Sr20det head build. - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

derass · 01-02-2016, 10:16 PM

Is that a typo or are you talking about the ISIS RS3871R? Because I would seriously avoid that. You'd be much better off with something "name-brand" like Garrett, Borg-Warner or Tomei.

You should also avoid all of that BC stuff. Do some research around here and you'll find it's no good. Many people swear by JWT cams without upgraded springs and there is much evidence to support that. However, I had another friend lose his motor because he experienced valve-float with S3's and stock springs. For that reason, I think Tomei 260's and upgraded springs are the better choice. That combination offers similar performance and added peace of mind from the springs for approximately the same cost as JWT cams alone.

If you get quality cams like Tomei, JWT or HKS there is no need for adjustable sprockets. They are "dialed in" quite well from the factory. Sure, you can squeeze out a bit more power by degreeing those cams, but the cost of dyno time outweighs the minimal gains IMO. Again, if you read up about the BC stuff, you'll find they need to be degreed just to get them the work properly.

As for RAS, I would avoid them. In the event the motor throws or breaks a rocker, the RAS can keep the dislodged/broken piece in place, hold the valve open as the piston is coming back up and cause internal damage. Without stoppers, the rocker is likely to be thrown clear, and the valve will close preventing further damage.

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01-02-2016, 10:16 PM	#6
derass Zilvia FREAK! Join Date: Jun 2010 Location: Toronto, ON Age: 37 Posts: 1,182 Trader Rating: (0) Feedback Score: 0 reviews	Is that a typo or are you talking about the ISIS RS3871R? Because I would seriously avoid that. You'd be much better off with something "name-brand" like Garrett, Borg-Warner or Tomei. You should also avoid all of that BC stuff. Do some research around here and you'll find it's no good. Many people swear by JWT cams without upgraded springs and there is much evidence to support that. However, I had another friend lose his motor because he experienced valve-float with S3's and stock springs. For that reason, I think Tomei 260's and upgraded springs are the better choice. That combination offers similar performance and added peace of mind from the springs for approximately the same cost as JWT cams alone. If you get quality cams like Tomei, JWT or HKS there is no need for adjustable sprockets. They are "dialed in" quite well from the factory. Sure, you can squeeze out a bit more power by degreeing those cams, but the cost of dyno time outweighs the minimal gains IMO. Again, if you read up about the BC stuff, you'll find they need to be degreed just to get them the work properly. As for RAS, I would avoid them. In the event the motor throws or breaks a rocker, the RAS can keep the dislodged/broken piece in place, hold the valve open as the piston is coming back up and cause internal damage. Without stoppers, the rocker is likely to be thrown clear, and the valve will close preventing further damage.