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That depends on the size of the turbo, rpm range etc etc etc etc
My boost gauge slams 30 lbs by 4000 RPM when I was having wastegate issues. No idea how high boost went. Judging by the 170% duty cycle on the 80 lb dekas, probably pretty high.
My boost gauge slams 30 lbs by 4000 RPM when I was having wastegate issues. No idea how high boost went. Judging by the 170% duty cycle on the 80 lb dekas, probably pretty high.
As you know, 170% duty is physically impossible. It's just a nonsense calculated value given by some dumb ecu's
And what happens with one turbo setup, will not happen with all.
You could very easily install a turbo big enough that might never see even 15psi or indeed half that.
Instead of controlling boost with the wastgate and associated bypass pipe back into the exhaust, why not put a feedback loop back to the throttle plate. The more boost you have, the more you have the feedback close the throttle.
Instead of controlling boost with the wastgate and associated bypass pipe back into the exhaust, why not put a feedback loop back to the throttle plate. The more boost you have, the more you have the feedback close the throttle.
I've heard of outlaw cars running no gates. There's a few threads about this subject on yellowbullet.
No I'm not talking about outlaw cars that are on the hairy edge of blowing up. I'm talking about your every day turbo car with boost control, but without the wastegates or bypass piping.
If you think about it, all a wastegate is, is a feedback device that uses the boost to open a valve. Just move that same functionality a bit upstream and use too much boost to close the throttle plate instead. The result should be close to the same. It's like having some automatic device take your foot of the pedal just enough to give you the desired boost, only you've got your foot matted to the floor.
In throttle by wire cars, it can be done through the electronics.
In cable throttle cars, it can be done at the throttle cable mount. I'll draw a picture and post it later.
No I'm not talking about outlaw cars that are on the hairy edge of blowing up. I'm talking about your every day turbo car with boost control, but without the wastegates or bypass piping.
If you think about it, all a wastegate is, is a feedback device that uses the boost to open a valve. Just move that same functionality a bit upstream and use too much boost to close the throttle plate instead. The result should be close to the same. It's like having some automatic device take your foot of the pedal just enough to give you the desired boost, only you've got your foot matted to the floor.
In throttle by wire cars, it can be done through the electronics.
In cable throttle cars, it can be done at the throttle cable mount. I'll draw a picture and post it later.
Absurd idea.
For one, you don't want to have your foot hard down and something fighting against it to close the throttle. Your foot is going to win, and you're going to break something. If your leg can easily depress a cable clutch pedal with a stiff clutch, there isn't a 'small device' that will be able to close the throttle.
2nd, when you pull the TPS back from 100%, you start skipping through multiple tables in the ECU. Your transmission won't behave anywhere close to the same at part throttle, among several other things.
Great article. But that's not the method I described. It is one of the three methods I was talking about however. They don't use wastegates either. They control the boost by bleeding air from the blow off valve.
That method does work, but you risk overspinning your turbo. I've been using that method for controlling low boost levels only, while launching.
For one, you don't want to have your foot hard down and something fighting against it to close the throttle. Your foot is going to win, and you're going to break something. If your leg can easily depress a cable clutch pedal with a stiff clutch, there isn't a 'small device' that will be able to close the throttle.
2nd, when you pull the TPS back from 100%, you start skipping through multiple tables in the ECU. Your transmission won't behave anywhere close to the same at part throttle, among several other things.
You're right. A system that fights your foot won't work. But there are ways of achieving this without fighting your foot.
For example in a throttle by wire, your foot may be all the way down asking for more power, but the engine management may not give it to you because it's protecting the engine. In the same way, when the engine management feels that you're approaching your target boost, it can start closing the throttle plate, allowing your manifold pressure to come to equilibrium at your desired target boost level.
For throttle cable setups, the mount that holds the throttle cable sheath is not fixed. Instead it can move closer or further away from the throttle assembly. As you move the mount closer, you reduce the amount of the throttle, even if the gas pedal is matted to the floor. The position of the mount is controlled by a standard wastegate actuator which sees manifold pressure. A boost solenoid can be used in the same way as boost solenoids that control wastegate.
08-15-2016, 07:11 PM
