Subject	Finally found out why my Z sucks
Posted by	dvice on April 18, 2013 at 1:22 PM
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Message	I've been searching for 6 months, bought well over $2K in new parts, and done multiple diagnostic tests trying to find out why my dyno is like this: [ http://i.imgur.com/z8kIZxw.jpg ] When I'm running 12 PSI on sport 500s. The one thing I always ruled out was bad compression, because the engine came from a mint condition '95 USDM TT that was in an accident. After they pulled the engine, they did a compression test and it had great compression. Then one day it finally hit me - the engine sat for a long time (over a year) so I thought "maybe the piston rings went bad.." Did a warm compression test that day (all 6 plugs removed, WOT, brand new compression kit), check out these results! #1 through #4 - 110 (give or take 1-2 psi) #5 - 118 #6 - 105 Dab of oil in #1 raised compression to 170. Didn't bother testing the rest of the cylinders - knew engine needs rebuild.
Follow Ups	Finally found out why my Z sucks - dvice 13:22:29 04/18/13 I'm curious: ".... had great compression." Did they provide - zellamay 13:58:34 04/18/13 Not trying to be a jerk but.... - Tanley 14:02:12 04/18/13 Just throw more boost at it to make up for it! j/k. - nemo1080 (Iowa) 14:25:45 04/18/13 I would check some other things. - Woody75 (Denver) 14:28:01 04/18/13 Yep, bad CAS is fairly common - ZXoltan 15:47:39 04/18/13 any way to test the CAS without just putting a new one on? (n/m) - fuzzymonkey 16:26:37 04/18/13 One way... - BOOZTD 3 00:21:23 04/19/13 That only tests 1 part of it. (n/m) - Woody75 (Denver) 11:29:19 04/19/13 Indeed it does not test the ability to advance/retard (n/m) - BOOZTD 3 13:04:12 04/19/13 I would double-check mechanical timing before anything else. (n/m) - ZinnZ32 15:07:08 04/18/13 Not be a jerk pt2.. - Hipendicular 16:35:35 04/18/13 Woody didnt say the Cas had anything to do with his low - Krazyd27(Houston) 17:56:15 04/18/13 Correct. (n/m) - Woody75 (Denver) 11:30:07 04/19/13 how exactly do rings "go bad" sitting?? - LJZTT 20:04:56 04/18/13 This order - Xteam300TT (South Tx ) 21:50:54 04/18/13 Wait... so if you let your engine sit for over a year you - nonstopna 01:19:18 04/19/13 Lol this--^ (n/m) - Terayonneo 01:56:31 04/19/13 wow everyone - BlackholeZ 03:15:42 04/19/13 You can make plenty of power with that low of compression... - BOOZTD 3 11:04:08 04/19/13 Got it (n/m) - BlackholeZ 12:14:55 04/19/13
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