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That is a massive difference.

I think 272s would kill the idle a little too much for my liking.

SK,

Do you think the 260s would be better than the 256/260 for my application? I think I will drop in a set of cams and keep the GT-RSs for now. If it doesn't work out, the cams won't be wasted with smaller turbines anyway.

I have attatched the GTRS graph from the HKS website. I would love to know what has been done to that engine, because it looks like the engine is making 1.8kg boost at about 5000RPM. I guess the Jap fuel helps because you can run heaps of timing on spoolup.

Is the R34 RB26 a bit better than the R33 version? Or is the extra torque on the R34 over the R33 just due to ECU mapping?

The R34 GTT RB25DET Neo has solid followers, so Tomei have 260 degree Poncams for them. The 256's are for the R33 GTST R25DET (non Neo) which has hydraulic followers.

As for the HKS dyno, I have yet to hear of anyone, anywhere in the world that has achieved that result. I don't know what HKS did on the engine dyno, but this is what I would do;

1. Run a highly oxygenated fuel with a high RON, like TurboMax (sold as HKS Drag Fuel in Japan) :idea:

2. Use a water to air intercooler with iced water :aroused:

3. Who cares about detonation, it only has to do one run

4. Don't worry about tuning for daily life, just screw everything up to the max.

5. Use a constant loss water cooling system (not a radiator) and maintain the perfect engine temp

6. No flywheel, alternator or water pump

7. Run the turbo inlet off the dyno room airconditioner outlet, with no restrictions

8. No exhaust, mufflers or restrictive pipe, straight off the tubo dumps into huge vacuum assited ducting

This would give me a "true" result, but hardly what I would call "real world". But maybe I am just more devious than HKS. :rolleyes:

The R34 GTT RB25DET Neo has solid followers, so Tomei have 260 degree Poncams for them.  The 256's are for the R33 GTST R25DET (non Neo) which has hydraulic followers.

As for the HKS dyno, I have yet to hear of anyone, anywhere in the world that has achieved that result.  I don't know what HKS did on the engine dyno, but this is what I would do;

1.  Run a highly oxygenated fuel with a high RON, like TurboMax (sold as HKS Drag Fuel in Japan) :idea:

2. Use a water to air intercooler with iced water :aroused:  

3. Who cares about detonation, it only has to do one run

4. Don't worry about tuning for daily life, just screw everything up to the max.

5. Use a constant loss water cooling system (not a radiator) and maintain the perfect engine temp

6. No flywheel, alternator or water pump

7. Run the turbo inlet off the dyno room airconditioner outlet, with no restrictions

8. No exhaust, mufflers or restrictive pipe, straight off the tubo dumps into huge vacuum assited ducting

This would give me a "true" result, but hardly what I would call "real world".  But maybe I am just more devious than HKS. :rolleyes:

Yeah...I see your point :D

Just a bit of an update, with more road tuning, I now reach 1.3 bar boost by about 5400RPM in third gear. The car feels much better to drive. If cams improve the midrange even slightly, the driveablility will be good enough for me.

The only thing is, I will definately need to fix my AFM issue first.

Mik,

im running standard BNR34 N1 bottom end and BNR34 N1 turbos in my 32. I also have trust 264 9.1mm camshafts and the car is making more power than your car and is making full boost by 4750 rpm. There is something funky going on.

TG

rev210: do you actually know of anyone that can source a C/F prop for an RB26?

LW.

These guys can do one for you.

http://www.ctgltd.co.uk/motorsport.php

Or these guys...(probably better since the Dollar conversion works better for us).

Ask them about a group buy discount.

http://www.acpt.com/

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