rb25de turbo cams

[R32GTS-R]

So a friend of mine has an rb25de with the det turbo added. Unfortunately he still has the de cams which causes boost to lag until about 4000rpm. Would swapping to the stock det cams bring that down to 3500 rpm or lower? If no, please offer suggestions. If yes, does anyone have a set for sale?

[Skym]

R32 or R33 RB25DE??? R33 RB25DE has VVT.

Check intercooler size, as might be too big.

Size of intercooler vs hp (engine + turbo) is mentioned here -

http://www.turbobygarrett.com/turbobygarrett/intercoolers

Stock side mount intercooler should be sized better and bring full boost on 500rpm or so earlier. But can heat soak.

On turbocharged engine with FMIC (to bring full boost on earlier in rpm) you fit full 3" exhaust from turbo, adjustable internal wastegate actuator (Garrett or HKS), camtiming adjustments via adjustable cam gears on intake, exhaust cams (cam specialist can modify stock camgears, so are adjustable), electronic boost controller (HKS, Blitz, etc), ECU tune. This helps to build full boost earlier (-500rpm or more, depending on settings).

[R32GTS-R]

It is from an r32. It is totally stock even with the smic. Are the cams from the de the same as the det?

[Skym]

Stock R32 RB25DE cam specs, etc are here -

http://www.tomei-p.co.jp/_2003web-catalogue/e090_camshaft-specs.html

In turbocharged applications (fitted onto RB30 bottomend) the R32 RB25DE valve springs can be too weak (especially if engine has done higher km).

[R32GTS-R]

So can we use cams from another rb motor to help with spool?

[Skym]

Could use RB20DET cams, as are non VVT and work with stock Mitsubishi CAS. But would need adjustable camgears, as camtiming probably will be out for RB25DE+T engine and ECU retune to suit (need to adjust ignition timing to match CAS, etc).

But with the stock R32 RB25DE cams, adjusting intake cam timing can help with reaching full boost earlier.

Camtiming adjustments with RB20DET -

http://www.300zx.com.au/Dyno/yx32gtstdyno.gif

A stock R33 RB25DET has VVT on intake cam, which helps it to reach full boost earlier in rpm.

[r33_gtst]

I also have an rb25det with the vvt disabled due to it not working with my power fc d jetro. I'm looking to do cams next year for a better power band, my compression across the board is 165-170psi so I have a very healthy motor.
Was thinkin of upgrading cams, intake manifold and turbo for a better power band. Any recommendations for cams in a stock block?

[Skym]

In Japan you would buy a kit with turbo, exhaust manifold, intake manifold (if part of kit), FMIC, cams, ECU, injectors, AFM, fuelpump, etc from tuners (worked out for you).

From what I understand, cams are designed to match powerband of engine that other parts (head, intake manifold, exhaust manifold, turbo, etc) change. For example the other parts create a 4000rpm - 7000rpm powerband where turbo is at full boost. You pick cams to match that powerband (4000rpm - 7000rpm). That's what people mean when they say cams, turbo, etc work together. At least that's how I understand how it works.

If want to work it out yourself, send head to cam specialist (or engine rebuilder if they have equipment) and they will flow test head. Also send info they require (intake, exhaust manifold, etc specs), as shown in link below (usually sent by engine rebuilder) -

https://www.capella.co.nz/sites/kelford.co.nz/design-shop/

They then can tell you what cam will work with head, intake, exhaust manifolds, turbo, etc. Otherwise you are just guessing what cam will work. Getting it correct will give you a very quick car.

I noticed on a few dynocharts for EVO? that the above cam specialist cams will give you more mid to peak hp over other brand cams at lower boost levels (seems to be more aggressive with cam specs). At higher boost levels there's not much difference between different brand cams. Japanese made cams seem to be mild for longevity and reliability of head parts (to do high km) and some are designed for stock ports, stock camgears, stock valve springs, stock exhaust manifold, etc (Tomei Poncams).