Pitts Posted January 4, 2014 Report Share Posted January 4, 2014 I've tried searching on google as well as this forum without any luck, so I'm hoping someone can help me out. I've got a 3100 SFI (95 GP) with the stock injectors currently (17 lbs hr). I was wondering if I could upgrade to the 19 lbs hr injectors without washing my cylinder walls. Currently it has a soft cam in it with 3400 heads. I will be porting my upper intake manifold to fit the LX5 throttle body onto it. I will also be adding a second pump (Walbro inline) as well as an adjustable fuel pressure regulator. Which herein lies my next question, what's the max psi the 17 lb or 19 lb injectors can safely handle? Thanks. Quote Link to comment Share on other sites More sharing options...
19Cutlass94 Posted January 4, 2014 Report Share Posted January 4, 2014 The injectors that came stock in your 3100 are 19lbs/hr @ 45psi. If you need a little more fuel, swap to a 55psi FPR. You do not need a second fuel pump. Thats a waste of money and IMHO a dumb idea. Its not how much they can flow, its how much pressure you put on them. Depending on the size of this "soft cam" Once you start tuning, you might max out the 19lbs/hr injectors. I ran a small cam in my motor and maxed out the 19lbs/hr @ 55psi quickly. It depends on the size of the cam in your motor as compared to what size injectors you need. Also depends on if you are running the stock 45psi FPR or are stepping up to the 55psi FPR. An adjustable FPR is a total waste of money unless your running high boost and have huge injectors ( about 60lbs/hr ) Before you start messing with fueling like this, you need to tune it. If you think you can tune it by throwing different injectors at it and playing with fuel pressure, youll make it run worse. Quote Link to comment Share on other sites More sharing options...
Pitts Posted January 5, 2014 Author Report Share Posted January 5, 2014 My cam is 262/262 adv duration at .480"/.480" lift. I'm still a little new to the W-Body modification area (while I know the engine bay better than I should -.-). I'm contemplating on doing the OBD2 swap (seeing as how I have everything I need just sitting around) as well as a light tune. Nothing too fancy there, but it'll be a few months before I decide to do a light tune or not. I've got my eye on one of the 55 psi FPRs right now, but are the 95 fuel rails the same ID as the 2000+? Thanks Quote Link to comment Share on other sites More sharing options...
19Cutlass94 Posted January 5, 2014 Report Share Posted January 5, 2014 I ran that cam before upgrading. If your going to tune, ( which you should be for it to run correctly ) you'll need bigger injectors. If your not going to, just upgrade to a 55psi FPR. Fuel rails are the same. Quote Link to comment Share on other sites More sharing options...
Pitts Posted January 6, 2014 Author Report Share Posted January 6, 2014 Alright, Thanks. Quote Link to comment Share on other sites More sharing options...
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