d16 turbo not spooling until late..help!

**JDMJ** · 08-04-2011, 12:14 AM

im having some trouble getting my turbo to spool. Ive got a built z6 with a 52 trim or so..( unmarked but dosent look large ) on 17psi My cam timing is all the way retarded..Could that do it? The ic piping on the driver side ( from side of ic to turbo) is smaller than all the rest. Could that do it? Im not seeing full boost until the 6k area..Any suggestions/ideas would be perfect!

**turbob20** · 08-04-2011, 02:26 AM

the piping being smaller from turbo to cooler is good so theres less pressure drop through the cooler. is this a new kit if so check and make sure nothing got in the piping or ic such as packing peanuts and stuff. check your A/R that should be stamped on the hot side on out side near entry bolt up to turbo or inside the exhaust entry square part where it bolt to manifold. you should need a .48-.63 to be all in by 3500-4500 with a stage 3 wheel! akso check shaft play up and down to see if the impeller on cold side is touching housing and check all couplers and BOV for boost leaks!

**JDMJ** · 08-04-2011, 10:21 AM

Havent checked leaks, and kit is a older kit. Like i said, its a unmarked turbo but looks similar to the last 50/63 i had. How is the best way to check for boost leaks?

**RBS** · 08-04-2011, 11:18 AM

if you know for a fact you are at 17psi at full boost then you do not have a boost leak... as well, it wouldnt boost then. the fact that your cam timing is retarded could be what is causing slow boost build, zero it out and test drive again. are you using an external wastegate? make sure that is installed properly and all vaccuum hoses are correct. maybe your exhaust manifold is leaking somewhere... the list can go on and on until you are real specific with your entire engine setup. just sayin..

**turbob20** · 08-04-2011, 08:39 PM

thats not necessarily true because you can see almost full boost with a medium leak but takes longer to build it and harder to maintain it and can gradually even drop psi cause mine did with scotty during my tune kept going from 14 gradually down to 12.7 psi and all it was when i went from 8 to 14.5 psi i had leaks i didnt have at 8. fixed em and boost was quicker and held better and i was good!

**turbob20** · 08-04-2011, 08:42 PM

also just curious as to the retarded timing! have you tried 0 timing as stated above? that would be a quick fix if it was.

**JDMJ** · 08-05-2011, 04:30 PM

d16z6, vitata build, turbonetic turbo, pfab log, turbonetics wastegate, blitz bov, turboxs man. boost cont. 17 psi...And the cam timing was set on Retarded when tuned..if i mess with it, it would run like doodoo, correct?

**turbob20** · 08-07-2011, 12:56 AM

just try it abd you can always set it back. in my opinion your bleeding off too much cylinder pressure or something to that effect!

**turbob20** · 08-07-2011, 12:58 AM

i shouldn't hurt anything your motor is set up for the size injectors and fuel it needs during the tune period all messing with the cam timing does is make it happen sooner or later in the firing cycle.