Dialling In Hks Cams (rb25)

[PM-R33]

Lol trust me, that thought has been in my mind for a long time.

The stock cams are back in there at the moment, going back on the dyno this week to see if the power returns to normal, atleast it will give us some indication of whats going on. If it goes back to 260ish kw's i think i might sell the cams and new valve springs and let some one else deal with it haha.

[dangerman4]

all your timing marks look ok, but have you checked your intake cam gear adjustment?

that may have slipped, or moved during the install process?

(the back of the VCT on the intake cam is adjustable)

[joeyjoejoejuniorshabadoo]

so what happened after the stock cams went in? prob solved?

[Cubes]

Mine worked out ok. Dropped in a set of regrinds 265/263 picked up power everywhere >2000rpm. Went 302rwkw at 17psi std manifolds gt3076r .82.

[PM-R33]

Mine worked out ok. Dropped in a set of regrinds 265/263 picked up power everywhere >2000rpm. Went 302rwkw at 17psi std manifolds gt3076r .82.

Dam u Why didn't mine work!

Yeah power went back to the way it was with the standard cams. It has to be something in the head, only thing we didn't touch.

[Cubes]

I'm not sure if you have mentioned but I saw you have oversized valves.

Are the install heights correct? Maybe they are off slightly which has reduced seat pressure resulting in valve float once you get some decent cams with higher ramp rate in to it?

When mine was floating I had huge issues with trying to push ignition timing in to it past 4000rpm; it would simply ping.

[Haines]

hey cubes do you have a dyno readout on ur run

I have got the 3076r with the .73 housing and would like to see how responsive yours is

mine goes for a tune this week or next week and id like to see it hit a good number

[Cubes]

Sorry bud no can do as it was on the dyno soon realised it needed more work so pulled it off and didn't bother playing with adj. cam gears and finishing it off.

Boost is dropping to 17psi from whatever I push in to it.

It is on an rb30det so they tend to have a little more mid range and super responsive.

3500rpm - 200rwkw

4000rpm - 256rwkw

5000rpm - 288rwkw

6000rpm - 302rwkw

7000rpm - 290rwkw

Cams need playing with as I want peak power up around 6.5k; currently its running a fair bit of overlap which hurts/flattens out the top end.

Realistically there's not much more in it as the stock exh. manifolds typically top out around 300-330rwkw depending on how well everything is working.

Has a couple of things holding it back.. small fmic with 2" piping :S weak/lazy actuator thats blowing open.

[PM-R33]

Dont have oversized valves man, head has never been off

[Cubes]

Ahh sorry bud that was your self stating what if. :S

Maybe the std log manifold just doesn't like the large duration on the exhaust.

[PM-R33]

An interesting thing i just came across, my mate has a highly modified S15 with hks 256/264 cams in it and when it last got tuned the car was down around 80rwkw, no matter what the tuner did he couldn't find the problem. Checked timing and it was 100% set at the correct TDC marks. He than took it to another tuner and they found that the exhaust cam needed to be 4 degrees retarded and the power returned to normal.... Is it possible that on certain setups, the cams aren't ment to be installed at TDC even though most people do?

Im gonna go talk to this tuner this week and ask how he set up the exhaust cam and why it was 4 degrees out...

[Cubes]

Get it back on the dyno.

Mine was quite off with the cams; it absolutely loved lots ignition timing.

Get it back on the dyno with possibly another tuner for some fresh idea's.

[joeyjoejoejuniorshabadoo]

its definately possible... that's why we have adjustable cam gears

[ydr030]

having very similar issues my self, i feel your pain.

i pulled everything down and found

when evrey things lined up ( crank sproket to cam pulleys) the harmo lined up on second mark..

when u removed the harmo maybe the key ways fallen out anh harmos not sitting in right place and thats why when u check the timing its way off scale....

that s wat idid....

[SATO GTS]

PM-R33 . yes you are on the money there. Even though they say the cams are drop in you still need to DIAL the cams in to the correct position as the instruction's state.

Yes Iknow they are in jap but you should still be able to work it out.

Make sure the Dial gauge is sitting directly on the hydraulic lifter and not the cam as it will give you a true reading.

[PM-R33]

Well i have new cams and a new head now. First the cat collapsed and restricted us to 170kw, now with that fixed we are up to 240kw on 20psi. On this boost and head setup we should have easily cracked 270kw. Still trying to find the problem.

Edited March 26, 2009 by PM-R33

[Fastrotor]

Any updates ?

[PM-R33]

Ended up doing low 260kw with good power every where in the rev range. Very happy with it. However it should still make more power and the only red flag we have is the MAP sensor on the Microtech. The internal sensor is a 20psi one, so we can't run more than 20psi. The thing is, when we run 20psi on the boost controller, the boost gauge and the dyno, the Microtech is seeing 25psi and getting a MAP error. So we can't tune for that boost. So in reality, anything over 15psi, the Micoretch sees 20psi and no more tuning available.

So i might send the ECU away and get them to swap it over to the 30psi one and go again, but for the time being i got uni and shit to concentrate on so i'm gonna leave it how it is for now.

[Fastrotor]

Ah ok. Yeah the MT's are a pain when your running close to 20psi .... as i won't let a car go without the map cut enabled, so you need a small leeway before it hits max to use it.

You should measure Turbine Inlet Pressures to see where the GTRS is at, at least give you a easy indication if much more is avail...... might not be worth it until you step up in turbo.

I got 272 rwkw on a 3500 histall auto yesterday, but the 135K std head gasket finally let go. Also the VCT isnt working down low, and killing my boost response.

How did you rate your head work ? I think i'll just get a good head gasket and bolt it all back on. Just weld up the VCT to full advance, and should get bottom end back and im happy with top end.

Gary

[Weapon]

I hate to say this but the i think the turbo is going to be the limiting factor in this set up, as the head is now to efficient and i'd imagine that it would run out of steam in the top end. However i have no doubt that this set up has monumental midrange and low end punch. I think to get 290-300rwkw with that turbo would all but be impossible. Have been for a ride in this car when it was running std cams and it was very impressive but even then i could still notice a slight drop off in power delivery towards the top end