Hks Cams Which Ones?

[ike]

Hi everybody

Have a stock r33 vspec with a very healthy engine.

Have a full weldina NE1(titanium) exhaust system( fitted by previous Japanese owner) - PFC - KN filter

Have purchased gtss turbos and was wondering which will be the best cams to fit .

Some track days mainly mountain roads so I want better response.

At the moment it is a toss up between hks 256/8.7 in out or hks 264/8.7 in out

or 256 in 264 out . With HKS adjustable cam gears.

Heard a few people say this will give a stable idle

So I am sure this has all been done before by someone in SAU

Would really appreciate any input from u guys in the know.

all the best

Ike

[Adriano]

For what your after, i would recommend 256in and 264 ex, still maintains good off boost torque and idle.

[Gav]

I originally had "mismatched" cams (264IN,272EX) both in step 2 lift. I changed out the IN cam to 272 and picked up both power and response. This was an a 2.8L with GT-RS terbs however.

My gut feel for your applications is that 256 both IN and EX would be the go, but probably better to get some other opinions from people using these terbs.

One thing that has come up time and again - cam timing plays a huge part in performance. This is time consuming on the dyno, but certainly worth while experimenting!

[Faid]

Poncams, 260 IN and 260 out @ 9.15mm lift. the best way to go, and adjust your cam timing good. with the poncams and untuned camgears, the car pulled lazy towards boost and the boost kicked in later @ 4900, but after tuning the gears, it was way more responsive towards boost and the moment ful boost hit was at abou 4600, and it pulled way better all the way through the rev range

[Bl4cK32]

U shouldnt need adj. cam gears with aftermarket cams.

btw, theres no such thing as step 1, step 2 in cams...

[Adriano]

^^^^^^^^^^^^^^^^Cummon who are you kidding, i would say camgears are essential to getting the expected performance gain from cams, cam timing can easily make 20 or 30 rwkw difference, even 20 with stock cams.

[Bl4cK32]

do a search...it has been covered a few times, however im sure that some have picked up a result using them...

[ike]

Thanks for the info on the cams

from what else I have gleaned around the place I am going with the HKS step 1 256 IO cams with the hks slide pulleys .HKS call this cam step1 by the way .

Will post dyno results soon

regards Ike

[ike]

Thanks for the info on the cams

from what else I have gleaned around the place I am going with the HKS step 1 256 IO cams with the hks slide pulleys .HKS call this cam step1 by the way .

Will post dyno results soon

regards Ike

Have since canned the slide pulleys and will see how they go with the normal pulleys - Found out the dowel (knock pin) has been indexed to the optimum position so any gains will be in the tune.

[Gav]

Have since canned the slide pulleys and will see how they go with the normal pulleys - Found out the dowel (knock pin) has been indexed to the optimum position so any gains will be in the tune.

Hmmmm......is that THEIR optimal position or YOUR optimal position?

Changing the cam timing affects variables such as fuel economy, exhaust emmissions and idle quality as well as changing the shape of the power curve (eg maximum power versus response).

In fact I would go as far to say that the gains you will get with adjusting the standard cams on the dyno (via adjustable pulleys of course) may be more significant than just adding the cams on their default timing setting.

Your call, but as I said previously, it's certainly worth playing with cam timing to optimise what YOU want from your engine.

Good luck

Gav

[ike]

Hmmmm......is that THEIR optimal position or YOUR optimal position?

Changing the cam timing affects variables such as fuel economy, exhaust emmissions and idle quality as well as changing the shape of the power curve (eg maximum power versus response).

In fact I would go as far to say that the gains you will get with adjusting the standard cams on the dyno (via adjustable pulleys of course) may be more significant than just adding the cams on their default timing setting.

Your call, but as I said previously, it's certainly worth playing with cam timing to optimise what YOU want from your engine.

Good luck

Gav

How would I know there optimal position Gav But I reckon HKS would after all they made them after a lot of experimentation and research. But it would be interesting to see - how about if you pay

for it .

Can do without your condescending presumptuous mouth though if you read it properly I said hks's optimal position.

Have you actually practiced any of the stuff you preach or is it all just stuff you have read

Get a life .

regards

Mike

[rev210]

U shouldnt need adj. cam gears with aftermarket cams.

The actual cam manufacturers including HKS and Tomei will tell you otherwise, the fact they even make them and sell them as a package with cams is case in point.

You do want to have them if you want to get anywhere near the full potential from the cams. They are a must have on the RB26 in question.

As an example my old GTR with 260 poncams on stock turbos picked up plenty more power everywhere over the '0' position starting points and again when turbos were upgraded to group A's.

food for thought

[ike]

The actual cam manufacturers including HKS and Tomei will tell you otherwise, the fact they even make them and sell them as a package with cams is case in point.

You do want to have them if you want to get anywhere near the full potential from the cams. They are a must have on the RB26 in question.

As an example my old GTR with 260 poncams on stock turbos picked up plenty more power everywhere over the '0' position starting points and again when turbos were upgraded to group A's.

food for thought

I do have the hks adjustables gears and yes you are probably right but it comes down to money in my case. I am not chasing every single kilowatt but wouldn,t mind seeing some comparos though

Cheers

[rev210]

I gained 20rwhp on tomei cams / stock turbos across the rpm range and slightly more than that with the group A turbos, a friend running garret turbos / poncams picked up almost 100rwhp up top with timing change (it went from 435rwhp to 529rwhp from memory, same boost).

every single kilowat is not what you are after its being able to control the power curve shape that is good. You get more than single kw's and more importantly better 'average power'. Peak power isn't as valuable.

Edited March 13, 2007 by rev210

[Gav]

How would I know there optimal position Gav But I reckon HKS would after all they made them after a lot of experimentation and research. But it would be interesting to see - how about if you pay

for it .

Can do without your condescending presumptuous mouth though if you read it properly I said hks's optimal position.

Have you actually practiced any of the stuff you preach or is it all just stuff you have read

Get a life .

regards

Mike

Chill Mike - nothing condescending or presumptuous meant.

My point was that "optimal" can relate to any of the properties that I mentioned in my post (peak power, early boost, maximum fuel economy etc). All that I'm saying is that many people (including me) have made gains be spending extra time (and as you point out money) on the dyno optimising cam timing to suit your goals. This is particularly the case if your goals change with time (as mine did).

I've played around with my GT-R few a few years now, have a click on my gallery here.

Again (genuinely) good luck

Gav

[ike]

Chill Mike - nothing condescending or presumptuous meant.

My point was that "optimal" can relate to any of the properties that I mentioned in my post (peak power, early boost, maximum fuel economy etc). All that I'm saying is that many people (including me) have made gains be spending extra time (and as you point out money) on the dyno optimising cam timing to suit your goals. This is particularly the case if your goals change with time (as mine did).

I've played around with my GT-R few a few years now, have a click on my gallery here.

Again (genuinely) good luck

Gav

I have chilled Gav sorry for the snap its all good .

That is a serious spec-list you have there.

You weren't kidding.

This thread is producing good info on the subject .

more comparos the better.

Edited March 13, 2007 by ike

[Devils_Advocate21]

I aggree on several points, You may get extra gains with cam gears, but is limited buy time and money at the end of the day, best to start with cams first then if your not happy get the gears later and then tune with the gears to gain extra potential. Stable idle also comes down alot to tuning aswell in this case, also best to talk to a recommended tuner about it for a secondary opinion. Good luck and keep us posted with results

Cheers

A

[rev210]

I aggree on several points, You may get extra gains with cam gears, but is limited buy time and money at the end of the day, best to start with cams first then if your not happy get the gears later and then tune with the gears to gain extra potential. Stable idle also comes down alot to tuning aswell in this case, also best to talk to a recommended tuner about it for a secondary opinion. Good luck and keep us posted with results

Cheers

A

I'd reccomend basically the opposite.

Putting cams gears on from the get go saves money in double tuning. By cam gears first then cams makes more sense if not only because on all the RB's from 20/25 & 26 gains can be had with stock cam timing changes, this is well proven.

Depending on the engine setup it is possible to go backwards at the '0' mark with aftermarket cams (I noticed this on the GTR with stock turbos) this is because they are designed around an intended engine spec and setup. Perhaps a certain type of compression / valve size / manifold / turbo spec / head porting etc.....

Bottom line is that if you are too broke to afford a few hundred bucks for some cam gears, re-consider the ownership of a GTR or RB26 equipped car.

[Steve]

On my rb25, used HKS cams with cam gears - and they ended back up at 0 (HKS 3037 and approx 320rwkw)

The tuner tried to tell me I was wasting my (his) time by experimenting, but I insisted - and paid.

I once asked a japanese mechanic from signal where he would set cam gears with HKS 256/264 step one cams for SR and RB - he said he didnt bother, they were already set correctly and there was no gain to be had for a midrange/street/drift type application. The only time he uses cam gears if for drag application to optimise top end.

A friend who had SR with 256/264 HKS cams and T518Z (drift car) found the same thing, fitted cam gears, ended up back at zero

All the above are with regards to the latest HKS cam grinds, which were revised around 3? years ago??? I have been told by unverified sources that the older style cams had good mid range gains available from dialing in

Would be good to hear what others have experienced with HKS cams

[rev210]

Interesting Steve.

Do you have enlarged valves or any porting work done?

Did the tuner alter the fuel and ignition map each time the cam timing was altered? This is critical as changing the cam timing alone will almost always see power go backwards. I have seen a tuner make this mistake before.

My old R33 Gtst had a HKS exhaust cam (factory inlet) and it needed moving to get the best result. Different kettle of fish again.

At the very least you ought to be able to alter cam timing to see the power curve move down (and lose top end) and up (lose bottom end).

Gav has I believe HKS cams for instance and doesn't run '0' either (they are new ones).