TAnderson22 wrote:I built 4.7 Stroker motor less the supercharger..... and built it with option to upgrade to turbo once I felt the brakes and suspension will perform well enough to allow it.
I also have built and stroked many subaru turbo gasoline engines, and have much experience with turbo diesel tech. I have manufacturer certification for many over the road turbo diesel engines.
As long as your knock sensor works, you are likely safe to 8-10 psi but take it in small steps if you don't have an electronic controller for the pressure.
I would suggest the following:
#1) LOOSE THE CHAMPION PLUGS before you cause a detonation problem and ruin that motor. I know they were the OEM choice, but NGK, Denso or AC is the best and don't wear out in 3,000 miles or less. Avoid HC attracting platinums, go to iridium, it is a PGM, but it does not trap HC because of it's valence charge. Platinum is great for converters, bad for plugs, no matter what marketing tells ya. iridium provides no catalytic effect.
#2) You are probably not having any detonation problems because you are running TOO rich in the 11's. Stochiometricy with gasoline is 14.6:1. You have a nice wide band gauge, but you can't control the fuel delivery, so your only watching it. (If you don't understand stochiometricy, the gauge is useless to you, evenmoreso if you can't control the fuel input!) Get a quality injector pulse width controller like APEXI makes. Don't screw with the ECM pressure sensor input - garbage in, garbage out is basic computer knowledge. You might want to visit some rice rocket sites to get some help with turbo and other aspiration questions that will not come up here. Watch that EGT gauge that's nice to have and is key too - if it gets too hot you need to add fuel to quench the heat before you melt. The length of the hydrocarbon chains in premium fuel also is important- so don't use anything less! The octane rating is needed to keep the fuel from exploding under compression (as diesel does) but your low compression ratio for a turbo/super (IMHO) is helping you not ignite here (and prob why it runs on regular)(deck should have been milled ).
#3) Up your injectors to at least 30lb/hr - I found that I don't need to increase the FP from stock with the correct sized injectors, and additionally, the need to modify the pulse width of the delivery was nullified. More volume/flow is better than longer injector on time or higher delivery pressures to band-aid it though. Better to be able to deliver too much and feather it off, than be running 100% dwell and still be short on fuel. All emission computers are programmed to find stochiometricy no matter what injector it is firing into any displacement motor. Investing in a fuel pressure gauge (mounted) will also tip you off to >VOLUME DELIVERY< problems no one ever thinks of on these boards.
