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JasonMate

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Posts posted by JasonMate

    R33 GTS25T Compression Issue

    in RB Series - R31, R32, R33, R34 (1986-2002)

    Posted · Edited by JasonMate

    Iv done nothing beside swap a boost t for a 2 stage and ill never go back. started smoking up at the lights and drive thru's at idle so i jammed a bolt in the pcv valve thinking its sucking in oil. After i did that it went super rich and hat to wind the idle screw out a fair bit. Then started popping my dipstick again so i made my own massive o ring and now its not coming out ever.
    but theres only a mist of fuely steam coming out of the catch can breather. its not chugging out of it like id think having 120psi compression... theres 0 smoke out of the exhaust, waited so damn long to rule out valve stem seals.
    is it normal to get boots cut around 26ish psi on stock ecu?

    Oh and a custom airbox for podfilter. sounds sick on dose

    R33 GTS25T Compression Issue

    in RB Series - R31, R32, R33, R34 (1986-2002)

    Posted · Edited by JasonMate

    hmm, its running 10psi atm, iv blown 2 turbos so far going any higher on the stock ones. Im still confused why the compression dropped 20psi just from warming up, and even more so why its 120psi hot and cold a year later. wouldnt it drop down to say 100psi once warmed up if its worn that much in the time iv owned it. if compression should be around 160-170+ and i have 120, shouldnt there be quite abit of blowby?
    I forgot to take the crank case vent valve out of the manifold to get a true reading of how much blowby there is, i dc that. i took the catch can hose out and you can bearly notice air coming out, you have to squeeze the hose end and then its enough to feel like a gentle flow of air. 0 smoke. same if you give it a rev.
    iv used the same comp tester for years to eliminate getting different readings.

    R33 GTS25T Compression Issue

    in RB Series - R31, R32, R33, R34 (1986-2002)

    Posted

    So i brought this car a year ago with 250k on it with a blown ECU and a tight cam belt, Fixed that and is was a new car again. The problem has been that the compression cold is 140psi throughout the 6 and once hot they all drop evenly 20psi down to 120psi throughout the 6. its been like that for a year now and hasn't changed. it doesn't use oil really and doesn't fill up the catch can. the k&n filter on the catch can looks abit oily however. There's no noticeable blow by just a puff of white smoke out the catch can when you give it a hard rev.

    I haven't done a leakdown test yet I've been putting it off. my question is what causes compression to drop like that? i have no information on the history besides it was owned my crackheads and it sat dormant for possibly more then 5 years. the motor looks super clean for how many km's it has and how trashed the suspension is. the car runs perfect but i can feel the 20psi loss as the car warms up.
    i was thinking someone put a thicker head gasket on to drop the cr but that still doesn't answer the compression drop. its suppose to rise isn't it lol.
    I've asked many mechanics and they cant explain it.
    Hope someone can help!
    Thanks.

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