_]

The VCT unit advanced/retards the intake camshaft 20 degrees to get the best power in the low end, as well as the top end. It's definitely worth keeping.

 

[s15dave]

thanks for the replys guys much appreciated.

i shall look into my cam options!