Mr.RNR Posted October 9, 2015 Report Share Posted October 9, 2015 (edited) Looking for help. First turbo build,lq9,ls3 heads, cam, etc... turbo is a s475,t6,a/r 1.32. 50mm turbosamrt wastegate with 17 psi spring and 50 mm tail bov. my problem is I am not building any boost on pedal brake to launch,I need to hit 35 mph to feel the boost and only goes up to 8psi on my mechanic gauge, and the trasmission is a 4l80e with 3200 tq, whats the problem can be? Edited October 9, 2015 by rnrnoriega (see edit history) Quote Link to comment Share on other sites More sharing options...
AKSSS Posted October 9, 2015 Report Share Posted October 9, 2015 Sounds to me like a vacuum line routing issue. How do you have the lines ran to the wastegate? But it could be lots of things. If this is your first turbo build, why do you have a 17# spring to start? That's a pretty big a/r also? 87mm turbine wheel? Quote Link to comment Share on other sites More sharing options...
Mr.RNR Posted October 9, 2015 Author Report Share Posted October 9, 2015 (edited) 91mm turbine, my tune is for 20 psi but i only have the 17 springs (7 and 10), and the route on the wg the bottom line goes to the turbo, and the other one to teh atmosphere. Edited October 9, 2015 by rnrnoriega (see edit history) Quote Link to comment Share on other sites More sharing options...
AKSSS Posted October 9, 2015 Report Share Posted October 9, 2015 That's a pretty big turbine. I have 408ci and a t4 s480 with an 87mm turbine and a 1.25 a/r and I start really building boost around 3300rpm. I find it pretty crazy you cant spool the turbo until 35mph? Where is your boost gauge referenced at? I am guessing it is off the manifold. Which would mean you have a huge boost leak between the turbo and the manifold. Again. There is 100 million different things it could be with out seeing it. Just start with the basics. Quote Link to comment Share on other sites More sharing options...
Mr.RNR Posted October 9, 2015 Author Report Share Posted October 9, 2015 (edited) boost referense is on top of the intake, and has a tee between bov. im going to check every songle tube tomorrow and see what happen. Edited October 9, 2015 by rnrnoriega (see edit history) Quote Link to comment Share on other sites More sharing options...
Mr.RNR Posted October 13, 2015 Author Report Share Posted October 13, 2015 I double check every hose and clamps and no boost leak, but im still without boost, Quote Link to comment Share on other sites More sharing options...
AKSSS Posted October 13, 2015 Report Share Posted October 13, 2015 Huh. Next I would check your wastegate setup. Doesn't make any sense. Do you have a boost controller? Quote Link to comment Share on other sites More sharing options...
Mr.RNR Posted October 14, 2015 Author Report Share Posted October 14, 2015 i dont have any boost controller and triple check my wg look good to me the fire ring and the valve seats good so i dont know im confuse Quote Link to comment Share on other sites More sharing options...
AKSSS Posted October 14, 2015 Report Share Posted October 14, 2015 oK, something is fishy. I would pull your wastegate off and hook the top port up to a vacuum pump. Like a brake bleeder pump. And see how much pressure it takes for the wastegate to start cracking open. Generally wastegates don't open at the exact spring pressure. For example, if you had a 10psi spring it might start cracking open at 8 or 9 psi. That is the next step I would take. If the waste gate is opening and closing properly you probably have something a little more serious wrong with the setup. Quote Link to comment Share on other sites More sharing options...
Mr.RNR Posted October 15, 2015 Author Report Share Posted October 15, 2015 New topic what pistons and rods do you recommend? 30 over or 40? and yes i blow my engine (rings) Quote Link to comment Share on other sites More sharing options...
AKSSS Posted October 18, 2015 Report Share Posted October 18, 2015 I'm no expert. But I have always gone along the lines of never going over .030 with boost. Other wise the cylinder walls can get weak. But I could be full of it. I know there is guys out there that are .060 with boost. Common size is .030 though. And for pistons. I think it is preference. I have had diamonds and weisco's. Both have done a good job. What happened? Over boost? Go lean? Kinda curious if you figured it out. Quote Link to comment Share on other sites More sharing options...
Mr.RNR Posted October 18, 2015 Author Report Share Posted October 18, 2015 bad wastegate , over boost, like i say first time,i learn thru the hard way but o well, if my crank is good i want to keep it so what rods are good ? and im thinking on diamods pistons. Quote Link to comment Share on other sites More sharing options...
AKSSS Posted October 19, 2015 Report Share Posted October 19, 2015 For off the shelf rods I like scat rods. But again. Just my opinion. Quote Link to comment Share on other sites More sharing options...
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