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Showing results for tags 'nissan cas'.
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have now installed a 36-2 trigger wheel on my RB26 and for interest sake, I have installed a 24-1 wheel in the stock nissan CAS and am only using the single window as a phase reset. I have an Emtron KV8 which shows something called sync position that tells you where the CAM signal comes in relative to the Crank signals (so 50% would be half way between two crank triggering events) this gives a very accurate display of how much variability there is between the crank and the cam signals. this is on an R34 gtr type CAS, HKS timing belt, kelford Beehive springs and tomei type B cams. I am using Hall effect triggers and a falling edge trigger threshold of 2v for both. under some load (but not extreme, this is only 10psi of boost) you can see over the course of less than a second there is a variance of 36.6% in sync position. because there are 10 degrees between trigger events on the crank, this ends up being a variance of 3.6 crank degrees! I will post more once I have data where the engine is under heavy load (30psi) to see if it gets worse. so you may say, well the keyway in the cam is to blame, not the timing belt. well here is the result at very low engine loads (idle) if there was play in the cam keyway this should still show up here as variance. but the sync position is only 4.2% which is only 0.4 crank degrees! I would like to get a very fast scope to verify the trigger edge slopes are remaining the same, as that is the only other factor here that I have not controlled for (but at a steady RPM, the slope should be consistent for each trigger event regardless.
