subyman1440 Posted March 21, 2017 Share Posted March 21, 2017 Hi all, I've finally decided to crawl out of my cave and surface my build here. I felt like I was taking more from this forum than I was giving. My build used a TON of info that I was able to unearth via this site. My hope is that my build adds to the plethora of information on here and helps others as much as it has helped me. Anyhow, I've been trying my best with the limited network/connections I have to get suggestions on where I should start with jetting for my turbo surge tank set up. I feel like I hit a dead end. I know that I have to fine tune the jetting for MY set up...so I'm currently in the process of installing a wide band O2 sensor and a boost gauge. However, does anyone here with experience have a ballpark estimate on jet sizes in an application like this? I don't want to start tuning my engine and have it catastrophically fail or damage my newly rebuilt motor because my jets are way out of line. Here is my set up: Engine: L28 N42 Block E88 Head (Debating on whether or not to install my spare P79 head in) 280zx Turbo dished pistons .020" oversize 1mm headgasket Stock L28 rods 280zxt stock exhaust manifold Custom 2.5" to 3" turbo back exhaust T3 Turbo w/internal wastegate: Compressor: Trim:55Inducer Diameter:50.5 mmExducer Diameter:76 mmA/R:0.5 Turbine Trim:73Inducer Diameter:65.5 mmExducer Diameter:55.9 mmA/R:0.63 Triple Mikuni 40PHH Carbs Main Jet: 145 Main Air Jet: 200 Pilot Jet: 60 Pump Nozzle: 0.45 I was able to find one member on here who ran a similar set up with a bone stock N42 block/internals 20+ years ago. He ran a 145 main jet. However, I was not able to find out what size his air correctors were. Any suggestions on baseline jet settings for a set up like this? Or am I just on my own with my O2 sensor analysis? I have included pictures for you! Please excuse the mess, it's still under construction. Thanks in advance! Quote Link to comment Share on other sites More sharing options...
Dat73z Posted March 21, 2017 Share Posted March 21, 2017 (edited) I am curious about this as well- my plan was to jet NA around 12-13 AFR across the board and see if I needed to make any adjustments after the surge tank on low boost (<7psi or so). Edit: Also, I am local to the Bay Area although my setup will be OER 47's. Let me know if you'd like to compare notes in tuning, I'm in the process of porting my turbo mani/turbo and getting them out for ceramic coating this week. Hoping to have my setup going in a couple of months. Edited March 21, 2017 by Dat73z Quote Link to comment Share on other sites More sharing options...
subyman1440 Posted March 24, 2017 Author Share Posted March 24, 2017 The jetting shouldn't be too off. My current plan of action is to keep my main jet size and downsize the air jet which will richen up the mixture. I'll post the jet sizes and my AFR readings as I begin to plot and graph for the ideal tune. My other concern is that the needle jet that I have may be too small to supply adequate enough fuel while under hard acceleration. We'll see though. Lemme know if you have any suggestions. Quote Link to comment Share on other sites More sharing options...
madkaw Posted March 24, 2017 Share Posted March 24, 2017 Haven't ran the pressurized version of the Mikunis , but I would agree that I would drop the main air down a couple of sizes and maybe even bump up the pilot one size . Maybe too much fuel but better than too little Quote Link to comment Share on other sites More sharing options...
Curtball Posted March 25, 2017 Share Posted March 25, 2017 Sub* Quote Link to comment Share on other sites More sharing options...
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