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also why do u rekon stock r34gtt's have more power than stock r33gtst from the factory..??? it would have to do with the timing etc and little things that all add up if abit more time and research is taken.

R34 GTT's have slightly different lobe offsets and they have solid lifters, not hydraulics like R32/33 GTST's. Plus VVT on the inlet cam is infinitely adjustable, not like an R33 GTST where it is on or off. The specs on the R34 GTT exhaust cam read 4 degrees retarded compared to the R33 specs. This may explain the lack of improvement available as this is where we generally find the best setting when fitting an adj exhaust pulley.

"So the difference in factory lobe centre timing is done with the pulleys"

Interesting thought Warpseed, but I have not noticed any difference in the standard pulleys. But I can say I have noted a difference in the orientation of the pulley bolts holes and drive pegs on the various camshafts. I think that is the more likely method that Nissan employs to change the base timing.

I await, with much interest, further developments on this topic

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Dont the japs leave the vct module disconected when they change the gears or cams? Maybe there's a reason.

I suppose if the standard computer is trying to advance the intake cam it may negate the gains somewhat from the lobe separation angle your 'setting' up to achieve?

Dont the japs leave the vct module disconected when they change the gears or cams? Maybe there's a reason.

I suppose if the standard computer is trying to advance the intake cam it may negate the gains somewhat from the lobe separation angle your 'setting' up to achieve?

Sometimes they do, sometimes they don't. Regardless of whether or not you leave the VVT connected on the inlet cam, changing the exhaust cam base timing will have some effect. Not NOTHING as was the case with this car.

No we set it back to zero, and the power picked up again.

I think you are spot on with the ignition timing, that's exactly what he did (put a mark on the cam cover, to line it back up on). I asked about the timing light, and he wasn't sure that you could use one on a skyline!

I guess that's what you get for using a Dyno operator in Nowra, he still happily took my $200 though

its a bit difficult if they dont know what they are doing - to check the timing, you can either do it off no1 coilpack (bit of messing around) or off the induction loop on the coilpack - might be worth a drive up to sydney, either that or find a timing light and do it yourself, now that you have seen it done.

Just dial in - 4 deg, check your timing, and see how she goes:)

I've been wondering about the ignition timing issues when retarding the exhaust cam.

If you are retarding the cam by 4 degrees than youre also retarding the cas by 4 degrees (effectively retarding ignition timing by 2 degrees?) if you reinstall it to a mark on the timing cover because the locating pin will be retarded in relation to the cas cover when reinstalled. Basically you base ignition timing will now be set to say 13 instead of 15 btdc.

Does that make sense? I'm struggling to explain what i'm thinking here.

  • 5 months later...
  • 2 years later...

Correct me if im wrong but my understanding was that ignition timing and cam angles (timing if you will) are 2 completely separate things. IE: one is adjusting the point of ignition and the other is adjusting the cam angle....

Correct me if im wrong but my understanding was that ignition timing and cam angles (timing if you will) are 2 completely separate things. IE: one is adjusting the point of ignition and the other is adjusting the cam angle....

But, moving the cam gear in relation to the crank (which is`what you do when you adjust cam timing) will also change the point of ignition timing as its the cam that drices the CAS

  • 2 weeks later...

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