Jump to content
SAU Community

Recommended Posts

Can someone tell me how does the overboost protection on a pfc equipped with a boost control kit works?

I know it will do some sort of saftey cut when boost goes over target by 0.25kg/cm2, but does it just drop back boost by varing the duty cycle of the solenoid itself or does it do an internal fuel or ign cut?

Link to comment
https://www.sau.com.au/forums/topic/368029-pfc-overboost-protection/
Share on other sites

I don't know for sure, but the whole point of such protection is to protect against a loss of boost control. So using the boost control gear that is not working (and hence allowed the overboost) is not smart. Therefore I would expect it to be an ignition cut, like the original ECU.

Wonder if this is a myth, I played around with my old boost kit on the PowerFC and the boost spike like +0.5 bar when I played around with the duty cycles, no cut there at all.

I had the boost set at 1 bar, with a pretty high duty cycle of around 60. In 2nd gear, the boost spike to like 1.45 bar and nothing :)

Wonder if this is a myth, I played around with my old boost kit on the PowerFC and the boost spike like +0.5 bar when I played around with the duty cycles, no cut there at all.

I had the boost set at 1 bar, with a pretty high duty cycle of around 60. In 2nd gear, the boost spike to like 1.45 bar and nothing :)

Definately works but its often glitchy some of the supra (map based) pfc's false cut even if there is no pfc boost control kit fitted... you need to input 2.0bar on the boost settings tabs.

No myth John.

You were going the wrong way if you wanted to test it out.

Set your boost way low, say 0.4 bar then give it a try.

The turbo will easily/quickly boost over approx 0.7 bar and you'll then experience the cut.

(Cut occurs if actual boost exceeds set boost by >0.25kg/cm3)

At normal boost settings, you'll rarely see the cut.

Wonder if this is a myth, I played around with my old boost kit on the PowerFC and the boost spike like +0.5 bar when I played around with the duty cycles, no cut there at all.

I had the boost set at 1 bar, with a pretty high duty cycle of around 60. In 2nd gear, the boost spike to like 1.45 bar and nothing :)

Yea...tested it and confirmed its a HARD fuel cut at 0.25kg/cm2 over the set target boost.

Can someone tell me if the the 2 wire harness for the boost control solenoid comes off the main engine harness(gtr) or if it comes off the wiring some where else in the engine bay??....I

Yea...tested it and confirmed its a HARD fuel cut at 0.25kg/cm2 over the set target boost.

Can someone tell me if the the 2 wire harness for the boost control solenoid comes off the main engine harness(gtr) or if it comes off the wiring some where else in the engine bay??....I

factory boost solenoid wiring.

hard fuel cut from memory, on the last supra i tested it on.

Trent...is this something new? When my car was tuned you said all you could do was set the maps so that if it goes into the dangerzone it would overfuel and pull all timing out...

Trent...is this something new? When my car was tuned you said all you could do was set the maps so that if it goes into the dangerzone it would overfuel and pull all timing out...

were you using the pfc boost controller? i thought you had an avcr?

im using PFC boost kit and have been for a while

very happy with it and works well

set and forget

and has bonus of simplistic safety cut instaed of unlimited boost

also when you use the boost kit by default boost correction is enabled in the powerfc

from memory it has boost correction for airtemp (GTR only) and low water temp (from memory it runs less boost on cold water)

In the gtst it is cut and shut to the stock harness for the stock boost solenoid. Not sure on a GTR but. It is in Paul's PFC FAQ somewhere

Yes gtr is the same

factory boost solenoid wiring.

Cant find it :D Its a rb26 ...but not in a gtr

I dont think its on the main enigine harness tho, ie. the one that goes into the plastic rail along the intake side cam cover, but it has to link back to the ecu somehow obviously to get control on the solenoid

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • Depending on how long the car sat it is very possible for injectors to be stuck open or closed, I'd get them cleaned and flow tested. Other than that, obviously when the loom changes and the car doesn't start any more....the loom is suspect so some tracing / comparing may be required
    • Harness is for a s1 Rb25det, and it is engine and lower harness.  the old harness had broken off plugs and was in very rough condition/exposed wires and splices etc. it is not able to be put back on the car, I could visually inspect to see if they had rewired any pins on the ecu plug. The fuel pump definitly isn’t turning off it’s an external pump and very loud you can hear it. Will look at the other harness tonight, am also going to pull the fuel rail and watch the injectors spray, will update here with what I find. Pretty sure at this point it has to be something to do with injectors because car will fire up on starting fluid and cas is clicking the Injectors. Fuel pressure is steady 43psi 
    • Check the injectors flow evenly, and are actually flowing what you and the ECU think they should be flowing. If it's starting up on starter fluid, you have a fuel issue. Is it possible under cranking your fuel pump is turning off?   The harness you replaced, is that the whole engine harness? Do yourself a test, and drop the old harness on and plug it into the Z32 ECU. It's possible they've wired things different. From memory S1 to S2 is different in RB25 and you may have a wrong loom
    • I haven’t pulled the injectors to watch them spray yet but they are clicking from the cas and all of the spark plugs are wet with fuel. I’ve thought the cylinders were being flooded from the beginning and was hoping fuel pressure would fix it. Tonight I am going to pull the rail and watch the injectors spray. Don’t know how to test/diagnose if the plugs are firing in correct sequence but that should be a timing thing and as far as timing goes my car still has the half moon for the cas can only install it 1 way. And my mechanical timing is 100% correct I posted photos above. Confirmed with the balancer on and off. 
×
×
  • Create New...