nycain Posted November 16, 2014 Report Share Posted November 16, 2014 Hey guys I'm running my maft t. My settings are base 2 idle 4 mid 4 Wot f I'm running Delphi 950 & trilogy 950 my fuel pressure at idle is 46psi .. My question is how much fuel pressure I should be seeing while driving .before boosting at around 50-70 KLM.. I have a in car fuel gauge . mods .04 forged piston ARP head studs ajusta head gasket 20gturbo tdo5 3" straight pipe maft t gm 3" draw through none jet valve head ... Any info will be appreciated Link to comment Share on other sites More sharing options...
Dred_85.5_TSI Posted November 16, 2014 Report Share Posted November 16, 2014 Fuel pressure should stay close to the idle setting until you see boost pressure, then it should rise 1:1 in relation to boost pressure. Link to comment Share on other sites More sharing options...
ucw458 Posted November 16, 2014 Report Share Posted November 16, 2014 Both injectors are delphi injectors. Trillogy just bought delphi injectors and put a sticker on them. Most aftermarket injectors are rated flow at 3 bar pressure (43.5 psi). With the engine off and pump on you set your regulator to 43.5 psi or as close to it as you can. The vacuum line on aftermarket injectors is connected to a manifold source that sees vacuum and boost. The reason behind that is you want to keep the fuel pressure at a constant 43.5 psi above what the intake side of the injector is exposed to. We all know rising rate = 1 psi fuel pressure for every 1 psi boost but the same applies when the engine is under vacuum. If the regulator is not connected to a vacuum source then you are tecnically feeding 50+ psi to the injectors when idling or cruising. That can cause a rich condition. Having the regulator connected to a vacuum source fixes the pressure differential by lowering base fuel pressure under vacuum to around 36 psi. Link to comment Share on other sites More sharing options...
scott87star Posted November 16, 2014 Report Share Posted November 16, 2014 The vacuum line on aftermarket injectors is connected to a manifold source that sees vacuum and boost. Don't forget (like I did once) that the injector discharge on a TBI is ABOVE the throttle plate so it never really sees any vacuum, there is a hose port right where the discharge is, connect the FPR reference line there. Link to comment Share on other sites More sharing options...
markhansenconquest Posted November 16, 2014 Report Share Posted November 16, 2014 all ways good info on here..........^^^^^^^^ THANKS GUYS........ Link to comment Share on other sites More sharing options...
ucw458 Posted November 16, 2014 Report Share Posted November 16, 2014 Don't forget (like I did once) that the injector discharge on a TBI is ABOVE the throttle plate so it never really sees any vacuum, there is a hose port right where the discharge is, connect the FPR reference line there. Yeah I forgot to add that little tidbit. I haven't had a TBI car for years so it's easy to forget. Link to comment Share on other sites More sharing options...
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