Hey, i am kinda new to this fourm i just recently purchased an 88 RX-7 10th Anniv i am wonder how much boost i can run safely without having the car lean out. I heard 7 psi was safe. If anyone could also tell me when fuel cut of is i would apreciate it. Thanks

 

The OEM computer cuts boost above 8PSI I think. Adding the "defeaters & defenders" will help with that, as will a boost controller.

I wouldn't push 15% over the stock HP though without an aftermarket computer, fuel deliever upgrades, etc..

Although the car's designed for 350+ HP though Drivetrain & engine can take it so long as you do it right.

 

So would running 7psi be fine?

 

7psi is fine. I am running 11psi with stock pump, injectors and a SAFC I wont run much more.

I have seen the stock turbo take over 20+ with out failure but this was with a ton of fuel, and it is not reccomended.

 

Rewire fuel pump power wire - this is good up to 10psi.
If you're running higher boost, you'll need an FCD, or you'll end up banging into the overboost fue-cut.



-Ted

 

I measured the voltage at my fuel pump with and without the headlights on, IIRC it was 11.9-11.6V. I added an FD fuel pump (don't think I needed it) and the voltage was about 11.6-11.3V. I'd check the voltage at the pump while the car is driving to be sure you need to rewire first. I think rewiring might get you up to 13V though. Instead of rewiring I used a wideband to check a/f ratios.

With a cone filter intake, RB FCD and a full exhaust I could run the car up to about 9.5-10 psi and have ~11.5 a/f ratio. Tested this with a FJO wideband. Also tinkered around with running a little with running more boost as the result of boost creep, a/f ratio got to 12.6 and I lifted, I think that was 11-12 psi boost.

Jeff
87 TII 13.42@104-105
93 R1 13.59@102.85

 

Voltage varies on the fuel pump to controll the fuel pressure

Rewiring will maintain maximum pressure write? Won't you run rich if your not pushing 10PSI?