Can't boost over 5-6 PSI
03-27-13, 01:26 PM
#26
I hope you have some sort of fuel tuner and wideband. Running higher boost without additional fuel could be bad news. I wouldn't want to gamble. I'm pretty sure this exact reason is why my car had a cracked rear iron from previous owner at 68000 miles.?
Fuel Cut, FCD and Fuel System Modifications
The stock fuel system is programmed to prevent overboosting the car by cutting fuel past about 8.5 PSI. This system is designed to protect the engine and must be defeated if higher then stock boost is run. Fuel cut feels a bit like the car hitting a wall just after 8 PSI. The Fuel Cut Defender (or FCD) is available from most of the vendors (there is also a DIY version) to trick the ECU into thinking that the car is running less then 8.5 PSI of boost, thus avoiding fuel cut. However, the FCD does not add more fuel to the engine in response to higher boost. Because of this, just running around with high boost levels and an FCD is a very bad thing and virtually guarantees short engine life. One would hope that there is a special place in hell for those that sell a car with cranked up boost, an FCD and no other supporting fuel mods.
For cars running the stock turbo at less then 10 PSI, a fuel pump is generally all that is required. Cars running more boost and upgraded turbochargers will require larger injectors, an upgraded pump and some way to control all of this. The exact configuration will depend on how the car is setup and there are many, many options. It is most important to verify that at least something has been done to supply the engine with the proper amount of fuel.
More radical modifications will require a complete fuel system upgrade, known as generically as a "standalone" or "standalone EMS". There are many options but most popular are the systems by Haltech, Microtech, Wolf and the Megasquirt. Each of these systems is set up differently and it is beyond the scope of this document to cover them all. However you will want to examine the wiring harness and quality of installation carefully. Is wiring neat and tidy? What is the condition of the connectors? Is everything fused? Beyond that, there is the quality of the tune. Does the car start easily cold or hot? Drive smoothly? Any smoke? It is definitely recommend that if you are not familiar with standalone systems that you seek out someone who is
heres the page:
How To Buy An '86-'92 Turbo RX-7
The stock fuel system is programmed to prevent overboosting the car by cutting fuel past about 8.5 PSI. This system is designed to protect the engine and must be defeated if higher then stock boost is run. Fuel cut feels a bit like the car hitting a wall just after 8 PSI. The Fuel Cut Defender (or FCD) is available from most of the vendors (there is also a DIY version) to trick the ECU into thinking that the car is running less then 8.5 PSI of boost, thus avoiding fuel cut. However, the FCD does not add more fuel to the engine in response to higher boost. Because of this, just running around with high boost levels and an FCD is a very bad thing and virtually guarantees short engine life. One would hope that there is a special place in hell for those that sell a car with cranked up boost, an FCD and no other supporting fuel mods.
For cars running the stock turbo at less then 10 PSI, a fuel pump is generally all that is required. Cars running more boost and upgraded turbochargers will require larger injectors, an upgraded pump and some way to control all of this. The exact configuration will depend on how the car is setup and there are many, many options. It is most important to verify that at least something has been done to supply the engine with the proper amount of fuel.
More radical modifications will require a complete fuel system upgrade, known as generically as a "standalone" or "standalone EMS". There are many options but most popular are the systems by Haltech, Microtech, Wolf and the Megasquirt. Each of these systems is set up differently and it is beyond the scope of this document to cover them all. However you will want to examine the wiring harness and quality of installation carefully. Is wiring neat and tidy? What is the condition of the connectors? Is everything fused? Beyond that, there is the quality of the tune. Does the car start easily cold or hot? Drive smoothly? Any smoke? It is definitely recommend that if you are not familiar with standalone systems that you seek out someone who is
heres the page:
How To Buy An '86-'92 Turbo RX-7
Last edited by tuscanidream; 03-27-13 at 01:31 PM.
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