Hondata Boost Control Solenoid
Control your boost pressure to avoid costly engine damage and increase acceleration with this Hondata Boost Control Solenoid. For use with the s300, K-Pro, and 2006+ Civic Si, the Hondata boost control solenoid is designed for use in high boost applications, but also works well in low boost applications. It is normally closed so that if there is a failure you will run off the wastegate spring instead of over boosting and damaging your engine. It uses 1/8th NPT fittings which allow you to use NPT to AN fittings if you wish. This boost control solenoid allows you to take advantage of the Hondata boost control features and control how much boost you are running directly from your ECU.
Hondata S300 Boost Control:
The S300 can control boost by using a duty cycle controlled output on OBD1 ECU pin A11 with a boost control solenoid to regulate air to the wastegate. Boost may be fixed, or varied by gear, with two settings which allow for wet/dry, pump/race gas or street tire/slicks settings to be selected with an external switch.
All US ECUs have the PWM Boost circuitry, but not the boost control components, for the PWM (pulse width modulated) output. JDM ECUs do not have the circuitry and cannot be used. Components must be added to the ECU for the PWM output to work. We also offer PWM boost control component installation in S300 ECU's for those who wish to take advantage of this feature.
How does the boost control work?
The ECU produces a square wave at a fixed frequency and variable duty cycle. Applied to a solenoid, the impedance of the solenoid results in a linear motion of the solenoid valve orifice.
The wastegate is normally connected so that manifold pressure acts on a diaphragm, so opening an exhaust bleed valve (the wastegate) at a certain manifold pressure. With a boost controller, additional air pressure is used on the other side ('the top') of the diaphragm, so that more manifold pressure is needed to open the wastegate - so the engine makes more boost. By varying the amount of air pressure on the 'top' side of the diaphragm with the solenoid, the ECU can control boost.
Because the solenoid can only add air pressure to hold the wastegate shut, the minimum boost is determined by the wastegate spring pressure. Therefore you need to run a spring which gives the minimum boost you want. The maximum boost is determined by many factors, but generally will be 2-4 times that of the minimum pressure.
Why boost per gear?
Assuming your aim is to maximize acceleration, then you need to utilize as much of the tractive capacity of the front tires as possible. The tractive capacity of the front tires is almost constant - it actually decreases a little with speed as the tire footprint shrinks and with front end aerodynamic lift. In order to provide a constant torque at the wheels to keep the tire at the peak tractive effort, two things are obvious: 1. The engine should have as flat a torque curve as possible (in the rev range) and 2. The engine should make more torque in each gear to offset the change in torque multiplication from the engine to the tires when you shift gears. You cannot do this by speed or rpm since this makes the torque output dependent on your shift point. By setting the boost level in each gear you are in effect altering the engine torque level to obtain the same wheel torque level, adjusted for inertial effects. If this all makes no sense to you then drive a high powered vehicle with boost by gear and you will understand.
How do I install the Hondata Boost Control Solenoid?
Hondata S300 Boost Control:
The S300 can control boost by using a duty cycle controlled output on OBD1 ECU pin A11 with a boost control solenoid to regulate air to the wastegate. Boost may be fixed, or varied by gear, with two settings which allow for wet/dry, pump/race gas or street tire/slicks settings to be selected with an external switch.
All US ECUs have the PWM Boost circuitry, but not the boost control components, for the PWM (pulse width modulated) output. JDM ECUs do not have the circuitry and cannot be used. Components must be added to the ECU for the PWM output to work. We also offer PWM boost control component installation in S300 ECU's for those who wish to take advantage of this feature.
How does the boost control work?
The ECU produces a square wave at a fixed frequency and variable duty cycle. Applied to a solenoid, the impedance of the solenoid results in a linear motion of the solenoid valve orifice.
The wastegate is normally connected so that manifold pressure acts on a diaphragm, so opening an exhaust bleed valve (the wastegate) at a certain manifold pressure. With a boost controller, additional air pressure is used on the other side ('the top') of the diaphragm, so that more manifold pressure is needed to open the wastegate - so the engine makes more boost. By varying the amount of air pressure on the 'top' side of the diaphragm with the solenoid, the ECU can control boost.
Because the solenoid can only add air pressure to hold the wastegate shut, the minimum boost is determined by the wastegate spring pressure. Therefore you need to run a spring which gives the minimum boost you want. The maximum boost is determined by many factors, but generally will be 2-4 times that of the minimum pressure.
Why boost per gear?
Assuming your aim is to maximize acceleration, then you need to utilize as much of the tractive capacity of the front tires as possible. The tractive capacity of the front tires is almost constant - it actually decreases a little with speed as the tire footprint shrinks and with front end aerodynamic lift. In order to provide a constant torque at the wheels to keep the tire at the peak tractive effort, two things are obvious: 1. The engine should have as flat a torque curve as possible (in the rev range) and 2. The engine should make more torque in each gear to offset the change in torque multiplication from the engine to the tires when you shift gears. You cannot do this by speed or rpm since this makes the torque output dependent on your shift point. By setting the boost level in each gear you are in effect altering the engine torque level to obtain the same wheel torque level, adjusted for inertial effects. If this all makes no sense to you then drive a high powered vehicle with boost by gear and you will understand.
How do I install the Hondata Boost Control Solenoid?
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