Jump to content
SAU Community

Recommended Posts

  • Replies 131
  • Created
  • Last Reply

Top Posters In This Topic

Dave/lukevl, As you can see, even with the stock cams it wasn't falling off as much as I would have expected. I kept the stock cams in so long just to see what power we could get out of them. They seem to have done very well.

Dave/lukevl, As you can see, even with the stock cams it wasn't falling off as much as I would have expected. I kept the stock cams in so long just to see what power we could get out of them. They seem to have done very well.

WOW.......What car is that on?

The cams are a good choice. I don't see anything wrong with them although I would use more lift. But with more lift you will need to machine the head. I have 9.9 mm of lift on STD base circle and the head needs machining to fit the lobes in

Paul - Do you have the @ 0.050" figures?

Sorry lukevl, your speaking to a cams dunce, but I can get ND4SPD to check the figures as he'll be putting them in.

These are NVCS cams, and as such haven't been able to find anything with higher lift, due in part to the hydraulic lifters.

Because they use hydraulics the lift isn't as aggressive as you get with solid lifters, but there the biggest I could find. 270duration  8.9mm lift. Shouldn't require any machining, and we're just putting a set of performance valve springs in to cope with high revs, 8.5k:D

What valve springs have you chosen?

Is that 8.5k spent on the engine?

i think in the case of the tomei poncams, sydneykid said that cam gears aren't necessary because tomei got the timing spot on. In the case of having normal cams in the rb25, cam gears in the series 1 rb25dets alot of ppl have seen nice improvements.

Great thread guys.

I just need to clear something up here, I have used the Tomei 256/260 Poncams in 2 X RB25's, one Neo in an R34GTT and one non Neo in an R33 GTST. Neither of them benefitted from having an adjustable exhaust camshaft pulley, they both made their best average power at zero degrees adjustment. The Poncams work very well with the VVT, I kept it, so no adjustable inlet camshaft pulley.

This has not been my experience with GTR's, they ALWAYS benefit from adjustable inlet and exhaust camshaft pulleys. The more extensive the mods, the more they benefit and no two engines are the same.

Hope that clarifies:cheers:

What valve springs have you chosen?

Is that 8.5k spent on the engine?

The 8.5k, is 8500rpm. There performance valve springs that we've ordered, to cope with the higher lift and high rpm, will find out off SST-Steve which manufacturer there from.

I have an adjustable exhaust cam gear, with the stock cams we found zero to be the best, will see what the apexi cams dial in at best.

what sort of cams would be good on an RB30DET using an RB25DET head with NO!! VCT.. its been welded up.

I take it that with the hydraulic lifters i'm limited to ~8.5mm lift.

I am worried if i get a set of Tomei poncams they wont be 'ideal' for me as they are designed to work WITH VCT... but i dont/wont be running that...

anyone shed some light for me?

:D

what sort of cams would be good on an RB30DET using an RB25DET head with NO!! VCT.. its been welded up.

I've been looking at cams for a similar application. You're right in that we're limited for lift since they're for hydraulic lifters. I think we're down to HKS 256/256 or 256/264 at 8.8mm lift, or Apexi 250/250 or 250/260 or 260/260 at 8.9mm lift. I'm leaning towards Apexi 8.9mm of some duration for similar reasons as vspec - the lift. We won't need as high duration cams as vspec because we won't be reving anywhere near 8.5k. :D

I've been looking at cams for a similar application. You're right in that we're limited for lift since they're for hydraulic lifters. I think we're down to HKS 256/256 or 256/264 at 8.8mm lift, or Apexi 250/250 or 250/260 or 260/260 at 8.9mm lift. I'm leaning towards Apexi 8.9mm of some duration for similar reasons as vspec - the lift. We won't need as high duration cams as vspec because we won't be reving anywhere near 8.5k. :)

I have found the Tomies to be superior to both of those brands in RB25DET's.:cheers

On the lift side of things the HKS cams for the RB25det do go as high as 9mm of lift @ 264deg duration, at least on the exhaust side. I put one of these in the old R33 gtst.

And did you have valve spring issues.Or was it fine and dandy??

What is the cost of valve springs and whats it like to install a set while the cams are out.Does it interfere with the valves when trying to install valve springs?

:flower:

I have found the Tomies to be superior to both of those brands in RB25DET's.:cheers

Yeah but SK he was talking about an RB30/31DET

what are your thoughts on cams for an RB30/31DET with NO VCT?

And did you have valve spring issues.Or was it fine and dandy??

What is the cost of valve springs and whats it like to install a set while the cams are out.Does it interfere with the valves when trying to install valve springs?

:flower:

No spring issues. My engine was set to develop a nice fat power band up to 7500rpm. I had only the aftermarket exhaust cam and a factory spec inlet cam.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now



  • Similar Content

  • Latest Posts

    • That R31 was so cool. Only did Orange Park once. Scared the hell out of me.
    • Selling my TE37SLs since I've switched to smaller wheels.  They're for sale in Japan but it's pretty simple to send them overseas; USA excluded, since JPPost isn't sending there at the moment. Specs Front: 18x9.5j +22 5x114 Rear: 18x10j +20 5x114 Price: 320,000 JPY/ 3,285 AUD (current FX rate) Condition: a few scratches here and there, no bends, distortions or cracks.  Tires will not be included for international buyers, I'll get them dismounted before shipping. They're currently listed on yahoo auction and will be shipped in Japan with the tires if they sell here. Shipping costs to Aus: EMS (1-2 weeks): AUD 1,175 (current FX rate) Sea (2 months): AUD 460  (current FX rate)
    • The alloy coolant reservoir has a sight glass, so as long as I can see coolant in the sight glass it's GTG, as for PS, it isn't anything catastrophic if it gets low, and as it hasn't lost a drop since I have owned the car I cannot see it being an issue, even after putting the "big block" 2.5 in....LOL The only time it gets slightly messy is at oil changes, as the oil filter sits above the frame, and I need to use a plastic bottle with its bottom cut off to catch the flow when loosening the filter
    • Good on you for taking on the job, but it is a big one. Even if you have bolt on manifold and turbo, you will need: Post throttle pressure source to boost controller to wastegate (and FPR, and ECU/MAP sensor) Pre throttle pressure source to top of BOV(s) Oil feed - you can take that from the standard port in the middle of the block Oil return to block under the turbo - this is much trickier than it seems to route a decent/wide pipe past the manifold. You really can't use rubber hose because it is way too hot there, and also the oil out of the turbo core is a bit frothy so it needs to have a decent diameter Water feed - you can take that from the standard port in the rear of the block. Water return - mine runs to a T into the heater box return, just make sure you don't create a high point making bleeding hard. All of those lines should use 200 series style teflon braided hose with heat shielding because everything needs to be routed past the manifold. Also a turbo beanie is a really good idea to minimise the chance of the car catching fire (under bonnet lining in particular) You also need to decide a cam cover breathing solution as well, will you vent externally via a catch can (probably illegal) or return to the intake (plumbing required and can oil up everything over time) Keep in mind the intake and exhaust piping in the engine bay will be custom so you either need to be able to fab ally and steel or have someone you can get a car that isn't running to. Get the wideband fitting welded into the dump pipe at the same time. Also, just my opinion, a screamer pipe attracts attention and doesn't add power, I'd plumb it back if you want to be allowed to keep the car on the road. BTW do you know anything about how healthy the motor is, and what power you are targeting? Doubling or tripling the factory power on an unknown motor is a little risky. Also fuel system will need some attention (pumps, high current hanger, direct power and earth feed, injectors etc)
    • Wrinkle black will be a thing for both
×
×
  • Create New...