Tuesday, March 28, 2006 - 08:14 am, by: Morgan Cross(Morgan)
I'll have a crack at answering this for you, I'll try my best.
1) There are 2 gears on a Soarer, as you said, exhaust and intake. You don't have to replace both, you can do one or the other, or both if you like, however, if you plan to replace the intake gear you will need a piggyback ecu / replacement ECU that does timing.
eg, if you run a SAFC, that only does fuel so you can only run an exhaust gear.
2) Some people say it's possible to replace the gears without completely removing the timing belt, however the 1JZ's have a hyrdrolic (sp?) tensioner on the timing belt and once you loosen it, it'll snap shut and you will have to remove the entire belt to fit the gear/s. When mine was fitted we tried to wedge the belt open, so it couldn't snap shut and when we tried to slide the gear out, it tensioned and we had to remove the whole lot.
All in all, it took about 2hrs maximum to replace the gears, once the belt is off, it's a piece of cake to change the gears over.
3) As far as I know, there is no power to be gained from fitting cam gears, it just alters your power delivery and allows you to set the gears for early or peak power. Most people go for peak on stock turbos to add a little more top-end punch.
However, I was speaking to a friend of mine the other night (Who is generally reliable) and he mentioned a 5rwkw gain is to be had from replacing both gears? I'm not sure on that anyways.
4) It can be done before you even put the gears on, however it's advised that you put them on in the zero'd position first, then have them altered on the dyno. Shouldn't take more than 2hrs maximum
5)The horror stories you heard about gears slipping were probably the HKS ones, the metal edges that the belt runs on are coming apart and they only had 3 points to fasten it, and they came loose. when looking for a gear, be sure to buy one with 5 fastening points.
Good luck.
Edit:Just noticed you have a 2JZ-GE. Sorry, I dont know much about them. I'm guessing the timing belt arrangement would be much in the same, I'm sure someone can verify.
Tuesday, March 28, 2006 - 09:38 am, by: Tobias Trinks(Toby)
Thank you for the extensive answer. I am about to get a Unichip which does ignition timing and fuel/ai r ratio. So I can get adjustable exhaust and intake cam gears, can't I? Can every company which has a dyno adjust them?
Tuesday, March 28, 2006 - 06:09 pm, by: Cihan Aday(Cihan)
Morgs, on a 2JZ running stock turbos, by altering the exhaust cam position relative to TDC by 12 degrees ( ≡ 6 degrees total retard), I net over 7hp at the flywheel on a reliable engine simulator. (engine analyzer pro v3.3) Started off at 7hp and worked its way upto 10 or so hp. 12 degrees is quite a lot and i dont know how much it would effect idle etc in real world applications. Im guessing it wont be very different at all.
Power delivery is best altered with the Intake camgear. It makes a larger difference to low end torque and spool times when advanced. But, as always theres a tradeoff between low end and peak power, you can only have one of them.
I would advise against fitting an intake camgear on an auto model unless your auto is fully manualised and you have a standalone doing ignition. I was informed that the auto box runs in limp home mode (3rd gear) and ignition doesnt work when the cam pos. sensor chucks a spaz.
If there is no ignition signal to begin with, there is no ignition signal to alter, so i dont think a piggyback ecu can function in this case. I may be wrong about there being no signal though.
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