My P1sc kit is supposed to be here this week and I need to know what plugs to run and what to gap them to.Also what fuel pressure should I run at 9lbs of boost with 42lb injectors and a boost sensitive gauge no fmu? Thanks for the help
I would HIGHLY recommend you buy a FMU as they are able to pull all kinds of power potential out of your motor.
That said, your pressure is determined by the a/f ratio which works best for your application. The needed pressures will go from 100 psi @ 15:1 on up to 175 psi @ 11:1. You'll need to figure those out for your application specifically.
You DO NOT need a FMU with a 42# inj on that combo, I would recommend a tuner or atleast a chip to help with satrt-up the 42# dump way too much fuel in then.
Start at 36-38# vac off, The AFR use a 3924 stock so you will want to use a Autolite 3923, gapped at .035"
***ANOTHER TIP***
Only use about 3/4 of the bottle of ATI oil, otherwise you will over fill it and it can leak out of the seals.
just got a chance to check out everyone's opinions, thanks for the input. From all of my research I've ruled out the fmu, nobody likes them at all. Everybody that still has them say that they are going to get rid of them. I'll stay clear.I have the pms so I can take out the fuel at start up, if I use3/4 of a bottle of fluid, that doesn't make it low? I have a buddy that has the p1sc kit on a 98 cobra which has holes on both sides of the block now from rods and pistons, but anyway he said his leaked from the start, so this will fix this?
People armed only with a simple understanding of EFI operation has plagued the backyard mechanics' opinion of an FMU. The theory is that the ECU monitors manifold pressure and when it sees an increase due to boost, let's say 6 psi, that it increases fuel pressure by 6 psi and everything is good. While this is true, it doesn't take into effect the differing needs of air/fuel ratios nor the increase in temperature due to boost which are the purposes of an FMU.
While this is fine under N/A applications (where you are likely to see the 4 - 6 psi difference in delta P) it can be dangerous in a boosted application. Most people are able to get away with not using an FMU because they stay in the mild to moderate ranges of boost (4 to 8 psi). The problem arises in the lack of injector pulse manipulation. Because airflow determines fuel flow, modifications for increased fuel flow must be made. Most people get around this by simply stepping up in injector size and thereby kill idle characteristics.
The only viable option I would be willing to recommend to someone is a rising-rate regulator. Rather than simply raising fuel pressure on a 1:1 basis, you can set up a higher ratio which forces more fuel through the injector without increasing pulse duration.
Any way you decide to go, I highly recommend you either talk to the tech guys at ATI or someone at a local speed shop who is knowledgable in tuning and installing superchargers.
It's your money, you need to decide what you can afford not to do and what you can't afford not to do.
thanks for your input I'll definitely take it into consideration, just going by what I've gathered off the internet, where I live no one even has a clue about making horsepower wit a fuel injected car. that's why I'm in the dark on alot of things sometimes.