20 psi? Hmmmmm!
Senior Member
Joined: Feb 2003
Posts: 564
From: Calgary
Turbosmart boost controller?, I tried one of them and half the time it was runaway boost. 20 psi isnt all that bad really, that was my low boost setting on pump gas, with 25 set as for scramble boost, just tune for it, unless your still on stock turbos then get it down... When shopping for fuel, disregard the advertised octane, look at the motor octane, and stay away from ethanol blends, unless tuned specifically for them.
Jims, that idea was tossed around a few years ago, while the timing wont neccesarily do anything bad, except push egts through the roof if done continually, whacking the fuel maps by huge amounts will give you 100% duty cycles, and high boost misfires, both of which are bad for the reasons we all know, but its interestin that most ems dont have a built in overboost strategy, like total engine cut, or a vent option, one could do that via a boost switch though and solenoid. Outside of a pop off valve, or a wastegate mounted to the intercooler piping, the best way to avoid overboost destruction is to tune as far up the map as you can and have a warning function on the boost guage, or like mazda appears to be doing with the new turbo cars, control VE of the engine and knock with electronic throttle control, regardless of what boost is being produced.
Jims, that idea was tossed around a few years ago, while the timing wont neccesarily do anything bad, except push egts through the roof if done continually, whacking the fuel maps by huge amounts will give you 100% duty cycles, and high boost misfires, both of which are bad for the reasons we all know, but its interestin that most ems dont have a built in overboost strategy, like total engine cut, or a vent option, one could do that via a boost switch though and solenoid. Outside of a pop off valve, or a wastegate mounted to the intercooler piping, the best way to avoid overboost destruction is to tune as far up the map as you can and have a warning function on the boost guage, or like mazda appears to be doing with the new turbo cars, control VE of the engine and knock with electronic throttle control, regardless of what boost is being produced.
Senior Member
Joined: Dec 2001
Posts: 2,934
From: Jensen Beach, FL / Sylva, NC
Originally Posted by Maxt' post='905407' date='Jul 26 2008, 10:23 AM
Turbosmart boost controller?, I tried one of them and half the time it was runaway boost. 20 psi isnt all that bad really, that was my low boost setting on pump gas, with 25 set as for scramble boost, just tune for it, unless your still on stock turbos then get it down... When shopping for fuel, disregard the advertised octane, look at the motor octane, and stay away from ethanol blends, unless tuned specifically for them.
Jims, that idea was tossed around a few years ago, while the timing wont neccesarily do anything bad, except push egts through the roof if done continually, whacking the fuel maps by huge amounts will give you 100% duty cycles, and high boost misfires, both of which are bad for the reasons we all know, but its interestin that most ems dont have a built in overboost strategy, like total engine cut, or a vent option, one could do that via a boost switch though and solenoid. Outside of a pop off valve, or a wastegate mounted to the intercooler piping, the best way to avoid overboost destruction is to tune as far up the map as you can and have a warning function on the boost guage, or like mazda appears to be doing with the new turbo cars, control VE of the engine and knock with electronic throttle control, regardless of what boost is being produced.
Jims, that idea was tossed around a few years ago, while the timing wont neccesarily do anything bad, except push egts through the roof if done continually, whacking the fuel maps by huge amounts will give you 100% duty cycles, and high boost misfires, both of which are bad for the reasons we all know, but its interestin that most ems dont have a built in overboost strategy, like total engine cut, or a vent option, one could do that via a boost switch though and solenoid. Outside of a pop off valve, or a wastegate mounted to the intercooler piping, the best way to avoid overboost destruction is to tune as far up the map as you can and have a warning function on the boost guage, or like mazda appears to be doing with the new turbo cars, control VE of the engine and knock with electronic throttle control, regardless of what boost is being produced.
Now that you say that, I have to go look at my ECU some more, I am running a Motec M4 and IIRC it might have some parameters to set for overboost.
I think it will allow me to cut the ignition and now that I am thinking about this I think I have it set to kill the ignition over 20 PSI. I still have not looked at my data logging from last week when I dyno'd when I do I will look at the over boost and see if I have it set.
Just for safety though I do have a lot of fuel, not 100% but enough to make her tell me something is wrong before something is broken.
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